Messages in this thread Patch in this message | | | From | "Eric W. Biederman" <> | Date | Wed, 18 May 2022 17:53:48 -0500 | Subject | [PATCH 09/16] ptrace: In ptrace_setsiginfo deal with invalid si_signo |
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If the tracer calls PTRACE_SETSIGINFO it only has an effect if the tracee is stopped in ptrace_signal.
When one of PTRACE_DETACH, PTRACE_SINGLESTEP, PTRACE_SINGLEBLOCK, PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP, PTRACE_SYSCALL, or PTRACE_CONT pass in a signel number to continue with the kernel validates that signal number and the ptrace_signal verifies the signal number matches the si_signo, before the siginfo is used.
As the signal number to continue with is verified to be a valid signal number the signal number in si_signo must be a valid signal number.
Make this obvious and avoid needing checks later by immediately clearing siginfo if si_signo is not valid.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> --- kernel/ptrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index a24eed725cec..a0a07d140751 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -716,7 +716,9 @@ static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t * if (unlikely(!child->last_siginfo)) return -EINVAL; - copy_siginfo(child->last_siginfo, info); + clear_siginfo(child->last_siginfo); + if (valid_signal(info->si_signo)) + copy_siginfo(child->last_siginfo, info); return 0; } -- 2.35.3
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