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netfilter: nf_conntrack_tcp: preserve liberal flag in tcp options
[ Upstream commitf2dd495a8d
] Do not reset IP_CT_TCP_FLAG_BE_LIBERAL flag in out-of-sync scenarios coming before the TCP window tracking, otherwise such connections will fail in the window check. Update tcp_options() to leave this flag in place and add a new helper function to reset the tcp window state. Based on patch from Sven Auhagen. Fixes:c4832c7bbc
("netfilter: nf_ct_tcp: improve out-of-sync situation in TCP tracking") Tested-by: Sven Auhagen <sven.auhagen@voleatech.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
c73c5c5632
commit
6923164d2e
1 changed files with 13 additions and 4 deletions
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@ -383,8 +383,8 @@ static void tcp_options(const struct sk_buff *skb,
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length, buff);
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BUG_ON(ptr == NULL);
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state->td_scale =
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state->flags = 0;
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state->td_scale = 0;
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state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
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while (length > 0) {
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int opcode=*ptr++;
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@ -797,6 +797,16 @@ static unsigned int *tcp_get_timeouts(struct net *net)
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return tcp_pernet(net)->timeouts;
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}
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static void nf_ct_tcp_state_reset(struct ip_ct_tcp_state *state)
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{
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state->td_end = 0;
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state->td_maxend = 0;
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state->td_maxwin = 0;
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state->td_maxack = 0;
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state->td_scale = 0;
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state->flags &= IP_CT_TCP_FLAG_BE_LIBERAL;
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}
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/* Returns verdict for packet, or -1 for invalid. */
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static int tcp_packet(struct nf_conn *ct,
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const struct sk_buff *skb,
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@ -897,8 +907,7 @@ static int tcp_packet(struct nf_conn *ct,
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ct->proto.tcp.last_flags &= ~IP_CT_EXP_CHALLENGE_ACK;
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ct->proto.tcp.seen[ct->proto.tcp.last_dir].flags =
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ct->proto.tcp.last_flags;
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memset(&ct->proto.tcp.seen[dir], 0,
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sizeof(struct ip_ct_tcp_state));
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nf_ct_tcp_state_reset(&ct->proto.tcp.seen[dir]);
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break;
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}
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ct->proto.tcp.last_index = index;
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