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1154bbd326
For X86_FEATURE_SMAP alternatives which replace NOP with STAC or CLAC,
uaccess validation skips the NOP branch to avoid following impossible
code paths, e.g. where a STAC would be patched but a CLAC wouldn't.
However, it's not safe to assume an X86_FEATURE_SMAP alternative is
patching STAC/CLAC. There can be other alternatives, like
static_cpu_has(), where both branches need to be validated.
Fix that by repurposing ANNOTATE_IGNORE_ALTERNATIVE for skipping either
original instructions or new ones. This is a more generic approach
which enables the removal of the feature checking hacks and the
insn->ignore bit.
Fixes the following warnings:
arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8ec: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h
arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8f1: unreachable instruction
[ mingo: Fix up conflicts with recent x86 changes. ]
Fixes: ea24213d80 ("objtool: Add UACCESS validation")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/de0621ca242130156a55d5d74fed86994dfa4c9c.1742852846.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202503181736.zkZUBv4N-lkp@intel.com/
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
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*/
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#ifndef _CHECK_H
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#define _CHECK_H
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#include <stdbool.h>
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#include <objtool/cfi.h>
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#include <objtool/arch.h>
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struct insn_state {
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struct cfi_state cfi;
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unsigned int uaccess_stack;
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bool uaccess;
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bool df;
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bool noinstr;
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s8 instr;
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};
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struct alt_group {
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/*
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* Pointer from a replacement group to the original group. NULL if it
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* *is* the original group.
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*/
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struct alt_group *orig_group;
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/* First and last instructions in the group */
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struct instruction *first_insn, *last_insn, *nop;
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/*
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* Byte-offset-addressed len-sized array of pointers to CFI structs.
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* This is shared with the other alt_groups in the same alternative.
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*/
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struct cfi_state **cfi;
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bool ignore;
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};
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#define INSN_CHUNK_BITS 8
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#define INSN_CHUNK_SIZE (1 << INSN_CHUNK_BITS)
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#define INSN_CHUNK_MAX (INSN_CHUNK_SIZE - 1)
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struct instruction {
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struct hlist_node hash;
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struct list_head call_node;
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struct section *sec;
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unsigned long offset;
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unsigned long immediate;
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u8 len;
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u8 prev_len;
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u8 type;
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s8 instr;
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u32 idx : INSN_CHUNK_BITS,
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dead_end : 1,
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ignore_alts : 1,
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hint : 1,
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save : 1,
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restore : 1,
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retpoline_safe : 1,
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noendbr : 1,
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unret : 1,
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visited : 4,
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no_reloc : 1;
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/* 10 bit hole */
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struct alt_group *alt_group;
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struct instruction *jump_dest;
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struct instruction *first_jump_src;
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union {
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struct symbol *_call_dest;
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struct {
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struct reloc *_jump_table;
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unsigned long _jump_table_size;
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};
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};
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struct alternative *alts;
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struct symbol *sym;
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struct stack_op *stack_ops;
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struct cfi_state *cfi;
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};
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static inline struct symbol *insn_func(struct instruction *insn)
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{
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struct symbol *sym = insn->sym;
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if (sym && sym->type != STT_FUNC)
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sym = NULL;
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return sym;
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}
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#define VISITED_BRANCH 0x01
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#define VISITED_BRANCH_UACCESS 0x02
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#define VISITED_BRANCH_MASK 0x03
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#define VISITED_UNRET 0x04
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static inline bool is_static_jump(struct instruction *insn)
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{
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return insn->type == INSN_JUMP_CONDITIONAL ||
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insn->type == INSN_JUMP_UNCONDITIONAL;
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}
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static inline bool is_dynamic_jump(struct instruction *insn)
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{
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return insn->type == INSN_JUMP_DYNAMIC ||
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insn->type == INSN_JUMP_DYNAMIC_CONDITIONAL;
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}
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static inline bool is_jump(struct instruction *insn)
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{
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return is_static_jump(insn) || is_dynamic_jump(insn);
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}
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struct instruction *find_insn(struct objtool_file *file,
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struct section *sec, unsigned long offset);
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struct instruction *next_insn_same_sec(struct objtool_file *file, struct instruction *insn);
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#define sec_for_each_insn(file, _sec, insn) \
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for (insn = find_insn(file, _sec, 0); \
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insn && insn->sec == _sec; \
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insn = next_insn_same_sec(file, insn))
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#endif /* _CHECK_H */
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