From: Colin Ian King <[email protected]>
There is a null check on the pointer bh to avoid a null pointer dereference
on bh->b_data however later bh is passed to mark_buffer_dirty that can also
cause a null pointer dereference on bh. Avoid this potential null pointer
dereference by moving the call to mark_buffer_dirty inside the null checked
block.
Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
Signed-off-by: Colin Ian King <[email protected]>
---
fs/udf/super.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/udf/super.c b/fs/udf/super.c
index a6940d90bedd..b7e9a83d39db 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
udf_finalize_lvid(lvid);
- }
- /*
- * Blockdevice will be synced later so we don't have to submit
- * the buffer for IO
- */
- mark_buffer_dirty(bh);
+ /*
+ * Blockdevice will be synced later so we don't have
+ * to submit the buffer for IO
+ */
+ mark_buffer_dirty(bh);
+ }
sbi->s_lvid_dirty = 0;
}
mutex_unlock(&sbi->s_alloc_mutex);
--
2.20.1
On Tue 19-02-19 11:44:03, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> There is a null check on the pointer bh to avoid a null pointer dereference
> on bh->b_data however later bh is passed to mark_buffer_dirty that can also
> cause a null pointer dereference on bh. Avoid this potential null pointer
> dereference by moving the call to mark_buffer_dirty inside the null checked
> block.
>
> Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
> Signed-off-by: Colin Ian King <[email protected]>
Thanks for the patch! In fact it is the 'if (bh)' check that's
unnecessarily defensive (we cannot have sbi->s_lvid_dirty and
!sbi->s_lvid_bh). So I'll just drop that check (attached patch).
Honza
> ---
> fs/udf/super.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index a6940d90bedd..b7e9a83d39db 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
>
> lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
> udf_finalize_lvid(lvid);
> - }
>
> - /*
> - * Blockdevice will be synced later so we don't have to submit
> - * the buffer for IO
> - */
> - mark_buffer_dirty(bh);
> + /*
> + * Blockdevice will be synced later so we don't have
> + * to submit the buffer for IO
> + */
> + mark_buffer_dirty(bh);
> + }
> sbi->s_lvid_dirty = 0;
> }
> mutex_unlock(&sbi->s_alloc_mutex);
> --
> 2.20.1
>
>
--
Jan Kara <[email protected]>
SUSE Labs, CR
On 2/19/19 8:02 AM, Jan Kara wrote:
> On Tue 19-02-19 11:44:03, Colin King wrote:
>> From: Colin Ian King <[email protected]>
>>
>> There is a null check on the pointer bh to avoid a null pointer dereference
>> on bh->b_data however later bh is passed to mark_buffer_dirty that can also
>> cause a null pointer dereference on bh. Avoid this potential null pointer
>> dereference by moving the call to mark_buffer_dirty inside the null checked
>> block.
>>
>> Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
>> Signed-off-by: Colin Ian King <[email protected]>
> Thanks for the patch! In fact it is the 'if (bh)' check that's
> unnecessarily defensive (we cannot have sbi->s_lvid_dirty and
> !sbi->s_lvid_bh). So I'll just drop that check (attached patch).
>
> Honza
>
>> ---
>> fs/udf/super.c | 12 ++++++------
>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/udf/super.c b/fs/udf/super.c
>> index a6940d90bedd..b7e9a83d39db 100644
>> --- a/fs/udf/super.c
>> +++ b/fs/udf/super.c
>> @@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
>>
>> lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
>> udf_finalize_lvid(lvid);
>> - }
>>
>> - /*
>> - * Blockdevice will be synced later so we don't have to submit
>> - * the buffer for IO
>> - */
>> - mark_buffer_dirty(bh);
>> + /*
>> + * Blockdevice will be synced later so we don't have
>> + * to submit the buffer for IO
>> + */
>> + mark_buffer_dirty(bh);
>> + }
>> sbi->s_lvid_dirty = 0;
>> }
>> mutex_unlock(&sbi->s_alloc_mutex);
>> --
>> 2.20.1
>>
Reviewed-by: Steven J. Magnani <[email protected]>
Doh! Thanks for the catch Colin.
------------------------------------------------------------------------
?Steven J. Magnani?????????????? "I claim this network for MARS!
?http://www.digidescorp.com????????????? Earthling, return my space modulator!"
?#include <standard.disclaimer>
On Tue 19-02-19 08:17:09, Steve Magnani wrote:
> On 2/19/19 8:02 AM, Jan Kara wrote:
> > On Tue 19-02-19 11:44:03, Colin King wrote:
> > > From: Colin Ian King <[email protected]>
> > >
> > > There is a null check on the pointer bh to avoid a null pointer dereference
> > > on bh->b_data however later bh is passed to mark_buffer_dirty that can also
> > > cause a null pointer dereference on bh. Avoid this potential null pointer
> > > dereference by moving the call to mark_buffer_dirty inside the null checked
> > > block.
> > >
> > > Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
> > > Signed-off-by: Colin Ian King <[email protected]>
> > Thanks for the patch! In fact it is the 'if (bh)' check that's
> > unnecessarily defensive (we cannot have sbi->s_lvid_dirty and
> > !sbi->s_lvid_bh). So I'll just drop that check (attached patch).
> >
> > Honza
> >
> > > ---
> > > fs/udf/super.c | 12 ++++++------
> > > 1 file changed, 6 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/fs/udf/super.c b/fs/udf/super.c
> > > index a6940d90bedd..b7e9a83d39db 100644
> > > --- a/fs/udf/super.c
> > > +++ b/fs/udf/super.c
> > > @@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
> > > lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
> > > udf_finalize_lvid(lvid);
> > > - }
> > > - /*
> > > - * Blockdevice will be synced later so we don't have to submit
> > > - * the buffer for IO
> > > - */
> > > - mark_buffer_dirty(bh);
> > > + /*
> > > + * Blockdevice will be synced later so we don't have
> > > + * to submit the buffer for IO
> > > + */
> > > + mark_buffer_dirty(bh);
> > > + }
> > > sbi->s_lvid_dirty = 0;
> > > }
> > > mutex_unlock(&sbi->s_alloc_mutex);
> > > --
> > > 2.20.1
> > >
> Reviewed-by: Steven J. Magnani <[email protected]>
Is this Reviewed-by for my fixup or the Colin's? Because I've decided to
rather remove the 'if (bh)' check completely since it is pointless...
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
> On Feb 20, 2019, at 3:50 AM, Jan Kara <[email protected]> wrote:
>
>> On Tue 19-02-19 08:17:09, Steve Magnani wrote:
>>> On 2/19/19 8:02 AM, Jan Kara wrote:
>>>> On Tue 19-02-19 11:44:03, Colin King wrote:
>>>> From: Colin Ian King <[email protected]>
>>>>
>>>> There is a null check on the pointer bh to avoid a null pointer dereference
>>>> on bh->b_data however later bh is passed to mark_buffer_dirty that can also
>>>> cause a null pointer dereference on bh. Avoid this potential null pointer
>>>> dereference by moving the call to mark_buffer_dirty inside the null checked
>>>> block.
>>>>
>>>> Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
>>>> Signed-off-by: Colin Ian King <[email protected]>
>>> Thanks for the patch! In fact it is the 'if (bh)' check that's
>>> unnecessarily defensive (we cannot have sbi->s_lvid_dirty and
>>> !sbi->s_lvid_bh). So I'll just drop that check (attached patch).
>>>
>>> Honza
>>>
>>>> ---
>>>> fs/udf/super.c | 12 ++++++------
>>>> 1 file changed, 6 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/fs/udf/super.c b/fs/udf/super.c
>>>> index a6940d90bedd..b7e9a83d39db 100644
>>>> --- a/fs/udf/super.c
>>>> +++ b/fs/udf/super.c
>>>> @@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
>>>> lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
>>>> udf_finalize_lvid(lvid);
>>>> - }
>>>> - /*
>>>> - * Blockdevice will be synced later so we don't have to submit
>>>> - * the buffer for IO
>>>> - */
>>>> - mark_buffer_dirty(bh);
>>>> + /*
>>>> + * Blockdevice will be synced later so we don't have
>>>> + * to submit the buffer for IO
>>>> + */
>>>> + mark_buffer_dirty(bh);
>>>> + }
>>>> sbi->s_lvid_dirty = 0;
>>>> }
>>>> mutex_unlock(&sbi->s_alloc_mutex);
>>>> --
>>>> 2.20.1
>>>>
>> Reviewed-by: Steven J. Magnani <[email protected]>
>
> Is this Reviewed-by for my fixup or the Colin's? Because I've decided to
> rather remove the 'if (bh)' check completely since it is pointless...
>
> Honza
> --
Sorry, I realized on rereading that this could be ambiguous. The R-B is for your patch.
Steve