linux-kernel - Re: [PATCH] ecryptfs: Fix explicit null dereference

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Message-ID: <20131114200234.GB7693@boyd>
Date:	Thu, 14 Nov 2013 12:02:34 -0800
From:	Tyler Hicks <tyhicks@...onical.com>
To:	Geyslan Gregório Bem <geyslan@...il.com>
Cc:	ecryptfs@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	Dan Carpenter <dan.carpenter@...cle.com>,
	Pekka Enberg <penberg@...nel.org>
Subject: Re: [PATCH] ecryptfs: Fix explicit null dereference

On 2013-11-14 17:58:40, Geyslan Gregório Bem wrote:
> 2013/11/14 Tyler Hicks <tyhicks@...onical.com>:
> > On 2013-11-14 15:42:14, Geyslan G. Bem wrote:
> >> If the condition 'ecryptfs_file_to_private(file)' takes false branch
> >> lower_file is dereferenced when NULL.
> >>
> >> Caught by Coverity: CIDs 1128834 and 1128833.
> >>
> >> Signed-off-by: Geyslan G. Bem <geyslan@...il.com>
> >> ---
> >
> > Hello - Smatch picked up on this earlier in week and Dan analyzed the
> > situation here:
> >
> >   http://article.gmane.org/gmane.comp.file-systems.ecryptfs.general/441
> >
> > I agree with his assessment and proposed the following patch:
> >
> >   http://article.gmane.org/gmane.comp.file-systems.ecryptfs.general/442
> >
> > It makes Smatch happy and it should also make Coverity happy.
> >
> > Tyler
> 
> True. Disregard mine.
> 
> Thanks Tyler.

Thank you! Can I add your Reviewed-by: tag to that patch prior to
pushing it to my next branch?

Tyler

> 
> >
> >>  fs/ecryptfs/file.c | 12 ++++++++----
> >>  1 file changed, 8 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
> >> index 2229a74..1c0403a 100644
> >> --- a/fs/ecryptfs/file.c
> >> +++ b/fs/ecryptfs/file.c
> >> @@ -316,10 +316,12 @@ ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> >>       struct file *lower_file = NULL;
> >>       long rc = -ENOTTY;
> >>
> >> -     if (ecryptfs_file_to_private(file))
> >> -             lower_file = ecryptfs_file_to_lower(file);
> >> +     if (!ecryptfs_file_to_private(file))
> >> +             goto out;
> >> +     lower_file = ecryptfs_file_to_lower(file);
> >>       if (lower_file->f_op->unlocked_ioctl)
> >>               rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
> >> +out:
> >>       return rc;
> >>  }
> >>
> >> @@ -330,10 +332,12 @@ ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> >>       struct file *lower_file = NULL;
> >>       long rc = -ENOIOCTLCMD;
> >>
> >> -     if (ecryptfs_file_to_private(file))
> >> -             lower_file = ecryptfs_file_to_lower(file);
> >> +     if (!ecryptfs_file_to_private(file))
> >> +             goto out;
> >> +     lower_file = ecryptfs_file_to_lower(file);
> >>       if (lower_file->f_op && lower_file->f_op->compat_ioctl)
> >>               rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
> >> +out:
> >>       return rc;
> >>  }
> >>  #endif
> >> --
> >> 1.8.4.2
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe ecryptfs" in
> >> the body of a message to majordomo@...r.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 
> -- 
> Regards,
> 
> Geyslan G. Bem
> hackingbits.com
> --
> To unsubscribe from this list: send the line "unsubscribe ecryptfs" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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