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| author | Al Viro <viro@zeniv.linux.org.uk> | 2006-12-12 00:29:52 -0800 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-12-13 16:48:23 -0800 |
| commit | e1b4b9f3986b80d5785d91dbd8d72cfaf9fd1117 (patch) | |
| tree | 96732395f387104b7af0641a5127352dc0d6124d /net/ipv6 | |
| parent | a96be24679198469df28976c809575423e70d843 (diff) | |
| download | lwn-e1b4b9f3986b80d5785d91dbd8d72cfaf9fd1117.tar.gz lwn-e1b4b9f3986b80d5785d91dbd8d72cfaf9fd1117.zip | |
[NETFILTER]: {ip,ip6,arp}_tables: fix exponential worst-case search for loops
If we come to node we'd already marked as seen and it's not a part of path
(i.e. we don't have a loop right there), we already know that it isn't a
part of any loop, so we don't need to revisit it.
That speeds the things up if some chain is refered to from several places
and kills O(exp(table size)) worst-case behaviour (without sleeping,
at that, so if you manage to self-LART that way, you are SOL for a long
time)...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/netfilter/ip6_tables.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 4eec4b3988b8..99502c5da4c4 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -413,6 +413,7 @@ mark_source_chains(struct xt_table_info *newinfo, unsigned int pos = newinfo->hook_entry[hook]; struct ip6t_entry *e = (struct ip6t_entry *)(entry0 + pos); + int visited = e->comefrom & (1 << hook); if (!(valid_hooks & (1 << hook))) continue; @@ -433,11 +434,11 @@ mark_source_chains(struct xt_table_info *newinfo, |= ((1 << hook) | (1 << NF_IP6_NUMHOOKS)); /* Unconditional return/END. */ - if (e->target_offset == sizeof(struct ip6t_entry) + if ((e->target_offset == sizeof(struct ip6t_entry) && (strcmp(t->target.u.user.name, IP6T_STANDARD_TARGET) == 0) && t->verdict < 0 - && unconditional(&e->ipv6)) { + && unconditional(&e->ipv6)) || visited) { unsigned int oldpos, size; if (t->verdict < -NF_MAX_VERDICT - 1) { |