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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
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

File diff suppressed because it is too large Load Diff

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);