diff options
| author | Florian Westphal <fw@strlen.de> | 2016-07-14 17:51:26 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-07-18 21:35:23 +0200 |
| commit | f4dc77713f8016d2e8a3295e1c9c53a21f296def (patch) | |
| tree | 62b548c4d29c9a509964a356469c20d41d2e17a7 /include | |
| parent | 3101e0fc1f6e809d38fbb5845c6c5eb0eefeda07 (diff) | |
netfilter: x_tables: speed up jump target validation
The dummy ruleset I used to test the original validation change was broken,
most rules were unreachable and were not tested by mark_source_chains().
In some cases rulesets that used to load in a few seconds now require
several minutes.
sample ruleset that shows the behaviour:
echo "*filter"
for i in $(seq 0 100000);do
printf ":chain_%06x - [0:0]\n" $i
done
for i in $(seq 0 100000);do
printf -- "-A INPUT -j chain_%06x\n" $i
printf -- "-A INPUT -j chain_%06x\n" $i
printf -- "-A INPUT -j chain_%06x\n" $i
done
echo COMMIT
[ pipe result into iptables-restore ]
This ruleset will be about 74mbyte in size, with ~500k searches
though all 500k[1] rule entries. iptables-restore will take forever
(gave up after 10 minutes)
Instead of always searching the entire blob for a match, fill an
array with the start offsets of every single ipt_entry struct,
then do a binary search to check if the jump target is present or not.
After this change ruleset restore times get again close to what one
gets when reverting 36472341017529e (~3 seconds on my workstation).
[1] every user-defined rule gets an implicit RETURN, so we get
300k jumps + 100k userchains + 100k returns -> 500k rule entries
Fixes: 36472341017529e ("netfilter: x_tables: validate targets of jumps")
Reported-by: Jeff Wu <wujiafu@gmail.com>
Tested-by: Jeff Wu <wujiafu@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/netfilter/x_tables.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h index e94e81ab2b58..2ad1a2b289b5 100644 --- a/include/linux/netfilter/x_tables.h +++ b/include/linux/netfilter/x_tables.h @@ -250,6 +250,10 @@ int xt_check_entry_offsets(const void *base, const char *elems, unsigned int target_offset, unsigned int next_offset); +unsigned int *xt_alloc_entry_offsets(unsigned int size); +bool xt_find_jump_offset(const unsigned int *offsets, + unsigned int target, unsigned int size); + int xt_check_match(struct xt_mtchk_param *, unsigned int size, u_int8_t proto, bool inv_proto); int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto, |