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x86/module: prepare module loading for ROX allocations of text

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When module text memory will be allocated with ROX permissions, the memory
at the actual address where the module will live will contain invalid
instructions and there will be a writable copy that contains the actual
module code.

Update relocations and alternatives patching to deal with it.

[rppt@kernel.org: fix writable address in cfi_rewrite_endbr()]
  Link: https://lkml.kernel.org/r/ZysRwR29Ji8CcbXc@kernel.org
Link: https://lkml.kernel.org/r/20241023162711.2579610-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Mike Rapoport (Microsoft) 2024-10-23 19:27:09 +03:00 committed by Andrew Morton
parent 0c6378a715
commit 9bfc4824fd
6 changed files with 171 additions and 121 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/um/kernel/um_arch.c
View File

@ -435,24 +435,25 @@ void __init arch_cpu_finalize_init(void)
os_check_bugs();
}
void apply_seal_endbr(s32 *start, s32 *end)
void apply_seal_endbr(s32 *start, s32 *end, struct module *mod)
{
}
void apply_retpolines(s32 *start, s32 *end)
void apply_retpolines(s32 *start, s32 *end, struct module *mod)
{
}
void apply_returns(s32 *start, s32 *end)
void apply_returns(s32 *start, s32 *end, struct module *mod)
{
}
void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
s32 *start_cfi, s32 *end_cfi)
s32 *start_cfi, s32 *end_cfi, struct module *mod)
{
}
void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
struct module *mod)
{
}

3
arch/x86/entry/vdso/vma.c
View File

@ -54,7 +54,8 @@ int __init init_vdso_image(const struct vdso_image *image)
apply_alternatives((struct alt_instr *)(image->data + image->alt),
(struct alt_instr *)(image->data + image->alt +
image->alt_len));
image->alt_len),
NULL);
return 0;
}

14
arch/x86/include/asm/alternative.h
View File

@ -96,16 +96,16 @@ extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
* instructions were patched in already:
*/
extern int alternatives_patched;
struct module;
extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
extern void apply_retpolines(s32 *start, s32 *end);
extern void apply_returns(s32 *start, s32 *end);
extern void apply_seal_endbr(s32 *start, s32 *end);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end,
struct module *mod);
extern void apply_retpolines(s32 *start, s32 *end, struct module *mod);
extern void apply_returns(s32 *start, s32 *end, struct module *mod);
extern void apply_seal_endbr(s32 *start, s32 *end, struct module *mod);
extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine,
s32 *start_cfi, s32 *end_cfi);
struct module;
s32 *start_cfi, s32 *end_cfi, struct module *mod);
struct callthunk_sites {
s32 *call_start, *call_end;

181
arch/x86/kernel/alternative.c
View File

@ -392,8 +392,10 @@ EXPORT_SYMBOL(BUG_func);
* Rewrite the "call BUG_func" replacement to point to the target of the
* indirect pv_ops call "call *disp(%ip)".
*/
static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a,
struct module *mod)
{
u8 *wr_instr = module_writable_address(mod, instr);
void *target, *bug = &BUG_func;
s32 disp;
@ -403,14 +405,14 @@ static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
}
if (a->instrlen != 6 ||
instr[0] != CALL_RIP_REL_OPCODE ||
instr[1] != CALL_RIP_REL_MODRM) {
wr_instr[0] != CALL_RIP_REL_OPCODE ||
wr_instr[1] != CALL_RIP_REL_MODRM) {
pr_err("ALT_FLAG_DIRECT_CALL set for unrecognized indirect call\n");
BUG();
}
/* Skip CALL_RIP_REL_OPCODE and CALL_RIP_REL_MODRM */
disp = *(s32 *)(instr + 2);
disp = *(s32 *)(wr_instr + 2);
#ifdef CONFIG_X86_64
/* ff 15 00 00 00 00 call *0x0(%rip) */
/* target address is stored at "next instruction + disp". */
@ -448,7 +450,8 @@ static inline u8 * instr_va(struct alt_instr *i)
* to refetch changed I$ lines.
*/
void __init_or_module noinline apply_alternatives(struct alt_instr *start,
struct alt_instr *end)
struct alt_instr *end,
struct module *mod)
{
u8 insn_buff[MAX_PATCH_LEN];
u8 *instr, *replacement;
@ -477,6 +480,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
*/
for (a = start; a < end; a++) {
int insn_buff_sz = 0;
u8 *wr_instr, *wr_replacement;
/*
* In case of nested ALTERNATIVE()s the outer alternative might
@ -490,7 +494,11 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
}
instr = instr_va(a);
wr_instr = module_writable_address(mod, instr);
replacement = (u8 *)&a->repl_offset + a->repl_offset;
wr_replacement = module_writable_address(mod, replacement);
BUG_ON(a->instrlen > sizeof(insn_buff));
BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
@ -501,9 +509,9 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
* patch if feature is *NOT* present.
*/
if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT)) {
memcpy(insn_buff, instr, a->instrlen);
memcpy(insn_buff, wr_instr, a->instrlen);
optimize_nops(instr, insn_buff, a->instrlen);
text_poke_early(instr, insn_buff, a->instrlen);
text_poke_early(wr_instr, insn_buff, a->instrlen);
continue;
}
@ -513,11 +521,12 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
instr, instr, a->instrlen,
replacement, a->replacementlen, a->flags);
memcpy(insn_buff, replacement, a->replacementlen);
memcpy(insn_buff, wr_replacement, a->replacementlen);
insn_buff_sz = a->replacementlen;
if (a->flags & ALT_FLAG_DIRECT_CALL) {
insn_buff_sz = alt_replace_call(instr, insn_buff, a);
insn_buff_sz = alt_replace_call(instr, insn_buff, a,
mod);
if (insn_buff_sz < 0)
continue;
}
@ -527,11 +536,11 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
apply_relocation(insn_buff, instr, a->instrlen, replacement, a->replacementlen);
DUMP_BYTES(ALT, instr, a->instrlen, "%px: old_insn: ", instr);
DUMP_BYTES(ALT, wr_instr, a->instrlen, "%px: old_insn: ", instr);
DUMP_BYTES(ALT, replacement, a->replacementlen, "%px: rpl_insn: ", replacement);
DUMP_BYTES(ALT, insn_buff, insn_buff_sz, "%px: final_insn: ", instr);
text_poke_early(instr, insn_buff, insn_buff_sz);
text_poke_early(wr_instr, insn_buff, insn_buff_sz);
}
kasan_enable_current();
@ -722,18 +731,20 @@ static int patch_retpoline(void *addr, struct insn *insn, u8 *bytes)
/*
* Generated by 'objtool --retpoline'.
*/
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end,
struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
struct insn insn;
int len, ret;
u8 bytes[16];
u8 op1, op2;
ret = insn_decode_kernel(&insn, addr);
ret = insn_decode_kernel(&insn, wr_addr);
if (WARN_ON_ONCE(ret < 0))
continue;
@ -761,9 +772,9 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end)
len = patch_retpoline(addr, &insn, bytes);
if (len == insn.length) {
optimize_nops(addr, bytes, len);
DUMP_BYTES(RETPOLINE, ((u8*)addr), len, "%px: orig: ", addr);
DUMP_BYTES(RETPOLINE, ((u8*)wr_addr), len, "%px: orig: ", addr);
DUMP_BYTES(RETPOLINE, ((u8*)bytes), len, "%px: repl: ", addr);
text_poke_early(addr, bytes, len);
text_poke_early(wr_addr, bytes, len);
}
}
}
@ -799,7 +810,8 @@ static int patch_return(void *addr, struct insn *insn, u8 *bytes)
return i;
}
void __init_or_module noinline apply_returns(s32 *start, s32 *end)
void __init_or_module noinline apply_returns(s32 *start, s32 *end,
struct module *mod)
{
s32 *s;
@ -808,12 +820,13 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
for (s = start; s < end; s++) {
void *dest = NULL, *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
struct insn insn;
int len, ret;
u8 bytes[16];
u8 op;
ret = insn_decode_kernel(&insn, addr);
ret = insn_decode_kernel(&insn, wr_addr);
if (WARN_ON_ONCE(ret < 0))
continue;
@ -833,32 +846,35 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end)
len = patch_return(addr, &insn, bytes);
if (len == insn.length) {
DUMP_BYTES(RET, ((u8*)addr), len, "%px: orig: ", addr);
DUMP_BYTES(RET, ((u8*)wr_addr), len, "%px: orig: ", addr);
DUMP_BYTES(RET, ((u8*)bytes), len, "%px: repl: ", addr);
text_poke_early(addr, bytes, len);
text_poke_early(wr_addr, bytes, len);
}
}
}
#else
void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
void __init_or_module noinline apply_returns(s32 *start, s32 *end,
struct module *mod) { }
#endif /* CONFIG_MITIGATION_RETHUNK */
#else /* !CONFIG_MITIGATION_RETPOLINE || !CONFIG_OBJTOOL */
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) { }
void __init_or_module noinline apply_returns(s32 *start, s32 *end) { }
void __init_or_module noinline apply_retpolines(s32 *start, s32 *end,
struct module *mod) { }
void __init_or_module noinline apply_returns(s32 *start, s32 *end,
struct module *mod) { }
#endif /* CONFIG_MITIGATION_RETPOLINE && CONFIG_OBJTOOL */
#ifdef CONFIG_X86_KERNEL_IBT
static void poison_cfi(void *addr);
static void poison_cfi(void *addr, void *wr_addr);
static void __init_or_module poison_endbr(void *addr, bool warn)
static void __init_or_module poison_endbr(void *addr, void *wr_addr, bool warn)
{
u32 endbr, poison = gen_endbr_poison();
if (WARN_ON_ONCE(get_kernel_nofault(endbr, addr)))
if (WARN_ON_ONCE(get_kernel_nofault(endbr, wr_addr)))
return;
if (!is_endbr(endbr)) {
@ -873,7 +889,7 @@ static void __init_or_module poison_endbr(void *addr, bool warn)
*/
DUMP_BYTES(ENDBR, ((u8*)addr), 4, "%px: orig: ", addr);
DUMP_BYTES(ENDBR, ((u8*)&poison), 4, "%px: repl: ", addr);
text_poke_early(addr, &poison, 4);
text_poke_early(wr_addr, &poison, 4);
}
/*
@ -882,22 +898,23 @@ static void __init_or_module poison_endbr(void *addr, bool warn)
* Seal the functions for indirect calls by clobbering the ENDBR instructions
* and the kCFI hash value.
*/
void __init_or_module noinline apply_seal_endbr(s32 *start, s32 *end)
void __init_or_module noinline apply_seal_endbr(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
poison_endbr(addr, true);
poison_endbr(addr, wr_addr, true);
if (IS_ENABLED(CONFIG_FINEIBT))
poison_cfi(addr - 16);
poison_cfi(addr - 16, wr_addr - 16);
}
}
#else
void __init_or_module apply_seal_endbr(s32 *start, s32 *end) { }
void __init_or_module apply_seal_endbr(s32 *start, s32 *end, struct module *mod) { }
#endif /* CONFIG_X86_KERNEL_IBT */
@ -1119,7 +1136,7 @@ static u32 decode_caller_hash(void *addr)
}
/* .retpoline_sites */
static int cfi_disable_callers(s32 *start, s32 *end)
static int cfi_disable_callers(s32 *start, s32 *end, struct module *mod)
{
/*
* Disable kCFI by patching in a JMP.d8, this leaves the hash immediate
@ -1131,20 +1148,23 @@ static int cfi_disable_callers(s32 *start, s32 *end)
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr;
u32 hash;
addr -= fineibt_caller_size;
hash = decode_caller_hash(addr);
wr_addr = module_writable_address(mod, addr);
hash = decode_caller_hash(wr_addr);
if (!hash) /* nocfi callers */
continue;
text_poke_early(addr, jmp, 2);
text_poke_early(wr_addr, jmp, 2);
}
return 0;
}
static int cfi_enable_callers(s32 *start, s32 *end)
static int cfi_enable_callers(s32 *start, s32 *end, struct module *mod)
{
/*
* Re-enable kCFI, undo what cfi_disable_callers() did.
@ -1154,106 +1174,115 @@ static int cfi_enable_callers(s32 *start, s32 *end)
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr;
u32 hash;
addr -= fineibt_caller_size;
hash = decode_caller_hash(addr);
wr_addr = module_writable_address(mod, addr);
hash = decode_caller_hash(wr_addr);
if (!hash) /* nocfi callers */
continue;
text_poke_early(addr, mov, 2);
text_poke_early(wr_addr, mov, 2);
}
return 0;
}
/* .cfi_sites */
static int cfi_rand_preamble(s32 *start, s32 *end)
static int cfi_rand_preamble(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
u32 hash;
hash = decode_preamble_hash(addr);
hash = decode_preamble_hash(wr_addr);
if (WARN(!hash, "no CFI hash found at: %pS %px %*ph\n",
addr, addr, 5, addr))
return -EINVAL;
hash = cfi_rehash(hash);
text_poke_early(addr + 1, &hash, 4);
text_poke_early(wr_addr + 1, &hash, 4);
}
return 0;
}
static int cfi_rewrite_preamble(s32 *start, s32 *end)
static int cfi_rewrite_preamble(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
u32 hash;
hash = decode_preamble_hash(addr);
hash = decode_preamble_hash(wr_addr);
if (WARN(!hash, "no CFI hash found at: %pS %px %*ph\n",
addr, addr, 5, addr))
return -EINVAL;
text_poke_early(addr, fineibt_preamble_start, fineibt_preamble_size);
WARN_ON(*(u32 *)(addr + fineibt_preamble_hash) != 0x12345678);
text_poke_early(addr + fineibt_preamble_hash, &hash, 4);
text_poke_early(wr_addr, fineibt_preamble_start, fineibt_preamble_size);
WARN_ON(*(u32 *)(wr_addr + fineibt_preamble_hash) != 0x12345678);
text_poke_early(wr_addr + fineibt_preamble_hash, &hash, 4);
}
return 0;
}
static void cfi_rewrite_endbr(s32 *start, s32 *end)
static void cfi_rewrite_endbr(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr = module_writable_address(mod, addr);
poison_endbr(addr+16, false);
poison_endbr(addr + 16, wr_addr + 16, false);
}
}
/* .retpoline_sites */
static int cfi_rand_callers(s32 *start, s32 *end)
static int cfi_rand_callers(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr;
u32 hash;
addr -= fineibt_caller_size;
hash = decode_caller_hash(addr);
wr_addr = module_writable_address(mod, addr);
hash = decode_caller_hash(wr_addr);
if (hash) {
hash = -cfi_rehash(hash);
text_poke_early(addr + 2, &hash, 4);
text_poke_early(wr_addr + 2, &hash, 4);
}
}
return 0;
}
static int cfi_rewrite_callers(s32 *start, s32 *end)
static int cfi_rewrite_callers(s32 *start, s32 *end, struct module *mod)
{
s32 *s;
for (s = start; s < end; s++) {
void *addr = (void *)s + *s;
void *wr_addr;
u32 hash;
addr -= fineibt_caller_size;
hash = decode_caller_hash(addr);
wr_addr = module_writable_address(mod, addr);
hash = decode_caller_hash(wr_addr);
if (hash) {
text_poke_early(addr, fineibt_caller_start, fineibt_caller_size);
WARN_ON(*(u32 *)(addr + fineibt_caller_hash) != 0x12345678);
text_poke_early(addr + fineibt_caller_hash, &hash, 4);
text_poke_early(wr_addr, fineibt_caller_start, fineibt_caller_size);
WARN_ON(*(u32 *)(wr_addr + fineibt_caller_hash) != 0x12345678);
text_poke_early(wr_addr + fineibt_caller_hash, &hash, 4);
}
/* rely on apply_retpolines() */
}
@ -1262,8 +1291,9 @@ static int cfi_rewrite_callers(s32 *start, s32 *end)
}
static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
s32 *start_cfi, s32 *end_cfi, bool builtin)
s32 *start_cfi, s32 *end_cfi, struct module *mod)
{
bool builtin = mod ? false : true;
int ret;
if (WARN_ONCE(fineibt_preamble_size != 16,
@ -1281,7 +1311,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
* rewrite them. This disables all CFI. If this succeeds but any of the
* later stages fails, we're without CFI.
*/
ret = cfi_disable_callers(start_retpoline, end_retpoline);
ret = cfi_disable_callers(start_retpoline, end_retpoline, mod);
if (ret)
goto err;
@ -1292,11 +1322,11 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
cfi_bpf_subprog_hash = cfi_rehash(cfi_bpf_subprog_hash);
}
ret = cfi_rand_preamble(start_cfi, end_cfi);
ret = cfi_rand_preamble(start_cfi, end_cfi, mod);
if (ret)
goto err;
ret = cfi_rand_callers(start_retpoline, end_retpoline);
ret = cfi_rand_callers(start_retpoline, end_retpoline, mod);
if (ret)
goto err;
}
@ -1308,7 +1338,7 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
return;
case CFI_KCFI:
ret = cfi_enable_callers(start_retpoline, end_retpoline);
ret = cfi_enable_callers(start_retpoline, end_retpoline, mod);
if (ret)
goto err;
@ -1318,17 +1348,17 @@ static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
case CFI_FINEIBT:
/* place the FineIBT preamble at func()-16 */
ret = cfi_rewrite_preamble(start_cfi, end_cfi);
ret = cfi_rewrite_preamble(start_cfi, end_cfi, mod);
if (ret)
goto err;
/* rewrite the callers to target func()-16 */
ret = cfi_rewrite_callers(start_retpoline, end_retpoline);
ret = cfi_rewrite_callers(start_retpoline, end_retpoline, mod);
if (ret)
goto err;
/* now that nobody targets func()+0, remove ENDBR there */
cfi_rewrite_endbr(start_cfi, end_cfi);
cfi_rewrite_endbr(start_cfi, end_cfi, mod);
if (builtin)
pr_info("Using FineIBT CFI\n");
@ -1347,7 +1377,7 @@ static inline void poison_hash(void *addr)
*(u32 *)addr = 0;
}
static void poison_cfi(void *addr)
static void poison_cfi(void *addr, void *wr_addr)
{
switch (cfi_mode) {
case CFI_FINEIBT:
@ -1359,8 +1389,8 @@ static void poison_cfi(void *addr)
* ud2
* 1: nop
*/
poison_endbr(addr, false);
poison_hash(addr + fineibt_preamble_hash);
poison_endbr(addr, wr_addr, false);
poison_hash(wr_addr + fineibt_preamble_hash);
break;
case CFI_KCFI:
@ -1369,7 +1399,7 @@ static void poison_cfi(void *addr)
* movl $0, %eax
* .skip 11, 0x90
*/
poison_hash(addr + 1);
poison_hash(wr_addr + 1);
break;
default:
@ -1380,22 +1410,21 @@ static void poison_cfi(void *addr)
#else
static void __apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
s32 *start_cfi, s32 *end_cfi, bool builtin)
s32 *start_cfi, s32 *end_cfi, struct module *mod)
{
}
#ifdef CONFIG_X86_KERNEL_IBT
static void poison_cfi(void *addr) { }
static void poison_cfi(void *addr, void *wr_addr) { }
#endif
#endif
void apply_fineibt(s32 *start_retpoline, s32 *end_retpoline,
s32 *start_cfi, s32 *end_cfi)
s32 *start_cfi, s32 *end_cfi, struct module *mod)
{
return __apply_fineibt(start_retpoline, end_retpoline,
start_cfi, end_cfi,
/* .builtin = */ false);
start_cfi, end_cfi, mod);
}
#ifdef CONFIG_SMP
@ -1692,16 +1721,16 @@ void __init alternative_instructions(void)
paravirt_set_cap();
__apply_fineibt(__retpoline_sites, __retpoline_sites_end,
__cfi_sites, __cfi_sites_end, true);
__cfi_sites, __cfi_sites_end, NULL);
/*
* Rewrite the retpolines, must be done before alternatives since
* those can rewrite the retpoline thunks.
*/
apply_retpolines(__retpoline_sites, __retpoline_sites_end);
apply_returns(__return_sites, __return_sites_end);
apply_retpolines(__retpoline_sites, __retpoline_sites_end, NULL);
apply_returns(__return_sites, __return_sites_end, NULL);
apply_alternatives(__alt_instructions, __alt_instructions_end);
apply_alternatives(__alt_instructions, __alt_instructions_end, NULL);
/*
* Now all calls are established. Apply the call thunks if
@ -1712,7 +1741,7 @@ void __init alternative_instructions(void)
/*
* Seal all functions that do not have their address taken.
*/
apply_seal_endbr(__ibt_endbr_seal, __ibt_endbr_seal_end);
apply_seal_endbr(__ibt_endbr_seal, __ibt_endbr_seal_end, NULL);
#ifdef CONFIG_SMP
/* Patch to UP if other cpus not imminent. */

30
arch/x86/kernel/ftrace.c
View File

@ -118,10 +118,13 @@ ftrace_modify_code_direct(unsigned long ip, const char *old_code,
return ret;
/* replace the text with the new text */
if (ftrace_poke_late)
if (ftrace_poke_late) {
text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL);
else
text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE);
} else {
mutex_lock(&text_mutex);
text_poke((void *)ip, new_code, MCOUNT_INSN_SIZE);
mutex_unlock(&text_mutex);
}
return 0;
}
@ -318,7 +321,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
unsigned const char op_ref[] = { 0x48, 0x8b, 0x15 };
unsigned const char retq[] = { RET_INSN_OPCODE, INT3_INSN_OPCODE };
union ftrace_op_code_union op_ptr;
int ret;
void *ret;
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
start_offset = (unsigned long)ftrace_regs_caller;
@ -349,15 +352,15 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
/* Copy ftrace_caller onto the trampoline memory */
ret = copy_from_kernel_nofault(trampoline, (void *)start_offset, size);
if (WARN_ON(ret < 0))
ret = text_poke_copy(trampoline, (void *)start_offset, size);
if (WARN_ON(!ret))
goto fail;
ip = trampoline + size;
if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
__text_gen_insn(ip, JMP32_INSN_OPCODE, ip, x86_return_thunk, JMP32_INSN_SIZE);
else
memcpy(ip, retq, sizeof(retq));
text_poke_copy(ip, retq, sizeof(retq));
/* No need to test direct calls on created trampolines */
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
@ -365,8 +368,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
ip = trampoline + (jmp_offset - start_offset);
if (WARN_ON(*(char *)ip != 0x75))
goto fail;
ret = copy_from_kernel_nofault(ip, x86_nops[2], 2);
if (ret < 0)
if (!text_poke_copy(ip, x86_nops[2], 2))
goto fail;
}
@ -379,7 +381,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
*/
ptr = (unsigned long *)(trampoline + size + RET_SIZE);
*ptr = (unsigned long)ops;
text_poke_copy(ptr, &ops, sizeof(unsigned long));
op_offset -= start_offset;
memcpy(&op_ptr, trampoline + op_offset, OP_REF_SIZE);
@ -395,7 +397,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
op_ptr.offset = offset;
/* put in the new offset to the ftrace_ops */
memcpy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
text_poke_copy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
/* put in the call to the function */
mutex_lock(&text_mutex);
@ -405,9 +407,9 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
* the depth accounting before the call already.
*/
dest = ftrace_ops_get_func(ops);
memcpy(trampoline + call_offset,
text_gen_insn(CALL_INSN_OPCODE, trampoline + call_offset, dest),
CALL_INSN_SIZE);
text_poke_copy_locked(trampoline + call_offset,
text_gen_insn(CALL_INSN_OPCODE, trampoline + call_offset, dest),
CALL_INSN_SIZE, false);
mutex_unlock(&text_mutex);
/* ALLOC_TRAMP flags lets us know we created it */

53
arch/x86/kernel/module.c
View File

@ -146,18 +146,21 @@ static int __write_relocate_add(Elf64_Shdr *sechdrs,
}
if (apply) {
if (memcmp(loc, &zero, size)) {
void *wr_loc = module_writable_address(me, loc);
if (memcmp(wr_loc, &zero, size)) {
pr_err("x86/modules: Invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
(int)ELF64_R_TYPE(rel[i].r_info), loc, val);
return -ENOEXEC;
}
write(loc, &val, size);
write(wr_loc, &val, size);
} else {
if (memcmp(loc, &val, size)) {
pr_warn("x86/modules: Invalid relocation target, existing value does not match expected value for type %d, loc %p, val %Lx\n",
(int)ELF64_R_TYPE(rel[i].r_info), loc, val);
return -ENOEXEC;
}
/* FIXME: needs care for ROX module allocations */
write(loc, &zero, size);
}
}
@ -224,7 +227,7 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
const Elf_Shdr *s, *alt = NULL, *locks = NULL,
const Elf_Shdr *s, *alt = NULL,
*orc = NULL, *orc_ip = NULL,
*retpolines = NULL, *returns = NULL, *ibt_endbr = NULL,
*calls = NULL, *cfi = NULL;
@ -233,8 +236,6 @@ int module_finalize(const Elf_Ehdr *hdr,
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (!strcmp(".altinstructions", secstrings + s->sh_name))
alt = s;
if (!strcmp(".smp_locks", secstrings + s->sh_name))
locks = s;
if (!strcmp(".orc_unwind", secstrings + s->sh_name))
orc = s;
if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
@ -265,20 +266,20 @@ int module_finalize(const Elf_Ehdr *hdr,
csize = cfi->sh_size;
}
apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize);
apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize, me);
}
if (retpolines) {
void *rseg = (void *)retpolines->sh_addr;
apply_retpolines(rseg, rseg + retpolines->sh_size);
apply_retpolines(rseg, rseg + retpolines->sh_size, me);
}
if (returns) {
void *rseg = (void *)returns->sh_addr;
apply_returns(rseg, rseg + returns->sh_size);
apply_returns(rseg, rseg + returns->sh_size, me);
}
if (alt) {
/* patch .altinstructions */
void *aseg = (void *)alt->sh_addr;
apply_alternatives(aseg, aseg + alt->sh_size);
apply_alternatives(aseg, aseg + alt->sh_size, me);
}
if (calls || alt) {
struct callthunk_sites cs = {};
@ -297,15 +298,7 @@ int module_finalize(const Elf_Ehdr *hdr,
}
if (ibt_endbr) {
void *iseg = (void *)ibt_endbr->sh_addr;
apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size);
}
if (locks) {
void *lseg = (void *)locks->sh_addr;
void *text = me->mem[MOD_TEXT].base;
void *text_end = text + me->mem[MOD_TEXT].size;
alternatives_smp_module_add(me, me->name,
lseg, lseg + locks->sh_size,
text, text_end);
apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size, me);
}
if (orc && orc_ip)
@ -315,6 +308,30 @@ int module_finalize(const Elf_Ehdr *hdr,
return 0;
}
int module_post_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
const Elf_Shdr *s, *locks = NULL;
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (!strcmp(".smp_locks", secstrings + s->sh_name))
locks = s;
}
if (locks) {
void *lseg = (void *)locks->sh_addr;
void *text = me->mem[MOD_TEXT].base;
void *text_end = text + me->mem[MOD_TEXT].size;
alternatives_smp_module_add(me, me->name,
lseg, lseg + locks->sh_size,
text, text_end);
}
return 0;
}
void module_arch_cleanup(struct module *mod)
{
alternatives_smp_module_del(mod);