user/sven/linux.git/lib/Makefile, branch v4.9.262

ubsan: build ubsan.c more conservatively

2020-05-27T14:42:00Z

commit af700eaed0564d5d3963a7a51cb0843629d7fe3d upstream. objtool points out several conditions that it does not like, depending on the combination with other configuration options and compiler variants: stack protector: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0xbf: call to __stack_chk_fail() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0xbe: call to __stack_chk_fail() with UACCESS enabled stackleak plugin: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x4a: call to stackleak_track_stack() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x4a: call to stackleak_track_stack() with UACCESS enabled kasan: lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x25: call to memcpy() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x25: call to memcpy() with UACCESS enabled The stackleak and kasan options just need to be disabled for this file as we do for other files already. For the stack protector, we already attempt to disable it, but this fails on clang because the check is mixed with the gcc specific -fno-conserve-stack option. According to Andrey Ryabinin, that option is not even needed, dropping it here fixes the stackprotector issue. Link: http://lkml.kernel.org/r/20190722125139.1335385-1-arnd@arndb.de Link: https://lore.kernel.org/lkml/20190617123109.667090-1-arnd@arndb.de/t/ Link: https://lore.kernel.org/lkml/20190722091050.2188664-1-arnd@arndb.de/t/ Fixes: d08965a27e84 ("x86/uaccess, ubsan: Fix UBSAN vs. SMAP") Signed-off-by: Arnd Bergmann Reviewed-by: Andrey Ryabinin Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Kees Cook Cc: Matthew Wilcox Cc: Ard Biesheuvel Cc: Andy Shevchenko Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

x86/uaccess, ubsan: Fix UBSAN vs. SMAP

2020-05-27T14:42:00Z

commit d08965a27e84ca090b504844d50c24fc98587b11 upstream. UBSAN can insert extra code in random locations; including AC=1 sections. Typically this code is not safe and needs wrapping. So far, only __ubsan_handle_type_mismatch* have been observed in AC=1 sections and therefore only those are annotated. Signed-off-by: Peter Zijlstra (Intel) Cc: Borislav Petkov Cc: Dmitry Vyukov Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar [stable backport: only take the lib/Makefile change to resolve gcc-10 build issues] Signed-off-by: Greg Kroah-Hartman

siphash: add cryptographically secure PRF

2019-08-25T08:51:42Z

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

kasan: prevent compiler from optimizing away memset in tests

2019-05-08T05:19:07Z

commit 69ca372c100fba99c78ef826a1795aa86e4f01a8 upstream. A compiler can optimize away memset calls by replacing them with mov instructions. There are KASAN tests that specifically test that KASAN correctly handles memset calls so we don't want this optimization to happen. The solution is to add -fno-builtin flag to test_kasan.ko Link: http://lkml.kernel.org/r/105ec9a308b2abedb1a0d1fdced0c22d765e4732.1519924383.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Acked-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Geert Uytterhoeven Cc: Nick Terrell Cc: Chris Mason Cc: Yury Norov Cc: Al Viro Cc: "Luis R . Rodriguez" Cc: Palmer Dabbelt Cc: "Paul E . McKenney" Cc: Jeff Layton Cc: "Jason A . Donenfeld" Cc: Kostya Serebryany Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Andrey Konovalov Signed-off-by: Greg Kroah-Hartman

kcov: do not instrument lib/stackdepot.c

2016-10-11T22:06:32Z

There's no point in collecting coverage from lib/stackdepot.c, as it is not a function of syscall inputs. Disabling kcov instrumentation for that file will reduce the coverage noise level. Link: http://lkml.kernel.org/r/1474640972-104131-1-git-send-email-glider@google.com Signed-off-by: Alexander Potapenko Acked-by: Dmitry Vyukov Cc: Kostya Serebryany Cc: Andrey Konovalov Cc: syzkaller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-4.9/block' of git://git.kernel.dk/linux-block

2016-10-07T21:42:05Z

Pull block layer updates from Jens Axboe: "This is the main pull request for block layer changes in 4.9. As mentioned at the last merge window, I've changed things up and now do just one branch for core block layer changes, and driver changes. This avoids dependencies between the two branches. Outside of this main pull request, there are two topical branches coming as well. This pull request contains: - A set of fixes, and a conversion to blk-mq, of nbd. From Josef. - Set of fixes and updates for lightnvm from Matias, Simon, and Arnd. Followup dependency fix from Geert. - General fixes from Bart, Baoyou, Guoqing, and Linus W. - CFQ async write starvation fix from Glauber. - Add supprot for delayed kick of the requeue list, from Mike. - Pull out the scalable bitmap code from blk-mq-tag.c and make it generally available under the name of sbitmap. Only blk-mq-tag uses it for now, but the blk-mq scheduling bits will use it as well. From Omar. - bdev thaw error progagation from Pierre. - Improve the blk polling statistics, and allow the user to clear them. From Stephen. - Set of minor cleanups from Christoph in block/blk-mq. - Set of cleanups and optimizations from me for block/blk-mq. - Various nvme/nvmet/nvmeof fixes from the various folks" * 'for-4.9/block' of git://git.kernel.dk/linux-block: (54 commits) fs/block_dev.c: return the right error in thaw_bdev() nvme: Pass pointers, not dma addresses, to nvme_get/set_features() nvme/scsi: Remove power management support nvmet: Make dsm number of ranges zero based nvmet: Use direct IO for writes admin-cmd: Added smart-log command support. nvme-fabrics: Add host_traddr options field to host infrastructure nvme-fabrics: revise host transport option descriptions nvme-fabrics: rework nvmf_get_address() for variable options nbd: use BLK_MQ_F_BLOCKING blkcg: Annotate blkg_hint correctly cfq: fix starvation of asynchronous writes blk-mq: add flag for drivers wanting blocking ->queue_rq() blk-mq: remove non-blocking pass in blk_mq_map_request blk-mq: get rid of manual run of queue with __blk_mq_run_hw_queue() block: export bio_free_pages to other modules lightnvm: propagate device_add() error code lightnvm: expose device geometry through sysfs lightnvm: control life of nvm_dev in driver blk-mq: register device instead of disk ...

lib/win_minmax: windowed min or max estimator

2016-09-21T04:22:59Z

This commit introduces a generic library to estimate either the min or max value of a time-varying variable over a recent time window. This is code originally from Kathleen Nichols. The current form of the code is from Van Jacobson. A single struct minmax_sample will track the estimated windowed-max value of the series if you call minmax_running_max() or the estimated windowed-min value of the series if you call minmax_running_min(). Nearly equivalent code is already in place for minimum RTT estimation in the TCP stack. This commit extracts that code and generalizes it to handle both min and max. Moving the code here reduces the footprint and complexity of the TCP code base and makes the filter generally available for other parts of the codebase, including an upcoming TCP congestion control module. This library works well for time series where the measurements are smoothly increasing or decreasing. Signed-off-by: Van Jacobson Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Nandita Dukkipati Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller

blk-mq: abstract tag allocation out into sbitmap library

2016-09-17T14:38:44Z

This is a generally useful data structure, so make it available to anyone else who might want to use it. It's also a nice cleanup separating the allocation logic from the rest of the tag handling logic. The code is behind a new Kconfig option, CONFIG_SBITMAP, which is only selected by CONFIG_BLOCK for now. This should be a complete noop functionality-wise. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

mm/usercopy: get rid of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

2016-08-30T17:10:21Z

There are three usercopy warnings which are currently being silenced for gcc 4.6 and newer: 1) "copy_from_user() buffer size is too small" compile warning/error This is a static warning which happens when object size and copy size are both const, and copy size > object size. I didn't see any false positives for this one. So the function warning attribute seems to be working fine here. Note this scenario is always a bug and so I think it should be changed to *always* be an error, regardless of CONFIG_DEBUG_STRICT_USER_COPY_CHECKS. 2) "copy_from_user() buffer size is not provably correct" compile warning This is another static warning which happens when I enable __compiletime_object_size() for new compilers (and CONFIG_DEBUG_STRICT_USER_COPY_CHECKS). It happens when object size is const, but copy size is *not*. In this case there's no way to compare the two at build time, so it gives the warning. (Note the warning is a byproduct of the fact that gcc has no way of knowing whether the overflow function will be called, so the call isn't dead code and the warning attribute is activated.) So this warning seems to only indicate "this is an unusual pattern, maybe you should check it out" rather than "this is a bug". I get 102(!) of these warnings with allyesconfig and the __compiletime_object_size() gcc check removed. I don't know if there are any real bugs hiding in there, but from looking at a small sample, I didn't see any. According to Kees, it does sometimes find real bugs. But the false positive rate seems high. 3) "Buffer overflow detected" runtime warning This is a runtime warning where object size is const, and copy size > object size. All three warnings (both static and runtime) were completely disabled for gcc 4.6 with the following commit: 2fb0815c9ee6 ("gcc4: disable __compiletime_object_size for GCC 4.6+") That commit mistakenly assumed that the false positives were caused by a gcc bug in __compiletime_object_size(). But in fact, __compiletime_object_size() seems to be working fine. The false positives were instead triggered by #2 above. (Though I don't have an explanation for why the warnings supposedly only started showing up in gcc 4.6.) So remove warning #2 to get rid of all the false positives, and re-enable warnings #1 and #3 by reverting the above commit. Furthermore, since #1 is a real bug which is detected at compile time, upgrade it to always be an error. Having done all that, CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is no longer needed. Signed-off-by: Josh Poimboeuf Cc: Kees Cook Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H . Peter Anvin" Cc: Andy Lutomirski Cc: Steven Rostedt Cc: Brian Gerst Cc: Peter Zijlstra Cc: Frederic Weisbecker Cc: Byungchul Park Cc: Nilay Vaish Signed-off-by: Linus Torvalds

Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

2016-07-27T22:11:55Z

Pull random driver updates from Ted Ts'o: "A number of improvements for the /dev/random driver; the most important is the use of a ChaCha20-based CRNG for /dev/urandom, which is faster, more efficient, and easier to make scalable for silly/abusive userspace programs that want to read from /dev/urandom in a tight loop on NUMA systems. This set of patches also improves entropy gathering on VM's running on Microsoft Azure, and will take advantage of a hw random number generator (if present) to initialize the /dev/urandom pool" (It turns out that the random tree hadn't been in linux-next this time around, because it had been dropped earlier as being too quiet. Oh well). * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: random: strengthen input validation for RNDADDTOENTCNT random: add backtracking protection to the CRNG random: make /dev/urandom scalable for silly userspace programs random: replace non-blocking pool with a Chacha20-based CRNG random: properly align get_random_int_hash random: add interrupt callback to VMBus IRQ handler random: print a warning for the first ten uninitialized random users random: initialize the non-blocking pool via add_hwgenerator_randomness()