[PATCH] Abnormal End of Processes

Hi,

I have been working on some code that detects abnormal events based on audit
system events. One kind of event that we currently have no visibility for is
when a program terminates due to segfault - which should never happen on a
production machine. And if it did, you'd want to investigate it. Attached is a
patch that collects these events and sends them into the audit system.

Signed-off-by: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/exec.c

@@ -1488,6 +1488,8 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
 	int flag = 0;
 	int ispipe = 0;
 
+	audit_core_dumps(signr);
+
 	binfmt = current->binfmt;
 	if (!binfmt || !binfmt->core_dump)
 		goto fail;

include/linux/audit.h

@@ -112,6 +112,7 @@
 #define AUDIT_FIRST_KERN_ANOM_MSG   1700
 #define AUDIT_LAST_KERN_ANOM_MSG    1799
 #define AUDIT_ANOM_PROMISCUOUS      1700 /* Device changed promiscuous mode */
+#define AUDIT_ANOM_ABEND            1701 /* Process ended abnormally */
 
 #define AUDIT_KERNEL		2000	/* Asynchronous audit record. NOT A REQUEST. */
 
@@ -377,6 +378,7 @@ static inline void audit_inode_child(const char *dname,
 	if (unlikely(!audit_dummy_context()))
 		__audit_inode_child(dname, inode, parent);
 }
+void audit_core_dumps(long signr);
 
 static inline void audit_ptrace(struct task_struct *t)
 {
@@ -467,6 +469,7 @@ extern int audit_signals;
 #define __audit_inode_child(d,i,p) do { ; } while (0)
 #define audit_inode(n,i) do { ; } while (0)
 #define audit_inode_child(d,i,p) do { ; } while (0)
+#define audit_core_dumps(i) do { ; } while (0)
 #define auditsc_get_stamp(c,t,s) do { BUG(); } while (0)
 #define audit_get_loginuid(c) ({ -1; })
 #define audit_log_task_context(b) do { ; } while (0)

kernel/auditsc.c

@@ -2037,3 +2037,42 @@ int __audit_signal_info(int sig, struct task_struct *t)
 
 	return 0;
 }
+
+/**
+ * audit_core_dumps - record information about processes that end abnormally
+ * @sig: signal value
+ *
+ * If a process ends with a core dump, something fishy is going on and we
+ * should record the event for investigation.
+ */
+void audit_core_dumps(long signr)
+{
+	struct audit_buffer *ab;
+	u32 sid;
+
+	if (!audit_enabled)
+		return;
+
+	if (signr == SIGQUIT)	/* don't care for those */
+		return;
+
+	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND);
+	audit_log_format(ab, "auid=%u uid=%u gid=%u",
+			audit_get_loginuid(current->audit_context),
+			current->uid, current->gid);
+	selinux_get_task_sid(current, &sid);
+	if (sid) {
+		char *ctx = NULL;
+		u32 len;
+
+		if (selinux_sid_to_string(sid, &ctx, &len))
+			audit_log_format(ab, " ssid=%u", sid);
+		else
+			audit_log_format(ab, " subj=%s", ctx);
+		kfree(ctx);
+	}
+	audit_log_format(ab, " pid=%d comm=", current->pid);
+	audit_log_untrustedstring(ab, current->comm);
+	audit_log_format(ab, " sig=%ld", signr);
+	audit_log_end(ab);
+}