From: syzbot <syzbot+cfc08744435c4cf94a40@syzkaller.appspotmail.com>
To: linux-kernel@vger.kernel.org, luto@kernel.org,
peterz@infradead.org, syzkaller-bugs@googlegroups.com,
tglx@linutronix.de, xrivendell7@gmail.com
Subject: Re: [syzbot] [kernel?] KMSAN: kernel-infoleak-after-free in copy_siginfo_to_user (2)
Date: Mon, 25 Dec 2023 14:15:18 -0800 [thread overview]
Message-ID: <000000000000a9d761060d5ce6cf@google.com> (raw)
In-Reply-To: <0000000000008fcf9806083e7405@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 861deac3b092 Linux 6.7-rc7
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15826ec9e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=cfc08744435c4cf94a40
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17ea5231e80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ea60ee8ed32/disk-861deac3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d69fdc33021/vmlinux-861deac3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f0158750d452/bzImage-861deac3.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cfc08744435c4cf94a40@syzkaller.appspotmail.com
=====================================================
BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_user+0xbc/0x100 lib/usercopy.c:40
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
_copy_to_user+0xbc/0x100 lib/usercopy.c:40
copy_to_user include/linux/uaccess.h:191 [inline]
copy_siginfo_to_user+0x40/0x130 kernel/signal.c:3374
ptrace_request+0xfa6/0x36d0 kernel/ptrace.c:1066
arch_ptrace+0x435/0x680 arch/x86/kernel/ptrace.c:848
__do_sys_ptrace kernel/ptrace.c:1305 [inline]
__se_sys_ptrace+0x2d8/0x750 kernel/ptrace.c:1278
__x64_sys_ptrace+0xbd/0x110 kernel/ptrace.c:1278
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was stored to memory at:
copy_siginfo include/linux/signal.h:17 [inline]
ptrace_getsiginfo kernel/ptrace.c:705 [inline]
ptrace_request+0xf32/0x36d0 kernel/ptrace.c:1064
arch_ptrace+0x435/0x680 arch/x86/kernel/ptrace.c:848
__do_sys_ptrace kernel/ptrace.c:1305 [inline]
__se_sys_ptrace+0x2d8/0x750 kernel/ptrace.c:1278
__x64_sys_ptrace+0xbd/0x110 kernel/ptrace.c:1278
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was stored to memory at:
copy_siginfo include/linux/signal.h:17 [inline]
collect_signal kernel/signal.c:596 [inline]
__dequeue_signal+0x548/0xa00 kernel/signal.c:625
dequeue_signal+0x14b/0xb10 kernel/signal.c:648
get_signal+0xc3f/0x2d10 kernel/signal.c:2784
arch_do_signal_or_restart+0x53/0xca0 arch/x86/kernel/signal.c:309
exit_to_user_mode_loop+0xe8/0x320 kernel/entry/common.c:168
exit_to_user_mode_prepare+0x163/0x220 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x2a/0x140 kernel/entry/common.c:296
do_syscall_64+0x50/0x110 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was created at:
slab_free_hook mm/slub.c:1770 [inline]
slab_free_freelist_hook mm/slub.c:1826 [inline]
slab_free mm/slub.c:3809 [inline]
kmem_cache_free+0x66f/0x1250 mm/slub.c:3831
__sigqueue_free kernel/signal.c:460 [inline]
collect_signal kernel/signal.c:603 [inline]
__dequeue_signal+0x998/0xa00 kernel/signal.c:625
dequeue_signal+0x14b/0xb10 kernel/signal.c:648
get_signal+0xc3f/0x2d10 kernel/signal.c:2784
arch_do_signal_or_restart+0x53/0xca0 arch/x86/kernel/signal.c:309
exit_to_user_mode_loop+0xe8/0x320 kernel/entry/common.c:168
exit_to_user_mode_prepare+0x163/0x220 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
syscall_exit_to_user_mode+0x2a/0x140 kernel/entry/common.c:296
do_syscall_64+0x50/0x110 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Bytes 12-15 of 48 are uninitialized
Memory access of size 48 starts at ffff888115d6bc80
Data copied to user address 00000000016164e0
CPU: 1 PID: 5004 Comm: strace-static-x Not tainted 6.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
next prev parent reply other threads:[~2023-12-25 22:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-21 18:49 [syzbot] [kernel?] KMSAN: kernel-infoleak-after-free in copy_siginfo_to_user (2) syzbot
2023-12-25 22:15 ` syzbot [this message]
2023-12-31 1:51 ` Edward Adam Davis
2023-12-31 2:15 ` syzbot
2023-12-31 2:41 ` [PATCH] ptrace: fix kernel-infoleak-after-free in copy_siginfo_to_user Edward Adam Davis
2024-03-24 9:13 ` [syzbot] [kernel?] KMSAN: kernel-infoleak-after-free in copy_siginfo_to_user (2) syzbot
-- strict thread matches above, loose matches on Subject: below --
2023-12-25 7:16 xingwei lee
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