Messages in this thread | | | From | Wei Chen <> | Date | Mon, 21 Nov 2022 22:11:04 +0800 | Subject | BUG: unable to handle kernel NULL pointer dereference in udpv6_sendmsg |
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Dear Linux Developer,
Recently when using our tool to fuzz kernel, the following crash was triggered.
HEAD commit: 147307c69ba git tree: upstream compiler: clang 12.0.0 console output: https://drive.google.com/file/d/1bYT7pFbYHlDqcmYuvw_x7kvX9_cNEscg/view?usp=share_link kernel config: https://drive.google.com/file/d/1NAf4S43d9VOKD52xbrqw-PUP1Mbj8z-S/view?usp=share_link Syz reproducer: https://drive.google.com/file/d/17GPbM4-sjSZMdakHzuLiksNE4xGUG3pU/view?usp=share_link
Unfortunately, if we transform the syz reproducer to C reproducer with syz-prog2c, the crash would not happen. Please consider to use syz-execprog and syz-executor to reproduce the crash.
IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: Wei Chen <harperchen1110@gmail.com>
BUG: kernel NULL pointer dereference, address: 000000000000004e #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 129e71067 P4D 129e71067 PUD 107f78067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 0 PID: 3472 Comm: syz-executor.0 Not tainted 6.1.0-rc5-next-20221118 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014 RIP: 0010:udpv6_sendmsg+0x4f3/0x16a0 net/ipv6/udp.c:1440 Code: b7 6f 02 31 ff 89 ee e8 ab 10 14 fd 85 ed 0f 84 41 03 00 00 66 89 ac 24 64 01 00 00 48 8b 6c 24 10 48 8d 7d 4e e8 9d 71 27 fd <0f> b7 6d 4e 83 e5 02 31 ff 89 ee e8 7d 10 14 fd 66 85 ed 0f 85 cb RSP: 0018:ffffc90002a1b710 EFLAGS: 00010246 RAX: ffff888128fbca48 RBX: 0000000000000000 RCX: ffffffff8413a4c3 RDX: 00000000000008cd RSI: 0000000000000000 RDI: 000000000000004e RBP: 0000000000000000 R08: 000000000000004f R09: 0000000000000000 R10: 0001ffffffffffff R11: ffff888128fbc000 R12: ffff88810117dee0 R13: ffff88810117db00 R14: 00000000ffff02ff R15: ffff8881280fd088 FS: 00007ffb0eb4e700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000004e CR3: 0000000129c82000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> do_udp_sendmsg net/rxrpc/output.c:27 [inline] rxrpc_send_data_packet+0x962/0x1690 net/rxrpc/output.c:485 rxrpc_queue_packet+0x5eb/0x6f0 net/rxrpc/sendmsg.c:264 rxrpc_send_data+0x8ca/0xcb0 net/rxrpc/sendmsg.c:411 rxrpc_do_sendmsg+0xb48/0xbe0 net/rxrpc/sendmsg.c:733 rxrpc_sendmsg+0x3d7/0x4c0 net/rxrpc/af_rxrpc.c:561 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0x38f/0x500 net/socket.c:2476 ___sys_sendmsg net/socket.c:2530 [inline] __sys_sendmsg+0x197/0x230 net/socket.c:2559 __do_sys_sendmsg net/socket.c:2568 [inline] __se_sys_sendmsg net/socket.c:2566 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2566 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x4697f9 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffb0eb4dc48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000077bf80 RCX: 00000000004697f9 RDX: 0000000000000000 RSI: 00000000200036c0 RDI: 0000000000000003 RBP: 00000000004d29e9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000077bf80 R13: 0000000000000000 R14: 000000000077bf80 R15: 00007ffd80eca0a0 </TASK> Modules linked in: CR2: 000000000000004e ---[ end trace 0000000000000000 ]--- RIP: 0010:udpv6_sendmsg+0x4f3/0x16a0 net/ipv6/udp.c:1440 Code: b7 6f 02 31 ff 89 ee e8 ab 10 14 fd 85 ed 0f 84 41 03 00 00 66 89 ac 24 64 01 00 00 48 8b 6c 24 10 48 8d 7d 4e e8 9d 71 27 fd <0f> b7 6d 4e 83 e5 02 31 ff 89 ee e8 7d 10 14 fd 66 85 ed 0f 85 cb RSP: 0018:ffffc90002a1b710 EFLAGS: 00010246 RAX: ffff888128fbca48 RBX: 0000000000000000 RCX: ffffffff8413a4c3 RDX: 00000000000008cd RSI: 0000000000000000 RDI: 000000000000004e RBP: 0000000000000000 R08: 000000000000004f R09: 0000000000000000 R10: 0001ffffffffffff R11: ffff888128fbc000 R12: ffff88810117dee0 R13: ffff88810117db00 R14: 00000000ffff02ff R15: ffff8881280fd088 FS: 00007ffb0eb4e700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000004e CR3: 0000000129c82000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: b7 6f mov $0x6f,%bh 2: 02 31 add (%rcx),%dh 4: ff 89 ee e8 ab 10 decl 0x10abe8ee(%rcx) a: 14 fd adc $0xfd,%al c: 85 ed test %ebp,%ebp e: 0f 84 41 03 00 00 je 0x355 14: 66 89 ac 24 64 01 00 mov %bp,0x164(%rsp) 1b: 00 1c: 48 8b 6c 24 10 mov 0x10(%rsp),%rbp 21: 48 8d 7d 4e lea 0x4e(%rbp),%rdi 25: e8 9d 71 27 fd callq 0xfd2771c7 * 2a: 0f b7 6d 4e movzwl 0x4e(%rbp),%ebp <-- trapping instruction 2e: 83 e5 02 and $0x2,%ebp 31: 31 ff xor %edi,%edi 33: 89 ee mov %ebp,%esi 35: e8 7d 10 14 fd callq 0xfd1410b7 3a: 66 85 ed test %bp,%bp 3d: 0f .byte 0xf 3e: 85 cb test %ecx,%ebx
Best, Wei
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