Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751310AbXJUC0F (ORCPT ); Sat, 20 Oct 2007 22:26:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751093AbXJUCZ4 (ORCPT ); Sat, 20 Oct 2007 22:25:56 -0400 Received: from ug-out-1314.google.com ([66.249.92.173]:51525 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751015AbXJUCZy (ORCPT ); Sat, 20 Oct 2007 22:25:54 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent:from; b=aOxpeN+wMnb2RN40km8YC3Tvo2Yzu+JTTBOFGWIa7N5jMTq51cFK5XQdlzF3U5Zja276as3QNvRrXMEJwHcCVZlG3MpybwveL005acf4CUU6R4ikO5MVgoYsmaMXs8kTmAzMZG5dRgmKU/iID1Uz0SNzFF9VVW2ZV7QfdxepT50= Date: Sun, 21 Oct 2007 04:25:43 +0200 To: Casey Schaufler , Al Viro Cc: torvalds@osdl.org, akpm@osdl.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Smackv8: Safe lockless {cipso,load} read operation Message-ID: <20071021022543.GB3091@Ahmed> References: <47158CE4.30706@schaufler-ca.com> <20071021014021.GA3091@Ahmed> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071021014021.GA3091@Ahmed> User-Agent: Mutt/1.5.11 From: "Ahmed S. Darwish" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2643 Lines: 100 Hi, Utilizing Al's concers about using smack_cipso_count without locking, here's a patch that remove smack_cipso_count and uses simple list traversing in read() without any counting mechanism. CC: Al Viro Signed-off-by: Ahmed S. Darwish --- Please apply over omit-non-cipso-lables-in-cipso-seq-start.patch Using smack_{list,cipso}_count in the read context was useless anyway cause we were just traversing the list. diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index b061cd0..c38d0d0 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -63,16 +63,17 @@ int smack_cipso_direct = SMACK_CIPSO_DIRECT_DEFAULT; static int smk_cipso_doi_value = SMACK_CIPSO_DOI_DEFAULT; static int smack_list_count; -static int smack_cipso_count; struct smk_list_entry *smack_list; +#define SEQ_READ_FINISHED 1 + /* * Seq_file read operations for /smack/load */ static void *load_seq_start(struct seq_file *s, loff_t *pos) { - if (*pos >= smack_list_count) + if (*pos == SEQ_READ_FINISHED) return NULL; return smack_list; @@ -80,8 +81,13 @@ static void *load_seq_start(struct seq_file *s, loff_t *pos) static void *load_seq_next(struct seq_file *s, void *v, loff_t *pos) { - (*pos)++; - return ((struct smk_list_entry *) v)->smk_next; + struct smk_list_entry *skp = ((struct smk_list_entry *) v)->smk_next; + + if (skp) + return skp; + + *pos = SEQ_READ_FINISHED; + return NULL; } static int load_seq_show(struct seq_file *s, void *v) @@ -306,7 +312,7 @@ static void *cipso_seq_start(struct seq_file *s, loff_t *pos) { struct smack_known *skp = smack_known; - if (*pos >= smack_cipso_count) + if (*pos == SEQ_READ_FINISHED) return NULL; while (skp && !skp->smk_cipso) @@ -319,12 +325,14 @@ static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos) { struct smack_known *skp = ((struct smack_known *) v)->smk_next; - (*pos)++; - while (skp && !skp->smk_cipso) skp = skp->smk_next; - return skp; + if (skp) + return skp; + + *pos = SEQ_READ_FINISHED; + return NULL; } /* @@ -488,7 +496,6 @@ static ssize_t smk_write_cipso(struct file *file, const char __user *buf, rc = -ENOMEM; break; } - ++smack_cipso_count; } else scp = NULL; -- Ahmed S. Darwish HomePage: http://darwish.07.googlepages.com Blog: http://darwish-07.blogspot.com - 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/