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From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: casey@schaufler-ca.com
Subject: [PATCH 69/90] LSM: Use full security context in security_inode_setsecctx
Date: Thu, 18 Apr 2019 17:45:56 -0700
Message-ID: <20190419004617.64627-70-casey@schaufler-ca.com> (raw)
In-Reply-To: <20190419004617.64627-1-casey@schaufler-ca.com>

The security hooks security_inode_setsecctx and security_inode_getsecctx
need to maintain the context strings for any and all LSMs that
provide contexts. This information is internal to the kernel
and volitile. If only one LSM uses this information the raw form is
used.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/security.c | 110 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 108 insertions(+), 2 deletions(-)

diff --git a/security/security.c b/security/security.c
index b8c90e7c4554..05a19b28e105 100644
--- a/security/security.c
+++ b/security/security.c
@@ -425,6 +425,9 @@ static int lsm_append(char *new, char **result)
 /* Base list of once-only hooks */
 struct lsm_one_hooks lsm_base_one;
 
+/* Count of inode_[gs]etsecctx hooks */
+static int lsm_inode_secctx_count;
+
 /**
  * security_add_hooks - Add a modules hooks to the hook lists.
  * @hooks: the hooks to add
@@ -442,6 +445,15 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 		hooks[i].lsm = lsm;
 		hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
 
+		/*
+		 * Keep count of the internal security context using hooks.
+		 * Assume that there is a 1:1 mapping from inode_getsecctx
+		 * to inode_setsecctx in the security modules.
+		 */
+		if (hooks[i].head == &security_hook_heads.inode_getsecctx) {
+			lsm_inode_secctx_count++;
+			continue;
+		}
 		/*
 		 * Check for the special hooks that are restricted to
 		 * a single module to create the base set. Use the hooks
@@ -2150,15 +2162,109 @@ int security_inode_notifysecctx(struct inode *inode, struct lsm_context *cp)
 }
 EXPORT_SYMBOL(security_inode_notifysecctx);
 
+/*
+ * The inode_[gs]etsecctx functions need to proved a context
+ * for multiple security modules. If there is more than one
+ * LSM supplying hooks the format will be
+ *	lsm1='value',lsm2='value'[,lsmN='value']...
+ */
+static void lsm_release_secctx(struct lsm_context *cp)
+{
+	kfree(cp->context);
+}
+
 int security_inode_setsecctx(struct dentry *dentry, struct lsm_context *cp)
 {
-	return call_int_hook(inode_setsecctx, 0, dentry, cp);
+	struct security_hook_list *hp;
+	struct lsm_context lc;
+	char *full;
+	char *ctx;
+	char *quote;
+	int rc = 0;
+
+	if (lsm_inode_secctx_count <= 1)
+		return call_int_hook(inode_setsecctx, 0, dentry, cp);
+
+	full = kstrndup(cp->context, cp->len, GFP_KERNEL);
+	if (full == NULL)
+		return -ENOMEM;
+
+	ctx = full;
+	hlist_for_each_entry(hp, &security_hook_heads.inode_setsecctx, list) {
+		if (strncmp(ctx, hp->lsm, strlen(hp->lsm))) {
+			WARN_ONCE(1, "security_inode_setsecctx form1 error\n");
+			rc = -EINVAL;
+			break;
+		}
+		ctx += strlen(hp->lsm);
+		if (ctx[0] != '=' || ctx[1] != '\'') {
+			WARN_ONCE(1, "security_inode_setsecctx form2 error\n");
+			rc = -EINVAL;
+			break;
+		}
+		ctx += 2;
+		quote = strnchr(ctx, cp->len, '\'');
+		if (quote == NULL) {
+			WARN_ONCE(1, "security_inode_setsecctx form3 error\n");
+			rc = -EINVAL;
+			break;
+		}
+		quote[0] = '\0';
+		if (quote[1] != ',' && quote[1] != '\0') {
+			WARN_ONCE(1, "security_inode_setsecctx form4 error\n");
+			rc = -EINVAL;
+			break;
+		}
+		lc.context = ctx;
+		lc.len = strlen(ctx);
+
+		ctx = quote + 2;
+
+		rc = hp->hook.inode_setsecctx(dentry, &lc);
+		if (rc)
+			break;
+	}
+
+	kfree(full);
+	return rc;
 }
 EXPORT_SYMBOL(security_inode_setsecctx);
 
 int security_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
 {
-	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, cp);
+	struct security_hook_list *hp;
+	struct lsm_context lc;
+	char *final = NULL;
+	char *tp;
+	int rc;
+
+	if (lsm_inode_secctx_count <= 1)
+		return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, cp);
+
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list) {
+		rc = hp->hook.inode_getsecctx(inode, &lc);
+		if (rc) {
+			kfree(final);
+			return rc;
+		}
+		if (final) {
+			tp = kasprintf(GFP_KERNEL, "%s,%s='%s'", final,
+				       hp->lsm, lc.context);
+			kfree(final);
+		} else
+			tp = kasprintf(GFP_KERNEL, "%s='%s'", hp->lsm,
+				       lc.context);
+		security_release_secctx(&lc);
+		if (tp == NULL) {
+			kfree(final);
+			return -ENOMEM;
+		}
+		final = tp;
+	}
+	cp->context = final;
+	cp->len = strlen(final);
+	cp->release = lsm_release_secctx;
+	return 0;
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
-- 
2.19.1


  parent reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-19  0:44 [PATCH 00/90] LSM: Module stacking for all Casey Schaufler
2019-04-19  0:44 ` [PATCH 01/90] LSM: Infrastructure management of the superblock Casey Schaufler
2019-04-19  0:44 ` [PATCH 02/90] LSM: Infrastructure management of the sock security Casey Schaufler
2019-04-19  0:44 ` [PATCH 03/90] LSM: Infrastructure management of the key security blob Casey Schaufler
2019-04-19  0:44 ` [PATCH 04/90] LSM: Create an lsm_export data structure Casey Schaufler
2019-04-19  0:44 ` [PATCH 05/90] LSM: Use lsm_export in the inode_getsecid hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 06/90] LSM: Use lsm_export in the cred_getsecid hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 07/90] LSM: Use lsm_export in the ipc_getsecid and task_getsecid hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 08/90] LSM: Use lsm_export in the kernel_ask_as hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 09/90] LSM: Use lsm_export in the getpeersec_dgram hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 10/90] LSM: Use lsm_export in the audit_rule_match hooks Casey Schaufler
2019-04-19  0:44 ` [PATCH 11/90] LSM: Fix logical operation in lsm_export checks Casey Schaufler
2019-04-19  0:44 ` [PATCH 12/90] LSM: Use lsm_export in the secid_to_secctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 13/90] LSM: Use lsm_export in the secctx_to_secid hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 14/90] LSM: Use lsm_export in security_audit_rule_match Casey Schaufler
2019-04-19  0:45 ` [PATCH 15/90] LSM: Use lsm_export in security_kernel_act_as Casey Schaufler
2019-04-19  0:45 ` [PATCH 16/90] LSM: Use lsm_export in security_socket_getpeersec_dgram Casey Schaufler
2019-04-19  0:45 ` [PATCH 17/90] LSM: Use lsm_export in security_secctx_to_secid Casey Schaufler
2019-04-19  0:45 ` [PATCH 18/90] LSM: Use lsm_export in security_secid_to_secctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 19/90] LSM: Use lsm_export in security_ipc_getsecid Casey Schaufler
2019-04-19  0:45 ` [PATCH 20/90] LSM: Use lsm_export in security_task_getsecid Casey Schaufler
2019-04-19  0:45 ` [PATCH 21/90] LSM: Use lsm_export in security_inode_getsecid Casey Schaufler
2019-04-19  0:45 ` [PATCH 22/90] LSM: Use lsm_export in security_cred_getsecid Casey Schaufler
2019-04-19  0:45 ` [PATCH 23/90] Audit: Change audit_sig_sid to audit_sig_lsm Casey Schaufler
2019-04-19  0:45 ` [PATCH 24/90] Audit: Convert target_sid to an lsm_export structure Casey Schaufler
2019-04-19  0:45 ` [PATCH 25/90] Audit: Convert osid " Casey Schaufler
2019-04-19  0:45 ` [PATCH 26/90] IMA: Clean out lsm_export scaffolding Casey Schaufler
2019-04-19  0:45 ` [PATCH 27/90] NET: Change the UNIXCB from a secid to an lsm_export Casey Schaufler
2019-04-19  0:45 ` [PATCH 28/90] NET: Remove scaffolding on secmarks Casey Schaufler
2019-04-19  0:45 ` [PATCH 29/90] NET: Remove scaffolding on new secmarks Casey Schaufler
2019-04-19  0:45 ` [PATCH 30/90] NET: Remove netfilter scaffolding for lsm_export Casey Schaufler
2019-04-19  0:45 ` [PATCH 31/90] Netlabel: Replace secids with lsm_export Casey Schaufler
2019-04-19  0:45 ` [PATCH 32/90] LSM: Remove lsm_export scaffolding functions Casey Schaufler
2019-04-19  0:45 ` [PATCH 33/90] IMA: FIXUP prototype using lsm_export Casey Schaufler
2019-04-19  0:45 ` [PATCH 34/90] Smack: Restore the release_secctx hook Casey Schaufler
2019-04-19  0:45 ` [PATCH 35/90] AppArmor: Remove unnecessary hook stub Casey Schaufler
2019-04-19  0:45 ` [PATCH 36/90] LSM: Limit calls to certain module hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 37/90] LSM: Create a data structure for a security context Casey Schaufler
2019-04-19  0:45 ` [PATCH 38/90] LSM: Use lsm_context in secid_to_secctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 39/90] LSM: Use lsm_context in secctx_to_secid hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 40/90] LSM: Use lsm_context in inode_getsecctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 41/90] LSM: Use lsm_context in inode_notifysecctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 42/90] LSM: Use lsm_context in dentry_init_security hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 43/90] LSM: Use lsm_context in security_dentry_init_security Casey Schaufler
2019-04-19  0:45 ` [PATCH 44/90] LSM: Use lsm_context in security_inode_notifysecctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 45/90] LSM: Use lsm_context in security_inode_getsecctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 46/90] LSM: Use lsm_context in security_secctx_to_secid Casey Schaufler
2019-04-19  0:45 ` [PATCH 47/90] LSM: Use lsm_context in release_secctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 48/90] LSM: Use lsm_context in security_release_secctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 49/90] LSM: Use lsm_context in security_secid_to_secctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 50/90] fs: remove lsm_context scaffolding Casey Schaufler
2019-04-19  0:45 ` [PATCH 51/90] LSM: Add the release function to the lsm_context Casey Schaufler
2019-04-19  0:45 ` [PATCH 52/90] LSM: Use lsm_context in inode_setsecctx hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 53/90] LSM: Use lsm_context in security_inode_setsecctx Casey Schaufler
2019-04-19  0:45 ` [PATCH 54/90] kernfs: remove lsm_context scaffolding Casey Schaufler
2019-04-19  0:45 ` [PATCH 55/90] LSM: Remove unused macro Casey Schaufler
2019-04-19  0:45 ` [PATCH 56/90] LSM: Special handling for secctx lsm hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 57/90] SELinux: Use blob offset in current_sid Casey Schaufler
2019-04-19  0:45 ` [PATCH 58/90] LSM: Specify which LSM to display Casey Schaufler
2019-04-19  0:45 ` [PATCH 59/90] AppArmor: Remove the exclusive flag Casey Schaufler
2019-04-19  0:45 ` [PATCH 60/90] LSM: Add secmark_relabel_packet to the set of one call hooks Casey Schaufler
2019-04-19  0:45 ` [PATCH 61/90] LSM: Make getting the secmark right cleaner Casey Schaufler
2019-04-19  0:45 ` [PATCH 62/90] netfilter: Fix memory leak introduced with lsm_context Casey Schaufler
2019-04-19  0:45 ` [PATCH 63/90] Smack: Consolidate secmark conversions Casey Schaufler
2019-04-19  0:45 ` [PATCH 64/90] netfilter: Remove unnecessary NULL check in lsm_context Casey Schaufler
2019-04-19  0:45 ` [PATCH 65/90] LSM: Add secmark refcounting to call_one list Casey Schaufler
2019-04-19  0:45 ` [PATCH 66/90] LSM: refactor security_setprocattr Casey Schaufler
2019-04-19  0:45 ` [PATCH 67/90] Smack: Detect if secmarks can be safely used Casey Schaufler
2019-04-19  0:45 ` [PATCH 68/90] LSM: Support multiple LSMs using inode_init_security Casey Schaufler
2019-04-19  0:45 ` Casey Schaufler [this message]
2019-04-22 13:13   ` [PATCH 69/90] LSM: Use full security context in security_inode_setsecctx Tetsuo Handa
2019-04-22 20:45     ` Casey Schaufler
2019-04-22 21:01       ` Tetsuo Handa
2019-04-19  0:45 ` [PATCH 70/90] LSM: Correct handling of ENOSYS in inode_setxattr Casey Schaufler
2019-04-19  0:45 ` [PATCH 71/90] LSM: Infrastructure security blobs for mount options Casey Schaufler
2019-04-19  0:45 ` [PATCH 72/90] LSM: Fix for security_init_inode_security Casey Schaufler
2019-04-19  0:46 ` [PATCH 73/90] Smack: Advertise the secid to netlabel Casey Schaufler
2019-04-19  0:46 ` [PATCH 74/90] LSM: Change error detection for UDP peer security Casey Schaufler
2019-04-19  0:46 ` [PATCH 75/90] Smack: Fix setting of the CIPSO MLS_CAT flags Casey Schaufler
2019-04-19  0:46 ` [PATCH 76/90] Smack: Set netlabel flags properly on new label import Casey Schaufler
2019-04-19  0:46 ` [PATCH 77/90] Netlabel: Add a secattr comparison API function Casey Schaufler
2019-04-19  0:46 ` [PATCH 78/90] Smack: Let netlabel do the work on the ambient domain Casey Schaufler
2019-04-19  0:46 ` [PATCH 79/90] Smack: Don't set the socket label on each send Casey Schaufler
2019-04-19  0:46 ` [PATCH 80/90] Smack: Let netlabel do the work on connections Casey Schaufler
2019-04-19  0:46 ` [PATCH 81/90] Netlabel: Return the labeling type on socket Casey Schaufler
2019-04-19 15:27 ` [PATCH 00/90] LSM: Module stacking for all Stephen Smalley
2019-04-21 17:31   ` Casey Schaufler
2019-04-22 12:46     ` Stephen Smalley
2019-04-22 16:10       ` Casey Schaufler

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