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authorEric W. Biederman <ebiederm@xmission.com>2011-04-24 01:54:57 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:06:46 -0700
commit7a1bbc3614696ea5e90d728f570f3ded8d49b487 (patch)
treeaf7b8668a90541a7652c55e4f473acf47af89a6f
parent6ee931e9812bdf3774cbd74571d2fdfba037aac9 (diff)
downloadlinux-2.6.38-lt-ux500-7a1bbc3614696ea5e90d728f570f3ded8d49b487.tar.gz
af_unix: Only allow recv on connected seqpacket sockets.
commit a05d2ad1c1f391c7f514a1d1e09b5417968a7d07 upstream. This fixes the following oops discovered by Dan Aloni: > Anyway, the following is the output of the Oops that I got on the > Ubuntu kernel on which I first detected the problem > (2.6.37-12-generic). The Oops that followed will be more useful, I > guess. >[ 5594.669852] BUG: unable to handle kernel NULL pointer dereference > at           (null) > [ 5594.681606] IP: [<ffffffff81550b7b>] unix_dgram_recvmsg+0x1fb/0x420 > [ 5594.687576] PGD 2a05d067 PUD 2b951067 PMD 0 > [ 5594.693720] Oops: 0002 [#1] SMP > [ 5594.699888] last sysfs file: The bug was that unix domain sockets use a pseduo packet for connecting and accept uses that psudo packet to get the socket. In the buggy seqpacket case we were allowing unconnected sockets to call recvmsg and try to receive the pseudo packet. That is always wrong and as of commit 7361c36c5 the pseudo packet had become enough different from a normal packet that the kernel started oopsing. Do for seqpacket_recv what was done for seqpacket_send in 2.5 and only allow it on connected seqpacket sockets. Tested-by: Dan Aloni <dan@aloni.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/unix/af_unix.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 437a99e560e..7a79ad0ecf4 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -524,6 +524,8 @@ static int unix_dgram_connect(struct socket *, struct sockaddr *,
int, int);
static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *,
struct msghdr *, size_t);
+static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
+ struct msghdr *, size_t, int);
static const struct proto_ops unix_stream_ops = {
.family = PF_UNIX,
@@ -583,7 +585,7 @@ static const struct proto_ops unix_seqpacket_ops = {
.setsockopt = sock_no_setsockopt,
.getsockopt = sock_no_getsockopt,
.sendmsg = unix_seqpacket_sendmsg,
- .recvmsg = unix_dgram_recvmsg,
+ .recvmsg = unix_seqpacket_recvmsg,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage,
};
@@ -1695,6 +1697,18 @@ static int unix_seqpacket_sendmsg(struct kiocb *kiocb, struct socket *sock,
return unix_dgram_sendmsg(kiocb, sock, msg, len);
}
+static int unix_seqpacket_recvmsg(struct kiocb *iocb, struct socket *sock,
+ struct msghdr *msg, size_t size,
+ int flags)
+{
+ struct sock *sk = sock->sk;
+
+ if (sk->sk_state != TCP_ESTABLISHED)
+ return -ENOTCONN;
+
+ return unix_dgram_recvmsg(iocb, sock, msg, size, flags);
+}
+
static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
{
struct unix_sock *u = unix_sk(sk);