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Objtool changes for v6.13:

Browse Source 
- Detect non-relocated text references for more robust
    IBT sealing (Josh Poimboeuf)
 
  - Fix build error when building stripped down
    UAPI headers (HONG Yifan)
 
  - Exclude __tracepoints data from ENDBR checks to fix
    false positives on clang builds (Peter Zijlstra)
 
  - Fix ORC unwind for newly forked tasks (Zheng Yejian)
 
  - Fix readelf related faddr2line regression (Carlos Llamas)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Detect non-relocated text references for more robust
   IBT sealing (Josh Poimboeuf)

 - Fix build error when building stripped down
   UAPI headers (HONG Yifan)

 - Exclude __tracepoints data from ENDBR checks to fix
   false positives on clang builds (Peter Zijlstra)

 - Fix ORC unwind for newly forked tasks (Zheng Yejian)

 - Fix readelf related faddr2line regression (Carlos Llamas)

* tag 'objtool-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Exclude __tracepoints data from ENDBR checks
  Revert "scripts/faddr2line: Check only two symbols when calculating symbol size"
  x86/unwind/orc: Fix unwind for newly forked tasks
  objtool: Also include tools/include/uapi
  objtool: Detect non-relocated text references
This commit is contained in:
Linus Torvalds 2024-11-19 13:27:52 -08:00
commit 9d7d4ad222
8 changed files with 81 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/kernel/acpi/wakeup_64.S
View File

@ -87,6 +87,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
.align 4
.Lresume_point:
ANNOTATE_NOENDBR
/* We don't restore %rax, it must be 0 anyway */
movq $saved_context, %rax
movq saved_context_cr4(%rax), %rbx

1
arch/x86/kernel/head_64.S
View File

@ -77,6 +77,7 @@ SYM_CODE_START_NOALIGN(startup_64)
lretq
.Lon_kernel_cs:
ANNOTATE_NOENDBR
UNWIND_HINT_END_OF_STACK
#ifdef CONFIG_AMD_MEM_ENCRYPT

2
arch/x86/kernel/unwind_orc.c
View File

@ -723,7 +723,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
state->sp = task->thread.sp + sizeof(*frame);
state->bp = READ_ONCE_NOCHECK(frame->bp);
state->ip = READ_ONCE_NOCHECK(frame->ret_addr);
state->signal = (void *)state->ip == ret_from_fork;
state->signal = (void *)state->ip == ret_from_fork_asm;
}
if (get_stack_info((unsigned long *)state->sp, state->task,

2
scripts/faddr2line
View File

@ -252,7 +252,7 @@ __faddr2line() {
found=2
break
fi
done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2 | ${GREP} -A1 --no-group-separator " ${sym_name}$")
done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -v sec=$sym_sec '$7 == sec' | sort --key=2)
if [[ $found = 0 ]]; then
warn "can't find symbol: sym_name: $sym_name sym_sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"

1
tools/objtool/Makefile
View File

@ -24,6 +24,7 @@ LIBELF_LIBS := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lel
all: $(OBJTOOL)
INCLUDES := -I$(srctree)/tools/include \
-I$(srctree)/tools/include/uapi \
-I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
-I$(srctree)/tools/arch/$(SRCARCH)/include \
-I$(srctree)/tools/objtool/include \

15
tools/objtool/arch/x86/decode.c
View File

@ -456,10 +456,6 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
if (!rex_w)
break;
/* skip RIP relative displacement */
if (is_RIP())
break;
/* skip nontrivial SIB */
if (have_SIB()) {
modrm_rm = sib_base;
@ -467,6 +463,12 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
break;
}
/* lea disp(%rip), %dst */
if (is_RIP()) {
insn->type = INSN_LEA_RIP;
break;
}
/* lea disp(%src), %dst */
ADD_OP(op) {
op->src.offset = ins.displacement.value;
@ -737,7 +739,10 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
break;
}
insn->immediate = ins.immediate.nbytes ? ins.immediate.value : 0;
if (ins.immediate.nbytes)
insn->immediate = ins.immediate.value;
else if (ins.displacement.nbytes)
insn->immediate = ins.displacement.value;
return 0;
}

113
tools/objtool/check.c
View File

@ -4392,6 +4392,51 @@ static bool noendbr_range(struct objtool_file *file, struct instruction *insn)
return insn->offset == sym->offset + sym->len;
}
static int __validate_ibt_insn(struct objtool_file *file, struct instruction *insn,
struct instruction *dest)
{
if (dest->type == INSN_ENDBR) {
mark_endbr_used(dest);
return 0;
}
if (insn_func(dest) && insn_func(insn) &&
insn_func(dest)->pfunc == insn_func(insn)->pfunc) {
/*
* Anything from->to self is either _THIS_IP_ or
* IRET-to-self.
*
* There is no sane way to annotate _THIS_IP_ since the
* compiler treats the relocation as a constant and is
* happy to fold in offsets, skewing any annotation we
* do, leading to vast amounts of false-positives.
*
* There's also compiler generated _THIS_IP_ through
* KCOV and such which we have no hope of annotating.
*
* As such, blanket accept self-references without
* issue.
*/
return 0;
}
/*
* Accept anything ANNOTATE_NOENDBR.
*/
if (dest->noendbr)
return 0;
/*
* Accept if this is the instruction after a symbol
* that is (no)endbr -- typical code-range usage.
*/
if (noendbr_range(file, dest))
return 0;
WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset));
return 1;
}
static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn)
{
struct instruction *dest;
@ -4404,6 +4449,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
* direct/indirect branches:
*/
switch (insn->type) {
case INSN_CALL:
case INSN_CALL_DYNAMIC:
case INSN_JUMP_CONDITIONAL:
@ -4413,6 +4459,23 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
case INSN_RETURN:
case INSN_NOP:
return 0;
case INSN_LEA_RIP:
if (!insn_reloc(file, insn)) {
/* local function pointer reference without reloc */
off = arch_jump_destination(insn);
dest = find_insn(file, insn->sec, off);
if (!dest) {
WARN_INSN(insn, "corrupt function pointer reference");
return 1;
}
return __validate_ibt_insn(file, insn, dest);
}
break;
default:
break;
}
@ -4423,13 +4486,6 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
reloc_offset(reloc) + 1,
(insn->offset + insn->len) - (reloc_offset(reloc) + 1))) {
/*
* static_call_update() references the trampoline, which
* doesn't have (or need) ENDBR. Skip warning in that case.
*/
if (reloc->sym->static_call_tramp)
continue;
off = reloc->sym->offset;
if (reloc_type(reloc) == R_X86_64_PC32 ||
reloc_type(reloc) == R_X86_64_PLT32)
@ -4441,47 +4497,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
if (!dest)
continue;
if (dest->type == INSN_ENDBR) {
mark_endbr_used(dest);
continue;
}
if (insn_func(dest) && insn_func(insn) &&
insn_func(dest)->pfunc == insn_func(insn)->pfunc) {
/*
* Anything from->to self is either _THIS_IP_ or
* IRET-to-self.
*
* There is no sane way to annotate _THIS_IP_ since the
* compiler treats the relocation as a constant and is
* happy to fold in offsets, skewing any annotation we
* do, leading to vast amounts of false-positives.
*
* There's also compiler generated _THIS_IP_ through
* KCOV and such which we have no hope of annotating.
*
* As such, blanket accept self-references without
* issue.
*/
continue;
}
/*
* Accept anything ANNOTATE_NOENDBR.
*/
if (dest->noendbr)
continue;
/*
* Accept if this is the instruction after a symbol
* that is (no)endbr -- typical code-range usage.
*/
if (noendbr_range(file, dest))
continue;
WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset));
warnings++;
warnings += __validate_ibt_insn(file, insn, dest);
}
return warnings;
@ -4557,6 +4573,7 @@ static int validate_ibt(struct objtool_file *file)
!strcmp(sec->name, "__jump_table") ||
!strcmp(sec->name, "__mcount_loc") ||
!strcmp(sec->name, ".kcfi_traps") ||
!strcmp(sec->name, "__tracepoints") ||
strstr(sec->name, "__patchable_function_entries"))
continue;

1
tools/objtool/include/objtool/arch.h
View File

@ -28,6 +28,7 @@ enum insn_type {
INSN_CLD,
INSN_TRAP,
INSN_ENDBR,
INSN_LEA_RIP,
INSN_OTHER,
};