kernel/linux.git, branch v3.16.38

Linux 3.16.38

2016-10-20T22:41:13+00:00

mm: remove gup_flags FOLL_WRITE games from __get_user_pages()

2016-10-20T22:41:12+00:00

commit 19be0eaffa3ac7d8eb6784ad9bdbc7d67ed8e619 upstream. This is an ancient bug that was actually attempted to be fixed once (badly) by me eleven years ago in commit 4ceb5db9757a ("Fix get_user_pages() race for write access") but that was then undone due to problems on s390 by commit f33ea7f404e5 ("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 abf09bed3cce ("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: Phil "not Paul" Oester Acked-by: Hugh Dickins Reviewed-by: Michal Hocko Cc: Andy Lutomirski Cc: Kees Cook Cc: Oleg Nesterov Cc: Willy Tarreau Cc: Nick Piggin Cc: Greg Thelen Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds [carnil: backport to 3.16, adjust context] Signed-off-by: Ben Hutchings

Linux 3.16.37

2016-08-22T21:38:32+00:00

Revert "netfilter: ensure number of counters is >0 in do_replace()"

2016-08-22T21:38:31+00:00

commit d26e2c9ffa385dd1b646f43c1397ba12af9ed431 upstream. This partially reverts commit 1086bbe97a07 ("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 1086bbe97a07 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 1086bbe97a07 makes this work again. Signed-off-by: Bernhard Thaler Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings

netfilter: ensure number of counters is >0 in do_replace()

2016-08-22T21:38:31+00:00

commit 1086bbe97a074844188c6c988fa0b1a98c3ccbb9 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: Dave Jones Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings

netfilter: x_tables: introduce and use xt_copy_counters_from_user

2016-08-22T21:38:31+00:00

commit d7591f0c41ce3e67600a982bab6989ef0f07b3ce 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: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings

netfilter: x_tables: do compat validation via translate_table

2016-08-22T21:38:31+00:00

commit 09d9686047dbbe1cf4faa558d3ecc4aae2046054 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: Florian Westphal Signed-off-by: Pablo Neira Ayuso [bwh: Backported to 3.16: deleted code is a little different] Signed-off-by: Ben Hutchings

netfilter: x_tables: xt_compat_match_from_user doesn't need a retval

2016-08-22T21:38:31+00:00

commit 0188346f21e6546498c2a0f84888797ad4063fc5 upstream. Always returned 0. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings

netfilter: ip6_tables: simplify translate_compat_table args

2016-08-22T21:38:30+00:00

commit 329a0807124f12fe1c8032f95d8a8eb47047fb0e upstream. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

netfilter: ip_tables: simplify translate_compat_table args

2016-08-22T21:38:30+00:00

commit 7d3f843eed29222254c9feab481f55175a1afcc9 upstream. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings