diff mbox series

ocfs2: check new file size on fallocate call

Message ID 20230529152645.32680-1-lhenriques@suse.de
State New
Headers
Series ocfs2: check new file size on fallocate call |

Commit Message

Luis Henriques May 29, 2023, 3:26 p.m. UTC 
  When changing a file size with fallocate() the new size isn't being
checked.  In particular, the FSIZE ulimit isn't being checked, which makes
fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
this issue.

Signed-off-by: Luís Henriques <lhenriques@suse.de>
---
 fs/ocfs2/file.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Mark Fasheh May 31, 2023, 3:32 a.m. UTC | #1 
On Mon, May 29, 2023 at 8:26 AM Luís Henriques <lhenriques@suse.de> wrote:
>
> When changing a file size with fallocate() the new size isn't being
> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
> this issue.
>
> Signed-off-by: Luís Henriques <lhenriques@suse.de>

Looks good, thanks Luis.

Reviewed-by: Mark Fasheh <mark@fasheh.com>
Joseph Qi May 31, 2023, 6 a.m. UTC | #2 
On 5/29/23 11:26 PM, Luís Henriques wrote:
> When changing a file size with fallocate() the new size isn't being
> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
> this issue.
> 
> Signed-off-by: Luís Henriques <lhenriques@suse.de>
> ---
>  fs/ocfs2/file.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index efb09de4343d..b173c36bcab3 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>  	struct ocfs2_space_resv sr;
>  	int change_size = 1;
>  	int cmd = OCFS2_IOC_RESVSP64;
> +	int ret = 0;
>  
>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>  		return -EOPNOTSUPP;

This means we only support keep-size and pouch_hole.
And it seems pouch_hole will also imply keep-size.

>  	if (!ocfs2_writes_unwritten_extents(osb))
>  		return -EOPNOTSUPP;
>  
> -	if (mode & FALLOC_FL_KEEP_SIZE)
> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>  		change_size = 0;
> +	} else {

Seems this will be a dead branch?

Thanks,
Joseph

> +		ret = inode_newsize_ok(inode, offset + len);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	if (mode & FALLOC_FL_PUNCH_HOLE)
>  		cmd = OCFS2_IOC_UNRESVSP64;
Luis Henriques May 31, 2023, 8:29 a.m. UTC | #3 
Joseph Qi <joseph.qi@linux.alibaba.com> writes:

> On 5/29/23 11:26 PM, Luís Henriques wrote:
>> When changing a file size with fallocate() the new size isn't being
>> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
>> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
>> this issue.
>> 
>> Signed-off-by: Luís Henriques <lhenriques@suse.de>
>> ---
>>  fs/ocfs2/file.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>> 
>> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
>> index efb09de4343d..b173c36bcab3 100644
>> --- a/fs/ocfs2/file.c
>> +++ b/fs/ocfs2/file.c
>> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>>  	struct ocfs2_space_resv sr;
>>  	int change_size = 1;
>>  	int cmd = OCFS2_IOC_RESVSP64;
>> +	int ret = 0;
>>  
>>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>>  		return -EOPNOTSUPP;
>
> This means we only support keep-size and pouch_hole.
> And it seems pouch_hole will also imply keep-size.

I think you're forgetting about mode = 0, which is also valid.  And the
default '0' will allow size to be changed.

>>  	if (!ocfs2_writes_unwritten_extents(osb))
>>  		return -EOPNOTSUPP;
>>  
>> -	if (mode & FALLOC_FL_KEEP_SIZE)
>> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>>  		change_size = 0;
>> +	} else {
>
> Seems this will be a dead branch?

Again, you need to consider '0' as a valid mode value.  If you run
generic/228 without this patch you'll see that test failing because it
*does* hit this branch.

Cheers,
Joseph Qi May 31, 2023, 8:31 a.m. UTC | #4 
On 5/31/23 4:29 PM, Luís Henriques wrote:
> Joseph Qi <joseph.qi@linux.alibaba.com> writes:
> 
>> On 5/29/23 11:26 PM, Luís Henriques wrote:
>>> When changing a file size with fallocate() the new size isn't being
>>> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
>>> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
>>> this issue.
>>>
>>> Signed-off-by: Luís Henriques <lhenriques@suse.de>
>>> ---
>>>  fs/ocfs2/file.c | 8 +++++++-
>>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
>>> index efb09de4343d..b173c36bcab3 100644
>>> --- a/fs/ocfs2/file.c
>>> +++ b/fs/ocfs2/file.c
>>> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>>>  	struct ocfs2_space_resv sr;
>>>  	int change_size = 1;
>>>  	int cmd = OCFS2_IOC_RESVSP64;
>>> +	int ret = 0;
>>>  
>>>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>>>  		return -EOPNOTSUPP;
>>
>> This means we only support keep-size and pouch_hole.
>> And it seems pouch_hole will also imply keep-size.
> 
> I think you're forgetting about mode = 0, which is also valid.  And the
> default '0' will allow size to be changed.
> 

Oops... You are right.

>>>  	if (!ocfs2_writes_unwritten_extents(osb))
>>>  		return -EOPNOTSUPP;
>>>  
>>> -	if (mode & FALLOC_FL_KEEP_SIZE)
>>> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>>>  		change_size = 0;
>>> +	} else {
>>
>> Seems this will be a dead branch?
> 
> Again, you need to consider '0' as a valid mode value.  If you run
> generic/228 without this patch you'll see that test failing because it
> *does* hit this branch.
> 
> Cheers,
Joseph Qi May 31, 2023, 8:32 a.m. UTC | #5 
On 5/29/23 11:26 PM, Luís Henriques wrote:
> When changing a file size with fallocate() the new size isn't being
> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
> this issue.
> 
> Signed-off-by: Luís Henriques <lhenriques@suse.de>

Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> ---
>  fs/ocfs2/file.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index efb09de4343d..b173c36bcab3 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>  	struct ocfs2_space_resv sr;
>  	int change_size = 1;
>  	int cmd = OCFS2_IOC_RESVSP64;
> +	int ret = 0;
>  
>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>  		return -EOPNOTSUPP;
>  	if (!ocfs2_writes_unwritten_extents(osb))
>  		return -EOPNOTSUPP;
>  
> -	if (mode & FALLOC_FL_KEEP_SIZE)
> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>  		change_size = 0;
> +	} else {
> +		ret = inode_newsize_ok(inode, offset + len);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	if (mode & FALLOC_FL_PUNCH_HOLE)
>  		cmd = OCFS2_IOC_UNRESVSP64;
Andrew Morton May 31, 2023, 10:11 p.m. UTC | #6 
On Mon, 29 May 2023 16:26:45 +0100 Luís Henriques via Ocfs2-devel <ocfs2-devel@oss.oracle.com> wrote:

> When changing a file size with fallocate() the new size isn't being
> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
> this issue.
> 
> ...
>
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>  	struct ocfs2_space_resv sr;
>  	int change_size = 1;
>  	int cmd = OCFS2_IOC_RESVSP64;
> +	int ret = 0;
>  
>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>  		return -EOPNOTSUPP;
>  	if (!ocfs2_writes_unwritten_extents(osb))
>  		return -EOPNOTSUPP;
>  
> -	if (mode & FALLOC_FL_KEEP_SIZE)
> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>  		change_size = 0;
> +	} else {
> +		ret = inode_newsize_ok(inode, offset + len);
> +		if (ret)
> +			return ret;
> +	}
>  

So userspace can exceed rlimit(RLIMIT_FSIZE).

Do we think this flaw is serious enough to justify backporting the fix
into earlier -stable kernels?
Joseph Qi June 1, 2023, 1:23 a.m. UTC | #7 
On 6/1/23 6:11 AM, Andrew Morton wrote:
> On Mon, 29 May 2023 16:26:45 +0100 Luís Henriques via Ocfs2-devel <ocfs2-devel@oss.oracle.com> wrote:
> 
>> When changing a file size with fallocate() the new size isn't being
>> checked.  In particular, the FSIZE ulimit isn't being checked, which makes
>> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
>> this issue.
>>
>> ...
>>
>> --- a/fs/ocfs2/file.c
>> +++ b/fs/ocfs2/file.c
>> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
>>  	struct ocfs2_space_resv sr;
>>  	int change_size = 1;
>>  	int cmd = OCFS2_IOC_RESVSP64;
>> +	int ret = 0;
>>  
>>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>>  		return -EOPNOTSUPP;
>>  	if (!ocfs2_writes_unwritten_extents(osb))
>>  		return -EOPNOTSUPP;
>>  
>> -	if (mode & FALLOC_FL_KEEP_SIZE)
>> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>>  		change_size = 0;
>> +	} else {
>> +		ret = inode_newsize_ok(inode, offset + len);
>> +		if (ret)
>> +			return ret;
>> +	}
>>  
> 
> So userspace can exceed rlimit(RLIMIT_FSIZE).
> 
> Do we think this flaw is serious enough to justify backporting the fix
> into earlier -stable kernels?

I think it's worth ccing stable kernel as well.

Thanks,
Joseph
diff mbox series

Patch

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index efb09de4343d..b173c36bcab3 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2100,14 +2100,20 @@  static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
 	struct ocfs2_space_resv sr;
 	int change_size = 1;
 	int cmd = OCFS2_IOC_RESVSP64;
+	int ret = 0;
 
 	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
 		return -EOPNOTSUPP;
 	if (!ocfs2_writes_unwritten_extents(osb))
 		return -EOPNOTSUPP;
 
-	if (mode & FALLOC_FL_KEEP_SIZE)
+	if (mode & FALLOC_FL_KEEP_SIZE) {
 		change_size = 0;
+	} else {
+		ret = inode_newsize_ok(inode, offset + len);
+		if (ret)
+			return ret;
+	}
 
 	if (mode & FALLOC_FL_PUNCH_HOLE)
 		cmd = OCFS2_IOC_UNRESVSP64;