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Probes fixes for 6.7-rc8:

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- Kprobes/x86: Fix to emulate indirect call which size is not 5 byte.
    Current code expects the indirect call instructions are 5 bytes, but
    that is incorrect. Usually indirect call based on register is shorter
    than that, thus the emulation causes a kernel crash by accessing
    wrong instruction boundary. This uses the instruction size to
    calculate the return address correctly.
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Merge tag 'probes-fixes-v6.7-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull kprobes/x86 fix from Masami Hiramatsu:

 - Fix to emulate indirect call which size is not 5 byte.

   Current code expects the indirect call instructions are 5 bytes, but
   that is incorrect. Usually indirect call based on register is shorter
   than that, thus the emulation causes a kernel crash by accessing
   wrong instruction boundary. This uses the instruction size to
   calculate the return address correctly.

* tag 'probes-fixes-v6.7-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  x86/kprobes: fix incorrect return address calculation in kprobe_emulate_call_indirect
This commit is contained in:
Linus Torvalds 2024-01-05 09:07:59 -08:00
commit 7131c2e9bb
1 changed files with 2 additions and 1 deletions
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3
arch/x86/kernel/kprobes/core.c
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@ -576,7 +576,8 @@ static void kprobe_emulate_call_indirect(struct kprobe *p, struct pt_regs *regs)
{
unsigned long offs = addrmode_regoffs[p->ainsn.indirect.reg];
int3_emulate_call(regs, regs_get_register(regs, offs));
int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + p->ainsn.size);
int3_emulate_jmp(regs, regs_get_register(regs, offs));
}
NOKPROBE_SYMBOL(kprobe_emulate_call_indirect);