diff options
Diffstat (limited to 'net/x25/af_x25.c')
| -rw-r--r-- | net/x25/af_x25.c | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c index 9796f3ed1ed..fe26c01ef3e 100644 --- a/net/x25/af_x25.c +++ b/net/x25/af_x25.c @@ -82,6 +82,41 @@ struct compat_x25_subscrip_struct { }; #endif + +int x25_parse_address_block(struct sk_buff *skb, + struct x25_address *called_addr, + struct x25_address *calling_addr) +{ + unsigned char len; + int needed; + int rc; + + if (skb->len < 1) { + /* packet has no address block */ + rc = 0; + goto empty; + } + + len = *skb->data; + needed = 1 + (len >> 4) + (len & 0x0f); + + if (skb->len < needed) { + /* packet is too short to hold the addresses it claims + to hold */ + rc = -1; + goto empty; + } + + return x25_addr_ntoa(skb->data, called_addr, calling_addr); + +empty: + *called_addr->x25_addr = 0; + *calling_addr->x25_addr = 0; + + return rc; +} + + int x25_addr_ntoa(unsigned char *p, struct x25_address *called_addr, struct x25_address *calling_addr) { @@ -921,16 +956,26 @@ int x25_rx_call_request(struct sk_buff *skb, struct x25_neigh *nb, /* * Extract the X.25 addresses and convert them to ASCII strings, * and remove them. + * + * Address block is mandatory in call request packets */ - addr_len = x25_addr_ntoa(skb->data, &source_addr, &dest_addr); + addr_len = x25_parse_address_block(skb, &source_addr, &dest_addr); + if (addr_len <= 0) + goto out_clear_request; skb_pull(skb, addr_len); /* * Get the length of the facilities, skip past them for the moment * get the call user data because this is needed to determine * the correct listener + * + * Facilities length is mandatory in call request packets */ + if (skb->len < 1) + goto out_clear_request; len = skb->data[0] + 1; + if (skb->len < len) + goto out_clear_request; skb_pull(skb,len); /* |