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authorFlorian Westphal <fw@strlen.de>2016-04-01 14:17:27 +0200
committerSasha Levin <sasha.levin@oracle.com>2016-07-12 08:48:32 -0400
commitc1380ecb022aacfc852426e182aa285420d18c9f (patch)
tree70772941d3b08c96bcfa6be057f4fd523930169e
parent7ef13f496d3bc0db5ce42451a6036c504cf6a7d6 (diff)
downloadlinux-linaro-stable-c1380ecb022aacfc852426e182aa285420d18c9f.tar.gz
netfilter: x_tables: check standard target size too
[ Upstream commit 7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44 ] We have targets and standard targets -- the latter carries a verdict. The ip/ip6tables validation functions will access t->verdict for the standard targets to fetch the jump offset or verdict for chainloop detection, but this happens before the targets get checked/validated. Thus we also need to check for verdict presence here, else t->verdict can point right after a blob. Spotted with UBSAN while testing malformed blobs. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
-rw-r--r--net/netfilter/x_tables.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 242245330ec3..a2bf3c58a1f1 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -542,6 +542,13 @@ int xt_compat_match_to_user(const struct xt_entry_match *m,
}
EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
+/* non-compat version may have padding after verdict */
+struct compat_xt_standard_target {
+ struct compat_xt_entry_target t;
+ compat_uint_t verdict;
+};
+
+/* see xt_check_entry_offsets */
int xt_compat_check_entry_offsets(const void *base,
unsigned int target_offset,
unsigned int next_offset)
@@ -559,6 +566,10 @@ int xt_compat_check_entry_offsets(const void *base,
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
+ if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
+ target_offset + sizeof(struct compat_xt_standard_target) != next_offset)
+ return -EINVAL;
+
return 0;
}
EXPORT_SYMBOL(xt_compat_check_entry_offsets);
@@ -598,6 +609,10 @@ int xt_check_entry_offsets(const void *base,
if (target_offset + t->u.target_size > next_offset)
return -EINVAL;
+ if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 &&
+ target_offset + sizeof(struct xt_standard_target) != next_offset)
+ return -EINVAL;
+
return 0;
}
EXPORT_SYMBOL(xt_check_entry_offsets);