[PATCH v39 25/42] audit: multiple subject lsm values for netlabel

[Casey Schaufler]

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.

Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
---
 include/linux/audit.h        |  8 ++++++++
 kernel/audit.c               | 21 ++++++++++++++-------
 net/netlabel/netlabel_user.c |  8 +-------
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 51b1b7054a23..8974500f730f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -36,6 +36,7 @@ struct mqstat;
 struct audit_watch;
 struct audit_tree;
 struct sk_buff;
+struct lsmblob;
 
 struct audit_krule {
 	u32			pflags;
@@ -184,6 +185,8 @@ 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);
 
@@ -244,6 +247,11 @@ 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 9d971fa96c0e..626942c38bca 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2225,20 +2225,18 @@ 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)
 {
 	struct lsmcontext ctx;
-	struct lsmblob blob;
 	bool space = false;
 	int error;
 	int i;
 
-	security_current_getlsmblob_subj(&blob);
-	if (!lsmblob_is_set(&blob))
+	if (!lsmblob_is_set(blob))
 		return 0;
 
 	if (lsm_blob_cnt < 2) {
-		error = security_lsmblob_to_secctx(&blob, &ctx, LSM_ID_UNDEF);
+		error = security_lsmblob_to_secctx(blob, &ctx, LSM_ID_UNDEF);
 		if (error < 0) {
 			if (error != -EINVAL)
 				goto error_path;
@@ -2257,7 +2255,7 @@ int audit_log_task_context(struct audit_buffer *ab)
 	for (i = 0; i < lsm_active_cnt; i++) {
 		if (!lsm_idlist[i]->lsmblob)
 			continue;
-		error = security_lsmblob_to_secctx(&blob, &ctx,
+		error = security_lsmblob_to_secctx(blob, &ctx,
 						   lsm_idlist[i]->id);
 		if (error < 0) {
 			if (error == -EOPNOTSUPP)
@@ -2277,9 +2275,18 @@ 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_getlsmblob_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 842a236540b0..4dd0f453bb4e 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 ctx;
 
 	if (audit_enabled == AUDIT_OFF)
 		return NULL;
@@ -97,12 +96,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
 			 from_kuid(&init_user_ns, audit_info->loginuid),
 			 audit_info->sessionid);
 
-	if (lsmblob_is_set(&audit_info->blob) &&
-	    security_lsmblob_to_secctx(&audit_info->blob, &ctx,
-				       LSM_ID_UNDEF) >= 0) {
-		audit_log_format(audit_buf, " subj=%s", ctx.context);
-		security_release_secctx(&ctx);
-	}
+	audit_log_subject_context(audit_buf, &audit_info->blob);
 
 	return audit_buf;
 }
-- 
2.41.0