From: David Ahern dsahern@gmail.com
[ Upstream commit d00ee64e1dcf09b3afefd1340f3e9eb637272714 ]
Eric reported a syzbot warning:
BUG: KMSAN: uninit-value in nh_valid_get_del_req+0x6f1/0x8c0 net/ipv4/nexthop.c:1510 CPU: 0 PID: 11812 Comm: syz-executor444 Not tainted 5.3.0-rc3+ #17 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+0x191/0x1f0 lib/dump_stack.c:113 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294 nh_valid_get_del_req+0x6f1/0x8c0 net/ipv4/nexthop.c:1510 rtm_del_nexthop+0x1b1/0x610 net/ipv4/nexthop.c:1543 rtnetlink_rcv_msg+0x115a/0x1580 net/core/rtnetlink.c:5223 netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5241 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0xf6c/0x1050 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x110f/0x1330 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg net/socket.c:657 [inline] ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311 __sys_sendmmsg+0x53a/0xae0 net/socket.c:2413 __do_sys_sendmmsg net/socket.c:2442 [inline] __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2439 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2439 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x63/0xe7
The root cause is nlmsg_parse calling __nla_parse which means the header struct size is not checked.
nlmsg_parse should be a wrapper around __nlmsg_parse with NL_VALIDATE_STRICT for the validate argument very much like nlmsg_parse_deprecated is for NL_VALIDATE_LIBERAL.
Fixes: 3de6440354465 ("netlink: re-add parse/validate functions in strict mode") Reported-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David Ahern dsahern@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/netlink.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/include/net/netlink.h b/include/net/netlink.h index 395b4406f4b08..222af2046086e 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -680,9 +680,8 @@ static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen, const struct nla_policy *policy, struct netlink_ext_ack *extack) { - return __nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen), - nlmsg_attrlen(nlh, hdrlen), policy, - NL_VALIDATE_STRICT, extack); + return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy, + NL_VALIDATE_STRICT, extack); }
/**