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* [syzbot] [mm?] KMSAN: kernel-infoleak in bpf_probe_write_user
@ 2024-04-13  2:27 syzbot
  2024-04-15 20:18 ` Andrew Morton
  0 siblings, 1 reply; 7+ messages in thread
From: syzbot @ 2024-04-13  2:27 UTC (permalink / raw)
  To: akpm, linux-kernel, linux-mm, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    fec50db7033e Linux 6.9-rc3
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16509ba1180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=13e7da432565d94c
dashboard link: https://syzkaller.appspot.com/bug?extid=79102ed905e5b2dc0fc3
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=10a4af9d180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12980f9d180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/901017b36ccc/disk-fec50db7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/16bfcf5618d3/vmlinux-fec50db7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dc9c5a1e7d02/bzImage-fec50db7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+79102ed905e5b2dc0fc3@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in __copy_to_user_inatomic include/linux/uaccess.h:125 [inline]
BUG: KMSAN: kernel-infoleak in copy_to_user_nofault+0x129/0x1f0 mm/maccess.c:149
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 __copy_to_user_inatomic include/linux/uaccess.h:125 [inline]
 copy_to_user_nofault+0x129/0x1f0 mm/maccess.c:149
 ____bpf_probe_write_user kernel/trace/bpf_trace.c:349 [inline]
 bpf_probe_write_user+0x104/0x180 kernel/trace/bpf_trace.c:327
 ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997
 __bpf_prog_run64+0xb5/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420
 __bpf_trace_kfree+0x29/0x40 include/trace/events/kmem.h:94
 trace_kfree include/trace/events/kmem.h:94 [inline]
 kfree+0x6a5/0xa30 mm/slub.c:4377
 vfs_writev+0x12bf/0x1450 fs/read_write.c:978
 do_writev+0x251/0x5c0 fs/read_write.c:1018
 __do_sys_writev fs/read_write.c:1091 [inline]
 __se_sys_writev fs/read_write.c:1088 [inline]
 __x64_sys_writev+0x98/0xe0 fs/read_write.c:1088
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

Local variable stack created at:
 __bpf_prog_run64+0x45/0xe0 kernel/bpf/core.c:2236
 bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
 __bpf_prog_run include/linux/filter.h:657 [inline]
 bpf_prog_run include/linux/filter.h:664 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
 bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420

Bytes 0-7 of 8 are uninitialized
Memory access of size 8 starts at ffff888121ec7ae8
Data copied to user address 00000000ffffffff

CPU: 1 PID: 4779 Comm: dhcpcd Not tainted 6.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
=====================================================


---
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^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2024-04-18  7:59 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-04-13  2:27 [syzbot] [mm?] KMSAN: kernel-infoleak in bpf_probe_write_user syzbot
2024-04-15 20:18 ` Andrew Morton
2024-04-15 21:06   ` Alexei Starovoitov
2024-04-16  8:46     ` Aleksandr Nogikh
2024-04-16  8:52     ` Alexander Potapenko
2024-04-16 15:16       ` Alexei Starovoitov
2024-04-18  7:58         ` Alexander Potapenko

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