* [PATCH] bcachefs: Fix invalid shift in validate_sb_layout()
@ 2024-10-23 21:30 Gianfranco Trad
2024-10-24 10:48 ` Gianfranco Trad
2024-10-24 11:23 ` Kent Overstreet
0 siblings, 2 replies; 5+ messages in thread
From: Gianfranco Trad @ 2024-10-23 21:30 UTC (permalink / raw)
To: kent.overstreet
Cc: linux-bcachefs, linux-kernel, skhan, Gianfranco Trad,
syzbot+089fad5a3a5e77825426
Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX
to prevent UBSAN shift-out-of-bounds in validate_sb_layout().
Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426
Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")
Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
---
fs/bcachefs/errcode.h | 1 +
fs/bcachefs/super-io.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
index 649263516ab1..b6cbd716000b 100644
--- a/fs/bcachefs/errcode.h
+++ b/fs/bcachefs/errcode.h
@@ -222,6 +222,7 @@
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
+ x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_sb_max_size_bits) \
x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
x(BCH_ERR_invalid_sb, invalid_sb_members) \
x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index ce7410d72089..44d0ac9b00dd 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -287,6 +287,11 @@ static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out
return -BCH_ERR_invalid_sb_layout_nr_superblocks;
}
+ if (layout->sb_max_size_bits > BCH_SB_LAYOUT_SIZE_BITS_MAX) {
+ prt_printf(out, "Invalid superblock layout: max_size_bits too high");
+ return -BCH_ERR_invalid_sb_layout_sb_max_size_bits;
+ }
+
max_sectors = 1 << layout->sb_max_size_bits;
prev_offset = le64_to_cpu(layout->sb_offset[0]);
--
2.43.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] bcachefs: Fix invalid shift in validate_sb_layout()
2024-10-23 21:30 [PATCH] bcachefs: Fix invalid shift in validate_sb_layout() Gianfranco Trad
@ 2024-10-24 10:48 ` Gianfranco Trad
2024-10-24 11:24 ` Kent Overstreet
2024-10-24 11:23 ` Kent Overstreet
1 sibling, 1 reply; 5+ messages in thread
From: Gianfranco Trad @ 2024-10-24 10:48 UTC (permalink / raw)
To: kent.overstreet
Cc: linux-bcachefs, linux-kernel, skhan, syzbot+089fad5a3a5e77825426
On 23/10/24 23:30, Gianfranco Trad wrote:
> Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX
> to prevent UBSAN shift-out-of-bounds in validate_sb_layout().
>
> Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426
> Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")
> Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
> ---
> fs/bcachefs/errcode.h | 1 +
> fs/bcachefs/super-io.c | 5 +++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
> index 649263516ab1..b6cbd716000b 100644
> --- a/fs/bcachefs/errcode.h
> +++ b/fs/bcachefs/errcode.h
> @@ -222,6 +222,7 @@
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
> + x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_sb_max_size_bits) \
> x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
> x(BCH_ERR_invalid_sb, invalid_sb_members) \
> x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
> diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
> index ce7410d72089..44d0ac9b00dd 100644
> --- a/fs/bcachefs/super-io.c
> +++ b/fs/bcachefs/super-io.c
> @@ -287,6 +287,11 @@ static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out
> return -BCH_ERR_invalid_sb_layout_nr_superblocks;
> }
>
> + if (layout->sb_max_size_bits > BCH_SB_LAYOUT_SIZE_BITS_MAX) {
> + prt_printf(out, "Invalid superblock layout: max_size_bits too high");
> + return -BCH_ERR_invalid_sb_layout_sb_max_size_bits;
> + }
> +
> max_sectors = 1 << layout->sb_max_size_bits;
>
> prev_offset = le64_to_cpu(layout->sb_offset[0]);
Wondering if this other patch might be considered more correct to
prevent shift oob, given also [0]:
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index ce7410d72089..428172897501 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -287,7 +287,7 @@ static int validate_sb_layout(struct bch_sb_layout
*layout, struct printbuf *out
return -BCH_ERR_invalid_sb_layout_nr_superblocks;
}
- max_sectors = 1 << layout->sb_max_size_bits;
+ max_sectors = 1 << min(BCH_SB_LAYOUT_SIZE_BITS_MAX,
layout->sb_max_size_bits);
prev_offset = le64_to_cpu(layout->sb_offset[0]);
Also this patch was already tested by syzbot [1]
[0] 71dac2482ad3c8d4a8b8998a96751f009bad895f ("bcachefs:
BCH_SB_LAYOUT_SIZE_BITS_MAX")
[1] https://syzkaller.appspot.com/x/log.txt?x=1640b640580000
Thanks for your time,
-- Gian
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] bcachefs: Fix invalid shift in validate_sb_layout()
2024-10-24 10:48 ` Gianfranco Trad
@ 2024-10-24 11:24 ` Kent Overstreet
2024-10-24 11:51 ` Gianfranco Trad
0 siblings, 1 reply; 5+ messages in thread
From: Kent Overstreet @ 2024-10-24 11:24 UTC (permalink / raw)
To: Gianfranco Trad
Cc: linux-bcachefs, linux-kernel, skhan, syzbot+089fad5a3a5e77825426
On Thu, Oct 24, 2024 at 12:48:30PM +0200, Gianfranco Trad wrote:
> On 23/10/24 23:30, Gianfranco Trad wrote:
> > Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX
> > to prevent UBSAN shift-out-of-bounds in validate_sb_layout().
> >
> > Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426
> > Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")
> > Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> > Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
> > ---
> > fs/bcachefs/errcode.h | 1 +
> > fs/bcachefs/super-io.c | 5 +++++
> > 2 files changed, 6 insertions(+)
> >
> > diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
> > index 649263516ab1..b6cbd716000b 100644
> > --- a/fs/bcachefs/errcode.h
> > +++ b/fs/bcachefs/errcode.h
> > @@ -222,6 +222,7 @@
> > x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
> > x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
> > x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
> > + x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_sb_max_size_bits) \
> > x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
> > x(BCH_ERR_invalid_sb, invalid_sb_members) \
> > x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
> > diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
> > index ce7410d72089..44d0ac9b00dd 100644
> > --- a/fs/bcachefs/super-io.c
> > +++ b/fs/bcachefs/super-io.c
> > @@ -287,6 +287,11 @@ static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out
> > return -BCH_ERR_invalid_sb_layout_nr_superblocks;
> > }
> > + if (layout->sb_max_size_bits > BCH_SB_LAYOUT_SIZE_BITS_MAX) {
> > + prt_printf(out, "Invalid superblock layout: max_size_bits too high");
> > + return -BCH_ERR_invalid_sb_layout_sb_max_size_bits;
> > + }
> > +
> > max_sectors = 1 << layout->sb_max_size_bits;
> > prev_offset = le64_to_cpu(layout->sb_offset[0]);
>
> Wondering if this other patch might be considered more correct to prevent
> shift oob, given also [0]:
Your first patch looks better, we want to know if we're feeding it
garbage
>
> diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
> index ce7410d72089..428172897501 100644
> --- a/fs/bcachefs/super-io.c
> +++ b/fs/bcachefs/super-io.c
> @@ -287,7 +287,7 @@ static int validate_sb_layout(struct bch_sb_layout
> *layout, struct printbuf *out
> return -BCH_ERR_invalid_sb_layout_nr_superblocks;
> }
>
> - max_sectors = 1 << layout->sb_max_size_bits;
> + max_sectors = 1 << min(BCH_SB_LAYOUT_SIZE_BITS_MAX,
> layout->sb_max_size_bits);
>
> prev_offset = le64_to_cpu(layout->sb_offset[0]);
>
> Also this patch was already tested by syzbot [1]
>
> [0] 71dac2482ad3c8d4a8b8998a96751f009bad895f ("bcachefs:
> BCH_SB_LAYOUT_SIZE_BITS_MAX")
> [1] https://syzkaller.appspot.com/x/log.txt?x=1640b640580000
>
> Thanks for your time,
>
> -- Gian
>
>
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] bcachefs: Fix invalid shift in validate_sb_layout()
2024-10-24 11:24 ` Kent Overstreet
@ 2024-10-24 11:51 ` Gianfranco Trad
0 siblings, 0 replies; 5+ messages in thread
From: Gianfranco Trad @ 2024-10-24 11:51 UTC (permalink / raw)
To: Kent Overstreet
Cc: linux-bcachefs, linux-kernel, skhan, syzbot+089fad5a3a5e77825426
On 24/10/24 13:24, Kent Overstreet wrote:
> On Thu, Oct 24, 2024 at 12:48:30PM +0200, Gianfranco Trad wrote:
>> On 23/10/24 23:30, Gianfranco Trad wrote:
>>> Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX
>>> to prevent UBSAN shift-out-of-bounds in validate_sb_layout().
>>>
>>> Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
>>> Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426
>>> Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")
>>> Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
>>> Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
>>> ---
>>> fs/bcachefs/errcode.h | 1 +
>>> fs/bcachefs/super-io.c | 5 +++++
>>> 2 files changed, 6 insertions(+)
>>>
>>> diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
>>> index 649263516ab1..b6cbd716000b 100644
>>> --- a/fs/bcachefs/errcode.h
>>> +++ b/fs/bcachefs/errcode.h
>>> @@ -222,6 +222,7 @@
>>> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
>>> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
>>> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
>>> + x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_sb_max_size_bits) \
>>> x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
>>> x(BCH_ERR_invalid_sb, invalid_sb_members) \
>>> x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
>>> diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
>>> index ce7410d72089..44d0ac9b00dd 100644
>>> --- a/fs/bcachefs/super-io.c
>>> +++ b/fs/bcachefs/super-io.c
>>> @@ -287,6 +287,11 @@ static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out
>>> return -BCH_ERR_invalid_sb_layout_nr_superblocks;
>>> }
>>> + if (layout->sb_max_size_bits > BCH_SB_LAYOUT_SIZE_BITS_MAX) {
>>> + prt_printf(out, "Invalid superblock layout: max_size_bits too high");
>>> + return -BCH_ERR_invalid_sb_layout_sb_max_size_bits;
>>> + }
>>> +
>>> max_sectors = 1 << layout->sb_max_size_bits;
>>> prev_offset = le64_to_cpu(layout->sb_offset[0]);
>>
>> Wondering if this other patch might be considered more correct to prevent
>> shift oob, given also [0]:
>
> Your first patch looks better, we want to know if we're feeding it
> garbage
>
Understood. Thanks Kent.
Have a nice day,
--Gian
>>
>> diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
>> index ce7410d72089..428172897501 100644
>> --- a/fs/bcachefs/super-io.c
>> +++ b/fs/bcachefs/super-io.c
>> @@ -287,7 +287,7 @@ static int validate_sb_layout(struct bch_sb_layout
>> *layout, struct printbuf *out
>> return -BCH_ERR_invalid_sb_layout_nr_superblocks;
>> }
>>
>> - max_sectors = 1 << layout->sb_max_size_bits;
>> + max_sectors = 1 << min(BCH_SB_LAYOUT_SIZE_BITS_MAX,
>> layout->sb_max_size_bits);
>>
>> prev_offset = le64_to_cpu(layout->sb_offset[0]);
>>
>> Also this patch was already tested by syzbot [1]
>>
>> [0] 71dac2482ad3c8d4a8b8998a96751f009bad895f ("bcachefs:
>> BCH_SB_LAYOUT_SIZE_BITS_MAX")
>> [1] https://syzkaller.appspot.com/x/log.txt?x=1640b640580000
>>
>> Thanks for your time,
>>
>> -- Gian
>>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] bcachefs: Fix invalid shift in validate_sb_layout()
2024-10-23 21:30 [PATCH] bcachefs: Fix invalid shift in validate_sb_layout() Gianfranco Trad
2024-10-24 10:48 ` Gianfranco Trad
@ 2024-10-24 11:23 ` Kent Overstreet
1 sibling, 0 replies; 5+ messages in thread
From: Kent Overstreet @ 2024-10-24 11:23 UTC (permalink / raw)
To: Gianfranco Trad
Cc: linux-bcachefs, linux-kernel, skhan, syzbot+089fad5a3a5e77825426
On Wed, Oct 23, 2024 at 11:30:44PM +0200, Gianfranco Trad wrote:
> Add check on layout->sb_max_size_bits against BCH_SB_LAYOUT_SIZE_BITS_MAX
> to prevent UBSAN shift-out-of-bounds in validate_sb_layout().
>
> Reported-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=089fad5a3a5e77825426
> Fixes: 03ef80b469d5 ("bcachefs: Ignore unknown mount options")
> Tested-by: syzbot+089fad5a3a5e77825426@syzkaller.appspotmail.com
> Signed-off-by: Gianfranco Trad <gianf.trad@gmail.com>
looks correct, applied
> ---
> fs/bcachefs/errcode.h | 1 +
> fs/bcachefs/super-io.c | 5 +++++
> 2 files changed, 6 insertions(+)
>
> diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
> index 649263516ab1..b6cbd716000b 100644
> --- a/fs/bcachefs/errcode.h
> +++ b/fs/bcachefs/errcode.h
> @@ -222,6 +222,7 @@
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
> x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
> + x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_sb_max_size_bits) \
> x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
> x(BCH_ERR_invalid_sb, invalid_sb_members) \
> x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
> diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
> index ce7410d72089..44d0ac9b00dd 100644
> --- a/fs/bcachefs/super-io.c
> +++ b/fs/bcachefs/super-io.c
> @@ -287,6 +287,11 @@ static int validate_sb_layout(struct bch_sb_layout *layout, struct printbuf *out
> return -BCH_ERR_invalid_sb_layout_nr_superblocks;
> }
>
> + if (layout->sb_max_size_bits > BCH_SB_LAYOUT_SIZE_BITS_MAX) {
> + prt_printf(out, "Invalid superblock layout: max_size_bits too high");
> + return -BCH_ERR_invalid_sb_layout_sb_max_size_bits;
> + }
> +
> max_sectors = 1 << layout->sb_max_size_bits;
>
> prev_offset = le64_to_cpu(layout->sb_offset[0]);
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2024-10-23 21:30 [PATCH] bcachefs: Fix invalid shift in validate_sb_layout() Gianfranco Trad
2024-10-24 10:48 ` Gianfranco Trad
2024-10-24 11:24 ` Kent Overstreet
2024-10-24 11:51 ` Gianfranco Trad
2024-10-24 11:23 ` Kent Overstreet
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