path: root/net
diff options
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>2011-08-24 19:45:03 -0700
committerDavid S. Miller <davem@davemloft.net>2011-08-24 19:45:03 -0700
commitbc909d9ddbf7778371e36a651d6e4194b1cc7d4c (patch)
tree45fb13261b012c61a64713ee13f5c7fe60a046dd /net
parentc6f59d13e24187ff95427a9f4a5a7e14fb8faf5a (diff)
sendmmsg/sendmsg: fix unsafe user pointer access
Dereferencing a user pointer directly from kernel-space without going through the copy_from_user family of functions is a bad idea. Two of such usages can be found in the sendmsg code path called from sendmmsg, added by commit c71d8ebe7a4496fb7231151cb70a6baa0cb56f9a upstream. commit 5b47b8038f183b44d2d8ff1c7d11a5c1be706b34 in the 3.0-stable tree. Usages are performed through memcmp() and memcpy() directly. Fix those by using the already copied msg_sys structure instead of the __user *msg structure. Note that msg_sys can be set to NULL by verify_compat_iovec() or verify_iovec(), which requires additional NULL pointer checks. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: David Goulet <dgoulet@ev0ke.net> CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> CC: Anton Blanchard <anton@samba.org> CC: David S. Miller <davem@davemloft.net> CC: stable <stable@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
1 files changed, 6 insertions, 4 deletions
diff --git a/net/socket.c b/net/socket.c
index 24a77400b65e..ffe92ca32f2a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1965,8 +1965,9 @@ static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
* used_address->name_len is initialized to UINT_MAX so that the first
* destination address never matches.
- if (used_address && used_address->name_len == msg_sys->msg_namelen &&
- !memcmp(&used_address->name, msg->msg_name,
+ if (used_address && msg_sys->msg_name &&
+ used_address->name_len == msg_sys->msg_namelen &&
+ !memcmp(&used_address->name, msg_sys->msg_name,
used_address->name_len)) {
err = sock_sendmsg_nosec(sock, msg_sys, total_len);
goto out_freectl;
@@ -1978,8 +1979,9 @@ static int __sys_sendmsg(struct socket *sock, struct msghdr __user *msg,
if (used_address && err >= 0) {
used_address->name_len = msg_sys->msg_namelen;
- memcpy(&used_address->name, msg->msg_name,
- used_address->name_len);
+ if (msg_sys->msg_name)
+ memcpy(&used_address->name, msg_sys->msg_name,
+ used_address->name_len);