Messages in this thread Patch in this message | | | From | Xin Long <> | Date | Sat, 30 Mar 2019 22:18:32 +0800 | Subject | Re: KMSAN: uninit-value in tipc_nl_compat_bearer_enable (2) |
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On Thu, Mar 28, 2019 at 1:55 AM syzbot <syzbot+8b707430713eb46e1e45@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 9536b452 kmsan: uaccess.h: fix variable name conflicts > git tree: kmsan > console output: https://syzkaller.appspot.com/x/log.txt?x=15f5d583200000 > kernel config: https://syzkaller.appspot.com/x/.config?x=a5675814e8eae69e > dashboard link: https://syzkaller.appspot.com/bug?extid=8b707430713eb46e1e45 > compiler: clang version 8.0.0 (trunk 350509) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16438e1b200000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16898cd7200000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+8b707430713eb46e1e45@syzkaller.appspotmail.com > > ================================================================== > BUG: KMSAN: uninit-value in memchr+0xce/0x110 lib/string.c:961 > CPU: 0 PID: 10526 Comm: syz-executor961 Not tainted 5.0.0+ #13 > 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+0x173/0x1d0 lib/dump_stack.c:113 > kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:600 > __msan_warning+0x82/0xf0 mm/kmsan/kmsan_instr.c:313 > memchr+0xce/0x110 lib/string.c:961 > string_is_valid net/tipc/netlink_compat.c:176 [inline] > tipc_nl_compat_bearer_enable+0x2c4/0x910 net/tipc/netlink_compat.c:401 It's using the wrong length to check if b->name is valid when b->name size < TIPC_MAX_BEARER_NAME. The right count should start from tipc_bearer_config->name.
diff --git a/net/tipc/netlink_compat.c b/net/tipc/netlink_compat.c index 4ad3586..895f368 100644 --- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -397,7 +397,9 @@ static int tipc_nl_compat_bearer_enable(struct tipc_nl_compat_cmd_doit *cmd, if (!bearer) return -EMSGSIZE;
- len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME); + len = TLV_GET_DATA_LEN(msg->req); + len -= offsetof(struct tipc_bearer_config, name); + len = min_t(int, len, TIPC_MAX_BEARER_NAME); if (!string_is_valid(b->name, len)) return -EINVAL;
The simliar thing should be done in: tipc_nl_compat_media_set() tipc_nl_compat_bearer_set() tipc_nl_compat_link_set() > __tipc_nl_compat_doit net/tipc/netlink_compat.c:321 [inline] > tipc_nl_compat_doit+0x3aa/0xaf0 net/tipc/netlink_compat.c:354 > tipc_nl_compat_handle net/tipc/netlink_compat.c:1162 [inline] > tipc_nl_compat_recv+0x1ae7/0x2750 net/tipc/netlink_compat.c:1265 > genl_family_rcv_msg net/netlink/genetlink.c:601 [inline] > genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626 > netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477 > genl_rcv+0x63/0x80 net/netlink/genetlink.c:637 > netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] > netlink_unicast+0xf3e/0x1020 net/netlink/af_netlink.c:1336 > netlink_sendmsg+0x127f/0x1300 net/netlink/af_netlink.c:1917 > sock_sendmsg_nosec net/socket.c:622 [inline] > sock_sendmsg net/socket.c:632 [inline] > ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2115 > __sys_sendmsg net/socket.c:2153 [inline] > __do_sys_sendmsg net/socket.c:2162 [inline] > __se_sys_sendmsg+0x305/0x460 net/socket.c:2160 > __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2160 > do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 > entry_SYSCALL_64_after_hwframe+0x63/0xe7 > RIP: 0033:0x440209 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffc77bfd0a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440209 > RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003 > RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a90 > R13: 0000000000401b20 R14: 0000000000000000 R15: 0000000000000000 > > Uninit was created at: > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:205 [inline] > kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:159 > kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:176 > kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:185 > slab_post_alloc_hook mm/slab.h:445 [inline] > slab_alloc_node mm/slub.c:2773 [inline] > __kmalloc_node_track_caller+0xe9e/0xff0 mm/slub.c:4398 > __kmalloc_reserve net/core/skbuff.c:140 [inline] > __alloc_skb+0x309/0xa20 net/core/skbuff.c:208 > alloc_skb include/linux/skbuff.h:1012 [inline] > netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline] > netlink_sendmsg+0xb82/0x1300 net/netlink/af_netlink.c:1892 > sock_sendmsg_nosec net/socket.c:622 [inline] > sock_sendmsg net/socket.c:632 [inline] > ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2115 > __sys_sendmsg net/socket.c:2153 [inline] > __do_sys_sendmsg net/socket.c:2162 [inline] > __se_sys_sendmsg+0x305/0x460 net/socket.c:2160 > __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2160 > 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 syzkaller@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
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