From: Matthew Leach <matthew.leach@xxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
[ 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@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
net/socket.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/socket.c b/net/socket.c
index e83c416708af..dc57dae20a9a 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1972,6 +1972,10 @@ 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;
--
1.9.2
--
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