From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754698Ab1HNQKE (ORCPT ); Sun, 14 Aug 2011 12:10:04 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36890 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754654Ab1HNQKA (ORCPT ); Sun, 14 Aug 2011 12:10:00 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Aug 12 14:05:58 2011 Message-Id: <20110812210558.874394229@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Fri, 12 Aug 2011 14:05:02 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, John Johansen , Tyler Hicks Subject: [77/90] Ecryptfs: Add mount option to check uid of device being In-Reply-To: <20110812210626.GA4725@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let us know. ------------------ mounted = expect uid From: John Johansen commit 764355487ea220fdc2faf128d577d7f679b91f97 upstream. Close a TOCTOU race for mounts done via ecryptfs-mount-private. The mount source (device) can be raced when the ownership test is done in userspace. Provide Ecryptfs a means to force the uid check at mount time. Signed-off-by: John Johansen Signed-off-by: Tyler Hicks Signed-off-by: Greg Kroah-Hartman --- fs/ecryptfs/main.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -175,6 +175,7 @@ enum { ecryptfs_opt_sig, ecryptfs_opt_ec ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig, ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes, ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only, + ecryptfs_opt_check_dev_ruid, ecryptfs_opt_err }; static const match_table_t tokens = { @@ -191,6 +192,7 @@ static const match_table_t tokens = { {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"}, {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"}, {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"}, + {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"}, {ecryptfs_opt_err, NULL} }; @@ -236,6 +238,7 @@ static void ecryptfs_init_mount_crypt_st * ecryptfs_parse_options * @sb: The ecryptfs super block * @options: The options passed to the kernel + * @check_ruid: set to 1 if device uid should be checked against the ruid * * Parse mount options: * debug=N - ecryptfs_verbosity level for debug output @@ -251,7 +254,8 @@ static void ecryptfs_init_mount_crypt_st * * Returns zero on success; non-zero on error */ -static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options) +static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, + uid_t *check_ruid) { char *p; int rc = 0; @@ -276,6 +280,8 @@ static int ecryptfs_parse_options(struct char *cipher_key_bytes_src; char *fn_cipher_key_bytes_src; + *check_ruid = 0; + if (!options) { rc = -EINVAL; goto out; @@ -380,6 +386,9 @@ static int ecryptfs_parse_options(struct mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY; break; + case ecryptfs_opt_check_dev_ruid: + *check_ruid = 1; + break; case ecryptfs_opt_err: default: printk(KERN_WARNING @@ -475,6 +484,7 @@ static struct dentry *ecryptfs_mount(str const char *err = "Getting sb failed"; struct inode *inode; struct path path; + uid_t check_ruid; int rc; sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL); @@ -483,7 +493,7 @@ static struct dentry *ecryptfs_mount(str goto out; } - rc = ecryptfs_parse_options(sbi, raw_data); + rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid); if (rc) { err = "Error parsing options"; goto out; @@ -521,6 +531,15 @@ static struct dentry *ecryptfs_mount(str "known incompatibilities\n"); goto out_free; } + + if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) { + rc = -EPERM; + printk(KERN_ERR "Mount of device (uid: %d) not owned by " + "requested user (uid: %d)\n", + path.dentry->d_inode->i_uid, current_uid()); + goto out_free; + } + ecryptfs_set_superblock_lower(s, path.dentry->d_sb); s->s_maxbytes = path.dentry->d_sb->s_maxbytes; s->s_blocksize = path.dentry->d_sb->s_blocksize;