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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, linux-audit@redhat.com,
        keescook@chromium.org, john.johansen@canonical.com,
        penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com,
        stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org
Subject: [PATCH v36 28/33] audit: multiple subject lsm values for netlabel
Date:   Thu,  9 Jun 2022 16:01:41 -0700
Message-Id: <20220609230146.319210-29-casey@schaufler-ca.com>
In-Reply-To: <20220609230146.319210-1-casey@schaufler-ca.com>
References: <20220609230146.319210-1-casey@schaufler-ca.com>
MIME-Version: 1.0
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Refactor audit_log_task_context(), creating a new
audit_log_subject_context(). This is used in netlabel auditing
to provide multiple subject security contexts as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/audit.h        |  7 +++++++
 kernel/audit.c               | 26 ++++++++++++++++----------
 net/netlabel/netlabel_user.c |  7 +------
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index a7226989d77e..de661c571401 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -190,6 +190,8 @@ extern void		    audit_log_path_denied(int type,
 						  const char *operation);
 extern void		    audit_log_lost(const char *message);
 
+extern int audit_log_subject_context(struct audit_buffer *ab,
+				     struct lsmblob *blob);
 extern int audit_log_task_context(struct audit_buffer *ab);
 extern void audit_log_task_info(struct audit_buffer *ab);
 
@@ -250,6 +252,11 @@ static inline void audit_log_key(struct audit_buffer *ab, char *key)
 { }
 static inline void audit_log_path_denied(int type, const char *operation)
 { }
+static inline int audit_log_subject_context(struct audit_buffer *ab,
+					    struct lsmblob *blob)
+{
+	return 0;
+}
 static inline int audit_log_task_context(struct audit_buffer *ab)
 {
 	return 0;
diff --git a/kernel/audit.c b/kernel/audit.c
index 2333d7f59285..4ec86d696753 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2226,20 +2226,17 @@ static void audit_buffer_aux_end(struct audit_buffer *ab)
 	ab->skb = skb_peek(&ab->skb_list);
 }
 
-int audit_log_task_context(struct audit_buffer *ab)
+int audit_log_subject_context(struct audit_buffer *ab, struct lsmblob *blob)
 {
 	int i;
 	int error;
-	struct lsmblob blob;
 	struct lsmcontext context;
 
-	security_current_getsecid_subj(&blob);
-	if (!lsmblob_is_set(&blob))
+	if (!lsmblob_is_set(blob))
 		return 0;
 
 	if (!lsm_multiple_contexts()) {
-		error = security_secid_to_secctx(&blob, &context,
-						 LSMBLOB_FIRST);
+		error = security_secid_to_secctx(blob, &context, LSMBLOB_FIRST);
 		if (error) {
 			if (error != -EINVAL)
 				goto error_path;
@@ -2254,15 +2251,15 @@ int audit_log_task_context(struct audit_buffer *ab)
 		if (error)
 			goto error_path;
 		for (i = 0; i < LSMBLOB_ENTRIES; i++) {
-			if (blob.secid[i] == 0)
+			if (blob->secid[i] == 0)
 				continue;
-			error = security_secid_to_secctx(&blob, &context, i);
+			error = security_secid_to_secctx(blob, &context, i);
 			if (error) {
 				audit_log_format(ab, "%ssubj_%s=?",
 						 i ? " " : "",
 						 lsm_slot_to_name(i));
 				if (error != -EINVAL)
-					audit_panic("error in audit_log_task_context");
+					audit_panic("error in audit_log_subject_context");
 			} else {
 				audit_log_format(ab, "%ssubj_%s=%s",
 						 i ? " " : "",
@@ -2277,9 +2274,18 @@ int audit_log_task_context(struct audit_buffer *ab)
 	return 0;
 
 error_path:
-	audit_panic("error in audit_log_task_context");
+	audit_panic("error in audit_log_subject_context");
 	return error;
 }
+EXPORT_SYMBOL(audit_log_subject_context);
+
+int audit_log_task_context(struct audit_buffer *ab)
+{
+	struct lsmblob blob;
+
+	security_current_getsecid_subj(&blob);
+	return audit_log_subject_context(ab, &blob);
+}
 EXPORT_SYMBOL(audit_log_task_context);
 
 void audit_log_d_path_exe(struct audit_buffer *ab,
diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
index 1941877fd16f..42812bdfc31a 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -84,7 +84,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 					       struct netlbl_audit *audit_info)
 {
 	struct audit_buffer *audit_buf;
-	struct lsmcontext context;
 	struct lsmblob blob;
 
 	if (audit_enabled == AUDIT_OFF)
@@ -99,11 +98,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 audit_info->sessionid);
 
 	lsmblob_init(&blob, audit_info->secid);
-	if (audit_info->secid != 0 &&
-	    security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST) == 0) {
-		audit_log_format(audit_buf, " subj=%s", context.context);
-		security_release_secctx(&context);
-	}
+	audit_log_subject_context(audit_buf, &blob);
 
 	return audit_buf;
 }
-- 
2.35.1