4.14-stable review patch. If anyone has any objections, please let me know.
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From: Ying Xue ying.xue@windriver.com
[ Upstream commit 94f6a80c0c11828cb7b3d79294459dd8d761ca89 ]
When we get link properties through netlink interface with tipc_nl_node_get_link(), we don't validate TIPC_NLA_LINK_NAME attribute at all, instead we directly use it. As a consequence, KMSAN detected the TIPC_NLA_LINK_NAME attribute was an uninitialized value, and then posted the following complaint:
================================================================== BUG: KMSAN: uninit-value in strcmp+0xf7/0x160 lib/string.c:329 CPU: 1 PID: 4527 Comm: syz-executor655 Not tainted 4.16.0+ #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 strcmp+0xf7/0x160 lib/string.c:329 tipc_nl_node_get_link+0x220/0x6f0 net/tipc/node.c:1881 genl_family_rcv_msg net/netlink/genetlink.c:599 [inline] genl_rcv_msg+0x1686/0x1810 net/netlink/genetlink.c:624 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2447 genl_rcv+0x63/0x80 net/netlink/genetlink.c:635 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x166b/0x1740 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x445589 RSP: 002b:00007fb7ee66cdb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445589 RDX: 0000000000000000 RSI: 0000000020023000 RDI: 0000000000000003 RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffa2bf3f3f R14: 00007fb7ee66d9c0 R15: 0000000000000001
Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline] netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 ==================================================================
To quiet the complaint, TIPC_NLA_LINK_NAME attribute has been validated in tipc_nl_node_get_link() before it's used.
Reported-by: syzbot+df0257c92ffd4fcc58cd@syzkaller.appspotmail.com Signed-off-by: Ying Xue ying.xue@windriver.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/node.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/net/tipc/node.c +++ b/net/tipc/node.c @@ -1831,6 +1831,7 @@ out: int tipc_nl_node_get_link(struct sk_buff *skb, struct genl_info *info) { struct net *net = genl_info_net(info); + struct nlattr *attrs[TIPC_NLA_LINK_MAX + 1]; struct tipc_nl_msg msg; char *name; int err; @@ -1838,9 +1839,19 @@ int tipc_nl_node_get_link(struct sk_buff msg.portid = info->snd_portid; msg.seq = info->snd_seq;
- if (!info->attrs[TIPC_NLA_LINK_NAME]) + if (!info->attrs[TIPC_NLA_LINK]) return -EINVAL; - name = nla_data(info->attrs[TIPC_NLA_LINK_NAME]); + + err = nla_parse_nested(attrs, TIPC_NLA_LINK_MAX, + info->attrs[TIPC_NLA_LINK], + tipc_nl_link_policy, info->extack); + if (err) + return err; + + if (!attrs[TIPC_NLA_LINK_NAME]) + return -EINVAL; + + name = nla_data(attrs[TIPC_NLA_LINK_NAME]);
msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); if (!msg.skb)