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author | David S. Miller <davem@davemloft.net> | 2013-08-10 13:44:22 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2013-08-10 13:44:22 -0700 |
commit | 4209423c29a593f8a1fe1c3337d9ad7d52a1caa9 (patch) | |
tree | 3d60148ff0419da8bb1ffe1780716ee3c7094d8d /net/netfilter/xt_TCPMSS.c | |
parent | 645359930231d5e78fd3296a38b98c1a658a7ade (diff) | |
parent | 356d7d88e088687b6578ca64601b0a2c9d145296 (diff) | |
download | op-kernel-dev-4209423c29a593f8a1fe1c3337d9ad7d52a1caa9.zip op-kernel-dev-4209423c29a593f8a1fe1c3337d9ad7d52a1caa9.tar.gz |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf
Pablo Neira Ayuso says:
====================
The following patchset contains four netfilter fixes, they are:
* Fix possible invalid access and mangling of the TCPMSS option in
xt_TCPMSS. This was spotted by Julian Anastasov.
* Fix possible off by one access and mangling of the TCP packet in
xt_TCPOPTSTRIP, also spotted by Julian Anastasov.
* Fix possible information leak due to missing initialization of one
padding field of several structures that are included in nfqueue and
nflog netlink messages, from Dan Carpenter.
* Fix TCP window tracking with Fast Open, from Yuchung Cheng.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netfilter/xt_TCPMSS.c')
-rw-r--r-- | net/netfilter/xt_TCPMSS.c | 28 |
1 files changed, 16 insertions, 12 deletions
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index 7011c71..6113cc7 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -52,7 +52,8 @@ tcpmss_mangle_packet(struct sk_buff *skb, { const struct xt_tcpmss_info *info = par->targinfo; struct tcphdr *tcph; - unsigned int tcplen, i; + int len, tcp_hdrlen; + unsigned int i; __be16 oldval; u16 newmss; u8 *opt; @@ -64,11 +65,14 @@ tcpmss_mangle_packet(struct sk_buff *skb, if (!skb_make_writable(skb, skb->len)) return -1; - tcplen = skb->len - tcphoff; + len = skb->len - tcphoff; + if (len < (int)sizeof(struct tcphdr)) + return -1; + tcph = (struct tcphdr *)(skb_network_header(skb) + tcphoff); + tcp_hdrlen = tcph->doff * 4; - /* Header cannot be larger than the packet */ - if (tcplen < tcph->doff*4) + if (len < tcp_hdrlen) return -1; if (info->mss == XT_TCPMSS_CLAMP_PMTU) { @@ -87,9 +91,8 @@ tcpmss_mangle_packet(struct sk_buff *skb, newmss = info->mss; opt = (u_int8_t *)tcph; - for (i = sizeof(struct tcphdr); i < tcph->doff*4; i += optlen(opt, i)) { - if (opt[i] == TCPOPT_MSS && tcph->doff*4 - i >= TCPOLEN_MSS && - opt[i+1] == TCPOLEN_MSS) { + for (i = sizeof(struct tcphdr); i <= tcp_hdrlen - TCPOLEN_MSS; i += optlen(opt, i)) { + if (opt[i] == TCPOPT_MSS && opt[i+1] == TCPOLEN_MSS) { u_int16_t oldmss; oldmss = (opt[i+2] << 8) | opt[i+3]; @@ -112,9 +115,10 @@ tcpmss_mangle_packet(struct sk_buff *skb, } /* There is data after the header so the option can't be added - without moving it, and doing so may make the SYN packet - itself too large. Accept the packet unmodified instead. */ - if (tcplen > tcph->doff*4) + * without moving it, and doing so may make the SYN packet + * itself too large. Accept the packet unmodified instead. + */ + if (len > tcp_hdrlen) return 0; /* @@ -143,10 +147,10 @@ tcpmss_mangle_packet(struct sk_buff *skb, newmss = min(newmss, (u16)1220); opt = (u_int8_t *)tcph + sizeof(struct tcphdr); - memmove(opt + TCPOLEN_MSS, opt, tcplen - sizeof(struct tcphdr)); + memmove(opt + TCPOLEN_MSS, opt, len - sizeof(struct tcphdr)); inet_proto_csum_replace2(&tcph->check, skb, - htons(tcplen), htons(tcplen + TCPOLEN_MSS), 1); + htons(len), htons(len + TCPOLEN_MSS), 1); opt[0] = TCPOPT_MSS; opt[1] = TCPOLEN_MSS; opt[2] = (newmss & 0xff00) >> 8; |