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>
This commit is contained in:
Ben Hutchings
2011-03-20 06:48:05 +00:00
committed by David S. Miller
parent be20250c13
commit e0bccd315d
5 changed files with 90 additions and 44 deletions

View File

@@ -861,7 +861,7 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25)
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 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25)
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 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25)
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;
}