Return-Path: From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Catalin Marinas , "David S. Miller" , Dan Carpenter , Zefan Li Subject: [PATCH 3.4 175/176] net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour Date: Thu, 9 Apr 2015 16:47:03 +0800 Message-Id: <1428569224-23820-175-git-send-email-lizf@kernel.org> In-Reply-To: <1428569028-23762-1-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Catalin Marinas 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [lizf: Backported to 3.4: s/uaddr/tmp1/] Signed-off-by: Zefan Li --- net/compat.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/compat.c b/net/compat.c index 2c774d8..5b17509 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); -- 1.9.1