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| author | Dan Rosenberg <dan.j.rosenberg@gmail.com> | 2010-07-19 16:58:20 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2010-07-19 16:58:20 -0400 |
| commit | 2ebc3464781ad24474abcbd2274e6254689853b5 (patch) | |
| tree | 3d58dfcc14948672c0aac1636cdd57cbe46a135d /fs/btrfs/ioctl.c | |
| parent | b5384d48f4e74edec3ca1887cb65e378a72af9a1 (diff) | |
| download | lwn-2ebc3464781ad24474abcbd2274e6254689853b5.tar.gz lwn-2ebc3464781ad24474abcbd2274e6254689853b5.zip | |
Btrfs: fix checks in BTRFS_IOC_CLONE_RANGE
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>
cc: stable@kernel.org
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 2a8b3a7568ad..9254b3d58dbe 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1458,7 +1458,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, */ /* 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); @@ -1511,7 +1511,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, /* 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; |