audit: Added exe field to audit core dump signal log

Currently when the coredump signals are logged by the audit system, the
actual path to the executable is not logged. Without details of exe, the
system admin may not have an exact idea on what program failed.

This patch changes the audit_log_task() so that the path to the exe is also
logged.

This was copied from audit_log_task_info() and the latter enhanced to avoid
disappearing text fields.
Signed-off-by: Paul Davies C <pauldaviesc@gmail.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

kernel/audit.c

@@ -1859,7 +1859,8 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 		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_task_context(ab);
 }
 EXPORT_SYMBOL(audit_log_task_info);

kernel/auditsc.c

@@ -2353,6 +2353,7 @@ 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;
 
 	auid = audit_get_loginuid(current);
 	sessionid = audit_get_sessionid(current);
@@ -2366,6 +2367,13 @@ static void audit_log_task(struct audit_buffer *ab)
 	audit_log_task_context(ab);
 	audit_log_format(ab, " pid=%d comm=", current->pid);
 	audit_log_untrustedstring(ab, current->comm);
+	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)");
 }
 
 /**