From 9032157250fb1be76edd1aa8fe652c22da211690 Mon Sep 17 00:00:00 2001 From: JingYi Hou Date: Mon, 17 Jun 2019 14:56:05 +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 --- net/core/sock.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/core/sock.c b/net/core/sock.c index a88579589946..c8d39092e8bf 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1358,9 +1358,6 @@ 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)); -- 2.20.1