* [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino()
@ 2024-04-17 13:48 Johannes Thumshirn
2024-04-17 13:49 ` Filipe Manana
2024-04-17 21:19 ` David Sterba
0 siblings, 2 replies; 3+ messages in thread
From: Johannes Thumshirn @ 2024-04-17 13:48 UTC (permalink / raw
To: linux-btrfs
Cc: Johannes Thumshirn, Filipe Manana, syzbot+510a1abbb8116eeb341d,
Johannes Thumshirn, Qu Wenruo
From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Syzbot reported the following information leak for in
btrfs_ioctl_logical_to_ino():
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:40
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
_copy_to_user+0xbc/0x110 lib/usercopy.c:40
copy_to_user include/linux/uaccess.h:191 [inline]
btrfs_ioctl_logical_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499
btrfs_ioctl+0x714/0x1260
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Uninit was created at:
__kmalloc_large_node+0x231/0x370 mm/slub.c:3921
__do_kmalloc_node mm/slub.c:3954 [inline]
__kmalloc_node+0xb07/0x1060 mm/slub.c:3973
kmalloc_node include/linux/slab.h:648 [inline]
kvmalloc_node+0xc0/0x2d0 mm/util.c:634
kvmalloc include/linux/slab.h:766 [inline]
init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779
btrfs_ioctl_logical_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480
btrfs_ioctl+0x714/0x1260
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:904 [inline]
__se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
__x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Bytes 40-65535 of 65536 are uninitialized
Memory access of size 65536 starts at ffff888045a40000
This happens, because we're copying a 'struct btrfs_data_container' back
to user-space. This btrfs_data_container is allocated in
'init_data_container()' via kvmalloc(), which does not zero-fill the
memory.
Fix this by using kvzalloc() which zeroes out the memory on allocation.
Reported-by: <syzbot+510a1abbb8116eeb341d@syzkaller.appspotmail.com>
Signed-off-by: Johannes Thumshirn <Johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/backref.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 0bc81b340295..a2de5c05f97c 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -2770,20 +2770,14 @@ struct btrfs_data_container *init_data_container(u32 total_bytes)
size_t alloc_bytes;
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
- data = kvmalloc(alloc_bytes, GFP_KERNEL);
+ data = kvzalloc(alloc_bytes, GFP_KERNEL);
if (!data)
return ERR_PTR(-ENOMEM);
- if (total_bytes >= sizeof(*data)) {
+ if (total_bytes >= sizeof(*data))
data->bytes_left = total_bytes - sizeof(*data);
- data->bytes_missing = 0;
- } else {
+ else
data->bytes_missing = sizeof(*data) - total_bytes;
- data->bytes_left = 0;
- }
-
- data->elem_cnt = 0;
- data->elem_missed = 0;
return data;
}
--
2.35.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino()
2024-04-17 13:48 [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino() Johannes Thumshirn
@ 2024-04-17 13:49 ` Filipe Manana
2024-04-17 21:19 ` David Sterba
1 sibling, 0 replies; 3+ messages in thread
From: Filipe Manana @ 2024-04-17 13:49 UTC (permalink / raw
To: Johannes Thumshirn
Cc: linux-btrfs, Johannes Thumshirn, syzbot+510a1abbb8116eeb341d,
Qu Wenruo
On Wed, Apr 17, 2024 at 2:49 PM Johannes Thumshirn <jth@kernel.org> wrote:
>
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> Syzbot reported the following information leak for in
> btrfs_ioctl_logical_to_ino():
>
> BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:40
> instrument_copy_to_user include/linux/instrumented.h:114 [inline]
> _copy_to_user+0xbc/0x110 lib/usercopy.c:40
> copy_to_user include/linux/uaccess.h:191 [inline]
> btrfs_ioctl_logical_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499
> btrfs_ioctl+0x714/0x1260
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:904 [inline]
> __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
> __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
> x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Uninit was created at:
> __kmalloc_large_node+0x231/0x370 mm/slub.c:3921
> __do_kmalloc_node mm/slub.c:3954 [inline]
> __kmalloc_node+0xb07/0x1060 mm/slub.c:3973
> kmalloc_node include/linux/slab.h:648 [inline]
> kvmalloc_node+0xc0/0x2d0 mm/util.c:634
> kvmalloc include/linux/slab.h:766 [inline]
> init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779
> btrfs_ioctl_logical_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480
> btrfs_ioctl+0x714/0x1260
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:904 [inline]
> __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
> __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
> x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Bytes 40-65535 of 65536 are uninitialized
> Memory access of size 65536 starts at ffff888045a40000
>
> This happens, because we're copying a 'struct btrfs_data_container' back
> to user-space. This btrfs_data_container is allocated in
> 'init_data_container()' via kvmalloc(), which does not zero-fill the
> memory.
>
> Fix this by using kvzalloc() which zeroes out the memory on allocation.
>
> Reported-by: <syzbot+510a1abbb8116eeb341d@syzkaller.appspotmail.com>
> Signed-off-by: Johannes Thumshirn <Johannes.thumshirn@wdc.com>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Looks good, thanks.
> ---
> fs/btrfs/backref.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index 0bc81b340295..a2de5c05f97c 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -2770,20 +2770,14 @@ struct btrfs_data_container *init_data_container(u32 total_bytes)
> size_t alloc_bytes;
>
> alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
> - data = kvmalloc(alloc_bytes, GFP_KERNEL);
> + data = kvzalloc(alloc_bytes, GFP_KERNEL);
> if (!data)
> return ERR_PTR(-ENOMEM);
>
> - if (total_bytes >= sizeof(*data)) {
> + if (total_bytes >= sizeof(*data))
> data->bytes_left = total_bytes - sizeof(*data);
> - data->bytes_missing = 0;
> - } else {
> + else
> data->bytes_missing = sizeof(*data) - total_bytes;
> - data->bytes_left = 0;
> - }
> -
> - data->elem_cnt = 0;
> - data->elem_missed = 0;
>
> return data;
> }
> --
> 2.35.3
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino()
2024-04-17 13:48 [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino() Johannes Thumshirn
2024-04-17 13:49 ` Filipe Manana
@ 2024-04-17 21:19 ` David Sterba
1 sibling, 0 replies; 3+ messages in thread
From: David Sterba @ 2024-04-17 21:19 UTC (permalink / raw
To: Johannes Thumshirn
Cc: linux-btrfs, Johannes Thumshirn, Filipe Manana,
syzbot+510a1abbb8116eeb341d, Qu Wenruo
On Wed, Apr 17, 2024 at 03:48:49PM +0200, Johannes Thumshirn wrote:
> From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>
> Syzbot reported the following information leak for in
> btrfs_ioctl_logical_to_ino():
>
> BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:40
> instrument_copy_to_user include/linux/instrumented.h:114 [inline]
> _copy_to_user+0xbc/0x110 lib/usercopy.c:40
> copy_to_user include/linux/uaccess.h:191 [inline]
> btrfs_ioctl_logical_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499
> btrfs_ioctl+0x714/0x1260
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:904 [inline]
> __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
> __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
> x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Uninit was created at:
> __kmalloc_large_node+0x231/0x370 mm/slub.c:3921
> __do_kmalloc_node mm/slub.c:3954 [inline]
> __kmalloc_node+0xb07/0x1060 mm/slub.c:3973
> kmalloc_node include/linux/slab.h:648 [inline]
> kvmalloc_node+0xc0/0x2d0 mm/util.c:634
> kvmalloc include/linux/slab.h:766 [inline]
> init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779
> btrfs_ioctl_logical_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480
> btrfs_ioctl+0x714/0x1260
> vfs_ioctl fs/ioctl.c:51 [inline]
> __do_sys_ioctl fs/ioctl.c:904 [inline]
> __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
> __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
> x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Bytes 40-65535 of 65536 are uninitialized
> Memory access of size 65536 starts at ffff888045a40000
>
> This happens, because we're copying a 'struct btrfs_data_container' back
> to user-space. This btrfs_data_container is allocated in
> 'init_data_container()' via kvmalloc(), which does not zero-fill the
> memory.
>
> Fix this by using kvzalloc() which zeroes out the memory on allocation.
>
> Reported-by: <syzbot+510a1abbb8116eeb341d@syzkaller.appspotmail.com>
> Signed-off-by: Johannes Thumshirn <Johannes.thumshirn@wdc.com>
> Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-04-17 21:26 UTC | newest]
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2024-04-17 13:48 [PATCH v2] btrfs: fix information leak in btrfs_ioctl_logical_to_ino() Johannes Thumshirn
2024-04-17 13:49 ` Filipe Manana
2024-04-17 21:19 ` David Sterba
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