On Thu, Sep 27, 2018 at 10:35:48AM +0200, Ard Biesheuvel wrote: > (+ Stefan) > > On Wed, 26 Sep 2018 at 22:24, syzbot > <syzbot+6d3612ba5e254e387153@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 739d0def85ca Merge branch 'hv_netvsc-Support-LRO-RSC-in-th.. > > git tree: net-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=1146ffae400000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=e79b9299baeb2298 > > dashboard link: https://syzkaller.appspot.com/bug?extid=6d3612ba5e254e387153 > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16200b9e400000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=102311c6400000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+6d3612ba5e254e387153@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > random: sshd: uninitialized urandom read (32 bytes read) > > ================================================================== > > BUG: KASAN: use-after-free in memcpy include/linux/string.h:345 [inline] > > BUG: KASAN: use-after-free in generic_gcmaes_encrypt+0xc6/0x186 > > arch/x86/crypto/aesni-intel_glue.c:1291 > > Read of size 12 at addr ffff8801d7ad0900 by task kworker/0:1/14 > > > > CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.0-rc4+ #228 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > Google 01/01/2011 > > Workqueue: pencrypt padata_parallel_worker > > Call Trace: > > __dump_stack lib/dump_stack.c:77 [inline] > > dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 > > print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 > > kasan_report_error mm/kasan/report.c:354 [inline] > > kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 > > check_memory_region_inline mm/kasan/kasan.c:260 [inline] > > check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 > > memcpy+0x23/0x50 mm/kasan/kasan.c:302 > > memcpy include/linux/string.h:345 [inline] > > generic_gcmaes_encrypt+0xc6/0x186 arch/x86/crypto/aesni-intel_glue.c:1291 > > crypto_aead_encrypt include/crypto/aead.h:335 [inline] > > gcmaes_wrapper_encrypt+0x162/0x200 arch/x86/crypto/aesni-intel_glue.c:1127 > > crypto_aead_encrypt include/crypto/aead.h:335 [inline] > > pcrypt_aead_enc+0xcb/0x190 crypto/pcrypt.c:143 > > padata_parallel_worker+0x49d/0x760 kernel/padata.c:86 > > process_one_work+0xc90/0x1b90 kernel/workqueue.c:2153 > > worker_thread+0x17f/0x1390 kernel/workqueue.c:2296 > > kthread+0x35a/0x420 kernel/kthread.c:246 > > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 > > > > Allocated by task 5474: > > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > > set_track mm/kasan/kasan.c:460 [inline] > > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > > kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620 > > kmalloc include/linux/slab.h:513 [inline] > > tls_set_sw_offload+0xcc4/0x14b0 net/tls/tls_sw.c:1741 > > do_tls_setsockopt_conf net/tls/tls_main.c:467 [inline] > > do_tls_setsockopt net/tls/tls_main.c:514 [inline] > > tls_setsockopt+0x689/0x770 net/tls/tls_main.c:533 > > sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:3038 > > __sys_setsockopt+0x1ba/0x3c0 net/socket.c:1902 > > __do_sys_setsockopt net/socket.c:1913 [inline] > > __se_sys_setsockopt net/socket.c:1910 [inline] > > __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1910 > > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > > > Freed by task 5472: > > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > > set_track mm/kasan/kasan.c:460 [inline] > > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > > __cache_free mm/slab.c:3498 [inline] > > kfree+0xcf/0x230 mm/slab.c:3813 > > tls_sk_proto_close+0x5fd/0x750 net/tls/tls_main.c:277 I'd say tls_sk_proto_close does not handle asynchronous crypto properly. The pcrypt template is used here, so all crypto requests are processed asynchronously. tls_sk_proto_close frees the needed recources before the remaining crypto requests are finalized.
