From: "Ahmed S. Darwish" <darwish.07@gmail.com> To: casey@schaufler-ca.com Cc: akpm@osdl.org, torvalds@osdl.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] Version 9 (2.6.24-rc1) Smack: Simplified Mandatory Access Control Kernel Date: Sat, 27 Oct 2007 05:00:10 +0200 Message-ID: <20071027030010.GA5450@Ahmed> (raw) In-Reply-To: <4720118C.5020906@schaufler-ca.com> Hi Casey, Casey <casey@schaufler-ca.com> wrote: > > This version is again aimed at addressing Al Viro's issues in > smackfs. Ahmed Darwish has again contributed in the repair of the > locking issues there. The move to 2.6.24 was also an important > release incentive. > My patches mentiond above is not applied in this version. The same lock issues remain. Did you forget applying them ? In that case, here're the same patches again (on ver8): ==> 1: cipso_seq_show should not be passed smack labels with no cipso mapping. Omit non-cipso mapped labels in cipso_seq_start and BUG in case cipso_seq_show was passed a non-cipso label. Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.coM> --- smackv8-omit-noncipso-in-seq-start.patch diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 55ba2dc..b061cd0 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -297,14 +297,22 @@ void smk_cipso_doi(void) /* * Seq_file read operations for /smack/cipso + * + * Omit labels with no associated cipso values from being + * displayed in seq_show() */ static void *cipso_seq_start(struct seq_file *s, loff_t *pos) { + struct smack_known *skp = smack_known; + if (*pos >= smack_cipso_count) return NULL; - return smack_known; + while (skp && !skp->smk_cipso) + skp = skp->smk_next; + + return skp; } static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos) @@ -313,9 +321,6 @@ static void *cipso_seq_next(struct seq_file *s, void *v, loff_t *pos) (*pos)++; - /* - * Omit labels with no associated cipso value - */ while (skp && !skp->smk_cipso) skp = skp->smk_next; @@ -336,12 +341,11 @@ static int cipso_seq_show(struct seq_file *s, void *v) int i; unsigned char m; - if (scp == NULL) - return 0; + BUG_ON(!scp); + cbp = scp->smk_catset; seq_printf(s, "%s %3d", (char *)&skp->smk_known, scp->smk_level); - cbp = scp->smk_catset; for (i = 0; i < SMK_LABELLEN; i++) for (m = 0x80; m != 0; m >>= 1) { if (m & cbp[i]) { ==> 2: Avoid racy use of smack_{list,cipso}_count in traversing lists. Simple smack_list and smack_known lockless list traversal is all what's needed. Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com> --- smackv8-lockless-read.patch diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index b061cd0..e343827 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 +81,12 @@ 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) + *pos = SEQ_READ_FINISHED; + + return skp; } static int load_seq_show(struct seq_file *s, void *v) @@ -306,7 +311,7 @@ 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) @@ -319,11 +324,12 @@ 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; + if (!skp) + *pos = SEQ_READ_FINISHED; + return skp; } @@ -488,7 +494,6 @@ 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
next prev parent reply index Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-10-25 3:46 Casey Schaufler 2007-10-25 15:07 ` Stephen Smalley 2007-10-25 18:58 ` Casey Schaufler 2007-10-26 20:34 ` Stephen Smalley 2007-10-27 3:00 ` Ahmed S. Darwish [this message] 2007-10-27 19:20 ` Casey Schaufler 2007-10-27 9:01 ` Ahmed S. Darwish 2007-10-27 23:47 ` Al Viro 2007-10-28 5:41 ` Casey Schaufler 2007-10-28 12:46 ` Ahmed S. Darwish
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