staging: exfat: issue with FFS_MEDIAERR error return assignment

staging: exfat: issue with FFS_MEDIAERR error return assignment

[Colin Ian King]

Hi,

Static analysis on exfat with Coverity has picked up an assignment of
FFS_MEDIAERR that gets over-written:


1750        if (is_dir) {
1751                if ((fid->dir.dir == p_fs->root_dir) &&
1752                    (fid->entry == -1)) {
1753                        if (p_fs->dev_ejected)

    CID 85797 (#1 of 1): Unused value (UNUSED_VALUE)
Assigning value 1 to ret here, but that stored value is overwritten
before it can be used.

1754                                ret = FFS_MEDIAERR;

    value_overwrite: Overwriting previous write to ret with value 0.

1755                        ret = FFS_SUCCESS;
1756                        goto out;
1757                }
1758        }

I doubt that's intentional, should it be instead the following?

				if (p_fs->dev_ejected)
					ret = FFS_MEDIAERR;
				else
					ret = FFS_SUCCESS;
				goto out;

Colin

Re: staging: exfat: issue with FFS_MEDIAERR error return assignment

[Dan Carpenter]

On Fri, Aug 30, 2019 at 07:38:00PM +0100, Colin Ian King wrote:
> Hi,
> 
> Static analysis on exfat with Coverity has picked up an assignment of
> FFS_MEDIAERR that gets over-written:
> 
> 
> 1750        if (is_dir) {
> 1751                if ((fid->dir.dir == p_fs->root_dir) &&
> 1752                    (fid->entry == -1)) {
> 1753                        if (p_fs->dev_ejected)

Idealy we would have both a filename and a function name but this email
doesn't have either so no one knows what code you are talking about.  :P

regards,
dan carpenter

Re: staging: exfat: issue with FFS_MEDIAERR error return assignment

[Colin Ian King]

On 10/09/2019 13:44, Dan Carpenter wrote:
> On Fri, Aug 30, 2019 at 07:38:00PM +0100, Colin Ian King wrote:
>> Hi,
>>
>> Static analysis on exfat with Coverity has picked up an assignment of
>> FFS_MEDIAERR that gets over-written:
>>
>>
>> 1750        if (is_dir) {
>> 1751                if ((fid->dir.dir == p_fs->root_dir) &&
>> 1752                    (fid->entry == -1)) {
>> 1753                        if (p_fs->dev_ejected)
> 
> Idealy we would have both a filename and a function name but this email
> doesn't have either so no one knows what code you are talking about.  :P

Oops, my bad.

drivers/staging/exfat/exfat_super.c ffsWriteStat()

> 
> regards,
> dan carpenter
> 

Re: staging: exfat: issue with FFS_MEDIAERR error return assignment

[Dan Carpenter]

On Tue, Sep 10, 2019 at 01:58:35PM +0100, Colin Ian King wrote:
> On 10/09/2019 13:44, Dan Carpenter wrote:
> > On Fri, Aug 30, 2019 at 07:38:00PM +0100, Colin Ian King wrote:
> >> Hi,
> >>
> >> Static analysis on exfat with Coverity has picked up an assignment of
> >> FFS_MEDIAERR that gets over-written:
> >>
> >>
> >> 1750        if (is_dir) {
> >> 1751                if ((fid->dir.dir == p_fs->root_dir) &&
> >> 1752                    (fid->entry == -1)) {
> >> 1753                        if (p_fs->dev_ejected)
> > 
> > Idealy we would have both a filename and a function name but this email
> > doesn't have either so no one knows what code you are talking about.  :P
> 
> Oops, my bad.
> 
> drivers/staging/exfat/exfat_super.c ffsWriteStat()

Yes, your solution is correct.

regards,
dan carpenter

Re: staging: exfat: issue with FFS_MEDIAERR error return assignment

[Valdis Klētnieks]

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On Tue, 10 Sep 2019 16:09:35 +0300, Dan Carpenter said:
> On Tue, Sep 10, 2019 at 01:58:35PM +0100, Colin Ian King wrote:
> > On 10/09/2019 13:44, Dan Carpenter wrote:
> > > On Fri, Aug 30, 2019 at 07:38:00PM +0100, Colin Ian King wrote:
> > >> Hi,
> > >>
> > >> Static analysis on exfat with Coverity has picked up an assignment of
> > >> FFS_MEDIAERR that gets over-written:
> > >>
> > >>
> > >> 1750        if (is_dir) {
> > >> 1751                if ((fid->dir.dir == p_fs->root_dir) &&
> > >> 1752                    (fid->entry == -1)) {
> > >> 1753                        if (p_fs->dev_ejected)
> > >
> > > Idealy we would have both a filename and a function name but this email
> > > doesn't have either so no one knows what code you are talking about.  :P
> >
> > Oops, my bad.
> >
> > drivers/staging/exfat/exfat_super.c ffsWriteStat()
>
> Yes, your solution is correct.

Actually, you can skip the else, because we initialized 'ret' at the start of the function.

The *bigger* issue - what should 'ret' be if dev_ejected is *false*?

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