sctp: add verification checks to SCTP_AUTH_KEY option

The structure used for SCTP_AUTH_KEY option contains a
length that needs to be verfied to prevent buffer overflow
conditions.  Spoted by Eugene Teo <eteo@redhat.com>.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 0 deletions

diff --git a/net/sctp/auth.c b/net/sctp/auth.c
index 675a5c3e68a6..1fcb4cf2f4c9 100644
--- a/net/sctp/auth.c
+++ b/net/sctp/auth.c
@@ -80,6 +80,10 @@ static struct sctp_auth_bytes *sctp_auth_create_key(__u32 key_len, gfp_t gfp)
 {
         struct sctp_auth_bytes *key;
 
+        /* Verify that we are not going to overflow INT_MAX */
+        if ((INT_MAX - key_len) < sizeof(struct sctp_auth_bytes))
+                return NULL;
+
         /* Allocate the shared key */
         key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
         if (!key)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index bb5c9ef13046..afa952e726d7 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3144,6 +3144,11 @@ static int sctp_setsockopt_auth_key(struct sock *sk,
                 goto out;
         }
 
+        if (authkey->sca_keylength > optlen) {
+                ret = -EINVAL;
+                goto out;
+        }
+
         asoc = sctp_id2assoc(sk, authkey->sca_assoc_id);
         if (!asoc && authkey->sca_assoc_id && sctp_style(sk, UDP)) {
                 ret = -EINVAL;