CVE-2022-0382 (published 2022-02-11T18:15Z)

An information leak flaw was found due to uninitialized memory in the Linux kernel's TIPC protocol subsystem, in the way a user sends a TIPC datagram to one or more destinations. This flaw allows a local user to read some kernel memory. This issue is limited to no more than 7 bytes, and the user cannot control what is read. This flaw affects the Linux kernel versions prior to 5.17-rc1.

Severity: LOW
CVSS v2 base score: 2.1 (AV:L/AC:L/Au:N/C:P/I:N/A:N)
CVSS v3 base score: 5.5, MEDIUM (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)

Weakness information:
cwe_id: CWE-909
cwe_name: Missing Initialization of Resource
description: The product does not initialize a critical resource.
extended_description: Many resources require initialization before they can be properly used. If a resource is not initialized, it could contain unpredictable or expired data, or it could be initialized to defaults that are invalid. This can have security implications when the resource is expected to have certain properties or values.
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Haimin Zhang
author_date: 2021-12-31 10:35:23+08:00
msg: net ticp:fix a kernel-infoleak in __tipc_sendmsg()

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@syzkaller.appspotmail.com
Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Link: https://lore.kernel.org/r/1640918123-14547-1-git-send-email-tcs.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: socket.c
change_type: ModificationType.MODIFY
diff: @@ -1461,6 +1461,8 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 		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);

programming_language: C