Commit 706b23bd authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds

Fix: kernel/ptrace.c: ptrace_peek_siginfo() missing __put_user() validation

This __put_user() could be used by unprivileged processes to write into
kernel memory.  The issue here is that even if copy_siginfo_to_user()
fails, the error code is not checked before __put_user() is executed.

Luckily, ptrace_peek_siginfo() has been added within the 3.10-rc cycle,
so it has not hit a stable release yet.
Signed-off-by: default avatarMathieu Desnoyers <>
Acked-by: default avatarOleg Nesterov <>
Cc: Andrey Vagin <>
Cc: Roland McGrath <>
Cc: Paul McKenney <>
Cc: David Howells <>
Cc: Dave Jones <>
Cc: Pavel Emelyanov <>
Cc: Pedro Alves <>
Cc: Andrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent bd2931b5
......@@ -665,20 +665,22 @@ static int ptrace_peek_siginfo(struct task_struct *child,
if (unlikely(is_compat_task())) {
compat_siginfo_t __user *uinfo = compat_ptr(data);
ret = copy_siginfo_to_user32(uinfo, &info);
ret |= __put_user(info.si_code, &uinfo->si_code);
if (copy_siginfo_to_user32(uinfo, &info) ||
__put_user(info.si_code, &uinfo->si_code)) {
ret = -EFAULT;
} else
siginfo_t __user *uinfo = (siginfo_t __user *) data;
ret = copy_siginfo_to_user(uinfo, &info);
ret |= __put_user(info.si_code, &uinfo->si_code);
if (ret) {
ret = -EFAULT;
if (copy_siginfo_to_user(uinfo, &info) ||
__put_user(info.si_code, &uinfo->si_code)) {
ret = -EFAULT;
data += sizeof(siginfo_t);
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