[PATCH 5.15 46/72] net ticp:fix a kernel-infoleak in __tipc_sendmsg()

From: Greg Kroah-Hartman
Date: Mon Jan 10 2022 - 02:41:14 EST


From: Haimin Zhang <tcs_kernel@xxxxxxxxxxx>

commit d6d86830705f173fca6087a3e67ceaf68db80523 upstream.

struct tipc_socket_addr.ref has a 4-byte hole,and __tipc_getname() currently
copying it to user space,causing kernel-infoleak.

BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline] lib/usercopy.c:33
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x1c9/0x270 lib/usercopy.c:33 lib/usercopy.c:33
instrument_copy_to_user include/linux/instrumented.h:121 [inline]
instrument_copy_to_user include/linux/instrumented.h:121 [inline] lib/usercopy.c:33
_copy_to_user+0x1c9/0x270 lib/usercopy.c:33 lib/usercopy.c:33
copy_to_user include/linux/uaccess.h:209 [inline]
copy_to_user include/linux/uaccess.h:209 [inline] net/socket.c:287
move_addr_to_user+0x3f6/0x600 net/socket.c:287 net/socket.c:287
__sys_getpeername+0x470/0x6b0 net/socket.c:1987 net/socket.c:1987
__do_sys_getpeername net/socket.c:1997 [inline]
__se_sys_getpeername net/socket.c:1994 [inline]
__do_sys_getpeername net/socket.c:1997 [inline] net/socket.c:1994
__se_sys_getpeername net/socket.c:1994 [inline] net/socket.c:1994
__x64_sys_getpeername+0xda/0x120 net/socket.c:1994 net/socket.c:1994
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_x64 arch/x86/entry/common.c:51 [inline] arch/x86/entry/common.c:82
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was stored to memory at:
tipc_getname+0x575/0x5e0 net/tipc/socket.c:757 net/tipc/socket.c:757
__sys_getpeername+0x3b3/0x6b0 net/socket.c:1984 net/socket.c:1984
__do_sys_getpeername net/socket.c:1997 [inline]
__se_sys_getpeername net/socket.c:1994 [inline]
__do_sys_getpeername net/socket.c:1997 [inline] net/socket.c:1994
__se_sys_getpeername net/socket.c:1994 [inline] net/socket.c:1994
__x64_sys_getpeername+0xda/0x120 net/socket.c:1994 net/socket.c:1994
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_x64 arch/x86/entry/common.c:51 [inline] arch/x86/entry/common.c:82
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was stored to memory at:
msg_set_word net/tipc/msg.h:212 [inline]
msg_set_destport net/tipc/msg.h:619 [inline]
msg_set_word net/tipc/msg.h:212 [inline] net/tipc/socket.c:1486
msg_set_destport net/tipc/msg.h:619 [inline] net/tipc/socket.c:1486
__tipc_sendmsg+0x44fa/0x5890 net/tipc/socket.c:1486 net/tipc/socket.c:1486
tipc_sendmsg+0xeb/0x140 net/tipc/socket.c:1402 net/tipc/socket.c:1402
sock_sendmsg_nosec net/socket.c:704 [inline]
sock_sendmsg net/socket.c:724 [inline]
sock_sendmsg_nosec net/socket.c:704 [inline] net/socket.c:2409
sock_sendmsg net/socket.c:724 [inline] net/socket.c:2409
____sys_sendmsg+0xe11/0x12c0 net/socket.c:2409 net/socket.c:2409
___sys_sendmsg net/socket.c:2463 [inline]
___sys_sendmsg net/socket.c:2463 [inline] net/socket.c:2492
__sys_sendmsg+0x704/0x840 net/socket.c:2492 net/socket.c:2492
__do_sys_sendmsg net/socket.c:2501 [inline]
__se_sys_sendmsg net/socket.c:2499 [inline]
__do_sys_sendmsg net/socket.c:2501 [inline] net/socket.c:2499
__se_sys_sendmsg net/socket.c:2499 [inline] net/socket.c:2499
__x64_sys_sendmsg+0xe2/0x120 net/socket.c:2499 net/socket.c:2499
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_x64 arch/x86/entry/common.c:51 [inline] arch/x86/entry/common.c:82
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae

Local variable skaddr created at:
__tipc_sendmsg+0x2d0/0x5890 net/tipc/socket.c:1419 net/tipc/socket.c:1419
tipc_sendmsg+0xeb/0x140 net/tipc/socket.c:1402 net/tipc/socket.c:1402

Bytes 4-7 of 16 are uninitialized
Memory access of size 16 starts at ffff888113753e00
Data copied to user address 0000000020000280

Reported-by: syzbot+cdbd40e0c3ca02cae3b7@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Haimin Zhang <tcs_kernel@xxxxxxxxxxx>
Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx>
Link: https://lore.kernel.org/r/1640918123-14547-1-git-send-email-tcs.kernel@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/tipc/socket.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1461,6 +1461,8 @@ static int __tipc_sendmsg(struct socket
msg_set_syn(hdr, 1);
}

+ memset(&skaddr, 0, sizeof(skaddr));
+
/* Determine destination */
if (atype == TIPC_SERVICE_RANGE) {
return tipc_sendmcast(sock, ua, m, dlen, timeout);