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fortify: Convert to struct vs member helpers

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In preparation for adding support for __builtin_dynamic_object_size(),
wrap each instance of __builtin_object_size(p, N) with either the new
__struct_size(p) as __bos(p, 0), or __member_size(p) as __bos(p, 1).
This will allow us to replace the definitions with __bdos() next.
There are no binary differences from this change.

Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: linux-hardening@vger.kernel.org
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/lkml/20220920192202.190793-4-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2022-09-19 19:50:32 -07:00
parent fa35198f39
commit 9f7d69c5cd
1 changed files with 35 additions and 33 deletions
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68
include/linux/fortify-string.h
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@ -20,7 +20,7 @@ void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("
({ \
unsigned char *__p = (unsigned char *)(p); \
size_t __ret = SIZE_MAX; \
size_t __p_size = __builtin_object_size(p, 1); \
size_t __p_size = __member_size(p); \
if (__p_size != SIZE_MAX && \
__builtin_constant_p(*__p)) { \
size_t __p_len = __p_size - 1; \
@ -72,13 +72,15 @@ extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
__underlying_memcpy(dst, src, bytes)
/*
* Clang's use of __builtin_object_size() within inlines needs hinting via
* __pass_object_size(). The preference is to only ever use type 1 (member
* Clang's use of __builtin_*object_size() within inlines needs hinting via
* __pass_*object_size(). The preference is to only ever use type 1 (member
* size, rather than struct size), but there remain some stragglers using
* type 0 that will be converted in the future.
*/
#define POS __pass_object_size(1)
#define POS0 __pass_object_size(0)
#define POS __pass_object_size(1)
#define POS0 __pass_object_size(0)
#define __struct_size(p) __builtin_object_size(p, 0)
#define __member_size(p) __builtin_object_size(p, 1)
#define __compiletime_lessthan(bounds, length) ( \
__builtin_constant_p((bounds) < (length)) && \
@ -120,7 +122,7 @@ extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
__FORTIFY_INLINE __diagnose_as(__builtin_strncpy, 1, 2, 3)
char *strncpy(char * const POS p, const char *q, __kernel_size_t size)
{
size_t p_size = __builtin_object_size(p, 1);
size_t p_size = __member_size(p);
if (__compiletime_lessthan(p_size, size))
__write_overflow();
@ -132,7 +134,7 @@ char *strncpy(char * const POS p, const char *q, __kernel_size_t size)
__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
char *strcat(char * const POS p, const char *q)
{
size_t p_size = __builtin_object_size(p, 1);
size_t p_size = __member_size(p);
if (p_size == SIZE_MAX)
return __underlying_strcat(p, q);
@ -144,7 +146,7 @@ char *strcat(char * const POS p, const char *q)
extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)
{
size_t p_size = __builtin_object_size(p, 1);
size_t p_size = __member_size(p);
size_t p_len = __compiletime_strlen(p);
size_t ret;
@ -174,7 +176,7 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)
__kernel_size_t __fortify_strlen(const char * const POS p)
{
__kernel_size_t ret;
size_t p_size = __builtin_object_size(p, 1);
size_t p_size = __member_size(p);
/* Give up if we don't know how large p is. */
if (p_size == SIZE_MAX)
@ -189,8 +191,8 @@ __kernel_size_t __fortify_strlen(const char * const POS p)
extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
__FORTIFY_INLINE size_t strlcpy(char * const POS p, const char * const POS q, size_t size)
{
size_t p_size = __builtin_object_size(p, 1);
size_t q_size = __builtin_object_size(q, 1);
size_t p_size = __member_size(p);
size_t q_size = __member_size(q);
size_t q_len; /* Full count of source string length. */
size_t len; /* Count of characters going into destination. */
@ -218,8 +220,8 @@ __FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, s
{
size_t len;
/* Use string size rather than possible enclosing struct size. */
size_t p_size = __builtin_object_size(p, 1);
size_t q_size = __builtin_object_size(q, 1);
size_t p_size = __member_size(p);
size_t q_size = __member_size(q);
/* If we cannot get size of p and q default to call strscpy. */
if (p_size == SIZE_MAX && q_size == SIZE_MAX)
@ -264,8 +266,8 @@ __FORTIFY_INLINE __diagnose_as(__builtin_strncat, 1, 2, 3)
char *strncat(char * const POS p, const char * const POS q, __kernel_size_t count)
{
size_t p_len, copy_len;
size_t p_size = __builtin_object_size(p, 1);
size_t q_size = __builtin_object_size(q, 1);
size_t p_size = __member_size(p);
size_t q_size = __member_size(q);
if (p_size == SIZE_MAX && q_size == SIZE_MAX)
return __underlying_strncat(p, q, count);
@ -323,11 +325,11 @@ __FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size,
})
/*
* __builtin_object_size() must be captured here to avoid evaluating argument
* side-effects further into the macro layers.
* __struct_size() vs __member_size() must be captured here to avoid
* evaluating argument side-effects further into the macro layers.
*/
#define memset(p, c, s) __fortify_memset_chk(p, c, s, \
__builtin_object_size(p, 0), __builtin_object_size(p, 1))
__struct_size(p), __member_size(p))
/*
* To make sure the compiler can enforce protection against buffer overflows,
@ -420,7 +422,7 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
* fake flexible arrays, until they are all converted to
* proper flexible arrays.
*
* The implementation of __builtin_object_size() behaves
* The implementation of __builtin_*object_size() behaves
* like sizeof() when not directly referencing a flexible
* array member, which means there will be many bounds checks
* that will appear at run-time, without a way for them to be
@ -486,22 +488,22 @@ __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
*/
/*
* __builtin_object_size() must be captured here to avoid evaluating argument
* side-effects further into the macro layers.
* __struct_size() vs __member_size() must be captured here to avoid
* evaluating argument side-effects further into the macro layers.
*/
#define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
__builtin_object_size(p, 0), __builtin_object_size(q, 0), \
__builtin_object_size(p, 1), __builtin_object_size(q, 1), \
__struct_size(p), __struct_size(q), \
__member_size(p), __member_size(q), \
memcpy)
#define memmove(p, q, s) __fortify_memcpy_chk(p, q, s, \
__builtin_object_size(p, 0), __builtin_object_size(q, 0), \
__builtin_object_size(p, 1), __builtin_object_size(q, 1), \
__struct_size(p), __struct_size(q), \
__member_size(p), __member_size(q), \
memmove)
extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
__FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size)
{
size_t p_size = __builtin_object_size(p, 0);
size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
@ -513,8 +515,8 @@ __FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size)
__FORTIFY_INLINE __diagnose_as(__builtin_memcmp, 1, 2, 3)
int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t size)
{
size_t p_size = __builtin_object_size(p, 0);
size_t q_size = __builtin_object_size(q, 0);
size_t p_size = __struct_size(p);
size_t q_size = __struct_size(q);
if (__builtin_constant_p(size)) {
if (__compiletime_lessthan(p_size, size))
@ -530,7 +532,7 @@ int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t
__FORTIFY_INLINE __diagnose_as(__builtin_memchr, 1, 2, 3)
void *memchr(const void * const POS0 p, int c, __kernel_size_t size)
{
size_t p_size = __builtin_object_size(p, 0);
size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
@ -542,7 +544,7 @@ void *memchr(const void * const POS0 p, int c, __kernel_size_t size)
void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
__FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size)
{
size_t p_size = __builtin_object_size(p, 0);
size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
@ -554,7 +556,7 @@ __FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size)
extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
__FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp)
{
size_t p_size = __builtin_object_size(p, 0);
size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
@ -567,8 +569,8 @@ __FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp
__FORTIFY_INLINE __diagnose_as(__builtin_strcpy, 1, 2)
char *strcpy(char * const POS p, const char * const POS q)
{
size_t p_size = __builtin_object_size(p, 1);
size_t q_size = __builtin_object_size(q, 1);
size_t p_size = __member_size(p);
size_t q_size = __member_size(q);
size_t size;
/* If neither buffer size is known, immediately give up. */