4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 45c180bc29babbedd6b8c01b975780ef44d9d09c upstream.
struct xfrm_userpolicy_type has two holes, so we should not use C99 style initializer.
KMSAN report:
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:140 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x1b14/0x2800 lib/iov_iter.c:571 CPU: 1 PID: 4520 Comm: syz-executor841 Not tainted 4.17.0+ #5 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+0x185/0x1d0 lib/dump_stack.c:113 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1117 kmsan_internal_check_memory+0x138/0x1f0 mm/kmsan/kmsan.c:1211 kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1253 copyout lib/iov_iter.c:140 [inline] _copy_to_iter+0x1b14/0x2800 lib/iov_iter.c:571 copy_to_iter include/linux/uio.h:106 [inline] skb_copy_datagram_iter+0x422/0xfa0 net/core/datagram.c:431 skb_copy_datagram_msg include/linux/skbuff.h:3268 [inline] netlink_recvmsg+0x6f1/0x1900 net/netlink/af_netlink.c:1959 sock_recvmsg_nosec net/socket.c:802 [inline] sock_recvmsg+0x1d6/0x230 net/socket.c:809 ___sys_recvmsg+0x3fe/0x810 net/socket.c:2279 __sys_recvmmsg+0x58e/0xe30 net/socket.c:2391 do_sys_recvmmsg+0x2a6/0x3e0 net/socket.c:2472 __do_sys_recvmmsg net/socket.c:2485 [inline] __se_sys_recvmmsg net/socket.c:2481 [inline] __x64_sys_recvmmsg+0x15d/0x1c0 net/socket.c:2481 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x446ce9 RSP: 002b:00007fc307918db8 EFLAGS: 00000293 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00000000006dbc24 RCX: 0000000000446ce9 RDX: 000000000000000a RSI: 0000000020005040 RDI: 0000000000000003 RBP: 00000000006dbc20 R08: 0000000020004e40 R09: 0000000000000000 R10: 0000000040000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc8d2df32f R14: 00007fc3079199c0 R15: 0000000000000001
Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline] kmsan_save_stack mm/kmsan/kmsan.c:294 [inline] kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:527 __msan_memcpy+0x109/0x160 mm/kmsan/kmsan_instr.c:413 __nla_put lib/nlattr.c:569 [inline] nla_put+0x276/0x340 lib/nlattr.c:627 copy_to_user_policy_type net/xfrm/xfrm_user.c:1678 [inline] dump_one_policy+0xbe1/0x1090 net/xfrm/xfrm_user.c:1708 xfrm_policy_walk+0x45a/0xd00 net/xfrm/xfrm_policy.c:1013 xfrm_dump_policy+0x1c0/0x2a0 net/xfrm/xfrm_user.c:1749 netlink_dump+0x9b5/0x1550 net/netlink/af_netlink.c:2226 __netlink_dump_start+0x1131/0x1270 net/netlink/af_netlink.c:2323 netlink_dump_start include/linux/netlink.h:214 [inline] xfrm_user_rcv_msg+0x8a3/0x9b0 net/xfrm/xfrm_user.c:2577 netlink_rcv_skb+0x37e/0x600 net/netlink/af_netlink.c:2448 xfrm_netlink_rcv+0xb2/0xf0 net/xfrm/xfrm_user.c:2598 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0x1680/0x1750 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x104f/0x1350 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg net/socket.c:639 [inline] ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117 __sys_sendmsg net/socket.c:2155 [inline] __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Local variable description: ----upt.i@dump_one_policy Variable was created at: dump_one_policy+0x78/0x1090 net/xfrm/xfrm_user.c:1689 xfrm_policy_walk+0x45a/0xd00 net/xfrm/xfrm_policy.c:1013
Byte 130 of 137 is uninitialized Memory access starts at ffff88019550407f
Fixes: c0144beaeca42 ("[XFRM] netlink: Use nla_put()/NLA_PUT() variantes") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Steffen Klassert steffen.klassert@secunet.com Cc: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/xfrm/xfrm_user.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -1628,9 +1628,11 @@ static inline size_t userpolicy_type_att #ifdef CONFIG_XFRM_SUB_POLICY static int copy_to_user_policy_type(u8 type, struct sk_buff *skb) { - struct xfrm_userpolicy_type upt = { - .type = type, - }; + struct xfrm_userpolicy_type upt; + + /* Sadly there are two holes in struct xfrm_userpolicy_type */ + memset(&upt, 0, sizeof(upt)); + upt.type = type;
return nla_put(skb, XFRMA_POLICY_TYPE, sizeof(upt), &upt); }