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| author | David Windsor <dwindsor@gmail.com> | 2026-06-29 20:13:33 -0400 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-07-02 13:21:49 +0200 |
| commit | abf08854d224085e2ebb3ba660e7995909f47d6a (patch) | |
| tree | f48461ec6a6eae8d75f739a4689cefb4200ce24b | |
| parent | 037a3c43edfb597665dd34457cd22b14692f2ba3 (diff) | |
| download | linux-2.6-abf08854d224085e2ebb3ba660e7995909f47d6a.tar.gz linux-2.6-abf08854d224085e2ebb3ba660e7995909f47d6a.zip | |
x86/uprobes: Keep shadow stack in sync for emulated CALLs
Uprobe CALL emulation updates the normal user stack, but not the CET user
shadow stack. The subsequent RET then sees a stale shadow stack entry and
raises #CP.
Update the relative CALL emulation and XOL CALL fixup paths to keep the
shadow stack in sync.
Fixes: 488af8ea7131 ("x86/shstk: Wire in shadow stack interface")
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Link: https://patch.msgid.link/8b5b1c7407b98f31664ad7b6a6faf20d2d4a6cad.1782777969.git.dwindsor@gmail.com
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index ebb1baf1eb1d..d74bb54543b6 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -1246,9 +1246,15 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs long correction = utask->vaddr - utask->xol_vaddr; regs->ip += correction; } else if (auprobe->defparam.fixups & UPROBE_FIX_CALL) { + unsigned long retaddr = utask->vaddr + auprobe->defparam.ilen; + int err; + regs->sp += sizeof_long(regs); /* Pop incorrect return address */ - if (emulate_push_stack(regs, utask->vaddr + auprobe->defparam.ilen)) + if (emulate_push_stack(regs, retaddr)) return -ERESTART; + err = shstk_update_last_frame(retaddr); + if (err) + return err; } /* popf; tell the caller to not touch TF */ if (auprobe->defparam.fixups & UPROBE_FIX_SETF) @@ -1338,6 +1344,10 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) */ if (emulate_push_stack(regs, new_ip)) return false; + if (shstk_push(new_ip) == -EFAULT) { + regs->sp += sizeof_long(regs); + return false; + } } else if (!check_jmp_cond(auprobe, regs)) { offs = 0; } |