| From 50535249f624d0072cd885bcdce4e4b6fb770160 Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Fri, 12 Mar 2021 08:59:48 -0800 |
| Subject: net: qrtr: fix a kernel-infoleak in qrtr_recvmsg() |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| commit 50535249f624d0072cd885bcdce4e4b6fb770160 upstream. |
| |
| struct sockaddr_qrtr has a 2-byte hole, and qrtr_recvmsg() currently |
| does not clear it before copying kernel data to user space. |
| |
| It might be too late to name the hole since sockaddr_qrtr structure is uapi. |
| |
| BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 |
| CPU: 0 PID: 29705 Comm: syz-executor.3 Not tainted 5.11.0-rc7-syzkaller #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 |
| Call Trace: |
| __dump_stack lib/dump_stack.c:79 [inline] |
| dump_stack+0x21c/0x280 lib/dump_stack.c:120 |
| kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118 |
| kmsan_internal_check_memory+0x202/0x520 mm/kmsan/kmsan.c:402 |
| kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249 |
| instrument_copy_to_user include/linux/instrumented.h:121 [inline] |
| _copy_to_user+0x1ac/0x270 lib/usercopy.c:33 |
| copy_to_user include/linux/uaccess.h:209 [inline] |
| move_addr_to_user+0x3a2/0x640 net/socket.c:237 |
| ____sys_recvmsg+0x696/0xd50 net/socket.c:2575 |
| ___sys_recvmsg net/socket.c:2610 [inline] |
| do_recvmmsg+0xa97/0x22d0 net/socket.c:2710 |
| __sys_recvmmsg net/socket.c:2789 [inline] |
| __do_sys_recvmmsg net/socket.c:2812 [inline] |
| __se_sys_recvmmsg+0x24a/0x410 net/socket.c:2805 |
| __x64_sys_recvmmsg+0x62/0x80 net/socket.c:2805 |
| do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 |
| entry_SYSCALL_64_after_hwframe+0x44/0xa9 |
| RIP: 0033:0x465f69 |
| Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 |
| RSP: 002b:00007f43659d6188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b |
| RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465f69 |
| RDX: 0000000000000008 RSI: 0000000020003e40 RDI: 0000000000000003 |
| RBP: 00000000004bfa8f R08: 0000000000000000 R09: 0000000000000000 |
| R10: 0000000000010060 R11: 0000000000000246 R12: 000000000056bf60 |
| R13: 0000000000a9fb1f R14: 00007f43659d6300 R15: 0000000000022000 |
| |
| Local variable ----addr@____sys_recvmsg created at: |
| ____sys_recvmsg+0x168/0xd50 net/socket.c:2550 |
| ____sys_recvmsg+0x168/0xd50 net/socket.c:2550 |
| |
| Bytes 2-3 of 12 are uninitialized |
| Memory access of size 12 starts at ffff88817c627b40 |
| Data copied to user address 0000000020000140 |
| |
| Fixes: bdabad3e363d ("net: Add Qualcomm IPC router") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: Courtney Cavin <courtney.cavin@sonymobile.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/qrtr/qrtr.c | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| --- a/net/qrtr/qrtr.c |
| +++ b/net/qrtr/qrtr.c |
| @@ -862,6 +862,11 @@ static int qrtr_recvmsg(struct socket *s |
| rc = copied; |
| |
| if (addr) { |
| + /* There is an anonymous 2-byte hole after sq_family, |
| + * make sure to clear it. |
| + */ |
| + memset(addr, 0, sizeof(*addr)); |
| + |
| cb = (struct qrtr_cb *)skb->cb; |
| addr->sq_family = AF_QIPCRTR; |
| addr->sq_node = cb->src_node; |