linux-kernel - [PATCH v34 12/29] LSM: Use lsmblob in security_inode

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Message-Id: <20220407212230.12893-13-casey@schaufler-ca.com>
Date:   Thu,  7 Apr 2022 14:22:13 -0700
From:   Casey Schaufler <casey@...aufler-ca.com>
To:     casey.schaufler@...el.com, jmorris@...ei.org,
        linux-security-module@...r.kernel.org, selinux@...r.kernel.org
Cc:     casey@...aufler-ca.com, linux-audit@...hat.com,
        keescook@...omium.org, john.johansen@...onical.com,
        penguin-kernel@...ove.sakura.ne.jp, paul@...l-moore.com,
        stephen.smalley.work@...il.com, linux-kernel@...r.kernel.org,
        linux-integrity@...r.kernel.org
Subject: [PATCH v34 12/29] LSM: Use lsmblob in security_inode_getsecid

Change the security_inode_getsecid() interface to fill in a
lsmblob structure instead of a u32 secid. This allows for its
callers to gather data from all registered LSMs. Data is provided
for IMA and audit.

Reviewed-by: Kees Cook <keescook@...omium.org>
Reviewed-by: John Johansen <john.johansen@...onical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@...il.com>
Acked-by: Paul Moore <paul@...l-moore.com>
Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
Cc: linux-integrity@...r.kernel.org
Cc: linux-audit@...hat.com
---
 include/linux/security.h            |  7 ++++---
 kernel/auditsc.c                    |  6 +++++-
 security/integrity/ima/ima_policy.c |  7 ++++---
 security/security.c                 | 11 +++++++++--
 4 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 10ff7db2232e..44c92e1aedf2 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -456,7 +456,7 @@ int security_inode_getsecurity(struct user_namespace *mnt_userns,
 			       void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
 int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
-void security_inode_getsecid(struct inode *inode, u32 *secid);
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob);
 int security_inode_copy_up(struct dentry *src, struct cred **new);
 int security_inode_copy_up_xattr(const char *name);
 int security_kernfs_init_security(struct kernfs_node *kn_dir,
@@ -1002,9 +1002,10 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer,
 	return 0;
 }
 
-static inline void security_inode_getsecid(struct inode *inode, u32 *secid)
+static inline void security_inode_getsecid(struct inode *inode,
+					   struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob, 0);
 }
 
 static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 5ad606cc4814..fbc0895a1a93 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2300,13 +2300,17 @@ static void audit_copy_inode(struct audit_names *name,
 			     const struct dentry *dentry,
 			     struct inode *inode, unsigned int flags)
 {
+	struct lsmblob blob;
+
 	name->ino   = inode->i_ino;
 	name->dev   = inode->i_sb->s_dev;
 	name->mode  = inode->i_mode;
 	name->uid   = inode->i_uid;
 	name->gid   = inode->i_gid;
 	name->rdev  = inode->i_rdev;
-	security_inode_getsecid(inode, &name->osid);
+	security_inode_getsecid(inode, &blob);
+	/* scaffolding until osid is updated */
+	name->osid = blob.secid[0];
 	if (flags & AUDIT_INODE_NOEVAL) {
 		name->fcap_ver = -1;
 		return;
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 97470354c8ae..3deedfb2775f 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -624,7 +624,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		return false;
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
-		u32 osid;
+		struct lsmblob lsmdata;
 
 		if (!rule->lsm[i].rule) {
 			if (!rule->lsm[i].args_p)
@@ -636,8 +636,9 @@ static bool ima_match_rules(struct ima_rule_entry *rule,
 		case LSM_OBJ_USER:
 		case LSM_OBJ_ROLE:
 		case LSM_OBJ_TYPE:
-			security_inode_getsecid(inode, &osid);
-			rc = ima_filter_rule_match(osid, rule->lsm[i].type,
+			security_inode_getsecid(inode, &lsmdata);
+			rc = ima_filter_rule_match(lsmdata.secid[rule->which],
+						   rule->lsm[i].type,
 						   Audit_equal,
 						   rule->lsm[i].rule,
 						   rule->which);
diff --git a/security/security.c b/security/security.c
index eae5b7f3a0db..297a6be2e23a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1566,9 +1566,16 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
 }
 EXPORT_SYMBOL(security_inode_listsecurity);
 
-void security_inode_getsecid(struct inode *inode, u32 *secid)
+void security_inode_getsecid(struct inode *inode, struct lsmblob *blob)
 {
-	call_void_hook(inode_getsecid, inode, secid);
+	struct security_hook_list *hp;
+
+	lsmblob_init(blob, 0);
+	hlist_for_each_entry(hp, &security_hook_heads.inode_getsecid, list) {
+		if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+			continue;
+		hp->hook.inode_getsecid(inode, &blob->secid[hp->lsmid->slot]);
+	}
 }
 
 int security_inode_copy_up(struct dentry *src, struct cred **new)
-- 
2.35.1