[ 107/143] net: socket: error on a negative msg_namelen

Willy Tarreau
2014-05-12T02:12:05Z

From: Matthew Leach <matthew.leach@arm.com>

[ Upstream commit dbb490b96584d4e958533fb637f08b557f505657 ]

When copying in a struct msghdr from the user, if the user has set the
msg_namelen parameter to a negative value it gets clamped to a valid
size due to a comparison between signed and unsigned values.

Ensure the syscall errors when the user passes in a negative value.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
net/socket.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/net/socket.c b/net/socket.c
index 0823497..bc151b8 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1871,6 +1871,10 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
{
if (copy_from_user(kmsg, umsg, sizeof(struct msghdr)))
return -EFAULT;
+
+ if (kmsg->msg_namelen < 0)
+ return -EINVAL;
+
if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
kmsg->msg_namelen = sizeof(struct sockaddr_storage);
return 0;
--
1.7.12.2.21.g234cd45.dirty