Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754824AbXLUPII (ORCPT ); Fri, 21 Dec 2007 10:08:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751476AbXLUPH5 (ORCPT ); Fri, 21 Dec 2007 10:07:57 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:45370 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbXLUPH4 (ORCPT ); Fri, 21 Dec 2007 10:07:56 -0500 Date: Fri, 21 Dec 2007 09:01:45 -0600 From: Michael Halcrow To: Eric Sandeen Cc: linux-kernel Mailing List , Andrew Morton , mike@halcrow.us, Jeff Moyer Subject: Re: [PATCH] ecryptfs: check for existing key_tfm at mount time Message-ID: <20071221150145.GE10989@localhost.austin.ibm.com> Reply-To: Michael Halcrow References: <476B4CB9.9070700@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <476B4CB9.9070700@redhat.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4866 Lines: 127 On Thu, Dec 20, 2007 at 11:18:49PM -0600, Eric Sandeen wrote: > Jeff Moyer pointed out that a mount; umount loop of ecryptfs, > with the same cipher & other mount options, created a new > ecryptfs_key_tfm_cache item each time, and the cache could > grow quite large this way. > > Looking at this with mhalcrow, we saw that ecryptfs_parse_options() > unconditionally called ecryptfs_add_new_key_tfm(), which is what > was adding these items. > > Refactor ecryptfs_get_tfm_and_mutex_for_cipher_name() to create a > new helper function, ecryptfs_tfm_exists(), which checks for the > cipher on the cached key_tfm_list, and sets a pointer > to it if it exists. This can then be called from > ecryptfs_parse_options(), and new key_tfm's can be added only when > a cached one is not found. > > Signed-off-by: Eric Sandeen Acked-by: Mike Halcrow > --- > > Index: linux-2.6.24-rc3/fs/ecryptfs/crypto.c > =================================================================== > --- linux-2.6.24-rc3.orig/fs/ecryptfs/crypto.c > +++ linux-2.6.24-rc3/fs/ecryptfs/crypto.c > @@ -1868,6 +1868,33 @@ out: > return rc; > } > > +/** > + * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. > + * @cipher_name: the name of the cipher to search for > + * @key_tfm: set to corresponding tfm if found > + * > + * Returns 1 if found, with key_tfm set > + * Returns 0 if not found, key_tfm set to NULL > + */ > +int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) > +{ > + struct ecryptfs_key_tfm *tmp_key_tfm; > + > + mutex_lock(&key_tfm_list_mutex); > + list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { > + if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { > + mutex_unlock(&key_tfm_list_mutex); > + if (key_tfm) > + (*key_tfm) = tmp_key_tfm; > + return 1; > + } > + } > + mutex_unlock(&key_tfm_list_mutex); > + if (key_tfm) > + (*key_tfm) = NULL; > + return 0; > +} > + > int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm, > struct mutex **tfm_mutex, > char *cipher_name) > @@ -1877,22 +1904,15 @@ int ecryptfs_get_tfm_and_mutex_for_ciphe > > (*tfm) = NULL; > (*tfm_mutex) = NULL; > - mutex_lock(&key_tfm_list_mutex); > - list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) { > - if (strcmp(key_tfm->cipher_name, cipher_name) == 0) { > - (*tfm) = key_tfm->key_tfm; > - (*tfm_mutex) = &key_tfm->key_tfm_mutex; > - mutex_unlock(&key_tfm_list_mutex); > + > + if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { > + rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); > + if (rc) { > + printk(KERN_ERR "Error adding new key_tfm to list; " > + "rc = [%d]\n", rc); > goto out; > } > } > - mutex_unlock(&key_tfm_list_mutex); > - rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); > - if (rc) { > - printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n", > - rc); > - goto out; > - } > (*tfm) = key_tfm->key_tfm; > (*tfm_mutex) = &key_tfm->key_tfm_mutex; > out: > Index: linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h > =================================================================== > --- linux-2.6.24-rc3.orig/fs/ecryptfs/ecryptfs_kernel.h > +++ linux-2.6.24-rc3/fs/ecryptfs/ecryptfs_kernel.h > @@ -623,6 +623,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs > size_t key_size); > int ecryptfs_init_crypto(void); > int ecryptfs_destroy_crypto(void); > +int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm); > int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm, > struct mutex **tfm_mutex, > char *cipher_name); > Index: linux-2.6.24-rc3/fs/ecryptfs/main.c > =================================================================== > --- linux-2.6.24-rc3.orig/fs/ecryptfs/main.c > +++ linux-2.6.24-rc3/fs/ecryptfs/main.c > @@ -410,9 +410,11 @@ static int ecryptfs_parse_options(struct > if (!cipher_key_bytes_set) { > mount_crypt_stat->global_default_cipher_key_size = 0; > } > - rc = ecryptfs_add_new_key_tfm( > - NULL, mount_crypt_stat->global_default_cipher_name, > - mount_crypt_stat->global_default_cipher_key_size); > + if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name, > + NULL)) > + rc = ecryptfs_add_new_key_tfm( > + NULL, mount_crypt_stat->global_default_cipher_name, > + mount_crypt_stat->global_default_cipher_key_size); > if (rc) { > printk(KERN_ERR "Error attempting to initialize cipher with " > "name = [%s] and key size = [%td]; rc = [%d]\n", > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/