diff options
author | Florian Westphal <fw@strlen.de> | 2016-04-01 14:17:27 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2016-04-14 00:30:37 +0200 |
commit | 7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44 (patch) | |
tree | 28bbf09d58ac4eb90e1912e6f16d0bc7809516f7 /net/netfilter/x_tables.c | |
parent | fc1221b3a163d1386d1052184202d5dc50d302d1 (diff) | |
download | linux-stable-7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44.tar.gz linux-stable-7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44.tar.bz2 linux-stable-7ed2abddd20cf8f6bd27f65bd218f26fa5bf7f44.zip |
netfilter: x_tables: check standard target size too
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>
Diffstat (limited to 'net/netfilter/x_tables.c')
-rw-r--r-- | net/netfilter/x_tables.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index fa206ceb269f..1cb7a271c024 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -540,6 +540,13 @@ 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) @@ -557,6 +564,10 @@ 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); @@ -596,6 +607,10 @@ 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); |