| From 7b7eba0f3515fca3296b8881d583f7c1042f5226 Mon Sep 17 00:00:00 2001 |
| From: Florian Westphal <fw@strlen.de> |
| Date: Wed, 1 Jun 2016 02:04:44 +0200 |
| Subject: netfilter: x_tables: don't reject valid target size on some architectures |
| |
| From: Florian Westphal <fw@strlen.de> |
| |
| commit 7b7eba0f3515fca3296b8881d583f7c1042f5226 upstream. |
| |
| Quoting John Stultz: |
| In updating a 32bit arm device from 4.6 to Linus' current HEAD, I |
| noticed I was having some trouble with networking, and realized that |
| /proc/net/ip_tables_names was suddenly empty. |
| Digging through the registration process, it seems we're catching on the: |
| |
| if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 && |
| target_offset + sizeof(struct xt_standard_target) != next_offset) |
| return -EINVAL; |
| |
| Where next_offset seems to be 4 bytes larger then the |
| offset + standard_target struct size. |
| |
| next_offset needs to be aligned via XT_ALIGN (so we can access all members |
| of ip(6)t_entry struct). |
| |
| This problem didn't show up on i686 as it only needs 4-byte alignment for |
| u64, but iptables userspace on other 32bit arches does insert extra padding. |
| |
| Reported-by: John Stultz <john.stultz@linaro.org> |
| Tested-by: John Stultz <john.stultz@linaro.org> |
| Fixes: 7ed2abddd20cf ("netfilter: x_tables: check standard target size too") |
| Signed-off-by: Florian Westphal <fw@strlen.de> |
| Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| net/netfilter/x_tables.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/net/netfilter/x_tables.c |
| +++ b/net/netfilter/x_tables.c |
| @@ -608,7 +608,7 @@ int xt_compat_check_entry_offsets(const |
| return -EINVAL; |
| |
| if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 && |
| - target_offset + sizeof(struct compat_xt_standard_target) != next_offset) |
| + COMPAT_XT_ALIGN(target_offset + sizeof(struct compat_xt_standard_target)) != next_offset) |
| return -EINVAL; |
| |
| /* compat_xt_entry match has less strict aligment requirements, |
| @@ -690,7 +690,7 @@ int xt_check_entry_offsets(const void *b |
| return -EINVAL; |
| |
| if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0 && |
| - target_offset + sizeof(struct xt_standard_target) != next_offset) |
| + XT_ALIGN(target_offset + sizeof(struct xt_standard_target)) != next_offset) |
| return -EINVAL; |
| |
| return xt_check_entry_match(elems, base + target_offset, |