[PATCH v6 6/8] x86/module: prepare module loading for ROX allocations of text

Mike Rapoport
2024-10-16T12:26:31Z

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
arch/um/kernel/um_arch.c | 11 +-
arch/x86/entry/vdso/vma.c | 3 +-
arch/x86/include/asm/alternative.h | 14 +--
arch/x86/kernel/alternative.c | 175 +++++++++++++++++------------
arch/x86/kernel/ftrace.c | 30 ++---
arch/x86/kernel/module.c | 45 +++++---
include/linux/module.h | 16 ++-
7 files changed, 171 insertions(+), 123 deletions(-)

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index f8de31a0c5d1..e8e8b54b3037 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -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)
{
}

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index b8fed8b8b9cc..ed21151923c3 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -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;
}
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ca9ae606aab9..dc03a647776d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -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;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index d17518ca19b8..cf782f431110 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -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.
@@ -1154,26 +1174,29 @@ 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);
@@ -1182,18 +1205,19 @@ static int cfi_rand_preamble(s32 *start, s32 *end)
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);
@@ -1201,59 +1225,64 @@ static int cfi_rewrite_preamble(s32 *start, s32 *end)
addr, addr, 5, addr))
return -EINVAL;

- text_poke_early(addr, fineibt_preamble_start, fineibt_preamble_size);
+ text_poke_early(wr_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_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, 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. */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8da0e66ca22d..b498897b213c 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -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 */
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 837450b6e882..8984abd91c00 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -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 = {};
@@ -297,8 +298,28 @@ 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);
+ apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size, me);
}
+
+ if (orc && orc_ip)
+ unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
+ (void *)orc->sh_addr, orc->sh_size);
+
+ 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;
@@ -308,10 +329,6 @@ int module_finalize(const Elf_Ehdr *hdr,
text, text_end);
}

- if (orc && orc_ip)
- unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
- (void *)orc->sh_addr, orc->sh_size);
-
return 0;
}

diff --git a/include/linux/module.h b/include/linux/module.h
index 7039f609c6ef..2c1a24ba99a3 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -376,15 +376,6 @@ struct module_memory {
#endif
};

-#ifdef CONFIG_MODULES
-void *module_writable_address(struct module *mod, void *loc);
-#else
-static inline void *module_writable_address(struct module *mod, void *loc)
-{
- return loc;
-}
-#endif
-
#ifdef CONFIG_MODULES_TREE_LOOKUP
/* Only touch one cacheline for common rbtree-for-core-layout case. */
#define __module_memory_align ____cacheline_aligned
@@ -778,6 +769,8 @@ static inline bool is_livepatch_module(struct module *mod)

void set_module_sig_enforced(void);

+void *module_writable_address(struct module *mod, void *loc);
+
#else /* !CONFIG_MODULES... */

static inline struct module *__module_address(unsigned long addr)
@@ -885,6 +878,11 @@ static inline bool module_is_coming(struct module *mod)
{
return false;
}
+
+static inline void *module_writable_address(struct module *mod, void *loc)
+{
+ return loc;
+}
#endif /* CONFIG_MODULES */

#ifdef CONFIG_SYSFS
--
2.43.0