From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934148AbXGSVcg (ORCPT ); Thu, 19 Jul 2007 17:32:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762250AbXGSVcX (ORCPT ); Thu, 19 Jul 2007 17:32:23 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:37588 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758590AbXGSVcV (ORCPT ); Thu, 19 Jul 2007 17:32:21 -0400 Date: Thu, 19 Jul 2007 16:30:06 -0500 From: Michael Halcrow To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, tchicks@us.ibm.com, trevor.highland@gmail.com, pregan@ic.sunysb.edu, toml@us.ibm.com, sergeh@us.ibm.com, mike@halcrow.us Subject: [PATCH 7/8] eCryptfs: Fix Tag 11 writing code Message-ID: <20070719213006.GH13821@halcrow.austin.ibm.com> Reply-To: Michael Halcrow References: <20070719212453.GA13821@halcrow.austin.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070719212453.GA13821@halcrow.austin.ibm.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Fix up the Tag 11 writing code to handle size limits and boundaries more explicitly. It looks like the packet length was 1 shorter than it should have been, chopping off the last byte of the key identifier. This is largely inconsequential, since it is not much more likely that a key identifier collision will occur with 7 bytes rather than 8. This patch fixes the packet to use the full number of bytes that were originally intended to be used for the key identifier. Signed-off-by: Michael Halcrow --- fs/ecryptfs/keystore.c | 39 ++++++++++++++++++++++----------------- 1 files changed, 22 insertions(+), 17 deletions(-) diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index 8c695e3..8485e77 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -1449,47 +1449,52 @@ out: * Returns zero on success; non-zero on error. */ static int -write_tag_11_packet(char *dest, int max, char *contents, size_t contents_length, - size_t *packet_length) +write_tag_11_packet(char *dest, int *remaining_bytes, char *contents, + size_t contents_length, size_t *packet_length) { size_t packet_size_length; + size_t max_packet_size; int rc = 0; (*packet_length) = 0; - if ((13 + contents_length) > max) { + /* This format is inspired by OpenPGP; see RFC 2440 + * packet tag 11 */ + max_packet_size = (1 /* Tag 11 identifier */ + + 3 /* Max Tag 11 packet size */ + + 1 /* Binary format specifier */ + + 1 /* Filename length */ + + 8 /* Filename ("_CONSOLE") */ + + 4 /* Modification date */ + + contents_length); /* Literal data */ + if (max_packet_size > (*remaining_bytes)) { + printk(KERN_ERR "Packet length larger than maximum allowable; " + "need up to [%d] bytes, but there are only [%d] " + "available\n", max_packet_size, (*remaining_bytes)); rc = -EINVAL; - ecryptfs_printk(KERN_ERR, "Packet length larger than " - "maximum allowable\n"); goto out; } - /* General packet header */ - /* Packet tag */ dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE; - /* Packet length */ rc = write_packet_length(&dest[(*packet_length)], - (13 + contents_length), &packet_size_length); + (max_packet_size - 4), &packet_size_length); if (rc) { - ecryptfs_printk(KERN_ERR, "Error generating tag 11 packet " - "header; cannot generate packet length\n"); + printk(KERN_ERR "Error generating tag 11 packet header; cannot " + "generate packet length. rc = [%d]\n", rc); goto out; } (*packet_length) += packet_size_length; - /* Tag 11 specific */ - /* One-octet field that describes how the data is formatted */ - dest[(*packet_length)++] = 0x62; /* binary data */ - /* One-octet filename length followed by filename */ + dest[(*packet_length)++] = 0x62; /* binary data format specifier */ dest[(*packet_length)++] = 8; memcpy(&dest[(*packet_length)], "_CONSOLE", 8); (*packet_length) += 8; - /* Four-octet number indicating modification date */ memset(&dest[(*packet_length)], 0x00, 4); (*packet_length) += 4; - /* Remainder is literal data */ memcpy(&dest[(*packet_length)], contents, contents_length); (*packet_length) += contents_length; out: if (rc) (*packet_length) = 0; + else + (*remaining_bytes) -= (*packet_length); return rc; } -- 1.4.4.4