From f04b2fb06a8e6422ccbf263bd70aefeb0280a267 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Fri, 20 Mar 2015 16:48:13 +0000 Subject: [PATCH] net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour commit 91edd096e224941131f896b86838b1e59553696a upstream. Commit db31c55a6fb2 (net: clamp ->msg_namelen instead of returning an error) introduced the clamping of msg_namelen when the unsigned value was larger than sizeof(struct sockaddr_storage). This caused a msg_namelen of -1 to be valid. The native code was subsequently fixed by commit dbb490b96584 (net: socket: error on a negative msg_namelen). In addition, the native code sets msg_namelen to 0 when msg_name is NULL. This was done in commit (6a2a2b3ae075 net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland) and subsequently updated by 08adb7dabd48 (fold verify_iovec() into copy_msghdr_from_user()). This patch brings the get_compat_msghdr() in line with copy_msghdr_from_user(). Fixes: db31c55a6fb2 (net: clamp ->msg_namelen instead of returning an error) Cc: David S. Miller Cc: Dan Carpenter Signed-off-by: Catalin Marinas Signed-off-by: David S. Miller [bwh: Backported to 3.2: s/uaddr/tmp1/] Signed-off-by: Ben Hutchings --- net/compat.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/compat.c b/net/compat.c index 012464b98c4e..f06994d64cd3 100644 --- a/net/compat.c +++ b/net/compat.c @@ -71,6 +71,13 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg) __get_user(kmsg->msg_controllen, &umsg->msg_controllen) || __get_user(kmsg->msg_flags, &umsg->msg_flags)) return -EFAULT; + + if (!tmp1) + kmsg->msg_namelen = 0; + + if (kmsg->msg_namelen < 0) + return -EINVAL; + if (kmsg->msg_namelen > sizeof(struct sockaddr_storage)) kmsg->msg_namelen = sizeof(struct sockaddr_storage); kmsg->msg_name = compat_ptr(tmp1); -- 2.39.2