[PATCH net-next 04/17] tipc: Prevent invalid memory access when sending to configuration service

From: Allan Stephens <redacted>

Reject TIPC configuration service messages without a full message
header.  Previously, an application that sent a message to the
configuration service that was too short could cause the validation
code to access an uninitialized field in the msghdr structure,
resulting in a memory access exception.

Signed-off-by: Allan Stephens <redacted>
Signed-off-by: Paul Gortmaker <redacted>
---
 net/tipc/socket.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 893ca6e..125dcb0 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c

@@ -493,6 +493,8 @@ static int dest_name_check(struct sockaddr_tipc *dest, struct msghdr *m)
 	if (likely(dest->addr.name.name.type != TIPC_CFG_SRV))
 		return -EACCES;
 
+	if (!m->msg_iovlen || (m->msg_iov[0].iov_len < sizeof(hdr)))
+		return -EMSGSIZE;
 	if (copy_from_user(&hdr, m->msg_iov[0].iov_base, sizeof(hdr)))
 		return -EFAULT;
 	if ((ntohs(hdr.tcm_type) & 0xC000) && (!capable(CAP_NET_ADMIN)))

-- 
1.7.3.3