Re: BUG: unable to handle kernel NULL pointer dereference in kfree
From: Eric Biggers <hidden>
Date: 2017-11-29 19:46:38
Also in:
lkml
On Wed, Nov 29, 2017 at 11:30:36AM +0100, 'Dmitry Vyukov' via syzkaller-bugs wrote:
On Wed, Nov 29, 2017 at 11:24 AM, syzbot [off-list ref] wrote:quoted
Hello, syzkaller hit the following crash on 43570f0383d6d5879ae585e6c3cf027ba321546f git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master compiler: gcc (GCC) 7.1.1 20170620 .config is attached Raw console output is attached. Unfortunately, I don't have any reproducer for this bug yet. netlink: 3 bytes leftover after parsing attributes in process `syz-executor3'. device gre0 entered promiscuous mode BUG: unable to handle kernel NULL pointer dereference at 0000000000000074 IP: virt_to_cache mm/slab.c:400 [inline] IP: kfree+0xb2/0x250 mm/slab.c:3802 PGD 1d369e067 P4D 1d369e067 PUD 1c8da0067 PMD 0 Oops: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 8031 Comm: syz-executor5 Not tainted 4.15.0-rc1+ #199 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8801d33f8540 task.stack: ffff8801d3b58000 RIP: 0010:virt_to_cache mm/slab.c:400 [inline] RIP: 0010:kfree+0xb2/0x250 mm/slab.c:3802 RSP: 0018:ffff8801d3b5f780 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff8801d3b5f948 RCX: ffffffffffffffff RDX: ffffea00074ed7c0 RSI: 0000000000000000 RDI: ffff8801d3b5f948 RBP: ffff8801d3b5f7a0 R08: ffffed003a2c3b7c R09: 0000000000000000 R10: 0000000000000001 R11: ffffed003a2c3b7b R12: 0000000000000286 R13: 0000000000000000 R14: ffff8801d3b5f948 R15: ffff8801d3b5f8b0 FS: 00007f7f80409700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000074 CR3: 00000001c97a2000 CR4: 00000000001426f0 DR0: 0000000020001000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: blkcipher_walk_done+0x72b/0xde0 crypto/blkcipher.c:139 encrypt+0x50a/0xaf0 crypto/salsa20_generic.c:208 skcipher_crypt_blkcipher crypto/skcipher.c:622 [inline] skcipher_decrypt_blkcipher+0x213/0x310 crypto/skcipher.c:640 crypto_skcipher_decrypt include/crypto/skcipher.h:463 [inline] _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline] skcipher_recvmsg+0xa54/0xf20 crypto/algif_skcipher.c:165 sock_recvmsg_nosec net/socket.c:805 [inline] sock_recvmsg+0xc9/0x110 net/socket.c:812 ___sys_recvmsg+0x29b/0x630 net/socket.c:2207 __sys_recvmsg+0xe2/0x210 net/socket.c:2252 SYSC_recvmsg net/socket.c:2264 [inline] SyS_recvmsg+0x2d/0x50 net/socket.c:2259 entry_SYSCALL_64_fastpath+0x1f/0x96
#syz dup: WARNING: suspicious RCU usage (3) All the following 5 reports appear to be the same bug in Salsa20, and I've marked them of duplicates of the first: WARNING: suspicious RCU usage (3) kernel BUG at ./include/linux/mm.h:LINE! (2) suspicious RCU usage at ./include/linux/mm.h:LINE suspicious RCU usage at ./include/trace/events/kmem.h:LINE BUG: unable to handle kernel NULL pointer dereference in kfree The bug involves an uninitialized pointer being kfreed, or an uninitialized 'struct page' being freed. Proposed fix is "crypto: salsa20 - fix blkcipher_walk API usage"