[PATCH] Btrfs: fix memory leak in the extent_same ioctl

[PATCH] Btrfs: fix memory leak in the extent_same ioctl

[fdmanana]

From: Filipe Manana <fdmanana@suse.com>

We were allocating memory with memdup_user() but we were never releasing
that memory. This affected pretty much every call to the ioctl, whether
it deduplicated extents or not.

This issue was reported on IRC by Julian Taylor and on the mailing list
by Marcel Ritter, credit goes to them for finding the issue.

Reported-by: Julian Taylor (jtaylor@IRC)
Reported-by: Marcel Ritter <ritter.marcel@gmail.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/ioctl.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c86b835..78e6a28 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2958,7 +2958,7 @@ out_unlock:
 static long btrfs_ioctl_file_extent_same(struct file *file,
 			struct btrfs_ioctl_same_args __user *argp)
 {
-	struct btrfs_ioctl_same_args *same;
+	struct btrfs_ioctl_same_args *same = NULL;
 	struct btrfs_ioctl_same_extent_info *info;
 	struct inode *src = file_inode(file);
 	u64 off;
@@ -2988,6 +2988,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
 
 	if (IS_ERR(same)) {
 		ret = PTR_ERR(same);
+		same = NULL;
 		goto out;
 	}
 
@@ -3058,6 +3059,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
 
 out:
 	mnt_drop_write_file(file);
+	kfree(same);
 	return ret;
 }
 
-- 
2.1.3

[PATCH v2] Btrfs: fix memory leak in the extent_same ioctl

[fdmanana]

From: Filipe Manana <fdmanana@suse.com>

We were allocating memory with memdup_user() but we were never releasing
that memory. This affected pretty much every call to the ioctl, whether
it deduplicated extents or not.

This issue was reported on IRC by Julian Taylor and on the mailing list
by Marcel Ritter, credit goes to them for finding the issue.

Reported-by: Julian Taylor <jtaylor.debian@googlemail.com>
Reported-by: Marcel Ritter <ritter.marcel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---

V2: Added cc to stable, forgotten in v1, and Julian's mail address.

 fs/btrfs/ioctl.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c86b835..78e6a28 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2958,7 +2958,7 @@ out_unlock:
 static long btrfs_ioctl_file_extent_same(struct file *file,
 			struct btrfs_ioctl_same_args __user *argp)
 {
-	struct btrfs_ioctl_same_args *same;
+	struct btrfs_ioctl_same_args *same = NULL;
 	struct btrfs_ioctl_same_extent_info *info;
 	struct inode *src = file_inode(file);
 	u64 off;
@@ -2988,6 +2988,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
 
 	if (IS_ERR(same)) {
 		ret = PTR_ERR(same);
+		same = NULL;
 		goto out;
 	}
 
@@ -3058,6 +3059,7 @@ static long btrfs_ioctl_file_extent_same(struct file *file,
 
 out:
 	mnt_drop_write_file(file);
+	kfree(same);
 	return ret;
 }
 
-- 
2.1.3

Re: [PATCH] Btrfs: fix memory leak in the extent_same ioctl

[Mark Fasheh]

That looks great, thanks for fixing this Filipe.

On Fri, Jul 03, 2015 at 08:48:22AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We were allocating memory with memdup_user() but we were never releasing
> that memory. This affected pretty much every call to the ioctl, whether
> it deduplicated extents or not.
> 
> This issue was reported on IRC by Julian Taylor and on the mailing list
> by Marcel Ritter, credit goes to them for finding the issue.
> 
> Reported-by: Julian Taylor (jtaylor@IRC)
> Reported-by: Marcel Ritter <ritter.marcel@gmail.com>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Mark Fasheh <mfasheh@suse.de>
	--Mark

--
Mark Fasheh

Re: [PATCH v2] Btrfs: fix memory leak in the extent_same ioctl

[Mark Fasheh]

Thanks for this Filipe,

On Fri, Jul 03, 2015 at 11:36:49AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We were allocating memory with memdup_user() but we were never releasing
> that memory. This affected pretty much every call to the ioctl, whether
> it deduplicated extents or not.
> 
> This issue was reported on IRC by Julian Taylor and on the mailing list
> by Marcel Ritter, credit goes to them for finding the issue.
> 
> Reported-by: Julian Taylor <jtaylor.debian@googlemail.com>
> Reported-by: Marcel Ritter <ritter.marcel@gmail.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Mark Fasheh <mfasheh@suse.de>
	--Mark

--
Mark Fasheh