2021-01-14 13:40:42 +00:00
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/buildid.h>
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2021-07-08 01:09:13 +00:00
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#include <linux/cache.h>
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2021-01-14 13:40:42 +00:00
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#include <linux/elf.h>
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2021-07-08 01:09:10 +00:00
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#include <linux/kernel.h>
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2021-01-14 13:40:42 +00:00
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#include <linux/pagemap.h>
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2024-10-17 17:47:13 +00:00
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#include <linux/secretmem.h>
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2021-01-14 13:40:42 +00:00
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#define BUILD_ID 3
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2021-07-08 01:09:10 +00:00
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2024-08-29 17:42:26 +00:00
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#define MAX_PHDR_CNT 256
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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struct freader {
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void *buf;
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u32 buf_sz;
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int err;
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union {
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struct {
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2024-08-29 17:42:28 +00:00
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struct file *file;
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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struct folio *folio;
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void *addr;
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loff_t folio_off;
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2024-08-29 17:42:28 +00:00
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bool may_fault;
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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};
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struct {
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const char *data;
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u64 data_sz;
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};
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};
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};
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static void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz,
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2024-08-29 17:42:28 +00:00
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struct file *file, bool may_fault)
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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{
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memset(r, 0, sizeof(*r));
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r->buf = buf;
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r->buf_sz = buf_sz;
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2024-08-29 17:42:28 +00:00
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r->file = file;
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r->may_fault = may_fault;
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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}
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static void freader_init_from_mem(struct freader *r, const char *data, u64 data_sz)
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{
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memset(r, 0, sizeof(*r));
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r->data = data;
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r->data_sz = data_sz;
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}
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static void freader_put_folio(struct freader *r)
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{
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if (!r->folio)
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return;
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kunmap_local(r->addr);
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folio_put(r->folio);
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r->folio = NULL;
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}
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static int freader_get_folio(struct freader *r, loff_t file_off)
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{
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/* check if we can just reuse current folio */
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if (r->folio && file_off >= r->folio_off &&
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file_off < r->folio_off + folio_size(r->folio))
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return 0;
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freader_put_folio(r);
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2024-10-17 17:47:13 +00:00
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/* reject secretmem folios created with memfd_secret() */
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if (secretmem_mapping(r->file->f_mapping))
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return -EFAULT;
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2024-08-29 17:42:28 +00:00
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r->folio = filemap_get_folio(r->file->f_mapping, file_off >> PAGE_SHIFT);
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/* if sleeping is allowed, wait for the page, if necessary */
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if (r->may_fault && (IS_ERR(r->folio) || !folio_test_uptodate(r->folio))) {
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filemap_invalidate_lock_shared(r->file->f_mapping);
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r->folio = read_cache_folio(r->file->f_mapping, file_off >> PAGE_SHIFT,
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NULL, r->file);
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filemap_invalidate_unlock_shared(r->file->f_mapping);
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}
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
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if (IS_ERR(r->folio) || !folio_test_uptodate(r->folio)) {
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if (!IS_ERR(r->folio))
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folio_put(r->folio);
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r->folio = NULL;
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return -EFAULT;
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}
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r->folio_off = folio_pos(r->folio);
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r->addr = kmap_local_folio(r->folio, 0);
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return 0;
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}
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static const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz)
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{
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size_t folio_sz;
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/* provided internal temporary buffer should be sized correctly */
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if (WARN_ON(r->buf && sz > r->buf_sz)) {
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r->err = -E2BIG;
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return NULL;
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}
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if (unlikely(file_off + sz < file_off)) {
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r->err = -EOVERFLOW;
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return NULL;
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}
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/* working with memory buffer is much more straightforward */
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if (!r->buf) {
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if (file_off + sz > r->data_sz) {
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r->err = -ERANGE;
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return NULL;
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}
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return r->data + file_off;
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}
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/* fetch or reuse folio for given file offset */
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r->err = freader_get_folio(r, file_off);
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if (r->err)
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return NULL;
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/* if requested data is crossing folio boundaries, we have to copy
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* everything into our local buffer to keep a simple linear memory
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* access interface
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*/
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folio_sz = folio_size(r->folio);
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if (file_off + sz > r->folio_off + folio_sz) {
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int part_sz = r->folio_off + folio_sz - file_off;
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/* copy the part that resides in the current folio */
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memcpy(r->buf, r->addr + (file_off - r->folio_off), part_sz);
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/* fetch next folio */
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r->err = freader_get_folio(r, r->folio_off + folio_sz);
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if (r->err)
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return NULL;
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/* copy the rest of requested data */
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memcpy(r->buf + part_sz, r->addr, sz - part_sz);
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return r->buf;
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}
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/* if data fits in a single folio, just return direct pointer */
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return r->addr + (file_off - r->folio_off);
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}
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static void freader_cleanup(struct freader *r)
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{
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if (!r->buf)
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return; /* non-file-backed mode */
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freader_put_folio(r);
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}
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2021-01-14 13:40:42 +00:00
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/*
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* Parse build id from the note segment. This logic can be shared between
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* 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
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* identical.
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*/
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2024-08-29 17:42:29 +00:00
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static int parse_build_id(struct freader *r, unsigned char *build_id, __u32 *size,
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loff_t note_off, Elf32_Word note_size)
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2021-01-14 13:40:42 +00:00
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{
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2024-08-29 17:42:23 +00:00
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const char note_name[] = "GNU";
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const size_t note_name_sz = sizeof(note_name);
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lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
u32 build_id_off, new_off, note_end, name_sz, desc_sz;
|
|
|
|
|
const Elf32_Nhdr *nhdr;
|
2024-08-29 17:42:23 +00:00
|
|
|
const char *data;
|
|
|
|
|
|
2024-08-29 17:42:29 +00:00
|
|
|
if (check_add_overflow(note_off, note_size, ¬e_end))
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
while (note_end - note_off > sizeof(Elf32_Nhdr) + note_name_sz) {
|
|
|
|
|
nhdr = freader_fetch(r, note_off, sizeof(Elf32_Nhdr) + note_name_sz);
|
|
|
|
|
if (!nhdr)
|
|
|
|
|
return r->err;
|
2024-08-29 17:42:23 +00:00
|
|
|
|
|
|
|
|
name_sz = READ_ONCE(nhdr->n_namesz);
|
|
|
|
|
desc_sz = READ_ONCE(nhdr->n_descsz);
|
|
|
|
|
|
|
|
|
|
new_off = note_off + sizeof(Elf32_Nhdr);
|
|
|
|
|
if (check_add_overflow(new_off, ALIGN(name_sz, 4), &new_off) ||
|
|
|
|
|
check_add_overflow(new_off, ALIGN(desc_sz, 4), &new_off) ||
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
new_off > note_end)
|
2024-08-29 17:42:23 +00:00
|
|
|
break;
|
2021-01-14 13:40:42 +00:00
|
|
|
|
|
|
|
|
if (nhdr->n_type == BUILD_ID &&
|
2024-08-29 17:42:23 +00:00
|
|
|
name_sz == note_name_sz &&
|
|
|
|
|
memcmp(nhdr + 1, note_name, note_name_sz) == 0 &&
|
|
|
|
|
desc_sz > 0 && desc_sz <= BUILD_ID_SIZE_MAX) {
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
build_id_off = note_off + sizeof(Elf32_Nhdr) + ALIGN(note_name_sz, 4);
|
|
|
|
|
|
|
|
|
|
/* freader_fetch() will invalidate nhdr pointer */
|
|
|
|
|
data = freader_fetch(r, build_id_off, desc_sz);
|
|
|
|
|
if (!data)
|
|
|
|
|
return r->err;
|
|
|
|
|
|
2024-08-29 17:42:23 +00:00
|
|
|
memcpy(build_id, data, desc_sz);
|
|
|
|
|
memset(build_id + desc_sz, 0, BUILD_ID_SIZE_MAX - desc_sz);
|
2021-01-14 13:40:43 +00:00
|
|
|
if (size)
|
2024-08-29 17:42:23 +00:00
|
|
|
*size = desc_sz;
|
2021-01-14 13:40:42 +00:00
|
|
|
return 0;
|
|
|
|
|
}
|
2024-08-29 17:42:23 +00:00
|
|
|
|
|
|
|
|
note_off = new_off;
|
2021-01-14 13:40:42 +00:00
|
|
|
}
|
2021-07-08 01:09:10 +00:00
|
|
|
|
2021-01-14 13:40:42 +00:00
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Parse build ID from 32-bit ELF */
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *size)
|
2021-01-14 13:40:42 +00:00
|
|
|
{
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
const Elf32_Ehdr *ehdr;
|
|
|
|
|
const Elf32_Phdr *phdr;
|
2024-08-29 17:42:25 +00:00
|
|
|
__u32 phnum, phoff, i;
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
|
|
|
|
|
ehdr = freader_fetch(r, 0, sizeof(Elf32_Ehdr));
|
|
|
|
|
if (!ehdr)
|
|
|
|
|
return r->err;
|
2021-01-14 13:40:42 +00:00
|
|
|
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
/* subsequent freader_fetch() calls invalidate pointers, so remember locally */
|
2024-08-29 17:42:23 +00:00
|
|
|
phnum = READ_ONCE(ehdr->e_phnum);
|
2024-08-29 17:42:25 +00:00
|
|
|
phoff = READ_ONCE(ehdr->e_phoff);
|
|
|
|
|
|
2024-08-29 17:42:26 +00:00
|
|
|
/* set upper bound on amount of segments (phdrs) we iterate */
|
|
|
|
|
if (phnum > MAX_PHDR_CNT)
|
|
|
|
|
phnum = MAX_PHDR_CNT;
|
2021-01-14 13:40:42 +00:00
|
|
|
|
2024-08-29 17:42:25 +00:00
|
|
|
/* check that phoff is not large enough to cause an overflow */
|
|
|
|
|
if (phoff + phnum * sizeof(Elf32_Phdr) < phoff)
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
2024-08-29 17:42:23 +00:00
|
|
|
for (i = 0; i < phnum; ++i) {
|
2024-08-29 17:42:25 +00:00
|
|
|
phdr = freader_fetch(r, phoff + i * sizeof(Elf32_Phdr), sizeof(Elf32_Phdr));
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
if (!phdr)
|
|
|
|
|
return r->err;
|
|
|
|
|
|
|
|
|
|
if (phdr->p_type == PT_NOTE &&
|
|
|
|
|
!parse_build_id(r, build_id, size, READ_ONCE(phdr->p_offset),
|
|
|
|
|
READ_ONCE(phdr->p_filesz)))
|
2021-01-14 13:40:42 +00:00
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Parse build ID from 64-bit ELF */
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
static int get_build_id_64(struct freader *r, unsigned char *build_id, __u32 *size)
|
2021-01-14 13:40:42 +00:00
|
|
|
{
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
const Elf64_Ehdr *ehdr;
|
|
|
|
|
const Elf64_Phdr *phdr;
|
|
|
|
|
__u32 phnum, i;
|
2024-08-29 17:42:25 +00:00
|
|
|
__u64 phoff;
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
|
|
|
|
|
ehdr = freader_fetch(r, 0, sizeof(Elf64_Ehdr));
|
|
|
|
|
if (!ehdr)
|
|
|
|
|
return r->err;
|
2021-01-14 13:40:42 +00:00
|
|
|
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
/* subsequent freader_fetch() calls invalidate pointers, so remember locally */
|
2024-08-29 17:42:23 +00:00
|
|
|
phnum = READ_ONCE(ehdr->e_phnum);
|
2024-08-29 17:42:25 +00:00
|
|
|
phoff = READ_ONCE(ehdr->e_phoff);
|
|
|
|
|
|
2024-08-29 17:42:26 +00:00
|
|
|
/* set upper bound on amount of segments (phdrs) we iterate */
|
|
|
|
|
if (phnum > MAX_PHDR_CNT)
|
|
|
|
|
phnum = MAX_PHDR_CNT;
|
2021-01-14 13:40:42 +00:00
|
|
|
|
2024-08-29 17:42:25 +00:00
|
|
|
/* check that phoff is not large enough to cause an overflow */
|
|
|
|
|
if (phoff + phnum * sizeof(Elf64_Phdr) < phoff)
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
2024-08-29 17:42:23 +00:00
|
|
|
for (i = 0; i < phnum; ++i) {
|
2024-08-29 17:42:25 +00:00
|
|
|
phdr = freader_fetch(r, phoff + i * sizeof(Elf64_Phdr), sizeof(Elf64_Phdr));
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
if (!phdr)
|
|
|
|
|
return r->err;
|
|
|
|
|
|
|
|
|
|
if (phdr->p_type == PT_NOTE &&
|
|
|
|
|
!parse_build_id(r, build_id, size, READ_ONCE(phdr->p_offset),
|
|
|
|
|
READ_ONCE(phdr->p_filesz)))
|
2021-01-14 13:40:42 +00:00
|
|
|
return 0;
|
|
|
|
|
}
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
|
2021-01-14 13:40:42 +00:00
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
/* enough for Elf64_Ehdr, Elf64_Phdr, and all the smaller requests */
|
|
|
|
|
#define MAX_FREADER_BUF_SZ 64
|
|
|
|
|
|
2024-08-29 17:42:28 +00:00
|
|
|
static int __build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
|
|
|
|
|
__u32 *size, bool may_fault)
|
2021-01-14 13:40:42 +00:00
|
|
|
{
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
const Elf32_Ehdr *ehdr;
|
|
|
|
|
struct freader r;
|
|
|
|
|
char buf[MAX_FREADER_BUF_SZ];
|
2021-01-14 13:40:42 +00:00
|
|
|
int ret;
|
|
|
|
|
|
|
|
|
|
/* only works for page backed storage */
|
|
|
|
|
if (!vma->vm_file)
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
2024-08-29 17:42:28 +00:00
|
|
|
freader_init_from_file(&r, buf, sizeof(buf), vma->vm_file, may_fault);
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
|
|
|
|
|
/* fetch first 18 bytes of ELF header for checks */
|
|
|
|
|
ehdr = freader_fetch(&r, 0, offsetofend(Elf32_Ehdr, e_type));
|
|
|
|
|
if (!ehdr) {
|
|
|
|
|
ret = r.err;
|
|
|
|
|
goto out;
|
2024-08-29 17:42:23 +00:00
|
|
|
}
|
2021-01-14 13:40:42 +00:00
|
|
|
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
|
|
|
|
|
/* compare magic x7f "ELF" */
|
|
|
|
|
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
|
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
|
|
/* only support executable file and shared object file */
|
|
|
|
|
if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
|
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
|
|
if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
ret = get_build_id_32(&r, build_id, size);
|
2021-01-14 13:40:42 +00:00
|
|
|
else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
ret = get_build_id_64(&r, build_id, size);
|
2021-01-14 13:40:42 +00:00
|
|
|
out:
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
freader_cleanup(&r);
|
2021-01-14 13:40:42 +00:00
|
|
|
return ret;
|
|
|
|
|
}
|
2021-07-08 01:09:10 +00:00
|
|
|
|
2024-08-29 17:42:28 +00:00
|
|
|
/*
|
|
|
|
|
* Parse build ID of ELF file mapped to vma
|
|
|
|
|
* @vma: vma object
|
|
|
|
|
* @build_id: buffer to store build id, at least BUILD_ID_SIZE long
|
|
|
|
|
* @size: returns actual build id size in case of success
|
|
|
|
|
*
|
|
|
|
|
* Assumes no page fault can be taken, so if relevant portions of ELF file are
|
|
|
|
|
* not already paged in, fetching of build ID fails.
|
|
|
|
|
*
|
|
|
|
|
* Return: 0 on success; negative error, otherwise
|
|
|
|
|
*/
|
|
|
|
|
int build_id_parse_nofault(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size)
|
|
|
|
|
{
|
|
|
|
|
return __build_id_parse(vma, build_id, size, false /* !may_fault */);
|
|
|
|
|
}
|
|
|
|
|
|
2024-08-29 17:42:27 +00:00
|
|
|
/*
|
|
|
|
|
* Parse build ID of ELF file mapped to VMA
|
|
|
|
|
* @vma: vma object
|
|
|
|
|
* @build_id: buffer to store build id, at least BUILD_ID_SIZE long
|
|
|
|
|
* @size: returns actual build id size in case of success
|
|
|
|
|
*
|
|
|
|
|
* Assumes faultable context and can cause page faults to bring in file data
|
|
|
|
|
* into page cache.
|
|
|
|
|
*
|
|
|
|
|
* Return: 0 on success; negative error, otherwise
|
|
|
|
|
*/
|
|
|
|
|
int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id, __u32 *size)
|
|
|
|
|
{
|
2024-08-29 17:42:28 +00:00
|
|
|
return __build_id_parse(vma, build_id, size, true /* may_fault */);
|
2024-08-29 17:42:27 +00:00
|
|
|
}
|
|
|
|
|
|
2021-07-08 01:09:10 +00:00
|
|
|
/**
|
|
|
|
|
* build_id_parse_buf - Get build ID from a buffer
|
2023-02-28 12:14:17 +00:00
|
|
|
* @buf: ELF note section(s) to parse
|
2021-07-08 01:09:10 +00:00
|
|
|
* @buf_size: Size of @buf in bytes
|
|
|
|
|
* @build_id: Build ID parsed from @buf, at least BUILD_ID_SIZE_MAX long
|
|
|
|
|
*
|
|
|
|
|
* Return: 0 on success, -EINVAL otherwise
|
|
|
|
|
*/
|
|
|
|
|
int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
|
|
|
|
|
{
|
lib/buildid: add single folio-based file reader abstraction
Add freader abstraction that transparently manages fetching and local
mapping of the underlying file page(s) and provides a simple direct data
access interface.
freader_fetch() is the only and single interface necessary. It accepts
file offset and desired number of bytes that should be accessed, and
will return a kernel mapped pointer that caller can use to dereference
data up to requested size. Requested size can't be bigger than the size
of the extra buffer provided during initialization (because, worst case,
all requested data has to be copied into it, so it's better to flag
wrongly sized buffer unconditionally, regardless if requested data range
is crossing page boundaries or not).
If folio is not paged in, or some of the conditions are not satisfied,
NULL is returned and more detailed error code can be accessed through
freader->err field. This approach makes the usage of freader_fetch()
cleaner.
To accommodate accessing file data that crosses folio boundaries, user
has to provide an extra buffer that will be used to make a local copy,
if necessary. This is done to maintain a simple linear pointer data
access interface.
We switch existing build ID parsing logic to it, without changing or
lifting any of the existing constraints, yet. This will be done
separately.
Given existing code was written with the assumption that it's always
working with a single (first) page of the underlying ELF file, logic
passes direct pointers around, which doesn't really work well with
freader approach and would be limiting when removing the single page (folio)
limitation. So we adjust all the logic to work in terms of file offsets.
There is also a memory buffer-based version (freader_init_from_mem())
for cases when desired data is already available in kernel memory. This
is used for parsing vmlinux's own build ID note. In this mode assumption
is that provided data starts at "file offset" zero, which works great
when parsing ELF notes sections, as all the parsing logic is relative to
note section's start.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240829174232.3133883-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-08-29 17:42:24 +00:00
|
|
|
struct freader r;
|
|
|
|
|
int err;
|
|
|
|
|
|
|
|
|
|
freader_init_from_mem(&r, buf, buf_size);
|
|
|
|
|
|
|
|
|
|
err = parse_build_id(&r, build_id, NULL, 0, buf_size);
|
|
|
|
|
|
|
|
|
|
freader_cleanup(&r);
|
|
|
|
|
return err;
|
2021-07-08 01:09:10 +00:00
|
|
|
}
|
2021-07-08 01:09:13 +00:00
|
|
|
|
2024-01-24 05:12:42 +00:00
|
|
|
#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_VMCORE_INFO)
|
2021-07-08 01:09:13 +00:00
|
|
|
unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* init_vmlinux_build_id - Compute and stash the running kernel's build ID
|
|
|
|
|
*/
|
|
|
|
|
void __init init_vmlinux_build_id(void)
|
|
|
|
|
{
|
2024-04-15 16:20:44 +00:00
|
|
|
extern const void __start_notes;
|
|
|
|
|
extern const void __stop_notes;
|
2021-07-08 01:09:13 +00:00
|
|
|
unsigned int size = &__stop_notes - &__start_notes;
|
|
|
|
|
|
|
|
|
|
build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
|
|
|
|
|
}
|
2021-07-08 01:09:17 +00:00
|
|
|
#endif
|