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/rose_route.c b/net/rose/rose_route.c
index 88a77e9..08dcd2f 100644
--- a/net/rose/rose_route.c
+++ b/net/rose/rose_route.c
@@ -861,7 +861,7 @@
unsigned int lci, new_lci;
unsigned char cause, diagnostic;
struct net_device *dev;
- int len, res = 0;
+ int res = 0;
char buf[11];
#if 0
@@ -869,10 +869,17 @@
return res;
#endif
+ if (skb->len < ROSE_MIN_LEN)
+ return res;
frametype = skb->data[2];
lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
- src_addr = (rose_address *)(skb->data + 9);
- dest_addr = (rose_address *)(skb->data + 4);
+ if (frametype == ROSE_CALL_REQUEST &&
+ (skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
+ skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
+ ROSE_CALL_REQ_ADDR_LEN_VAL))
+ return res;
+ src_addr = (rose_address *)(skb->data + ROSE_CALL_REQ_SRC_ADDR_OFF);
+ dest_addr = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
spin_lock_bh(&rose_neigh_list_lock);
spin_lock_bh(&rose_route_list_lock);
@@ -1010,12 +1017,11 @@
goto out;
}
- len = (((skb->data[3] >> 4) & 0x0F) + 1) >> 1;
- len += (((skb->data[3] >> 0) & 0x0F) + 1) >> 1;
-
memset(&facilities, 0x00, sizeof(struct rose_facilities_struct));
- 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(rose_neigh, lci, ROSE_INVALID_FACILITY, 76);
goto out;
}