| From 45c180bc29babbedd6b8c01b975780ef44d9d09c Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Mon, 18 Jun 2018 21:35:07 -0700 |
| Subject: xfrm_user: prevent leaking 2 bytes of kernel memory |
| |
| 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); |
| } |