Hello, The following program causes use-after-free in hash_sock_destruct: // autogenerated by syzkaller (http://github.com/google/syzkaller) #include <syscall.h> #include <string.h> #include <stdint.h> #include <sys/types.h> #include <sys/socket.h> #include <pthread.h> struct sockaddr_alg { unsigned short salg_family; char salg_type[14]; unsigned salg_feat; unsigned salg_mask; char salg_name[64]; }; int fd; void *thr0(void *arg) { struct sockaddr_alg sa = {}; sa.salg_family = 0x26; memcpy(sa.salg_type, "\x68\x61\x73\x68\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 14); sa.salg_feat = 0xf; sa.salg_mask = 0x100; memcpy(sa.salg_name, "\x6d\x64\x34\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 64); bind(fd, (struct sockaddr*)&sa, sizeof(sa)); return 0; } void *thr1(void *arg) { accept4(fd, 0, 0, 0x800ul); return 0; } int main() { fd = socket(PF_ALG, SOCK_SEQPACKET, 0); pthread_t th[4]; pthread_create(&th[0], 0, thr0, 0); pthread_create(&th[1], 0, thr1, 0); pthread_create(&th[2], 0, thr0, 0); pthread_create(&th[3], 0, thr1, 0); pthread_join(th[0], 0); pthread_join(th[1], 0); pthread_join(th[2], 0); pthread_join(th[3], 0); return 0; } ================================================================== BUG: KASAN: use-after-free in hash_sock_destruct+0x1de/0x260 at addr ffff88005f057090 Read of size 8 by task a.out/6844 ============================================================================= BUG kmalloc-192 (Not tainted): kasan: bad access detected ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in crypto_create_tfm+0x87/0x2a0 age=3 cpu=2 pid=6845 [< none >] ___slab_alloc+0x648/0x8c0 mm/slub.c:2438 [< none >] __slab_alloc+0x4c/0x90 mm/slub.c:2467 [< inline >] slab_alloc_node mm/slub.c:2530 [< inline >] slab_alloc mm/slub.c:2572 [< none >] __kmalloc+0x2d9/0x480 mm/slub.c:3532 [< inline >] kmalloc include/linux/slab.h:463 [< inline >] kzalloc include/linux/slab.h:602 [< none >] crypto_create_tfm+0x87/0x2a0 crypto/api.c:470 [< none >] crypto_alloc_tfm+0x138/0x3f0 crypto/api.c:555 [< none >] crypto_alloc_ahash+0x2c/0x40 crypto/ahash.c:538 [< none >] hash_bind+0x25/0x30 crypto/algif_hash.c:240 [< none >] alg_bind+0x1a9/0x410 crypto/af_alg.c:155 [< none >] SYSC_bind+0x20a/0x2c0 net/socket.c:1383 [< none >] SyS_bind+0x24/0x30 net/socket.c:1369 [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 INFO: Freed in kzfree+0x28/0x30 age=2 cpu=1 pid=6847 [< none >] __slab_free+0x21e/0x3e0 mm/slub.c:2648 [< inline >] slab_free mm/slub.c:2803 [< none >] kfree+0x26f/0x3e0 mm/slub.c:3632 [< none >] kzfree+0x28/0x30 mm/slab_common.c:1270 [< none >] crypto_destroy_tfm+0xdd/0x1e0 crypto/api.c:596 [< inline >] crypto_free_ahash include/crypto/hash.h:258 [< none >] hash_release+0x19/0x20 crypto/algif_hash.c:245 [< inline >] alg_do_release crypto/af_alg.c:116 [< none >] alg_bind+0x26a/0x410 crypto/af_alg.c:170 [< none >] SYSC_bind+0x20a/0x2c0 net/socket.c:1383 [< none >] SyS_bind+0x24/0x30 net/socket.c:1369 [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 INFO: Slab 0xffffea00017c1580 objects=16 used=15 fp=0xffff88005f057000 flags=0x5fffc0000004080 INFO: Object 0xffff88005f057000 @offset=4096 fp=0x (null) CPU: 1 PID: 6844 Comm: a.out Tainted: G B 4.4.0-rc3+ #151 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 0000000000000001 ffff8800379779e0 ffffffff82e0f4b8 0000000041b58ab3 ffffffff87a9a265 ffffffff82e0f406 ffff88003d8c0000 ffffffff87abb3aa ffff88003e804a00 0000000000000008 ffff88005f057000 ffff8800379779e0 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82e0f4b8>] dump_stack+0xb2/0xfa lib/dump_stack.c:50 [<ffffffff8183680c>] print_trailer+0x12c/0x210 mm/slub.c:652 [<ffffffff8184162f>] object_err+0x2f/0x40 mm/slub.c:659 [< inline >] print_address_description mm/kasan/report.c:138 [<ffffffff81845399>] kasan_report_error+0x5d9/0x860 mm/kasan/report.c:251 [< inline >] kasan_report mm/kasan/report.c:274 [<ffffffff818457c4>] __asan_report_load8_noabort+0x54/0x70 mm/kasan/report.c:295 [< inline >] crypto_ahash_digestsize include/crypto/hash.h:290 [<ffffffff82d2a7ae>] hash_sock_destruct+0x1de/0x260 crypto/algif_hash.c:259 [<ffffffff856c9255>] sk_destruct+0xa5/0x5f0 net/core/sock.c:1446 [<ffffffff856c982c>] __sk_free+0x8c/0x260 net/core/sock.c:1474 [<ffffffff856c9a30>] sk_free+0x30/0x40 net/core/sock.c:1485 [< inline >] sock_put include/net/sock.h:1625 [<ffffffff82d26c50>] af_alg_release+0x60/0x90 crypto/af_alg.c:123 [<ffffffff856b06b6>] sock_release+0x96/0x260 net/socket.c:571 [<ffffffff856b0896>] sock_close+0x16/0x20 net/socket.c:1022 [<ffffffff8189d9e4>] __fput+0x244/0x860 fs/file_table.c:208 [<ffffffff8189e095>] ____fput+0x15/0x20 fs/file_table.c:244 [<ffffffff813e34d0>] task_work_run+0x130/0x240 kernel/task_work.c:115 [< inline >] exit_task_work include/linux/task_work.h:21 [<ffffffff8137d8f5>] do_exit+0x885/0x3050 kernel/exit.c:750 [<ffffffff8138021c>] do_group_exit+0xec/0x390 kernel/exit.c:880 [< inline >] SYSC_exit_group kernel/exit.c:891 [<ffffffff813804dd>] SyS_exit_group+0x1d/0x20 kernel/exit.c:889 [<ffffffff86a89fb6>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 ================================================================== BUG: unable to handle kernel paging request at fffffffffffffff8 IP: [<ffffffff82d2a6ae>] hash_sock_destruct+0xde/0x260 crypto/algif_hash.c:258 PGD 7c2f067 PUD 7c31067 PMD 0 Oops: 0000 [#1] SMP KASAN Modules linked in: CPU: 1 PID: 6844 Comm: a.out Tainted: G B 4.4.0-rc3+ #151 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88003d8c0000 ti: ffff880037970000 task.ti: ffff880037970000 RIP: 0010:[<ffffffff82d2a6ae>] [<ffffffff82d2a6ae>] hash_sock_destruct+0xde/0x260 RSP: 0018:ffff880037977b30 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff88005f94dc80 RCX: 0000000000000001 RDX: 1fffffffffffffff RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffff880037977b58 R08: 0000000000000001 R09: 0000000000000000 R10: ffffed0006f2ef55 R11: 0000000000000000 R12: ffff88005f94e5c0 R13: 0000000000000000 R14: fffffffffffffff8 R15: ffffffff856b0880 FS: 0000000000000000(0000) GS:ffff88003ed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: fffffffffffffff8 CR3: 0000000007c2e000 CR4: 00000000000006e0 Stack: ffff880000000000 ffff88005f94e5c0 ffffffff82d2a5d0 1ffff10006f2ef6d 0000000000000000 ffff880037977bf0 ffffffff856c9255 0000000041b58ab3 ffffffff87a9a273 ffffffff856c91b0 ffff8800602c8610 ffff88003d8c0000 Call Trace: [<ffffffff856c9255>] sk_destruct+0xa5/0x5f0 net/core/sock.c:1446 [<ffffffff856c982c>] __sk_free+0x8c/0x260 net/core/sock.c:1474 [<ffffffff856c9a30>] sk_free+0x30/0x40 net/core/sock.c:1485 [< inline >] sock_put include/net/sock.h:1625 [<ffffffff82d26c50>] af_alg_release+0x60/0x90 crypto/af_alg.c:123 [<ffffffff856b06b6>] sock_release+0x96/0x260 net/socket.c:571 [<ffffffff856b0896>] sock_close+0x16/0x20 net/socket.c:1022 [<ffffffff8189d9e4>] __fput+0x244/0x860 fs/file_table.c:208 [<ffffffff8189e095>] ____fput+0x15/0x20 fs/file_table.c:244 [<ffffffff813e34d0>] task_work_run+0x130/0x240 kernel/task_work.c:115 [< inline >] exit_task_work include/linux/task_work.h:21 [<ffffffff8137d8f5>] do_exit+0x885/0x3050 kernel/exit.c:750 [<ffffffff8138021c>] do_group_exit+0xec/0x390 kernel/exit.c:880 [< inline >] SYSC_exit_group kernel/exit.c:891 [<ffffffff813804dd>] SyS_exit_group+0x1d/0x20 kernel/exit.c:889 [<ffffffff86a89fb6>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 Code: 08 0f 84 7c 01 00 00 4c 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e d4 00 00 00 48 85 db <41> 8b 55 f8 0f 84 35 01 00 00 48 8d bb 30 03 00 00 48 b8 00 00 RIP [<ffffffff82d2a6ae>] hash_sock_destruct+0xde/0x260 crypto/algif_hash.c:258 RSP <ffff880037977b30> CR2: fffffffffffffff8 ---[ end trace b367ebac5d601601 ]--- Fixing recursive fault but reboot is needed! On upstream commit 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8 (Nov 29). -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
