On Wed, Jun 19, 2019 at 11:48 PM syzbot <syzbot+30eaa8bf392f7faff...@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: f75e4cfe kmsan: use kmsan_handle_urb() in urb.c > git tree: kmsan > console output: https://syzkaller.appspot.com/x/log.txt?x=13d0a6fea00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a > dashboard link: https://syzkaller.appspot.com/bug?extid=30eaa8bf392f7fafffaf > compiler: clang version 9.0.0 (/home/glider/llvm/clang > 06d00afa61eef8f7f501ebdb4e8612ea43ec2d78) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15b4a95aa00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=162fc761a00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+30eaa8bf392f7faff...@syzkaller.appspotmail.com > > IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready > 8021q: adding VLAN 0 to HW filter on device batadv0 > ================================================================== > BUG: KMSAN: uninit-value in memchr+0xce/0x110 lib/string.c:981 > CPU: 0 PID: 12554 Comm: syz-executor731 Not tainted 5.1.0+ #1 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x191/0x1f0 lib/dump_stack.c:113 > kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622 > __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310 > memchr+0xce/0x110 lib/string.c:981 > string_is_valid net/tipc/netlink_compat.c:176 [inline] > tipc_nl_compat_bearer_disable+0x2a1/0x480 net/tipc/netlink_compat.c:449 TLV_GET_DATA_LEN(msg->req) may return a negtive value, which will be used as size_t (a big unsigned long) passed into memchr(), triggered this issue.
@@ -446,7 +446,7 @@ static int tipc_nl_compat_bearer_disable(struct tipc_nl_compat_cmd_doit *cmd, return -EMSGSIZE; len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME); - if (!string_is_valid(name, len)) + if (len <=0 || !string_is_valid(name, len)) return -EINVAL; The same fix is needed for some other places, and I will give a fix-ups. > __tipc_nl_compat_doit net/tipc/netlink_compat.c:327 [inline] > tipc_nl_compat_doit+0x3ac/0xb00 net/tipc/netlink_compat.c:360 > tipc_nl_compat_handle net/tipc/netlink_compat.c:1178 [inline] > tipc_nl_compat_recv+0x1b1b/0x27b0 net/tipc/netlink_compat.c:1281 > genl_family_rcv_msg net/netlink/genetlink.c:602 [inline] > genl_rcv_msg+0x185a/0x1a40 net/netlink/genetlink.c:627 > netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2486 > genl_rcv+0x63/0x80 net/netlink/genetlink.c:638 > netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] > netlink_unicast+0xf3e/0x1020 net/netlink/af_netlink.c:1337 > netlink_sendmsg+0x127e/0x12f0 net/netlink/af_netlink.c:1926 > sock_sendmsg_nosec net/socket.c:651 [inline] > sock_sendmsg net/socket.c:661 [inline] > ___sys_sendmsg+0xcc6/0x1200 net/socket.c:2260 > __sys_sendmsg net/socket.c:2298 [inline] > __do_sys_sendmsg net/socket.c:2307 [inline] > __se_sys_sendmsg+0x305/0x460 net/socket.c:2305 > __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2305 > do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 > entry_SYSCALL_64_after_hwframe+0x63/0xe7 > RIP: 0033:0x442639 > Code: 41 02 00 85 c0 b8 00 00 00 00 48 0f 44 c3 5b c3 90 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 0f 83 fb 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00000000007efea8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442639 > RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003 > RBP: 00000000007eff00 R08: 0000000000000003 R09: 0000000000000003 > R10: 00000000bb1414ac R11: 0000000000000246 R12: 0000000000000003 > R13: 0000000000403c50 R14: 0000000000000000 R15: 0000000000000000 > > Uninit was created at: > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:208 [inline] > kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:162 > kmsan_kmalloc+0xa4/0x130 mm/kmsan/kmsan_hooks.c:175 > kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:184 > slab_post_alloc_hook mm/slab.h:442 [inline] > slab_alloc_node mm/slub.c:2771 [inline] > __kmalloc_node_track_caller+0xcba/0xf30 mm/slub.c:4399 > __kmalloc_reserve net/core/skbuff.c:140 [inline] > __alloc_skb+0x306/0xa10 net/core/skbuff.c:208 > alloc_skb include/linux/skbuff.h:1059 [inline] > netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline] > netlink_sendmsg+0xb81/0x12f0 net/netlink/af_netlink.c:1901 > sock_sendmsg_nosec net/socket.c:651 [inline] > sock_sendmsg net/socket.c:661 [inline] > ___sys_sendmsg+0xcc6/0x1200 net/socket.c:2260 > __sys_sendmsg net/socket.c:2298 [inline] > __do_sys_sendmsg net/socket.c:2307 [inline] > __se_sys_sendmsg+0x305/0x460 net/socket.c:2305 > __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2305 > do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 > entry_SYSCALL_64_after_hwframe+0x63/0xe7 > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches