eCryptfs: Allow 2 scatterlist entries for encrypted filenames
commite06b5bf516bfcc0f55d0577b14261fee1824c646
authorTyler Hicks <tyhicks@linux.vnet.ibm.com>
Tue, 17 May 2011 05:50:33 +0000 (17 00:50 -0500)
committerAndi Kleen <ak@linux.intel.com>
Mon, 1 Aug 2011 20:54:53 +0000 (1 13:54 -0700)
treea1d9d92aa098b94a44487e75376730adbca1dd9e
parent117c0bc1b8a17622e4f93a744ba492b5da9d9fee
eCryptfs: Allow 2 scatterlist entries for encrypted filenames

commit 8d08dab786ad5cc2aca2bf870de370144b78c85a upstream.

The buffers allocated while encrypting and decrypting long filenames can
sometimes straddle two pages. In this situation, virt_to_scatterlist()
will return -ENOMEM, causing the operation to fail and the user will get
scary error messages in their logs:

kernel: ecryptfs_write_tag_70_packet: Internal error whilst attempting
to convert filename memory to scatterlist; expected rc = 1; got rc =
[-12]. block_aligned_filename_size = [272]
kernel: ecryptfs_encrypt_filename: Error attempting to generate tag 70
packet; rc = [-12]
kernel: ecryptfs_encrypt_and_encode_filename: Error attempting to
encrypt filename; rc = [-12]
kernel: ecryptfs_lookup: Error attempting to encrypt and encode
filename; rc = [-12]

The solution is to allow up to 2 scatterlist entries to be used.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
fs/ecryptfs/keystore.c