kernel/linux.git/lib, branch v4.9.209

dma-debug: add a schedule point in debug_dma_dump_mappings()

2020-01-04T12:40:44+00:00

[ Upstream commit 9ff6aa027dbb98755f0265695354f2dd07c0d1ce ] debug_dma_dump_mappings() can take a lot of cpu cycles : lpk43:/# time wc -l /sys/kernel/debug/dma-api/dump 163435 /sys/kernel/debug/dma-api/dump real 0m0.463s user 0m0.003s sys 0m0.459s Let's add a cond_resched() to avoid holding cpu for too long. Signed-off-by: Eric Dumazet Cc: Corentin Labbe Cc: Christoph Hellwig Cc: Marek Szyprowski Signed-off-by: Christoph Hellwig Signed-off-by: Sasha Levin

lib: raid6: fix awk build warnings

2019-12-21T09:42:00+00:00

commit 702600eef73033ddd4eafcefcbb6560f3e3a90f7 upstream. Newer versions of awk spit out these fun warnings: awk: ../lib/raid6/unroll.awk:16: warning: regexp escape sequence `\#' is not a known regexp operator As commit 700c1018b86d ("x86/insn: Fix awk regexp warnings") showed, it turns out that there are a number of awk strings that do not need to be escaped and newer versions of awk now warn about this. Fix the string up so that no warning is produced. The exact same kernel module gets created before and after this patch, showing that it wasn't needed. Link: https://lore.kernel.org/r/20191206152600.GA75093@kroah.com Signed-off-by: Greg Kroah-Hartman

lib/genalloc.c: include vmalloc.h

2019-12-05T14:35:05+00:00

[ Upstream commit 35004f2e55807a1a1491db24ab512dd2f770a130 ] Fixes build break on most ARM/ARM64 defconfigs: lib/genalloc.c: In function 'gen_pool_add_virt': lib/genalloc.c:190:10: error: implicit declaration of function 'vzalloc_node'; did you mean 'kzalloc_node'? lib/genalloc.c:190:8: warning: assignment to 'struct gen_pool_chunk *' from 'int' makes pointer from integer without a cast [-Wint-conversion] lib/genalloc.c: In function 'gen_pool_destroy': lib/genalloc.c:254:3: error: implicit declaration of function 'vfree'; did you mean 'kfree'? Fixes: 6862d2fc8185 ('lib/genalloc.c: use vzalloc_node() to allocate the bitmap') Cc: Huang Shijie Cc: Andrew Morton Cc: Alexey Skidanov Signed-off-by: Olof Johansson Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

lib/genalloc.c: use vzalloc_node() to allocate the bitmap

2019-12-05T14:35:03+00:00

[ Upstream commit 6862d2fc81859f88c1f3f660886427893f2b4f3f ] Some devices may have big memory on chip, such as over 1G. In some cases, the nbytes maybe bigger then 4M which is the bounday of the memory buddy system (4K default). So use vzalloc_node() to allocate the bitmap. Also use vfree to free it. Link: http://lkml.kernel.org/r/20181225015701.6289-1-sjhuang@iluvatar.ai Signed-off-by: Huang Shijie Reviewed-by: Andrew Morton Cc: Alexey Skidanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

lib/genalloc.c: fix allocation of aligned buffer from non-aligned chunk

2019-12-05T14:35:02+00:00

[ Upstream commit 52fbf1134d479234d7e64ba9dcbaea23405f229e ] gen_pool_alloc_algo() uses different allocation functions implementing different allocation algorithms. With gen_pool_first_fit_align() allocation function, the returned address should be aligned on the requested boundary. If chunk start address isn't aligned on the requested boundary, the returned address isn't aligned too. The only way to get properly aligned address is to initialize the pool with chunks aligned on the requested boundary. If want to have an ability to allocate buffers aligned on different boundaries (for example, 4K, 1MB, ...), the chunk start address should be aligned on the max possible alignment. This happens because gen_pool_first_fit_align() looks for properly aligned memory block without taking into account the chunk start address alignment. To fix this, we provide chunk start address to gen_pool_first_fit_align() and change its implementation such that it starts looking for properly aligned block with appropriate offset (exactly as is done in CMA). Link: https://lkml.kernel.org/lkml/a170cf65-6884-3592-1de9-4c235888cc8a@intel.com Link: http://lkml.kernel.org/r/1541690953-4623-1-git-send-email-alexey.skidanov@intel.com Signed-off-by: Alexey Skidanov Reviewed-by: Andrew Morton Cc: Logan Gunthorpe Cc: Daniel Mentz Cc: Mathieu Desnoyers Cc: Laura Abbott Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

dump_stack: avoid the livelock of the dump_lock

2019-11-12T18:15:43+00:00

commit 5cbf2fff3bba8d3c6a4d47c1754de1cf57e2b01f upstream. In the current code, we use the atomic_cmpxchg() to serialize the output of the dump_stack(), but this implementation suffers the thundering herd problem. We have observed such kind of livelock on a Marvell cn96xx board(24 cpus) when heavily using the dump_stack() in a kprobe handler. Actually we can let the competitors to wait for the releasing of the lock before jumping to atomic_cmpxchg(). This will definitely mitigate the thundering herd problem. Thanks Linus for the suggestion. [akpm@linux-foundation.org: fix comment] Link: http://lkml.kernel.org/r/20191030031637.6025-1-haokexin@gmail.com Fixes: b58d977432c8 ("dump_stack: serialize the output from dump_stack()") Signed-off-by: Kevin Hao Suggested-by: Linus Torvalds Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K

2019-10-07T16:53:19+00:00

[ Upstream commit b751c52bb587ae66f773b15204ef7a147467f4c7 ] The current default value (400) is too low on many systems (e.g. some ARM64 platform takes up 1000+ entries). syzbot uses 16000 as default value, and has proved to be enough on beefy configurations, so let's pick that value. This consumes more RAM on boot (each entry is 160 bytes, so in total ~2.5MB of RAM), but the memory would later be freed (early_log is __initdata). Link: http://lkml.kernel.org/r/20190730154027.101525-1-drinkcat@chromium.org Signed-off-by: Nicolas Boichat Suggested-by: Dmitry Vyukov Acked-by: Catalin Marinas Acked-by: Dmitry Vyukov Cc: Masahiro Yamada Cc: Kees Cook Cc: Petr Mladek Cc: Thomas Gleixner Cc: Tetsuo Handa Cc: Joe Lawrence Cc: Uladzislau Rezki Cc: Andy Shevchenko Cc: Stephen Rothwell Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

siphash: implement HalfSipHash1-3 for hash tables

2019-08-25T08:51:42+00:00

commit 1ae2324f732c9c4e2fa4ebd885fa1001b70d52e1 upstream. HalfSipHash, or hsiphash, is a shortened version of SipHash, which generates 32-bit outputs using a weaker 64-bit key. It has *much* lower security margins, and shouldn't be used for anything too sensitive, but it could be used as a hashtable key function replacement, if the output is never exposed, and if the security requirement is not too high. The goal is to make this something that performance-critical jhash users would be willing to use. On 64-bit machines, HalfSipHash1-3 is slower than SipHash1-3, so we alias SipHash1-3 to HalfSipHash1-3 on those systems. 64-bit x86_64: [ 0.509409] test_siphash: SipHash2-4 cycles: 4049181 [ 0.510650] test_siphash: SipHash1-3 cycles: 2512884 [ 0.512205] test_siphash: HalfSipHash1-3 cycles: 3429920 [ 0.512904] test_siphash: JenkinsHash cycles: 978267 So, we map hsiphash() -> SipHash1-3 32-bit x86: [ 0.509868] test_siphash: SipHash2-4 cycles: 14812892 [ 0.513601] test_siphash: SipHash1-3 cycles: 9510710 [ 0.515263] test_siphash: HalfSipHash1-3 cycles: 3856157 [ 0.515952] test_siphash: JenkinsHash cycles: 1148567 So, we map hsiphash() -> HalfSipHash1-3 hsiphash() is roughly 3 times slower than jhash(), but comes with a considerable security improvement. Signed-off-by: Jason A. Donenfeld Reviewed-by: Jean-Philippe Aumasson Signed-off-by: David S. Miller [bwh: Backported to 4.9 to avoid regression for WireGuard with only half the siphash API present] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

siphash: add cryptographically secure PRF

2019-08-25T08:51:42+00:00

commit 2c956a60778cbb6a27e0c7a8a52a91378c90e1d1 upstream. SipHash is a 64-bit keyed hash function that is actually a cryptographically secure PRF, like HMAC. Except SipHash is super fast, and is meant to be used as a hashtable keyed lookup function, or as a general PRF for short input use cases, such as sequence numbers or RNG chaining. For the first usage: There are a variety of attacks known as "hashtable poisoning" in which an attacker forms some data such that the hash of that data will be the same, and then preceeds to fill up all entries of a hashbucket. This is a realistic and well-known denial-of-service vector. Currently hashtables use jhash, which is fast but not secure, and some kind of rotating key scheme (or none at all, which isn't good). SipHash is meant as a replacement for jhash in these cases. There are a modicum of places in the kernel that are vulnerable to hashtable poisoning attacks, either via userspace vectors or network vectors, and there's not a reliable mechanism inside the kernel at the moment to fix it. The first step toward fixing these issues is actually getting a secure primitive into the kernel for developers to use. Then we can, bit by bit, port things over to it as deemed appropriate. While SipHash is extremely fast for a cryptographically secure function, it is likely a bit slower than the insecure jhash, and so replacements will be evaluated on a case-by-case basis based on whether or not the difference in speed is negligible and whether or not the current jhash usage poses a real security risk. For the second usage: A few places in the kernel are using MD5 or SHA1 for creating secure sequence numbers, syn cookies, port numbers, or fast random numbers. SipHash is a faster and more fitting, and more secure replacement for MD5 in those situations. Replacing MD5 and SHA1 with SipHash for these uses is obvious and straight-forward, and so is submitted along with this patch series. There shouldn't be much of a debate over its efficacy. Dozens of languages are already using this internally for their hash tables and PRFs. Some of the BSDs already use this in their kernels. SipHash is a widely known high-speed solution to a widely known set of problems, and it's time we catch-up. Signed-off-by: Jason A. Donenfeld Reviewed-by: Jean-Philippe Aumasson Cc: Linus Torvalds Cc: Eric Biggers Cc: David Laight Cc: Eric Dumazet Signed-off-by: David S. Miller [bwh: Backported to 4.9 as dependency of commits df453700e8d8 "inet: switch IP ID generator to siphash" and 3c79107631db "netfilter: ctnetlink: don't use conntrack/expect object addresses as id"] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

lib/strscpy: Shut up KASAN false-positives in strscpy()

2019-08-04T07:33:32+00:00

[ Upstream commit 1a3241ff10d038ecd096d03380327f2a0b5840a6 ] strscpy() performs the word-at-a-time optimistic reads. So it may may access the memory past the end of the object, which is perfectly fine since strscpy() doesn't use that (past-the-end) data and makes sure the optimistic read won't cross a page boundary. Use new read_word_at_a_time() to shut up the KASAN. Note that this potentially could hide some bugs. In example bellow, stscpy() will copy more than we should (1-3 extra uninitialized bytes): char dst[8]; char *src; src = kmalloc(5, GFP_KERNEL); memset(src, 0xff, 5); strscpy(dst, src, 8); Signed-off-by: Andrey Ryabinin Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin