From: Darrick J. Wong djwong@kernel.org
commit a7e9d977e031fceefe1e7cd69ebd7202d5758b56 upstream.
If userspace provides a longer UUID buffer than is required, we shouldn't fail the call with EINVAL -- rather, we can fill the caller's buffer with the bytes we /can/ fill, and update the length field to reflect what we copied. This doesn't break the UAPI since we're enabling a case that currently fails, and so far Ted hasn't released a version of e2fsprogs that uses the new ext4 ioctl.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Catherine Hoang catherine.hoang@oracle.com Link: https://lore.kernel.org/r/166811139478.327006.13879198441587445544.stgit@mag... Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/ioctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1162,14 +1162,16 @@ static int ext4_ioctl_getuuid(struct ext return -EINVAL; }
- if (fsuuid.fsu_len != UUID_SIZE || fsuuid.fsu_flags != 0) + if (fsuuid.fsu_len < UUID_SIZE || fsuuid.fsu_flags != 0) return -EINVAL;
lock_buffer(sbi->s_sbh); memcpy(uuid, sbi->s_es->s_uuid, UUID_SIZE); unlock_buffer(sbi->s_sbh);
- if (copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE)) + fsuuid.fsu_len = UUID_SIZE; + if (copy_to_user(ufsuuid, &fsuuid, sizeof(fsuuid)) || + copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE)) return -EFAULT; return 0; }