Dmitry Mishin wrote:
> On Saturday 02 June 2007 16:54, Patrick McHardy wrote:
>
>>Here it is, could you please test whether it fixes the crash by
>>backing out the hashlimit compat patch and triggering the size
>>error again? Thanks.
>
> Patrick,
> it looks like translate_compat_table() should be fixed also.
You're right, thanks for catching this. This patch should be
better.
[NETFILTER]: ip_tables: fix compat related crash
check_compat_entry_size_and_hooks iterates over the matches and calls
compat_check_calc_match, which loads the match and calculates the
compat offsets, but unlike the non-compat version, doesn't call
->checkentry yet. On error however it calls cleanup_matches, which in
turn calls ->destroy, which can result in crashes if the destroy
function (validly) expects to only get called after the checkentry
function.
Add a compat_release_match function that only drops the module reference
on error and rename compat_check_calc_match to compat_find_calc_match to
reflect the fact that it doesn't call the checkentry function.
Reported by Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
commit b2b15a77343e2baadee22a5e64f691732874b10b
tree 7d82cf0a9fd3cf77933205a7a1834e958293e293
parent e7d815ef75f70dcdf55001f1f88ae7ae8827a7ba
author Patrick McHardy <kaber@xxxxxxxxx> Sun, 03 Jun 2007 18:57:04 +0200
committer Patrick McHardy <kaber@xxxxxxxxx> Sun, 03 Jun 2007 18:57:04 +0200
net/ipv4/netfilter/ip_tables.c | 41 ++++++++++++++++++++++++++++++++--------
1 files changed, 33 insertions(+), 8 deletions(-)
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index e3f83bf..0a35639 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1425,7 +1425,7 @@ out:
}
static inline int
-compat_check_calc_match(struct ipt_entry_match *m,
+compat_find_calc_match(struct ipt_entry_match *m,
const char *name,
const struct ipt_ip *ip,
unsigned int hookmask,
@@ -1449,6 +1449,31 @@ compat_check_calc_match(struct ipt_entry_match *m,
}
static inline int
+compat_release_match(struct ipt_entry_match *m, unsigned int *i)
+{
+ if (i && (*i)-- == 0)
+ return 1;
+
+ module_put(m->u.kernel.match->me);
+ return 0;
+}
+
+static inline int
+compat_release_entry(struct ipt_entry *e, unsigned int *i)
+{
+ struct ipt_entry_target *t;
+
+ if (i && (*i)-- == 0)
+ return 1;
+
+ /* Cleanup all matches */
+ IPT_MATCH_ITERATE(e, compat_release_match, NULL);
+ t = ipt_get_target(e);
+ module_put(t->u.kernel.target->me);
+ return 0;
+}
+
+static inline int
check_compat_entry_size_and_hooks(struct ipt_entry *e,
struct xt_table_info *newinfo,
unsigned int *size,
@@ -1485,10 +1510,10 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
off = 0;
entry_offset = (void *)e - (void *)base;
j = 0;
- ret = IPT_MATCH_ITERATE(e, compat_check_calc_match, name, &e->ip,
+ ret = IPT_MATCH_ITERATE(e, compat_find_calc_match, name, &e->ip,
e->comefrom, &off, &j);
if (ret != 0)
- goto cleanup_matches;
+ goto release_matches;
t = ipt_get_target(e);
target = try_then_request_module(xt_find_target(AF_INET,
@@ -1499,7 +1524,7 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
t->u.user.name);
ret = target ? PTR_ERR(target) : -ENOENT;
- goto cleanup_matches;
+ goto release_matches;
}
t->u.kernel.target = target;
@@ -1526,8 +1551,8 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
out:
module_put(t->u.kernel.target->me);
-cleanup_matches:
- IPT_MATCH_ITERATE(e, cleanup_match, &j);
+release_matches:
+ IPT_MATCH_ITERATE(e, compat_release_match, &j);
return ret;
}
@@ -1690,13 +1715,13 @@ translate_compat_table(const char *name,
free_newinfo:
xt_free_table_info(newinfo);
-out:
IPT_ENTRY_ITERATE(entry0, total_size, cleanup_entry, &j);
return ret;
out_unlock:
compat_flush_offsets();
xt_compat_unlock(AF_INET);
- goto out;
+ IPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
+ return ret;
}
static int
