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SubjectRe: [PATCH] ecryptfs: Fix explicit null dereference
From
2013/11/14 Tyler Hicks <tyhicks@canonical.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@gmail.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.

>
>> 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
>>
>> --
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--
Regards,

Geyslan G. Bem
hackingbits.com


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