| From: Paolo Abeni <pabeni@redhat.com> |
| Date: Fri, 13 Apr 2018 13:59:25 +0200 |
| Subject: team: avoid adding twice the same option to the event list |
| |
| commit 4fb0534fb7bbc2346ba7d3a072b538007f4135a5 upstream. |
| |
| When parsing the options provided by the user space, |
| team_nl_cmd_options_set() insert them in a temporary list to send |
| multiple events with a single message. |
| While each option's attribute is correctly validated, the code does |
| not check for duplicate entries before inserting into the event |
| list. |
| |
| Exploiting the above, the syzbot was able to trigger the following |
| splat: |
| |
| kernel BUG at lib/list_debug.c:31! |
| invalid opcode: 0000 [#1] SMP KASAN |
| Dumping ftrace buffer: |
| (ftrace buffer empty) |
| Modules linked in: |
| CPU: 0 PID: 4466 Comm: syzkaller556835 Not tainted 4.16.0+ #17 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS |
| Google 01/01/2011 |
| RIP: 0010:__list_add_valid+0xaa/0xb0 lib/list_debug.c:29 |
| RSP: 0018:ffff8801b04bf248 EFLAGS: 00010286 |
| RAX: 0000000000000058 RBX: ffff8801c8fc7a90 RCX: 0000000000000000 |
| RDX: 0000000000000058 RSI: ffffffff815fbf41 RDI: ffffed0036097e3f |
| RBP: ffff8801b04bf260 R08: ffff8801b0b2a700 R09: ffffed003b604f90 |
| R10: ffffed003b604f90 R11: ffff8801db027c87 R12: ffff8801c8fc7a90 |
| R13: ffff8801c8fc7a90 R14: dffffc0000000000 R15: 0000000000000000 |
| FS: 0000000000b98880(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 |
| CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| CR2: 000000000043fc30 CR3: 00000001afe8e000 CR4: 00000000001406f0 |
| DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 |
| Call Trace: |
| __list_add include/linux/list.h:60 [inline] |
| list_add include/linux/list.h:79 [inline] |
| team_nl_cmd_options_set+0x9ff/0x12b0 drivers/net/team/team.c:2571 |
| genl_family_rcv_msg+0x889/0x1120 net/netlink/genetlink.c:599 |
| genl_rcv_msg+0xc6/0x170 net/netlink/genetlink.c:624 |
| netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2448 |
| genl_rcv+0x28/0x40 net/netlink/genetlink.c:635 |
| netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] |
| netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336 |
| netlink_sendmsg+0x9f0/0xfa0 net/netlink/af_netlink.c:1901 |
| sock_sendmsg_nosec net/socket.c:629 [inline] |
| sock_sendmsg+0xd5/0x120 net/socket.c:639 |
| ___sys_sendmsg+0x805/0x940 net/socket.c:2117 |
| __sys_sendmsg+0x115/0x270 net/socket.c:2155 |
| SYSC_sendmsg net/socket.c:2164 [inline] |
| SyS_sendmsg+0x29/0x30 net/socket.c:2162 |
| do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 |
| entry_SYSCALL_64_after_hwframe+0x42/0xb7 |
| RIP: 0033:0x4458b9 |
| RSP: 002b:00007ffd1d4a7278 EFLAGS: 00000213 ORIG_RAX: 000000000000002e |
| RAX: ffffffffffffffda RBX: 000000000000001b RCX: 00000000004458b9 |
| RDX: 0000000000000010 RSI: 0000000020000d00 RDI: 0000000000000004 |
| RBP: 00000000004a74ed R08: 0000000000000000 R09: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000000213 R12: 00007ffd1d4a7348 |
| R13: 0000000000402a60 R14: 0000000000000000 R15: 0000000000000000 |
| Code: 75 e8 eb a9 48 89 f7 48 89 75 e8 e8 d1 85 7b fe 48 8b 75 e8 eb bb 48 |
| 89 f2 48 89 d9 4c 89 e6 48 c7 c7 a0 84 d8 87 e8 ea 67 28 fe <0f> 0b 0f 1f |
| 40 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 |
| RIP: __list_add_valid+0xaa/0xb0 lib/list_debug.c:29 RSP: ffff8801b04bf248 |
| |
| This changeset addresses the avoiding list_add() if the current |
| option is already present in the event list. |
| |
| Reported-and-tested-by: syzbot+4d4af685432dc0e56c91@syzkaller.appspotmail.com |
| Signed-off-by: Paolo Abeni <pabeni@redhat.com> |
| Fixes: 2fcdb2c9e659 ("team: allow to send multiple set events in one message") |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| drivers/net/team/team.c | 19 +++++++++++++++++++ |
| 1 file changed, 19 insertions(+) |
| |
| --- a/drivers/net/team/team.c |
| +++ b/drivers/net/team/team.c |
| @@ -253,6 +253,17 @@ static void __team_option_inst_mark_remo |
| } |
| } |
| |
| +static bool __team_option_inst_tmp_find(const struct list_head *opts, |
| + const struct team_option_inst *needle) |
| +{ |
| + struct team_option_inst *opt_inst; |
| + |
| + list_for_each_entry(opt_inst, opts, tmp_list) |
| + if (opt_inst == needle) |
| + return true; |
| + return false; |
| +} |
| + |
| static int __team_options_register(struct team *team, |
| const struct team_option *option, |
| size_t option_count) |
| @@ -2520,6 +2531,14 @@ static int team_nl_cmd_options_set(struc |
| if (err) |
| goto team_put; |
| opt_inst->changed = true; |
| + |
| + /* dumb/evil user-space can send us duplicate opt, |
| + * keep only the last one |
| + */ |
| + if (__team_option_inst_tmp_find(&opt_inst_list, |
| + opt_inst)) |
| + continue; |
| + |
| list_add(&opt_inst->tmp_list, &opt_inst_list); |
| } |
| if (!opt_found) { |