KMSAN: kernel-infoleak in move_addr_to

KMSAN: kernel-infoleak in move_addr_to_user (6)
Status: upstream: reported C repro on 2021/12/20 16:33
Reported-by: syzbot+cdbd40e0c3ca02cae3b7@syzkaller.appspotmail.com
Fix commit: d6d86830705f net ticp:fix a kernel-infoleak in __tipc_sendmsg()
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-riscv64 ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386]
First crash: 38d, last: 25d

similar bugs (5):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
upstream	KMSAN: kernel-infoleak in move_addr_to_user (3)	C	79	495d	529d	17/22	fixed on 2020/09/28 09:09
upstream	KMSAN: kernel-infoleak in move_addr_to_user (2)	C	8	1034d	1049d	12/22	fixed on 2019/03/28 12:00
upstream	KMSAN: kernel-infoleak in move_addr_to_user (4)	C	59	327d	379d	21/22	fixed on 2021/03/10 01:48
upstream	KMSAN: kernel-infoleak in move_addr_to_user (5)		3	177d	318d	22/22	fixed on 2021/11/10 00:50
upstream	KMSAN: kernel-infoleak in move_addr_to_user		5	1062d	1112d	12/22	fixed on 2019/03/06 07:43

Sample crash report:

=====================================================
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

CPU: 1 PID: 3479 Comm: syz-executor115 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kmsan-gce	2021/12/17 12:20	https://github.com/google/kmsan.git master	b0a8b5053e8b	44068e19	.config	log	report	syz	C		KMSAN: kernel-infoleak in move_addr_to_user
ci-upstream-kmsan-gce	2021/12/30 05:11	https://github.com/google/kmsan.git master	81c325bbf94e	6cc879d4	.config	log	report			info	KMSAN: kernel-infoleak in move_addr_to_user
ci-upstream-kmsan-gce	2021/12/17 11:04	https://github.com/google/kmsan.git master	b0a8b5053e8b	44068e19	.config	log	report			info	KMSAN: kernel-infoleak in move_addr_to_user