I tested different kernels and two filesystem (xfs and ext4). It turns out that we cannot read less than value_size (which is 81 in ecryptfs) buffer when doing ecryptfs_read_and_validate_xattr_region(). In ecryptfs_read_and_validate_xattr_region() function, "file_size" array is the buffer we're going to read from xatte region and write. The reasonable solution is read 4096 instead of 16 from xattr region.
Any thoughts? -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1612492 Title: remounting breaks size reporting and rsync Status in eCryptfs: Triaged Status in ecryptfs-utils: Invalid Status in linux package in Ubuntu: Confirmed Bug description: Sorry to resurrect an old bug, it looks like a fix applied a while back may end up breaking rsync. For reference, it looks like the decision in this bug fix was to pass on the encrypted file size on disk to stat calls looking at the unencrypted mount: https://bugs.launchpad.net/ecryptfs/+bug/390833 For reference, to reproduce: mkdir /mnt/raw mkdir /mnt/decrypted dd if=/dev/urandom of=file.out2 bs=1MB count=100 mount -t ecryptfs -o ecryptfs_passthrough=n,no_sig_cache,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_xattr,ecryptfs_enable_filename_crypto=y,passphrase_passwd=SECRET,ecryptfs_fnek_sig=SECRET /mnt/raw /mnt/decrypted rsync file.out2 /mnt/decrypted/ stat /mnt/decrypted/file.out2 # you get size 100000000 umount /mnt/decrypted/ mount -t ecryptfs -o ecryptfs_passthrough=n,no_sig_cache,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_xattr,ecryptfs_enable_filename_crypto=y,passphrase_passwd=SECRET,ecryptfs_fnek_sig=SECRET /mnt/raw /mnt/decrypted stat /mnt/decrypted/file.out2 # you get size 100003840 What this means in practice is any additional rsyncs to that target after remounting will see the file size as different than the original, and issue a full new copy. My use case is ecryptfs over a remote file system, so rsync is no better than cp. Would it be possible to make file size reporting consistent, and reflective of the size of the file as a reader would see it? To manage notifications about this bug go to: https://bugs.launchpad.net/ecryptfs/+bug/1612492/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
