Messages in this thread Patch in this message | | | Date | Fri, 30 Jul 2010 10:14:17 -0700 | From | Greg KH <> | Subject | [029/165] Btrfs: fix checks in BTRFS_IOC_CLONE_RANGE |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Dan Rosenberg <dan.j.rosenberg@gmail.com>
commit 2ebc3464781ad24474abcbd2274e6254689853b5 upstream.
1. The BTRFS_IOC_CLONE and BTRFS_IOC_CLONE_RANGE ioctls should check whether the donor file is append-only before writing to it.
2. The BTRFS_IOC_CLONE_RANGE ioctl appears to have an integer overflow that allows a user to specify an out-of-bounds range to copy from the source file (if off + len wraps around). I haven't been able to successfully exploit this, but I'd imagine that a clever attacker could use this to read things he shouldn't. Even if it's not exploitable, it couldn't hurt to be safe.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/btrfs/ioctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -947,7 +947,7 @@ static noinline long btrfs_ioctl_clone(s */ /* the destination must be opened for writing */ - if (!(file->f_mode & FMODE_WRITE)) + if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) return -EINVAL; ret = mnt_want_write(file->f_path.mnt); @@ -1000,7 +1000,7 @@ static noinline long btrfs_ioctl_clone(s /* determine range to clone */ ret = -EINVAL; - if (off >= src->i_size || off + len > src->i_size) + if (off + len > src->i_size || off + len < off) goto out_unlock; if (len == 0) olen = len = src->i_size - off;
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