lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 25 May 2021 10:29:25 -0700 From: Eric Biggers <ebiggers@...nel.org> To: Daniel Rosenberg <drosen@...gle.com> Cc: "Theodore Y . Ts'o" <tytso@....edu>, Andreas Dilger <adilger.kernel@...ger.ca>, linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, Gabriel Krisman Bertazi <krisman@...labora.com>, kernel-team@...roid.com Subject: Re: [PATCH] ext4: Fix no-key deletion for encrypt+casefold On Sat, May 22, 2021 at 12:41:32AM +0000, Daniel Rosenberg wrote: > commit 471fbbea7ff7 ("ext4: handle casefolding with encryption") is > missing a few checks for the encryption key which are needed to > support deleting enrypted casefolded files when the key is not > present. > > Note from ebiggers: > (These checks for the encryption key are still racy since they happen > too late, but apparently they worked well enough...) > > This bug made it impossible to delete encrypted+casefolded directories > without the encryption key, due to errors like: > > W : EXT4-fs warning (device vdc): __ext4fs_dirhash:270: inode #49202: comm Binder:378_4: Siphash requires key > > Repro steps in kvm-xfstests test appliance: > mkfs.ext4 -F -E encoding=utf8 -O encrypt /dev/vdc > mount /vdc > mkdir /vdc/dir > chattr +F /vdc/dir > keyid=$(head -c 64 /dev/zero | xfs_io -c add_enckey /vdc | awk '{print $NF}') > xfs_io -c "set_encpolicy $keyid" /vdc/dir > for i in `seq 1 100`; do > mkdir /vdc/dir/$i > done > xfs_io -c "rm_enckey $keyid" /vdc > rm -rf /vdc/dir # fails with the bug Looks fine, but can you please turn this reproducer into an xfstest? I'm also wondering if you've done any investigation into fixing ext4 to handle filenames properly like f2fs does, so that the above-mentioned race condition is eliminated. In particular, we should decide whether the user-supplied filename is a no-key name, and whether it needs casefolding or not, just once -- rather than separately for each directory entry compared in ext4_match(). - Eric
Powered by blists - more mailing lists