2013-10-09 23:44:56

by Geyslan G. Bem

Subject: [PATCH v3] btrfs: Fix memory leakage in the tree-log.c

In some cases, add_inode_ref() is returning without freeing
the 'name' pointer.

Added bail out to explicitly call kfree when necessary.

Signed-off-by: Geyslan G. Bem <[email protected]>
---
fs/btrfs/tree-log.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 79f057c..ad7cc5f 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1170,13 +1170,16 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
if (!dir)
dir = read_one_inode(root, parent_objectid);
if (!dir)
- return -ENOENT;
+ {
+ ret = -ENOENT;
+ goto bail;
+ }
} else {
ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
&ref_index);
}
if (ret)
- return ret;
+ goto bail;

/* if we already have a perfect match, we're done */
if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
@@ -1227,6 +1230,9 @@ out:
btrfs_release_path(path);
iput(dir);
iput(inode);
+bail:
+ if (name)
+ kfree(name);
return ret;
}

--
1.8.4

2013-10-09 23:46:35

by Geyslan G. Bem

Subject: Re: [PATCH v3] btrfs: Fix memory leakage in the tree-log.c

Please,

Analyze [PATCH v3].

Regards,

Geyslan Gregório Bem
hackingbits.com


2013/10/9 Geyslan G. Bem <[email protected]>:
> In some cases, add_inode_ref() is returning without freeing
> the 'name' pointer.
>
> Added bail out to explicitly call kfree when necessary.
>
> Signed-off-by: Geyslan G. Bem <[email protected]>
> ---
> fs/btrfs/tree-log.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 79f057c..ad7cc5f 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -1170,13 +1170,16 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> if (!dir)
> dir = read_one_inode(root, parent_objectid);
> if (!dir)
> - return -ENOENT;
> + {
> + ret = -ENOENT;
> + goto bail;
> + }
> } else {
> ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
> &ref_index);
> }
> if (ret)
> - return ret;
> + goto bail;
>
> /* if we already have a perfect match, we're done */
> if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
> @@ -1227,6 +1230,9 @@ out:
> btrfs_release_path(path);
> iput(dir);
> iput(inode);
> +bail:
> + if (name)
> + kfree(name);
> return ret;
> }
>
> --
> 1.8.4
>

2013-10-10 00:52:26

by Josef Bacik

Subject: Re: [PATCH v3] btrfs: Fix memory leakage in the tree-log.c

On Wed, Oct 09, 2013 at 08:40:30PM -0300, Geyslan G. Bem wrote:
> In some cases, add_inode_ref() is returning without freeing
> the 'name' pointer.
>
> Added bail out to explicitly call kfree when necessary.
>
> Signed-off-by: Geyslan G. Bem <[email protected]>
> ---
> fs/btrfs/tree-log.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 79f057c..ad7cc5f 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -1170,13 +1170,16 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> if (!dir)
> dir = read_one_inode(root, parent_objectid);
> if (!dir)
> - return -ENOENT;
> + {
> + ret = -ENOENT;
> + goto bail;
> + }

Code formatting is

if () {
}

not

if ()
{
}


> } else {
> ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
> &ref_index);
> }
> if (ret)
> - return ret;
> + goto bail;
>
> /* if we already have a perfect match, we're done */
> if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
> @@ -1227,6 +1230,9 @@ out:
> btrfs_release_path(path);
> iput(dir);
> iput(inode);
> +bail:
> + if (name)
> + kfree(name);

kfree already does the if (name) part of this so this is redundant. Also if you
are going to do this you need to set name = NULL; after the kfree above it
otherwise we have a double free. Thanks,

Josef

2013-10-10 01:19:34

by Geyslan G. Bem

Subject: Re: [PATCH v3] btrfs: Fix memory leakage in the tree-log.c

Josef,

Thank you. Sending v4.

Geyslan Gregório Bem
hackingbits.com


2013/10/9 Josef Bacik <[email protected]>:
> On Wed, Oct 09, 2013 at 08:40:30PM -0300, Geyslan G. Bem wrote:
>> In some cases, add_inode_ref() is returning without freeing
>> the 'name' pointer.
>>
>> Added bail out to explicitly call kfree when necessary.
>>
>> Signed-off-by: Geyslan G. Bem <[email protected]>
>> ---
>> fs/btrfs/tree-log.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
>> index 79f057c..ad7cc5f 100644
>> --- a/fs/btrfs/tree-log.c
>> +++ b/fs/btrfs/tree-log.c
>> @@ -1170,13 +1170,16 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
>> if (!dir)
>> dir = read_one_inode(root, parent_objectid);
>> if (!dir)
>> - return -ENOENT;
>> + {
>> + ret = -ENOENT;
>> + goto bail;
>> + }
>
> Code formatting is
>
> if () {
> }
>
> not
>
> if ()
> {
> }
>
>
>> } else {
>> ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
>> &ref_index);
>> }
>> if (ret)
>> - return ret;
>> + goto bail;
>>
>> /* if we already have a perfect match, we're done */
>> if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
>> @@ -1227,6 +1230,9 @@ out:
>> btrfs_release_path(path);
>> iput(dir);
>> iput(inode);
>> +bail:
>> + if (name)
>> + kfree(name);
>
> kfree already does the if (name) part of this so this is redundant. Also if you
> are going to do this you need to set name = NULL; after the kfree above it
> otherwise we have a double free. Thanks,
>
> Josef