From be3855141e81c84faf5125e9a239f0a2026673d0 Mon Sep 17 00:00:00 2001 From: JingYi Hou Date: Thu, 4 Jul 2019 11:39:53 +0800 Subject: [PATCH] net: remove duplicate fetch in sock_getsockopt [ Upstream commit d0bae4a0e3d8c5690a885204d7eb2341a5b4884d ] In sock_getsockopt(), 'optlen' is fetched the first time from userspace. 'len < 0' is then checked. Then in condition 'SO_MEMINFO', 'optlen' is fetched the second time from userspace. If change it between two fetches may cause security problems or unexpected behaivor, and there is no reason to fetch it a second time. To fix this, we need to remove the second fetch. Signed-off-by: JingYi Hou Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- net/core/sock.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index a0dda2bf9d7c..f4f7a00dcb63 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1370,9 +1370,6 @@ int sock_getsockopt(struct socket *sock, int level, int optname, { u32 meminfo[SK_MEMINFO_VARS]; - if (get_user(len, optlen)) - return -EFAULT; - sk_get_meminfo(sk, meminfo); len = min_t(unsigned int, len, sizeof(meminfo)); -- GitLab