4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ido Schimmel idosch@mellanox.com
[ Upstream commit da71577545a52be3e0e9225a946e5fd79cfab015 ]
When an FDB entry is configured, the address is validated to have the length of an Ethernet address, but the device for which the address is configured can be of any type.
The above can result in the use of uninitialized memory when the address is later compared against existing addresses since 'dev->addr_len' is used and it may be greater than ETH_ALEN, as with ip6tnl devices.
Fix this by making sure that FDB entries are only configured for Ethernet devices.
BUG: KMSAN: uninit-value in memcmp+0x11d/0x180 lib/string.c:863 CPU: 1 PID: 4318 Comm: syz-executor998 Not tainted 4.19.0-rc3+ #49 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+0x14b/0x190 lib/dump_stack.c:113 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:956 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645 memcmp+0x11d/0x180 lib/string.c:863 dev_uc_add_excl+0x165/0x7b0 net/core/dev_addr_lists.c:464 ndo_dflt_fdb_add net/core/rtnetlink.c:3463 [inline] rtnl_fdb_add+0x1081/0x1270 net/core/rtnetlink.c:3558 rtnetlink_rcv_msg+0xa0b/0x1530 net/core/rtnetlink.c:4715 netlink_rcv_skb+0x36e/0x5f0 net/netlink/af_netlink.c:2454 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4733 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x1638/0x1720 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x1205/0x1290 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114 __sys_sendmsg net/socket.c:2152 [inline] __do_sys_sendmsg net/socket.c:2161 [inline] __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x440ee9 Code: e8 cc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff6a93b518 EFLAGS: 00000213 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440ee9 RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000213 R12: 000000000000b4b0 R13: 0000000000401ec0 R14: 0000000000000000 R15: 0000000000000000
Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:181 kmsan_kmalloc+0x98/0x100 mm/kmsan/kmsan_hooks.c:91 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:100 slab_post_alloc_hook mm/slab.h:446 [inline] slab_alloc_node mm/slub.c:2718 [inline] __kmalloc_node_track_caller+0x9e7/0x1160 mm/slub.c:4351 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2f5/0x9e0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:996 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1189 [inline] netlink_sendmsg+0xb49/0x1290 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114 __sys_sendmsg net/socket.c:2152 [inline] __do_sys_sendmsg net/socket.c:2161 [inline] __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7
v2: * Make error message more specific (David)
Fixes: 090096bf3db1 ("net: generic fdb support for drivers without ndo_fdb_<op>") Signed-off-by: Ido Schimmel idosch@mellanox.com Reported-and-tested-by: syzbot+3a288d5f5530b901310e@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+d53ab4e92a1db04110ff@syzkaller.appspotmail.com Cc: Vlad Yasevich vyasevich@gmail.com Cc: David Ahern dsahern@gmail.com Reviewed-by: David Ahern dsahern@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/rtnetlink.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2734,6 +2734,11 @@ static int rtnl_fdb_add(struct sk_buff * return -EINVAL; }
+ if (dev->type != ARPHRD_ETHER) { + pr_info("PF_BRIDGE: FDB add only supported for Ethernet devices"); + return -EINVAL; + } + addr = nla_data(tb[NDA_LLADDR]);
err = fdb_vid_parse(tb[NDA_VLAN], &vid); @@ -2836,6 +2841,11 @@ static int rtnl_fdb_del(struct sk_buff * return -EINVAL; }
+ if (dev->type != ARPHRD_ETHER) { + pr_info("PF_BRIDGE: FDB delete only supported for Ethernet devices"); + return -EINVAL; + } + addr = nla_data(tb[NDA_LLADDR]);
err = fdb_vid_parse(tb[NDA_VLAN], &vid);