kernel/linux.git/lib, branch v4.4.296

siphash: use _unaligned version by default

2021-12-08T07:44:08+00:00

commit f7e5b9bfa6c8820407b64eabc1f29c9a87e8993d upstream. On ARM v6 and later, we define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS because the ordinary load/store instructions (ldr, ldrh, ldrb) can tolerate any misalignment of the memory address. However, load/store double and load/store multiple instructions (ldrd, ldm) may still only be used on memory addresses that are 32-bit aligned, and so we have to use the CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS macro with care, or we may end up with a severe performance hit due to alignment traps that require fixups by the kernel. Testing shows that this currently happens with clang-13 but not gcc-11. In theory, any compiler version can produce this bug or other problems, as we are dealing with undefined behavior in C99 even on architectures that support this in hardware, see also https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100363. Fortunately, the get_unaligned() accessors do the right thing: when building for ARMv6 or later, the compiler will emit unaligned accesses using the ordinary load/store instructions (but avoid the ones that require 32-bit alignment). When building for older ARM, those accessors will emit the appropriate sequence of ldrb/mov/orr instructions. And on architectures that can truly tolerate any kind of misalignment, the get_unaligned() accessors resolve to the leXX_to_cpup accessors that operate on aligned addresses. Since the compiler will in fact emit ldrd or ldm instructions when building this code for ARM v6 or later, the solution is to use the unaligned accessors unconditionally on architectures where this is known to be fast. The _aligned version of the hash function is however still needed to get the best performance on architectures that cannot do any unaligned access in hardware. This new version avoids the undefined behavior and should produce the fastest hash on all architectures we support. Link: https://lore.kernel.org/linux-arm-kernel/20181008211554.5355-4-ard.biesheuvel@linaro.org/ Link: https://lore.kernel.org/linux-crypto/CAK8P3a2KfmmGDbVHULWevB0hv71P2oi2ZCHEAqT=8dQfa0=cqQ@mail.gmail.com/ Reported-by: Ard Biesheuvel Fixes: 2c956a60778c ("siphash: add cryptographically secure PRF") Signed-off-by: Arnd Bergmann Reviewed-by: Jason A. Donenfeld Acked-by: Ard Biesheuvel Signed-off-by: Jason A. Donenfeld Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

lib/xz: Validate the value before assigning it to an enum variable

2021-11-26T10:58:38+00:00

[ Upstream commit 4f8d7abaa413c34da9d751289849dbfb7c977d05 ] This might matter, for example, if the underlying type of enum xz_check was a signed char. In such a case the validation wouldn't have caught an unsupported header. I don't know if this problem can occur in the kernel on any arch but it's still good to fix it because some people might copy the XZ code to their own projects from Linux instead of the upstream XZ Embedded repository. This change may increase the code size by a few bytes. An alternative would have been to use an unsigned int instead of enum xz_check but using an enumeration looks cleaner. Link: https://lore.kernel.org/r/20211010213145.17462-3-xiang@kernel.org Signed-off-by: Lasse Collin Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin

lib/xz: Avoid overlapping memcpy() with invalid input with in-place decompression

2021-11-26T10:58:38+00:00

[ Upstream commit 83d3c4f22a36d005b55f44628f46cc0d319a75e8 ] With valid files, the safety margin described in lib/decompress_unxz.c ensures that these buffers cannot overlap. But if the uncompressed size of the input is larger than the caller thought, which is possible when the input file is invalid/corrupt, the buffers can overlap. Obviously the result will then be garbage (and usually the decoder will return an error too) but no other harm will happen when such an over-run occurs. This change only affects uncompressed LZMA2 chunks and so this should have no effect on performance. Link: https://lore.kernel.org/r/20211010213145.17462-2-xiang@kernel.org Signed-off-by: Lasse Collin Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin

bpf/tests: Do not PASS tests without actually testing the result

2021-09-22T09:41:24+00:00

[ Upstream commit 2b7e9f25e590726cca76700ebdb10e92a7a72ca1 ] Each test case can have a set of sub-tests, where each sub-test can run the cBPF/eBPF test snippet with its own data_size and expected result. Before, the end of the sub-test array was indicated by both data_size and result being zero. However, most or all of the internal eBPF tests has a data_size of zero already. When such a test also had an expected value of zero, the test was never run but reported as PASS anyway. Now the test runner always runs the first sub-test, regardless of the data_size and result values. The sub-test array zero-termination only applies for any additional sub-tests. There are other ways fix it of course, but this solution at least removes the surprise of eBPF tests with a zero result always succeeding. Signed-off-by: Johan Almbladh Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210721103822.3755111-1-johan.almbladh@anyfinetworks.com Signed-off-by: Sasha Levin

bpf/tests: Fix copy-and-paste error in double word test

2021-09-22T09:41:24+00:00

[ Upstream commit ae7f47041d928b1a2f28717d095b4153c63cbf6a ] This test now operates on DW as stated instead of W, which was already covered by another test. Signed-off-by: Johan Almbladh Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210721104058.3755254-1-johan.almbladh@anyfinetworks.com Signed-off-by: Sasha Levin

lib/string.c: add multibyte memset functions

2021-08-04T09:56:45+00:00

commit 3b3c4babd898715926d24ae10aa64778ace33aae upstream. Patch series "Multibyte memset variations", v4. A relatively common idiom we're missing is a function to fill an area of memory with a pattern which is larger than a single byte. I first noticed this with a zram patch which wanted to fill a page with an 'unsigned long' value. There turn out to be quite a few places in the kernel which can benefit from using an optimised function rather than a loop; sometimes text size, sometimes speed, and sometimes both. The optimised PowerPC version (not included here) improves performance by about 30% on POWER8 on just the raw memset_l(). Most of the extra lines of code come from the three testcases I added. This patch (of 8): memset16(), memset32() and memset64() are like memset(), but allow the caller to fill the destination with a value larger than a single byte. memset_l() and memset_p() allow the caller to use unsigned long and pointer values respectively. Link: http://lkml.kernel.org/r/20170720184539.31609-2-willy@infradead.org Signed-off-by: Matthew Wilcox Cc: "H. Peter Anvin" Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: David Miller Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Michael Ellerman Cc: Minchan Kim Cc: Ralf Baechle Cc: Richard Henderson Cc: Russell King Cc: Sam Ravnborg Cc: Sergey Senozhatsky Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Nobuhiro Iwamatsu (CIP) Signed-off-by: Greg Kroah-Hartman

lib/decompress_unlz4.c: correctly handle zero-padding around initrds.

2021-07-20T14:22:42+00:00

[ Upstream commit 2c484419efc09e7234c667aa72698cb79ba8d8ed ] lz4 compatible decompressor is simple. The format is underspecified and relies on EOF notification to determine when to stop. Initramfs buffer format[1] explicitly states that it can have arbitrary number of zero padding. Thus when operating without a fill function, be extra careful to ensure that sizes less than 4, or apperantly empty chunksizes are treated as EOF. To test this I have created two cpio initrds, first a normal one, main.cpio. And second one with just a single /test-file with content "second" second.cpio. Then i compressed both of them with gzip, and with lz4 -l. Then I created a padding of 4 bytes (dd if=/dev/zero of=pad4 bs=1 count=4). To create four testcase initrds: 1) main.cpio.gzip + extra.cpio.gzip = pad0.gzip 2) main.cpio.lz4 + extra.cpio.lz4 = pad0.lz4 3) main.cpio.gzip + pad4 + extra.cpio.gzip = pad4.gzip 4) main.cpio.lz4 + pad4 + extra.cpio.lz4 = pad4.lz4 The pad4 test-cases replicate the initrd load by grub, as it pads and aligns every initrd it loads. All of the above boot, however /test-file was not accessible in the initrd for the testcase #4, as decoding in lz4 decompressor failed. Also an error message printed which usually is harmless. Whith a patched kernel, all of the above testcases now pass, and /test-file is accessible. This fixes lz4 initrd decompress warning on every boot with grub. And more importantly this fixes inability to load multiple lz4 compressed initrds with grub. This patch has been shipping in Ubuntu kernels since January 2021. [1] ./Documentation/driver-api/early-userspace/buffer-format.rst BugLink: https://bugs.launchpad.net/bugs/1835660 Link: https://lore.kernel.org/lkml/20210114200256.196589-1-xnox@ubuntu.com/ # v0 Link: https://lkml.kernel.org/r/20210513104831.432975-1-dimitri.ledkov@canonical.com Signed-off-by: Dimitri John Ledkov Cc: Kyungsik Lee Cc: Yinghai Lu Cc: Bongkyu Kim Cc: Kees Cook Cc: Sven Schmidt <4sschmid@informatik.uni-hamburg.de> Cc: Rajat Asthana Cc: Nick Terrell Cc: Gao Xiang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

seq_buf: Fix overflow in seq_buf_putmem_hex()

2021-07-20T14:22:40+00:00

commit d3b16034a24a112bb83aeb669ac5b9b01f744bb7 upstream. There's two variables being increased in that loop (i and j), and i follows the raw data, and j follows what is being written into the buffer. We should compare 'i' to MAX_MEMHEX_BYTES or compare 'j' to HEX_CHARS. Otherwise, if 'j' goes bigger than HEX_CHARS, it will overflow the destination buffer. Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/ Link: https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou@windriver.com Cc: stable@vger.kernel.org Fixes: 5e3ca0ec76fce ("ftrace: introduce the "hex" output method") Signed-off-by: Yun Zhou Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

seq_buf: Make trace_seq_putmem_hex() support data longer than 8

2021-07-20T14:22:31+00:00

commit 6a2cbc58d6c9d90cd74288cc497c2b45815bc064 upstream. Since the raw memory 'data' does not go forward, it will dump repeated data if the data length is more than 8. If we want to dump longer data blocks, we need to repeatedly call macro SEQ_PUT_HEX_FIELD. I think it is a bit redundant, and multiple function calls also affect the performance. Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/ Link: https://lkml.kernel.org/r/20210626032156.47889-2-yun.zhou@windriver.com Cc: stable@vger.kernel.org Fixes: 6d2289f3faa7 ("tracing: Make trace_seq_putmem_hex() more robust") Signed-off-by: Yun Zhou Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman

iov_iter_fault_in_readable() should do nothing in xarray case

2021-07-20T14:22:30+00:00

commit 0e8f0d67401589a141950856902c7d0ec8d9c985 upstream. ... and actually should just check it's given an iovec-backed iterator in the first place. Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman