4.9-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit f505754fd6599230371cb01b9332754ddc104be1 upstream.
We were using the path name received from user space without checking that it is null terminated. While btrfs-progs is well behaved and does proper validation and null termination, someone could call the ioctl and pass a non-null terminated patch, leading to buffer overrun problems in the kernel. The ioctl is protected by CAP_SYS_ADMIN.
So just set the last byte of the path to a null character, similar to what we do in other ioctls (add/remove/resize device, snapshot creation, etc).
CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/super.c | 1 + 1 file changed, 1 insertion(+)
--- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2226,6 +2226,7 @@ static long btrfs_control_ioctl(struct f vol = memdup_user((void __user *)arg, sizeof(*vol)); if (IS_ERR(vol)) return PTR_ERR(vol); + vol->name[BTRFS_PATH_NAME_MAX] = '\0';
switch (cmd) { case BTRFS_IOC_SCAN_DEV: