user/sven/linux.git/lib/Kconfig.debug, branch v4.4.265

kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K

2019-10-07T19:01:03Z

[ 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: add cryptographically secure PRF

2019-09-06T08:18:12Z

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 4.4 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": - Adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Sasha Levin

kasan: rework Kconfig settings

2018-02-25T10:03:52Z

commit e7c52b84fb18f08ce49b6067ae6285aca79084a8 upstream. We get a lot of very large stack frames using gcc-7.0.1 with the default -fsanitize-address-use-after-scope --param asan-stack=1 options, which can easily cause an overflow of the kernel stack, e.g. drivers/gpu/drm/i915/gvt/handlers.c:2434:1: warning: the frame size of 46176 bytes is larger than 3072 bytes drivers/net/wireless/ralink/rt2x00/rt2800lib.c:5650:1: warning: the frame size of 23632 bytes is larger than 3072 bytes lib/atomic64_test.c:250:1: warning: the frame size of 11200 bytes is larger than 3072 bytes drivers/gpu/drm/i915/gvt/handlers.c:2621:1: warning: the frame size of 9208 bytes is larger than 3072 bytes drivers/media/dvb-frontends/stv090x.c:3431:1: warning: the frame size of 6816 bytes is larger than 3072 bytes fs/fscache/stats.c:287:1: warning: the frame size of 6536 bytes is larger than 3072 bytes To reduce this risk, -fsanitize-address-use-after-scope is now split out into a separate CONFIG_KASAN_EXTRA Kconfig option, leading to stack frames that are smaller than 2 kilobytes most of the time on x86_64. An earlier version of this patch also prevented combining KASAN_EXTRA with KASAN_INLINE, but that is no longer necessary with gcc-7.0.1. All patches to get the frame size below 2048 bytes with CONFIG_KASAN=y and CONFIG_KASAN_EXTRA=n have been merged by maintainers now, so we can bring back that default now. KASAN_EXTRA=y still causes lots of warnings but now defaults to !COMPILE_TEST to disable it in allmodconfig, and it remains disabled in all other defconfigs since it is a new option. I arbitrarily raise the warning limit for KASAN_EXTRA to 3072 to reduce the noise, but an allmodconfig kernel still has around 50 warnings on gcc-7. I experimented a bit more with smaller stack frames and have another follow-up series that reduces the warning limit for 64-bit architectures to 1280 bytes (without CONFIG_KASAN). With earlier versions of this patch series, I also had patches to address the warnings we get with KASAN and/or KASAN_EXTRA, using a "noinline_if_stackbloat" annotation. That annotation now got replaced with a gcc-8 bugfix (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715) and a workaround for older compilers, which means that KASAN_EXTRA is now just as bad as before and will lead to an instant stack overflow in a few extreme cases. This reverts parts of commit 3f181b4d8652 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with KASAN=y"). Two patches in linux-next should be merged first to avoid introducing warnings in an allmodconfig build: 3cd890dbe2a4 ("media: dvb-frontends: fix i2c access helpers for KASAN") 16c3ada89cff ("media: r820t: fix r820t_write_reg for KASAN") Do we really need to backport this? I think we do: without this patch, enabling KASAN will lead to unavoidable kernel stack overflow in certain device drivers when built with gcc-7 or higher on linux-4.10+ or any version that contains a backport of commit c5caf21ab0cf8. Most people are probably still on older compilers, but it will get worse over time as they upgrade their distros. The warnings we get on kernels older than this should all be for code that uses dangerously large stack frames, though most of them do not cause an actual stack overflow by themselves.The asan-stack option was added in linux-4.0, and commit 3f181b4d8652 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with KASAN=y") effectively turned off the warning for allmodconfig kernels, so I would like to see this fix backported to any kernels later than 4.0. I have done dozens of fixes for individual functions with stack frames larger than 2048 bytes with asan-stack, and I plan to make sure that all those fixes make it into the stable kernels as well (most are already there). Part of the complication here is that asan-stack (from 4.0) was originally assumed to always require much larger stacks, but that turned out to be a combination of multiple gcc bugs that we have now worked around and fixed, but sanitize-address-use-after-scope (from v4.10) has a much higher inherent stack usage and also suffers from at least three other problems that we have analyzed but not yet fixed upstream, each of them makes the stack usage more severe than it should be. Link: http://lkml.kernel.org/r/20171221134744.2295529-1-arnd@arndb.de Signed-off-by: Arnd Bergmann Acked-by: Andrey Ryabinin Cc: Mauro Carvalho Chehab Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrey Konovalov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [arnd: rebase to v4.4; only re-enable warning] Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

lib/Kconfig.debug: fix frv build failure

2017-08-11T16:08:59Z

[ Upstream commit da0510c47519fe0999cffe316e1d370e29f952be ] The build of frv allmodconfig was failing with the errors like: /tmp/cc0JSPc3.s: Assembler messages: /tmp/cc0JSPc3.s:1839: Error: symbol `.LSLT0' is already defined /tmp/cc0JSPc3.s:1842: Error: symbol `.LASLTP0' is already defined /tmp/cc0JSPc3.s:1969: Error: symbol `.LELTP0' is already defined /tmp/cc0JSPc3.s:1970: Error: symbol `.LELT0' is already defined Commit 866ced950bcd ("kbuild: Support split debug info v4") introduced splitting the debug info and keeping that in a separate file. Somehow, the frv-linux gcc did not like that and I am guessing that instead of splitting it started copying. The first report about this is at: https://lists.01.org/pipermail/kbuild-all/2015-July/010527.html. I will try and see if this can work with frv and if still fails I will open a bug report with gcc. But meanwhile this is the easiest option to solve build failure of frv. Fixes: 866ced950bcd ("kbuild: Support split debug info v4") Link: http://lkml.kernel.org/r/1482062348-5352-1-git-send-email-sudipm.mukherjee@gmail.com Signed-off-by: Sudip Mukherjee Reported-by: Fengguang Wu Cc: Andi Kleen Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-11-09T23:53:39Z

Pull module updates from Rusty Russell: "Nothing exciting, minor tweaks and cleanups" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: scripts: [modpost] add new sections to white list modpost: Add flag -E for making section mismatches fatal params: don't ignore the rest of cmdline if parse_one() fails modpost: abort if a module symbol is too long

test_printf: test printf family at runtime

2015-11-07T01:50:42Z

This adds a simple module for testing the kernel's printf facilities. Previously, some %p extensions have caused a wrong return value in case the entire output didn't fit and/or been unusable in kasprintf(). This should help catch such issues. Also, it should help ensure that changes to the formatting algorithms don't break anything. I'm not sure if we have a struct dentry or struct file lying around at boot time or if we can fake one, but most %p extensions should be testable, as should the ordinary number and string formatting. The nature of vararg functions means we can't use a more conventional table-driven approach. For now, this is mostly a skeleton; contributions are very welcome. Some tests are/will be slightly annoying to write, since the expected output depends on stuff like CONFIG_*, sizeof(long), runtime values etc. Signed-off-by: Rasmus Villemoes Reviewed-by: Kees Cook Cc: Andy Shevchenko Cc: Martin Kletzander Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/Kconfig.debug: disable -Wframe-larger-than warnings with KASAN=y

2015-10-23T08:55:10Z

When the kernel compiled with KASAN=y, GCC adds redzones for each variable on stack. This enlarges function's stack frame and causes: 'warning: the frame size of X bytes is larger than Y bytes' The worst case I've seen for now is following: ../net/wireless/nl80211.c: In function `nl80211_send_wiphy': ../net/wireless/nl80211.c:1731:1: warning: the frame size of 5448 bytes is larger than 2048 bytes [-Wframe-larger-than=] That kind of warning becomes useless with KASAN=y. It doesn't necessarily indicate that there is some problem in the code, thus we should turn it off. (The KASAN=y stack size in increased from 16k to 32k for this reason) Signed-off-by: Andrey Ryabinin Reported-by: Fengguang Wu Acked-by: Abylay Ospan Cc: Andi Kleen Cc: Ingo Molnar Cc: Mauro Carvalho Chehab Cc: Kozlov Sergey Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

modpost: Add flag -E for making section mismatches fatal

2015-10-06T00:16:21Z

The section mismatch warning can be easy to miss during the kernel build process. Allow it to be marked as fatal to be easily caught and prevent bugs from slipping in. Setting CONFIG_SECTION_MISMATCH_WARN_ONLY=y causes these warnings to be non-fatal, since there are a number of section mismatches when using allmodconfig on some architectures, and we do not want to break these builds by default. Signed-off-by: Nicolas Boichat Change-Id: Ic346706e3297c9f0d790e3552aa94e5cff9897a6 Signed-off-by: Rusty Russell

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-09-03T22:46:07Z

Pull locking and atomic updates from Ingo Molnar: "Main changes in this cycle are: - Extend atomic primitives with coherent logic op primitives (atomic_{or,and,xor}()) and deprecate the old partial APIs (atomic_{set,clear}_mask()) The old ops were incoherent with incompatible signatures across architectures and with incomplete support. Now every architecture supports the primitives consistently (by Peter Zijlstra) - Generic support for 'relaxed atomics': - _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return() - atomic_read_acquire() - atomic_set_release() This came out of porting qwrlock code to arm64 (by Will Deacon) - Clean up the fragile static_key APIs that were causing repeat bugs, by introducing a new one: DEFINE_STATIC_KEY_TRUE(name); DEFINE_STATIC_KEY_FALSE(name); which define a key of different types with an initial true/false value. Then allow: static_branch_likely() static_branch_unlikely() to take a key of either type and emit the right instruction for the case. To be able to know the 'type' of the static key we encode it in the jump entry (by Peter Zijlstra) - Static key self-tests (by Jason Baron) - qrwlock optimizations (by Waiman Long) - small futex enhancements (by Davidlohr Bueso) - ... and misc other changes" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits) jump_label/x86: Work around asm build bug on older/backported GCCs locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics locking/qrwlock: Implement queue_write_unlock() using smp_store_release() locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t' locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic locking/static_keys: Make verify_keys() static jump label, locking/static_keys: Update docs locking/static_keys: Provide a selftest jump_label: Provide a self-test s390/uaccess, locking/static_keys: employ static_branch_likely() x86, tsc, locking/static_keys: Employ static_branch_likely() locking/static_keys: Add selftest locking/static_keys: Add a new static_key interface locking/static_keys: Rework update logic locking/static_keys: Add static_key_{en,dis}able() helpers ...

Merge branches 'fixes.2015.07.22a' and 'initexp.2015.08.04a' into HEAD

2015-08-04T15:40:58Z

fixes.2015.07.22a: Miscellaneous fixes. initexp.2015.08.04a: Initialization and expedited updates. (Single branch due to conflicts.)