rose: Add length checks to CALL_REQUEST parsing
Define some constant offsets for CALL_REQUEST based on the description
at <http://www.techfest.com/networking/wan/x25plp.htm> and the
definition of ROSE as using 10-digit (5-byte) addresses. Use them
consistently. Validate all implicit and explicit facilities lengths.
Validate the address length byte rather than either trusting or
assuming its value.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 5ee0c62..a80aef6 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -978,7 +978,7 @@
struct sock *make;
struct rose_sock *make_rose;
struct rose_facilities_struct facilities;
- int n, len;
+ int n;
skb->sk = NULL; /* Initially we don't know who it's for */
@@ -987,9 +987,9 @@
*/
memset(&facilities, 0x00, sizeof(struct rose_facilities_struct));
- len = (((skb->data[3] >> 4) & 0x0F) + 1) >> 1;
- len += (((skb->data[3] >> 0) & 0x0F) + 1) >> 1;
- if (!rose_parse_facilities(skb->data + len + 4, &facilities)) {
+ if (!rose_parse_facilities(skb->data + ROSE_CALL_REQ_FACILITIES_OFF,
+ skb->len - ROSE_CALL_REQ_FACILITIES_OFF,
+ &facilities)) {
rose_transmit_clear_request(neigh, lci, ROSE_INVALID_FACILITY, 76);
return 0;
}