From: Eric Dumazet Date: Sun, 14 Apr 2019 18:02:05 +0000 (-0700) Subject: rtnetlink: fix rtnl_valid_stats_req() nlmsg_len check X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=69f23a09daf9790acb801aaef4bc7aea6f69eec1;p=openwrt%2Fstaging%2Fblogic.git rtnetlink: fix rtnl_valid_stats_req() nlmsg_len check Jakub forgot to either use nlmsg_len() or nlmsg_msg_size(), allowing KMSAN to detect a possible uninit-value in rtnl_stats_get BUG: KMSAN: uninit-value in rtnl_stats_get+0x6d9/0x11d0 net/core/rtnetlink.c:4997 CPU: 0 PID: 10428 Comm: syz-executor034 Not tainted 5.1.0-rc2+ #24 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+0x131/0x2a0 mm/kmsan/kmsan.c:619 __msan_warning+0x7a/0xf0 mm/kmsan/kmsan_instr.c:310 rtnl_stats_get+0x6d9/0x11d0 net/core/rtnetlink.c:4997 rtnetlink_rcv_msg+0x115b/0x1550 net/core/rtnetlink.c:5192 netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2485 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5210 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:1925 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg net/socket.c:632 [inline] ___sys_sendmsg+0xdb3/0x1220 net/socket.c:2137 __sys_sendmsg net/socket.c:2175 [inline] __do_sys_sendmsg net/socket.c:2184 [inline] __se_sys_sendmsg+0x305/0x460 net/socket.c:2182 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2182 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 Fixes: 51bc860d4a99 ("rtnetlink: stats: validate attributes in get as well as dumps") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Jakub Kicinski Signed-off-by: David S. Miller --- diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index a51cab95ba64..220c56e93659 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -4948,7 +4948,7 @@ static int rtnl_valid_stats_req(const struct nlmsghdr *nlh, bool strict_check, { struct if_stats_msg *ifsm; - if (nlh->nlmsg_len < sizeof(*ifsm)) { + if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ifsm))) { NL_SET_ERR_MSG(extack, "Invalid header for stats dump"); return -EINVAL; }