On 08/02/2017 02:38 AM, Megha Dey wrote: > It was reported that the sha1 AVX2 function(sha1_transform_avx2) is > reading ahead beyond its intended data, and causing a crash if the next > block is beyond page boundary: > http://marc.info/?l=linux-crypto-vger&m=149373371023377 > > This patch makes sure that there is no overflow for any buffer length. > > It passes the tests written by Jan Stancek that revealed this problem: > https://github.com/jstancek/sha1-avx2-crash > > Jan, can you verify this fix? Hi, Looks good, my tests (below) PASS-ed. I updated reproducer at [1] to try more than just single scenario. It now tries thousands of combinations with different starting offset within page and sizes of data chunks. (without patch) v4.13-rc3-102-g26c5ceb with avx2 enabled: [ 106.455175] sha_test module loaded [ 106.460458] data is at 0xffff8c88e58f8000, page_after_data: 0xffff8c88e58fa000 [ 106.468625] sha_test testing hash: sha1-generic, maxlen: 8192 [ 127.091237] sha_test hash: sha1-generic calculated 1764032 hashes [ 127.098038] sha_test testing hash: sha1-ni, maxlen: 8192 [ 127.108805] failed to alloc sha1-ni [ 127.112703] sha_test testing hash: sha1-avx, maxlen: 8192 [ 141.166611] sha_test hash: sha1-avx calculated 1764032 hashes [ 141.173023] sha_test testing hash: sha1-avx2, maxlen: 8192 [ 141.180046] BUG: unable to handle kernel paging request at ffff8c88e58fa000 [ 141.187817] IP: _begin+0x28/0x187 [ 141.191512] PGD 89c578067 [ 141.191513] P4D 89c578067 [ 141.194529] PUD c61f0a063 [ 141.197545] PMD c64cb1063 [ 141.200561] PTE 8000000c658fa062 [ 141.203577] [ 141.208832] Oops: 0000 [#1] SMP ... With patch "[Patch V2] crypto: x86/sha1 : Fix reads beyond the number of blocks passed": [ 406.323781] sha_test module loaded [ 406.329062] data is at 0xffff93ab97108000, page_after_data: 0xffff93ab9710a000 [ 406.337185] sha_test testing hash: sha1-generic, maxlen: 8192 [ 426.157242] sha_test hash: sha1-generic calculated 1764032 hashes [ 426.164043] sha_test testing hash: sha1-ni, maxlen: 8192 [ 426.174244] failed to alloc sha1-ni [ 426.178139] sha_test testing hash: sha1-avx, maxlen: 8192 [ 440.226240] sha_test hash: sha1-avx calculated 1764032 hashes [ 440.232651] sha_test testing hash: sha1-avx2, maxlen: 8192 [ 452.497988] sha_test hash: sha1-avx2 calculated 1764032 hashes [ 452.504495] sha_test testing hash: sha1-ssse3, maxlen: 8192 [ 467.319316] sha_test hash: sha1-ssse3 calculated 1764032 hashes [ 467.325922] sha_test done [ 471.827083] sha_test module unloaded I also ran a test at [2], which is comparing hashes produced by kernel with hashes produced by user-space utilities (e.g. 'sha1sum'). This test also PASS-ed. Regards, Jan [1] https://github.com/jstancek/sha1-avx2-crash [2] https://github.com/jstancek/kernel_sha_test/tree/sha1-avx2-4.13 > Herbert, can you re-enable sha1-avx2 once Jan has checked it out and > revert commit b82ce24426a4071da9529d726057e4e642948667 ? > > Originally-by: Ilya Albrekht <ilya.albrekht@xxxxxxxxx> > Signed-off-by: Megha Dey <megha.dey@xxxxxxxxxxxxxxx> > Reported-by: Jan Stancek <jstancek@xxxxxxxxxx>
