From 8c5dbf2ae00bb8667f61c5edc6521c1fa2bbe4d7 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 24 Jul 2017 15:28:56 -0500 Subject: [PATCH] signal: Introduce clear_siginfo Unfortunately struct siginfo has holes both in the common part of the structure, in the union members, and in the lack of padding of the union members. The result of those wholes is that the C standard does not guarantee those bits will be initialized. As struct siginfo is for communication between the kernel and userspace that is a problem. Add the helper function clear_siginfo that is guaranteed to clear all of the bits in struct siginfo so when the structure is copied there is no danger of copying old kernel data and causing a leak of information from kernel space to userspace. Signed-off-by: "Eric W. Biederman" --- include/linux/signal.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/signal.h b/include/linux/signal.h index 8037b503ce91..87abf0c29ed7 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -16,6 +16,11 @@ static inline void copy_siginfo(struct siginfo *to, const struct siginfo *from) memcpy(to, from, sizeof(*to)); } +static inline void clear_siginfo(struct siginfo *info) +{ + memset(info, 0, sizeof(*info)); +} + int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from); enum siginfo_layout { -- GitLab