Implement partial-file NFS lock testing.

Submitted by: "Andrew P. Lentvorski" <andrewl@io.com>

usr.sbin/rpc.lockd/lock_proc.c

@@ -87,6 +87,40 @@ log_from_addr(fun_name, req)
 	syslog(LOG_DEBUG, "%s from %s", fun_name, hostname_buf);
 }
 
+/* log_netobj ----------------------------------------------------------- */
+/*
+ * Purpose:	Log a netobj
+ * Returns:	Nothing
+ * Notes:	This function should only really be called as part of
+ *  		a debug subsystem.
+*/
+static void
+log_netobj(obj)
+	netobj *obj;
+{
+	char objvalbuffer[(sizeof(char)*2)*MAX_NETOBJ_SZ+2];
+	char objascbuffer[sizeof(char)*MAX_NETOBJ_SZ+1];
+	int i, maxlen;
+	char *tmp1, *tmp2;
+
+	/* Notify of potential security attacks */
+	if (obj->n_len > MAX_NETOBJ_SZ)	{
+		syslog(LOG_DEBUG, "SOMEONE IS TRYING TO DO SOMETHING NASTY!\n");
+		syslog(LOG_DEBUG, "netobj too large! Should be %d was %d\n",
+		    MAX_NETOBJ_SZ, obj->n_len);
+	}
+	/* Prevent the security hazard from the buffer overflow */
+	maxlen = (obj->n_len < MAX_NETOBJ_SZ ? obj->n_len : MAX_NETOBJ_SZ);
+	for (i=0, tmp1 = objvalbuffer, tmp2 = objascbuffer; i < obj->n_len;
+	    i++, tmp1 +=2, tmp2 +=1) {
+		sprintf(tmp1,"%02X",*(obj->n_bytes+i));
+		sprintf(tmp2,"%c",*(obj->n_bytes+i));
+	}
+	*tmp1 = '\0';
+	*tmp2 = '\0';
+	syslog(LOG_DEBUG,"netobjvals: %s\n",objvalbuffer);
+	syslog(LOG_DEBUG,"netobjascs: %s\n",objascbuffer);
+}
 /* get_client -------------------------------------------------------------- */
 /*
  * Purpose:	Get a CLIENT* for making RPC calls to lockd on given host
@@ -382,7 +416,7 @@ nlm_test_1_svc(arg, rqstp)
 	if (debug_level)
 		log_from_addr("nlm_test", rqstp);
 
-	holder = testlock(&arg4, 0);
+	holder = testlock(&arg4, arg->exclusive, 0);
 	/*
 	 * Copy the cookie from the argument into the result.  Note that this
 	 * is slightly hazardous, as the structure contains a pointer to a
@@ -422,7 +456,7 @@ nlm_test_msg_1_svc(arg, rqstp)
 	if (debug_level)
 		log_from_addr("nlm_test_msg", rqstp);
 
-	holder = testlock(&arg4, 0);
+	holder = testlock(&arg4, arg->exclusive, 0);
 
 	res.cookie = arg->cookie;
 	if (holder == NULL) {
@@ -867,8 +901,23 @@ nlm4_test_4_svc(arg, rqstp)
 
 	if (debug_level)
 		log_from_addr("nlm4_test", rqstp);
+	if (debug_level > 5) {
+		syslog(LOG_DEBUG, "Locking arguments:\n");
+		log_netobj(&(arg->cookie));
+		syslog(LOG_DEBUG, "Alock arguments:\n");
+		syslog(LOG_DEBUG, "Caller Name: %s\n",arg->alock.caller_name);
+		syslog(LOG_DEBUG, "File Handle:\n");
+		log_netobj(&(arg->alock.fh));
+		syslog(LOG_DEBUG, "Owner Handle:\n");
+		log_netobj(&(arg->alock.oh));
+		syslog(LOG_DEBUG, "SVID:        %d\n", arg->alock.svid);
+		syslog(LOG_DEBUG, "Lock Offset: %d\n", arg->alock.l_offset);
+		syslog(LOG_DEBUG, "Lock Length: %d\n", arg->alock.l_len);
+		syslog(LOG_DEBUG, "Exclusive:   %s\n",
+		    (arg->exclusive ? "true" : "false"));
+	}
 
-	holder = testlock(&arg->alock, LOCK_V4);
+	holder = testlock(&arg->alock, arg->exclusive, LOCK_V4);
 
 	/*
 	 * Copy the cookie from the argument into the result.  Note that this
@@ -904,7 +953,7 @@ nlm4_test_msg_4_svc(arg, rqstp)
 	if (debug_level)
 		log_from_addr("nlm4_test_msg", rqstp);
 
-	holder = testlock(&arg->alock, LOCK_V4);
+	holder = testlock(&arg->alock, arg->exclusive, LOCK_V4);
 
 	res.cookie = arg->cookie;
 	if (holder == NULL) {
@@ -948,6 +997,23 @@ nlm4_lock_4_svc(arg, rqstp)
 
 	if (debug_level)
 		log_from_addr("nlm4_lock", rqstp);
+	if (debug_level > 5) {
+		syslog(LOG_DEBUG, "Locking arguments:\n");
+		log_netobj(&(arg->cookie));
+		syslog(LOG_DEBUG, "Alock arguments:\n");
+		syslog(LOG_DEBUG, "Caller Name: %s\n",arg->alock.caller_name);
+		syslog(LOG_DEBUG, "File Handle:\n");
+		log_netobj(&(arg->alock.fh));
+		syslog(LOG_DEBUG, "Owner Handle:\n");
+		log_netobj(&(arg->alock.oh));
+		syslog(LOG_DEBUG, "SVID:        %d\n", arg->alock.svid);
+		syslog(LOG_DEBUG, "Lock Offset: %d\n", arg->alock.l_offset);
+		syslog(LOG_DEBUG, "Lock Length: %d\n", arg->alock.l_len);
+		syslog(LOG_DEBUG, "Block:       %s\n", (arg->block ? "true" : "false"));
+		syslog(LOG_DEBUG, "Exclusive:   %s\n", (arg->exclusive ? "true" : "false"));
+		syslog(LOG_DEBUG, "Reclaim:     %s\n", (arg->reclaim ? "true" : "false"));
+		syslog(LOG_DEBUG, "State num:   %d\n", arg->state);
+	}
 
 	/* copy cookie from arg to result.  See comment in nlm_test_4() */
 	res.cookie = arg->cookie;

usr.sbin/rpc.lockd/lockd_lock.c

@@ -54,7 +54,12 @@
 #include "lockd_lock.h"
 #include "lockd.h"
 
-/* A set of utilities for managing file locking */
+/*
+ * A set of utilities for managing file locking
+ *
+ * XXX: All locks are in a linked list, a better structure should be used
+ * to improve search/access effeciency.
+ */
 LIST_HEAD(lcklst_head, file_lock);
 struct lcklst_head lcklst_head = LIST_HEAD_INITIALIZER(lcklst_head);
 
@@ -75,6 +80,7 @@ struct file_lock {
 
 /* lock status */
 #define LKST_LOCKED	1 /* lock is locked */
+/* XXX: Is this flag file specific or lock specific? */
 #define LKST_WAITING	2 /* file is already locked by another host */
 #define LKST_PROCESSING	3 /* child is trying to aquire the lock */
 #define LKST_DYING	4 /* must dies when we get news from the child */
@@ -85,6 +91,8 @@ enum nlm_stats do_unlock __P((struct file_lock *));
 void send_granted __P((struct file_lock *, int));
 void siglock __P((void));
 void sigunlock __P((void));
+int  regions_overlap __P((u_int64_t start1, u_int64_t len1, u_int64_t start2,
+	u_int64_t len2));
 
 /* list of hosts we monitor */
 LIST_HEAD(hostlst_head, host);
@@ -99,6 +107,35 @@ struct host {
 
 void do_mon __P((char *));
 
+/*
+ * regions_overlap(): This function examines the two provided regions for overlap.
+ * It is non-trivial because start+len *CAN* overflow a 64-bit unsigned integer
+ * and NFS semantics are unspecified on this account.
+ */
+int
+regions_overlap(start1, len1, start2, len2)
+	u_int64_t start1, len1, start2, len2;
+{
+	int result;
+
+	/* XXX: Need to adjust checks to account for integer overflow */
+	if (len1 == 0 && len2 == 0) {
+		/* Regions *must* overlap if they both extend to the end */
+		result = TRUE;
+	} else if (len1 == 0 && start2+len2 < start1) {
+		/* Region 2 is completely to the left of Region 1 */
+		result = FALSE;
+	} else if (start1+len1 < start2 && len2 == 0) {
+		/* Region 1 is completely to the left of region 2 */
+		result = FALSE;
+	} else if (start1 + len1 <= start2 || start2+len2 <= start1) {
+		/* 1 is completely left of 2 or 2 is completely left of 1 */
+		result = FALSE;
+	} else {
+		result = TRUE;
+	}
+	return (result);
+}
 /*
  * testlock(): inform the caller if the requested lock would be granted or not
  * returns NULL if lock would granted, or pointer to the current nlm4_holder
@@ -106,8 +143,9 @@ void do_mon __P((char *));
  */
 
 struct nlm4_holder *
-testlock(lock, flags)
+testlock(lock, exclusive, flags)
 	struct nlm4_lock *lock;
+	bool_t exclusive;
 	int flags;
 {
 	struct file_lock *fl;
@@ -122,18 +160,40 @@ testlock(lock, flags)
 	    fl = LIST_NEXT(fl, lcklst)) {
 		if (fl->status != LKST_LOCKED)
 			continue;
+		/*
+		 * XXX: Could we possibly have identical filehandles
+		 * on different systems?
+		 * ie. Do we need to check more than just the filehandle?
+		 * ie. Could someone artificially create requests which are
+		 * security violations?
+		 */
 		if (memcmp(&fl->filehandle, &filehandle, sizeof(filehandle)))
 			continue;
-		/* got it ! */
+		/* File handles match, look for lock region overlap */
+		if (regions_overlap(lock->l_offset, lock->l_len,
+				    fl->client.l_offset, fl->client.l_len)) {
+			syslog(LOG_DEBUG,
+			    "Region overlap found %llu : %llu -- %llu : %llu\n",
+			    lock->l_offset, lock->l_len,
+			    fl->client.l_offset,fl->client.l_len);
+			/* Regions overlap. Now check for exclusivity. */
+			if (exclusive || fl->client.exclusive) {
+				/* Lock test must fail, regions are exclusive */
+				break;
+			}
+		}
+		/* Continue looping through all locks */
+	}
+	sigunlock();
+	if (fl == NULL) {
+		syslog(LOG_DEBUG, "test for %s: no lock found",
+		    lock->caller_name);
+		return NULL;
+	} else {
 		syslog(LOG_DEBUG, "test for %s: found lock held by %s",
 		    lock->caller_name, fl->client_name);
-		sigunlock();
 		return (&fl->client);
 	}
-	/* not found */
-	sigunlock();
-	syslog(LOG_DEBUG, "test for %s: no lock found", lock->caller_name);
-	return NULL;
 }
 
 /*

usr.sbin/rpc.lockd/lockd_lock.h

@@ -3,7 +3,7 @@
 
 /* Headers and function declarations for file-locking utilities */
 
-struct nlm4_holder * testlock __P((struct nlm4_lock *, int));
+struct nlm4_holder * testlock __P((struct nlm4_lock *, int, int));
 
 enum nlm_stats getlock __P((nlm4_lockargs *, struct svc_req *, int));
 enum nlm_stats unlock __P((nlm4_lock *, int));