On 10/7/11 1:35 PM, Darrick J. Wong wrote: > On Fri, Oct 07, 2011 at 12:11:05AM -0700, Allison Henderson wrote: >> This patch modifies both ext4 and jbd2 such that the journal >> blocks which may contain file data, are securely deleted >> after the files data blocks are deleted. >> >> Because old journal blocks may contain file data, we need >> a way to find those blocks again when it comes time to secure >> delete the file. This patch adds a new list to the journal >> structure to keep track of which vfs blocks the journal blocks >> contain. >> >> After a truncate or a punch hole operation has completed, a >> new function ext4_secure_delete_jblks is called that flushes >> the journal, and then searches the list for any journal blocks >> that were used to journal the blocks that were just removed. >> The found journal blocks are then secure deleted. And what about directory data? Those would appear to remain in the journal at least... And xattrs? #!/bin/bash rm -f testsecdel truncate --size 256m testsecdel mkfs.ext4 -F testsecdel &>/dev/null mount -o loop testsecdel mnt/ echo securedata > mnt/securefilename setfattr -n user.securexattrname -v securexattrvalue mnt/securefilename LONGATTR=`for I in 1 2 3 4 5 6 7 8 9 0; do echo -n veryveryveryveryveryveryverylongsecurexattrvalue; done` setfattr -n user.longsecurexattrname -v $LONGATTR mnt/securefilename sync rm -f mnt/securefilename umount mnt strings testsecdel yields: /mnt/test2/mnt lost+found securexattrname Ylongsecurexattrname mselinux veryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvalueveryveryveryveryveryveryverylongsecurexattrvaluesecurexattrvalueunconfined_u:object_r:file_t:s0 lost+found securefilename /mnt/test2/mnt (this was with ext4.ko hacked to always enable secure delete) -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
