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  1. 20 Nov, 2016 33 commits
  3. 20 Oct, 2016 2 commits
    • Ben Hutchings's avatar
      Linux 3.16.38 · fa1703ff
      Ben Hutchings authored
      fa1703ff
    • Linus Torvalds's avatar
      mm: remove gup_flags FOLL_WRITE games from __get_user_pages() · 2649c26f
      Linus Torvalds authored 
      commit 19be0eaf upstream.

This is an ancient bug that was actually attempted to be fixed once
(badly) by me eleven years ago in commit 4ceb5db9 ("Fix
get_user_pages() race for write access") but that was then undone due to
problems on s390 by commit f33ea7f4 ("fix get_user_pages bug").

In the meantime, the s390 situation has long been fixed, and we can now
fix it by checking the pte_dirty() bit properly (and do it better).  The
s390 dirty bit was implemented in abf09bed ("s390/mm: implement
software dirty bits") which made it into v3.9.  Earlier kernels will
have to look at the page state itself.

Also, the VM has become more scalable, and what used a purely
theoretical race back then has become easier to trigger.

To fix it, we introduce a new internal FOLL_COW flag to mark the "yes,
we already did a COW" rather than play racy games with FOLL_WRITE that
is very fundamental, and then use the pte dirty flag to validate that
the FOLL_COW flag is still valid.
Reported-and-tested-by: default avatarPhil "not Paul" Oester <kernel@linuxace.com>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[carnil: backport to 3.16, adjust context]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      2649c26f
  5. 22 Aug, 2016 5 commits
    • Ben Hutchings's avatar
      Linux 3.16.37 · c8b431a1
      Ben Hutchings authored
      c8b431a1
    • Bernhard Thaler's avatar
      Revert "netfilter: ensure number of counters is >0 in do_replace()" · 023c4816
      Bernhard Thaler authored 
      commit d26e2c9f upstream.

This partially reverts commit 1086bbe9 ("netfilter: ensure number of
counters is >0 in do_replace()") in net/bridge/netfilter/ebtables.c.

Setting rules with ebtables does not work any more with 1086bbe9 place.

There is an error message and no rules set in the end.

e.g.

~# ebtables -t nat -A POSTROUTING --src 12:34:56:78:9a:bc -j DROP
Unable to update the kernel. Two possible causes:
1. Multiple ebtables programs were executing simultaneously. The ebtables
   userspace tool doesn't by default support multiple ebtables programs
running

Reverting the ebtables part of 1086bbe9 makes this work again.
Signed-off-by: default avatarBernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      023c4816
    • Dave Jones's avatar
      netfilter: ensure number of counters is >0 in do_replace() · 30efc09c
      Dave Jones authored 
      commit 1086bbe9 upstream.

After improving setsockopt() coverage in trinity, I started triggering
vmalloc failures pretty reliably from this code path:

warn_alloc_failed+0xe9/0x140
__vmalloc_node_range+0x1be/0x270
vzalloc+0x4b/0x50
__do_replace+0x52/0x260 [ip_tables]
do_ipt_set_ctl+0x15d/0x1d0 [ip_tables]
nf_setsockopt+0x65/0x90
ip_setsockopt+0x61/0xa0
raw_setsockopt+0x16/0x60
sock_common_setsockopt+0x14/0x20
SyS_setsockopt+0x71/0xd0

It turns out we don't validate that the num_counters field in the
struct we pass in from userspace is initialized.

The same problem also exists in ebtables, arptables, ipv6, and the
compat variants.
Signed-off-by: default avatarDave Jones <davej@codemonkey.org.uk>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      30efc09c
    • Florian Westphal's avatar
      netfilter: x_tables: introduce and use xt_copy_counters_from_user · 019475d6
      Florian Westphal authored 
      commit d7591f0c upstream.

The three variants use same copy&pasted code, condense this into a
helper and use that.

Make sure info.name is 0-terminated.
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      019475d6
    • Florian Westphal's avatar
      netfilter: x_tables: do compat validation via translate_table · 49b9f189
      Florian Westphal authored 
      commit 09d96860 upstream.

This looks like refactoring, but its also a bug fix.

Problem is that the compat path (32bit iptables, 64bit kernel) lacks a few
sanity tests that are done in the normal path.

For example, we do not check for underflows and the base chain policies.

While its possible to also add such checks to the compat path, its more
copy&pastry, for instance we cannot reuse check_underflow() helper as
e->target_offset differs in the compat case.

Other problem is that it makes auditing for validation errors harder; two
places need to be checked and kept in sync.

At a high level 32 bit compat works like this:
1- initial pass over blob:
   validate match/entry offsets, bounds checking
   lookup all matches and targets
   do bookkeeping wrt. size delta of 32/64bit structures
   assign match/target.u.kernel pointer (points at kernel
   implementation, needed to access ->compatsize etc.)

2- allocate memory according to the total bookkeeping size to
   contain the translated ruleset

3- second pass over original blob:
   for each entry, copy the 32bit representation to the newly allocated
   memory.  This also does any special match translations (e.g.
   adjust 32bit to 64bit longs, etc).

4- check if ruleset is free of loops (chase all jumps)

5-first pass over translated blob:
   call the checkentry function of all matches and targets.

The alternative implemented by this patch is to drop steps 3&4 from the
compat process, the translation is changed into an intermediate step
rather than a full 1:1 translate_table replacement.

In the 2nd pass (step #3), change the 64bit ruleset back to a kernel
representation, i.e. put() the kernel pointer and restore ->u.user.name .

This gets us a 64bit ruleset that is in the format generated by a 64bit
iptables userspace -- we can then use translate_table() to get the
'native' sanity checks.

This has two drawbacks:

1. we re-validate all the match and target entry structure sizes even
though compat translation is supposed to never generate bogus offsets.
2. we put and then re-lookup each match and target.

THe upside is that we get all sanity tests and ruleset validations
provided by the normal path and can remove some duplicated compat code.

iptables-restore time of autogenerated ruleset with 300k chains of form
-A CHAIN0001 -m limit --limit 1/s -j CHAIN0002
-A CHAIN0002 -m limit --limit 1/s -j CHAIN0003

shows no noticeable differences in restore times:
old:   0m30.796s
new:   0m31.521s
64bit: 0m25.674s
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
[bwh: Backported to 3.16: deleted code is a little different]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      49b9f189
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