audit: consolidate handling of mm->exe_file

This patch adds a audit_log_d_path_exe() helper function
to share how we handle auditing of the exe_file's path.
Used by both audit and auditsc. No functionality is changed.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
[PM: tweaked subject line]
Signed-off-by: Paul Moore <pmoore@redhat.com>

3 files changed, 19 insertions, 16 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index d219bb03a364..684b51d612a3 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1848,11 +1848,24 @@ error_path:
 }
 EXPORT_SYMBOL(audit_log_task_context);
 
+void audit_log_d_path_exe(struct audit_buffer *ab,
+                          struct mm_struct *mm)
+{
+        if (!mm) {
+                audit_log_format(ab, " exe=(null)");
+                return;
+        }
+
+        down_read(&mm->mmap_sem);
+        if (mm->exe_file)
+                audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
+        up_read(&mm->mmap_sem);
+}
+
 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 {
         const struct cred *cred;
         char comm[sizeof(tsk->comm)];
-        struct mm_struct *mm = tsk->mm;
         char *tty;
 
         if (!ab)
@@ -1888,13 +1901,7 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
         audit_log_format(ab, " comm=");
         audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
 
-        if (mm) {
-                down_read(&mm->mmap_sem);
-                if (mm->exe_file)
-                        audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
-                up_read(&mm->mmap_sem);
-        } else
-                audit_log_format(ab, " exe=(null)");
+        audit_log_d_path_exe(ab, tsk->mm);
         audit_log_task_context(ab);
 }
 EXPORT_SYMBOL(audit_log_task_info);
diff --git a/kernel/audit.h b/kernel/audit.h
index 3cdffad5a1d9..28067c50fd04 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -270,6 +270,9 @@ extern struct list_head audit_filter_list[];
 
 extern struct audit_entry *audit_dupe_rule(struct audit_krule *old);
 
+extern void audit_log_d_path_exe(struct audit_buffer *ab,
+                                 struct mm_struct *mm);
+
 /* audit watch functions */
 #ifdef CONFIG_AUDIT_WATCH
 extern void audit_put_watch(struct audit_watch *watch);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 793e9e98f7f8..4b89f7f95d84 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2460,7 +2460,6 @@ static void audit_log_task(struct audit_buffer *ab)
         kuid_t auid, uid;
         kgid_t gid;
         unsigned int sessionid;
-        struct mm_struct *mm = current->mm;
         char comm[sizeof(current->comm)];
 
         auid = audit_get_loginuid(current);
@@ -2475,13 +2474,7 @@ static void audit_log_task(struct audit_buffer *ab)
         audit_log_task_context(ab);
         audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
         audit_log_untrustedstring(ab, get_task_comm(comm, current));
-        if (mm) {
-                down_read(&mm->mmap_sem);
-                if (mm->exe_file)
-                        audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
-                up_read(&mm->mmap_sem);
-        } else
-                audit_log_format(ab, " exe=(null)");
+        audit_log_d_path_exe(ab, current->mm);
 }
 
 /**