[Bug 1645232] Re: e2fsprogs - could not preserve ACL permissions : The getxattr() returns with (EINVAL)

[Theodore Ts'o]

Thanks for the patch; it definitely helps identify the problem.  I don't
think it is a completely correct change, however.

The problem is that it's doing the translation in
write_xattrs_to_buffer(), but it is not making the translation in the
opposite direction in read_xattrs_to_buffer().   This means if some
other program using this library function --- for example, fuse2fs,
reads in an existing xattr block with an ACL, it will read it the on-
disk format, _not_ translate it to a standard acl format, and then
write_xattrs_to_buffer() will take as input an acl encoded in the on-
disk format, and then try to convert it from lgetxattr format to on-disk
format again, and Much Hilarity will result.

I also wonder if write_xattrs_to_buffer() is the right place to make
this conversion, or rather ext2fs_{read,write}_ext_attr3().   Then what
is stored in the handle structure is the on-disk encoding, and we would
do the translation at the higher layer function rather than the low-
level read/write functions.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to e2fsprogs in Ubuntu.
https://bugs.launchpad.net/bugs/1645232

Title:
  e2fsprogs - could not preserve ACL permissions  : The getxattr()
  returns with (EINVAL)

Status in e2fsprogs package in Ubuntu:
  Confirmed

Bug description:
  The original installed e2fsprogs did not support mke2fs -d /directory
  " option . So ,  git cloned from e2fsprogs packages from repository
  and installed it and followed below steps to reproduce this :

  1. set the ACL rules as below to one of the binary :

      $ setfacl -m u:vipatil:r-- rootfs/usr/bin/helloworld
      $ getfacl rootfs/usr/bin/helloworld
      # file: rootfs/usr/bin/helloworld
      # owner: shkumar
      # group: hardev
      user::rwx
      user:vipatil:r--
      group::---
      mask::r--
      other::---

  2. $ dd if=/dev/zero of=test.ext4 bs=1M count=60

  3. $ mke2fs -t ext4 test.ext4 -d rootfs/
      mke2fs 1.43.3 (04-Sep-2016)
      Discarding device blocks: done
      Creating filesystem with 61440 1k blocks and 15360 inodes
      Filesystem UUID: 495713b3-5f1f-427a-8359-a736dfb2ece9
      Superblock backups stored on blocks:
          8193, 24577, 40961, 57345

  Allocating group tables: done
  Writing inode tables: done
  Creating journal (4096 blocks): done
  Copying files into the device: done
  Writing superblocks and filesystem accounting information: done

  4. sudo mount -o loop,acl,user_xattr,rw,sync test.ext4 mountpoint

  5.@/mountpoint$ getfacl usr/bin/helloworld
      getfacl: usr/bin/helloworld: Invalid argument

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/e2fsprogs/+bug/1645232/+subscriptions