Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753744Ab3FFFik (ORCPT ); Thu, 6 Jun 2013 01:38:40 -0400 Received: from mail-pb0-f44.google.com ([209.85.160.44]:60163 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752660Ab3FFFii (ORCPT ); Thu, 6 Jun 2013 01:38:38 -0400 From: Andy Lutomirski To: x86@kernel.org, torvalds@linux-foundation.org, "David S. Miller" Cc: Michael Neuling , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Linux PPC dev , trinity@vger.kernel.org Subject: [PATCH] net: Unbreak compat_sys_{send,recv}msg Date: Wed, 5 Jun 2013 22:38:26 -0700 Message-Id: X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <20130606132926.f4161ddff87dc9a55e33a8ca@canb.auug.org.au> References: <20130606132926.f4161ddff87dc9a55e33a8ca@canb.auug.org.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8962 Lines: 273 I broke them in this commit: commit 1be374a0518a288147c6a7398792583200a67261 Author: Andy Lutomirski Date: Wed May 22 14:07:44 2013 -0700 net: Block MSG_CMSG_COMPAT in send(m)msg and recv(m)msg This patch adds __sys_sendmsg and __sys_sendmsg as common helpers that accept MSG_CMSG_COMPAT and blocks MSG_CMSG_COMPAT at the syscall entrypoints. It also reverts some unnecessary checks in sys_socketcall. Apparently I was suffering from underscore blindness the first time around. Signed-off-by: Andy Lutomirski --- I've tested this a little, but I'm not sure I have a great test case. If the decision is that it's better to leave this for the 3.11, I can send a squashed version. Note that the oops that this fixes is only an oops if the other patches in the original series are applied. (FWIW, I wasn't sure how to submit this stuff in the first place. I submitted some kernel hardening patches for the x86 tree that converted an access_ok oddity in the net code into an actual oops. In a bit of looking, I couldn't find any failure mode other than a -EFAULT return without the other patches applied. This was clear in the patch series description but not in the change log message for the net part.) include/linux/socket.h | 3 +++ net/compat.c | 13 +++++++-- net/socket.c | 72 +++++++++++++++++++++++--------------------------- 3 files changed, 47 insertions(+), 41 deletions(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 2b9f74b..e897bdc 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -321,6 +321,9 @@ extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data); struct timespec; +/* The __sys_...msg variants allow MSG_CMSG_COMPAT */ +extern long __sys_recvmsg(int fd, struct msghdr __user *msg, unsigned flags); +extern long __sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags); extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags, struct timespec *timeout); extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, diff --git a/net/compat.c b/net/compat.c index 79ae884..f0a1ba6 100644 --- a/net/compat.c +++ b/net/compat.c @@ -734,19 +734,25 @@ static unsigned char nas[21] = { asmlinkage long compat_sys_sendmsg(int fd, struct compat_msghdr __user *msg, unsigned int flags) { - return sys_sendmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT); + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + return __sys_sendmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT); } asmlinkage long compat_sys_sendmmsg(int fd, struct compat_mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags) { + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, flags | MSG_CMSG_COMPAT); } asmlinkage long compat_sys_recvmsg(int fd, struct compat_msghdr __user *msg, unsigned int flags) { - return sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT); + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + return __sys_recvmsg(fd, (struct msghdr __user *)msg, flags | MSG_CMSG_COMPAT); } asmlinkage long compat_sys_recv(int fd, void __user *buf, size_t len, unsigned int flags) @@ -768,6 +774,9 @@ asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg, int datagrams; struct timespec ktspec; + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + if (COMPAT_USE_64BIT_TIME) return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, flags | MSG_CMSG_COMPAT, diff --git a/net/socket.c b/net/socket.c index 0e16888..e216502 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1978,7 +1978,7 @@ struct used_address { unsigned int name_len; }; -static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg, +static int ___sys_sendmsg(struct socket *sock, struct msghdr __user *msg, struct msghdr *msg_sys, unsigned int flags, struct used_address *used_address) { @@ -2093,26 +2093,30 @@ out: * BSD sendmsg interface */ -SYSCALL_DEFINE3(sendmsg, int, fd, struct msghdr __user *, msg, unsigned int, flags) +long __sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags) { int fput_needed, err; struct msghdr msg_sys; struct socket *sock; - if (flags & MSG_CMSG_COMPAT) - return -EINVAL; - sock = sockfd_lookup_light(fd, &err, &fput_needed); if (!sock) goto out; - err = __sys_sendmsg(sock, msg, &msg_sys, flags, NULL); + err = ___sys_sendmsg(sock, msg, &msg_sys, flags, NULL); fput_light(sock->file, fput_needed); out: return err; } +SYSCALL_DEFINE3(sendmsg, int, fd, struct msghdr __user *, msg, unsigned int, flags) +{ + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + return __sys_sendmsg(fd, msg, flags); +} + /* * Linux sendmmsg interface */ @@ -2143,15 +2147,16 @@ int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, while (datagrams < vlen) { if (MSG_CMSG_COMPAT & flags) { - err = __sys_sendmsg(sock, (struct msghdr __user *)compat_entry, - &msg_sys, flags, &used_address); + err = ___sys_sendmsg(sock, (struct msghdr __user *)compat_entry, + &msg_sys, flags, &used_address); if (err < 0) break; err = __put_user(err, &compat_entry->msg_len); ++compat_entry; } else { - err = __sys_sendmsg(sock, (struct msghdr __user *)entry, - &msg_sys, flags, &used_address); + err = ___sys_sendmsg(sock, + (struct msghdr __user *)entry, + &msg_sys, flags, &used_address); if (err < 0) break; err = put_user(err, &entry->msg_len); @@ -2180,7 +2185,7 @@ SYSCALL_DEFINE4(sendmmsg, int, fd, struct mmsghdr __user *, mmsg, return __sys_sendmmsg(fd, mmsg, vlen, flags); } -static int __sys_recvmsg(struct socket *sock, struct msghdr __user *msg, +static int ___sys_recvmsg(struct socket *sock, struct msghdr __user *msg, struct msghdr *msg_sys, unsigned int flags, int nosec) { struct compat_msghdr __user *msg_compat = @@ -2272,27 +2277,31 @@ out: * BSD recvmsg interface */ -SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg, - unsigned int, flags) +long __sys_recvmsg(int fd, struct msghdr __user *msg, unsigned flags) { int fput_needed, err; struct msghdr msg_sys; struct socket *sock; - if (flags & MSG_CMSG_COMPAT) - return -EINVAL; - sock = sockfd_lookup_light(fd, &err, &fput_needed); if (!sock) goto out; - err = __sys_recvmsg(sock, msg, &msg_sys, flags, 0); + err = ___sys_recvmsg(sock, msg, &msg_sys, flags, 0); fput_light(sock->file, fput_needed); out: return err; } +SYSCALL_DEFINE3(recvmsg, int, fd, struct msghdr __user *, msg, + unsigned int, flags) +{ + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + return __sys_recvmsg(fd, msg, flags); +} + /* * Linux recvmmsg interface */ @@ -2330,17 +2339,18 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, * No need to ask LSM for more than the first datagram. */ if (MSG_CMSG_COMPAT & flags) { - err = __sys_recvmsg(sock, (struct msghdr __user *)compat_entry, - &msg_sys, flags & ~MSG_WAITFORONE, - datagrams); + err = ___sys_recvmsg(sock, (struct msghdr __user *)compat_entry, + &msg_sys, flags & ~MSG_WAITFORONE, + datagrams); if (err < 0) break; err = __put_user(err, &compat_entry->msg_len); ++compat_entry; } else { - err = __sys_recvmsg(sock, (struct msghdr __user *)entry, - &msg_sys, flags & ~MSG_WAITFORONE, - datagrams); + err = ___sys_recvmsg(sock, + (struct msghdr __user *)entry, + &msg_sys, flags & ~MSG_WAITFORONE, + datagrams); if (err < 0) break; err = put_user(err, &entry->msg_len); @@ -2525,31 +2535,15 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) (int __user *)a[4]); break; case SYS_SENDMSG: - if (a[2] & MSG_CMSG_COMPAT) { - err = -EINVAL; - break; - } err = sys_sendmsg(a0, (struct msghdr __user *)a1, a[2]); break; case SYS_SENDMMSG: - if (a[3] & MSG_CMSG_COMPAT) { - err = -EINVAL; - break; - } err = sys_sendmmsg(a0, (struct mmsghdr __user *)a1, a[2], a[3]); break; case SYS_RECVMSG: - if (a[2] & MSG_CMSG_COMPAT) { - err = -EINVAL; - break; - } err = sys_recvmsg(a0, (struct msghdr __user *)a1, a[2]); break; case SYS_RECVMMSG: - if (a[3] & MSG_CMSG_COMPAT) { - err = -EINVAL; - break; - } err = sys_recvmmsg(a0, (struct mmsghdr __user *)a1, a[2], a[3], (struct timespec __user *)a[4]); 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