diff options
Diffstat (limited to 'net/netfilter/xt_TCPOPTSTRIP.c')
| -rw-r--r-- | net/netfilter/xt_TCPOPTSTRIP.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/net/netfilter/xt_TCPOPTSTRIP.c b/net/netfilter/xt_TCPOPTSTRIP.c index 1eb1a44bfd3..625fa1d636a 100644 --- a/net/netfilter/xt_TCPOPTSTRIP.c +++ b/net/netfilter/xt_TCPOPTSTRIP.c @@ -38,7 +38,7 @@ tcpoptstrip_mangle_packet(struct sk_buff *skb, struct tcphdr *tcph; u_int16_t n, o; u_int8_t *opt; - int len; + int len, tcp_hdrlen; /* This is a fragment, no TCP header is available */ if (par->fragoff != 0) @@ -48,21 +48,25 @@ tcpoptstrip_mangle_packet(struct sk_buff *skb, return NF_DROP; len = skb->len - tcphoff; - if (len < (int)sizeof(struct tcphdr) || - tcp_hdr(skb)->doff * 4 > len) + if (len < (int)sizeof(struct tcphdr)) return NF_DROP; tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); + tcp_hdrlen = tcph->doff * 4; + + if (len < tcp_hdrlen) + return NF_DROP; + opt = (u_int8_t *)tcph; /* * Walk through all TCP options - if we find some option to remove, * set all octets to %TCPOPT_NOP and adjust checksum. */ - for (i = sizeof(struct tcphdr); i < tcp_hdrlen(skb); i += optl) { + for (i = sizeof(struct tcphdr); i < tcp_hdrlen - 1; i += optl) { optl = optlen(opt, i); - if (i + optl > tcp_hdrlen(skb)) + if (i + optl > tcp_hdrlen) break; if (!tcpoptstrip_test_bit(info->strip_bmap, opt[i])) |