svn commit: r261882 - in head: sbin/pfctl sys/net sys/netpfil/pf

Gleb Smirnoff glebius at FreeBSD.org
Fri Feb 14 10:05:23 UTC 2014


Author: glebius
Date: Fri Feb 14 10:05:21 2014
New Revision: 261882
URL: http://svnweb.freebsd.org/changeset/base/261882

Log:
  Once pf became not covered by a single mutex, many counters in it became
  race prone. Some just gather statistics, but some are later used in
  different calculations.
  
  A real problem was the race provoked underflow of the states_cur counter
  on a rule. Once it goes below zero, it wraps to UINT32_MAX. Later this
  value is used in pf_state_expires() and any state created by this rule
  is immediately expired.
  
  Thus, make fields states_cur, states_tot and src_nodes of struct
  pf_rule be counter(9)s.
  
  Thanks to Dennis for providing me shell access to problematic box and
  his help with reproducing, debugging and investigating the problem.
  
  Thanks to:		Dennis Yusupoff <dyr smartspb.net>
  Also reported by:	dumbbell, pgj, Rambler
  Sponsored by:		Nginx, Inc.

Modified:
  head/sbin/pfctl/pfctl.c
  head/sys/net/pfvar.h
  head/sys/netpfil/pf/if_pfsync.c
  head/sys/netpfil/pf/pf.c
  head/sys/netpfil/pf/pf_ioctl.c

Modified: head/sbin/pfctl/pfctl.c
==============================================================================
--- head/sbin/pfctl/pfctl.c	Fri Feb 14 08:42:39 2014	(r261881)
+++ head/sbin/pfctl/pfctl.c	Fri Feb 14 10:05:21 2014	(r261882)
@@ -791,17 +791,17 @@ pfctl_print_rule_counters(struct pf_rule
 	}
 	if (opts & PF_OPT_VERBOSE) {
 		printf("  [ Evaluations: %-8llu  Packets: %-8llu  "
-			    "Bytes: %-10llu  States: %-6u]\n",
+			    "Bytes: %-10llu  States: %-6lu]\n",
 			    (unsigned long long)rule->evaluations,
 			    (unsigned long long)(rule->packets[0] +
 			    rule->packets[1]),
 			    (unsigned long long)(rule->bytes[0] +
-			    rule->bytes[1]), rule->states_cur);
+			    rule->bytes[1]), (uint64_t)rule->states_cur);
 		if (!(opts & PF_OPT_DEBUG))
 			printf("  [ Inserted: uid %u pid %u "
-			    "State Creations: %-6u]\n",
+			    "State Creations: %-6lu]\n",
 			    (unsigned)rule->cuid, (unsigned)rule->cpid,
-			    rule->states_tot);
+			    (uint64_t)rule->states_tot);
 	}
 }
 

Modified: head/sys/net/pfvar.h
==============================================================================
--- head/sys/net/pfvar.h	Fri Feb 14 08:42:39 2014	(r261881)
+++ head/sys/net/pfvar.h	Fri Feb 14 10:05:21 2014	(r261882)
@@ -35,6 +35,7 @@
 
 #include <sys/param.h>
 #include <sys/queue.h>
+#include <sys/counter.h>
 #include <sys/refcount.h>
 #include <sys/tree.h>
 
@@ -512,13 +513,9 @@ struct pf_rule {
 
 	int			 rtableid;
 	u_int32_t		 timeout[PFTM_MAX];
-	u_int32_t		 states_cur;
-	u_int32_t		 states_tot;
 	u_int32_t		 max_states;
-	u_int32_t		 src_nodes;
 	u_int32_t		 max_src_nodes;
 	u_int32_t		 max_src_states;
-	u_int32_t		 spare1;			/* netgraph */
 	u_int32_t		 max_src_conn;
 	struct {
 		u_int32_t		limit;
@@ -532,6 +529,10 @@ struct pf_rule {
 	uid_t			 cuid;
 	pid_t			 cpid;
 
+	counter_u64_t		 states_cur;
+	counter_u64_t		 states_tot;
+	counter_u64_t		 src_nodes;
+
 	u_int16_t		 return_icmp;
 	u_int16_t		 return_icmp6;
 	u_int16_t		 max_mss;

Modified: head/sys/netpfil/pf/if_pfsync.c
==============================================================================
--- head/sys/netpfil/pf/if_pfsync.c	Fri Feb 14 08:42:39 2014	(r261881)
+++ head/sys/netpfil/pf/if_pfsync.c	Fri Feb 14 10:05:21 2014	(r261882)
@@ -438,7 +438,8 @@ pfsync_state_import(struct pfsync_state 
 	else
 		r = &V_pf_default_rule;
 
-	if ((r->max_states && r->states_cur >= r->max_states))
+	if ((r->max_states &&
+	    counter_u64_fetch(r->states_cur) >= r->max_states))
 		goto cleanup;
 
 	/*
@@ -516,18 +517,15 @@ pfsync_state_import(struct pfsync_state 
 	st->pfsync_time = time_uptime;
 	st->sync_state = PFSYNC_S_NONE;
 
-	/* XXX when we have nat_rule/anchors, use STATE_INC_COUNTERS */
-	r->states_cur++;
-	r->states_tot++;
-
 	if (!(flags & PFSYNC_SI_IOCTL))
 		st->state_flags |= PFSTATE_NOSYNC;
 
-	if ((error = pf_state_insert(kif, skw, sks, st)) != 0) {
-		/* XXX when we have nat_rule/anchors, use STATE_DEC_COUNTERS */
-		r->states_cur--;
+	if ((error = pf_state_insert(kif, skw, sks, st)) != 0)
 		goto cleanup_state;
-	}
+
+	/* XXX when we have nat_rule/anchors, use STATE_INC_COUNTERS */
+	counter_u64_add(r->states_cur, 1);
+	counter_u64_add(r->states_tot, 1);
 
 	if (!(flags & PFSYNC_SI_IOCTL)) {
 		st->state_flags &= ~PFSTATE_NOSYNC;

Modified: head/sys/netpfil/pf/pf.c
==============================================================================
--- head/sys/netpfil/pf/pf.c	Fri Feb 14 08:42:39 2014	(r261881)
+++ head/sys/netpfil/pf/pf.c	Fri Feb 14 10:05:21 2014	(r261882)
@@ -335,27 +335,27 @@ enum { PF_ICMP_MULTI_NONE, PF_ICMP_MULTI
 #define	BOUND_IFACE(r, k) \
 	((r)->rule_flag & PFRULE_IFBOUND) ? (k) : V_pfi_all
 
-#define	STATE_INC_COUNTERS(s)				\
-	do {						\
-		s->rule.ptr->states_cur++;		\
-		s->rule.ptr->states_tot++;		\
-		if (s->anchor.ptr != NULL) {		\
-			s->anchor.ptr->states_cur++;	\
-			s->anchor.ptr->states_tot++;	\
-		}					\
-		if (s->nat_rule.ptr != NULL) {		\
-			s->nat_rule.ptr->states_cur++;	\
-			s->nat_rule.ptr->states_tot++;	\
-		}					\
+#define	STATE_INC_COUNTERS(s)						\
+	do {								\
+		counter_u64_add(s->rule.ptr->states_cur, 1);		\
+		counter_u64_add(s->rule.ptr->states_tot, 1);		\
+		if (s->anchor.ptr != NULL) {				\
+			counter_u64_add(s->anchor.ptr->states_cur, 1);	\
+			counter_u64_add(s->anchor.ptr->states_tot, 1);	\
+		}							\
+		if (s->nat_rule.ptr != NULL) {				\
+			counter_u64_add(s->nat_rule.ptr->states_cur, 1);\
+			counter_u64_add(s->nat_rule.ptr->states_tot, 1);\
+		}							\
 	} while (0)
 
-#define	STATE_DEC_COUNTERS(s)				\
-	do {						\
-		if (s->nat_rule.ptr != NULL)		\
-			s->nat_rule.ptr->states_cur--;	\
-		if (s->anchor.ptr != NULL)		\
-			s->anchor.ptr->states_cur--;	\
-		s->rule.ptr->states_cur--;		\
+#define	STATE_DEC_COUNTERS(s)						\
+	do {								\
+		if (s->nat_rule.ptr != NULL)				\
+			counter_u64_add(s->nat_rule.ptr->states_cur, -1);\
+		if (s->anchor.ptr != NULL)				\
+			counter_u64_add(s->anchor.ptr->states_cur, -1);	\
+		counter_u64_add(s->rule.ptr->states_cur, -1);		\
 	} while (0)
 
 static MALLOC_DEFINE(M_PFHASH, "pf_hash", "pf(4) hash header structures");
@@ -647,7 +647,7 @@ pf_insert_src_node(struct pf_src_node **
 		PF_HASHROW_ASSERT(sh);
 
 		if (!rule->max_src_nodes ||
-		    rule->src_nodes < rule->max_src_nodes)
+		    counter_u64_fetch(rule->src_nodes) < rule->max_src_nodes)
 			(*sn) = uma_zalloc(V_pf_sources_z, M_NOWAIT | M_ZERO);
 		else
 			V_pf_status.lcounters[LCNT_SRCNODES]++;
@@ -667,7 +667,7 @@ pf_insert_src_node(struct pf_src_node **
 		(*sn)->creation = time_uptime;
 		(*sn)->ruletype = rule->action;
 		if ((*sn)->rule.ptr != NULL)
-			(*sn)->rule.ptr->src_nodes++;
+			counter_u64_add((*sn)->rule.ptr->src_nodes, 1);
 		PF_HASHROW_UNLOCK(sh);
 		V_pf_status.scounters[SCNT_SRC_NODE_INSERT]++;
 		V_pf_status.src_nodes++;
@@ -692,7 +692,7 @@ pf_unlink_src_node_locked(struct pf_src_
 #endif
 	LIST_REMOVE(src, entry);
 	if (src->rule.ptr)
-		src->rule.ptr->src_nodes--;
+		counter_u64_add(src->rule.ptr->src_nodes, -1);
 	V_pf_status.scounters[SCNT_SRC_NODE_REMOVALS]++;
 	V_pf_status.src_nodes--;
 }
@@ -1478,7 +1478,7 @@ pf_state_expires(const struct pf_state *
 	start = state->rule.ptr->timeout[PFTM_ADAPTIVE_START];
 	if (start) {
 		end = state->rule.ptr->timeout[PFTM_ADAPTIVE_END];
-		states = state->rule.ptr->states_cur;	/* XXXGL */
+		states = counter_u64_fetch(state->rule.ptr->states_cur);
 	} else {
 		start = V_pf_default_rule.timeout[PFTM_ADAPTIVE_START];
 		end = V_pf_default_rule.timeout[PFTM_ADAPTIVE_END];
@@ -1587,11 +1587,7 @@ pf_unlink_state(struct pf_state *s, u_in
 	if (pfsync_delete_state_ptr != NULL)
 		pfsync_delete_state_ptr(s);
 
-	--s->rule.ptr->states_cur;
-	if (s->nat_rule.ptr != NULL)
-		--s->nat_rule.ptr->states_cur;
-	if (s->anchor.ptr != NULL)
-		--s->anchor.ptr->states_cur;
+	STATE_DEC_COUNTERS(s);
 
 	s->timeout = PFTM_UNLINKED;
 
@@ -3606,7 +3602,8 @@ pf_create_state(struct pf_rule *r, struc
 	u_short			 reason;
 
 	/* check maximums */
-	if (r->max_states && (r->states_cur >= r->max_states)) {
+	if (r->max_states &&
+	    (counter_u64_fetch(r->states_cur) >= r->max_states)) {
 		V_pf_status.lcounters[LCNT_STATES]++;
 		REASON_SET(&reason, PFRES_MAXSTATES);
 		return (PF_DROP);

Modified: head/sys/netpfil/pf/pf_ioctl.c
==============================================================================
--- head/sys/netpfil/pf/pf_ioctl.c	Fri Feb 14 08:42:39 2014	(r261881)
+++ head/sys/netpfil/pf/pf_ioctl.c	Fri Feb 14 10:05:21 2014	(r261882)
@@ -229,6 +229,10 @@ pfattach(void)
 	V_pf_default_rule.nr = -1;
 	V_pf_default_rule.rtableid = -1;
 
+	V_pf_default_rule.states_cur = counter_u64_alloc(M_WAITOK);
+	V_pf_default_rule.states_tot = counter_u64_alloc(M_WAITOK);
+	V_pf_default_rule.src_nodes = counter_u64_alloc(M_WAITOK);
+
 	/* initialize default timeouts */
 	my_timeout[PFTM_TCP_FIRST_PACKET] = PFTM_TCP_FIRST_PACKET_VAL;
 	my_timeout[PFTM_TCP_OPENING] = PFTM_TCP_OPENING_VAL;
@@ -398,6 +402,9 @@ pf_free_rule(struct pf_rule *rule)
 		pfi_kif_unref(rule->kif);
 	pf_anchor_remove(rule);
 	pf_empty_pool(&rule->rpool.list);
+	counter_u64_free(rule->states_cur);
+	counter_u64_free(rule->states_tot);
+	counter_u64_free(rule->src_nodes);
 	free(rule, M_PFRULE);
 }
 
@@ -1149,6 +1156,9 @@ pfioctl(struct cdev *dev, u_long cmd, ca
 		bcopy(&pr->rule, rule, sizeof(struct pf_rule));
 		if (rule->ifname[0])
 			kif = malloc(sizeof(*kif), PFI_MTYPE, M_WAITOK);
+		rule->states_cur = counter_u64_alloc(M_WAITOK);
+		rule->states_tot = counter_u64_alloc(M_WAITOK);
+		rule->src_nodes = counter_u64_alloc(M_WAITOK);
 		rule->cuid = td->td_ucred->cr_ruid;
 		rule->cpid = td->td_proc ? td->td_proc->p_pid : 0;
 		TAILQ_INIT(&rule->rpool.list);
@@ -1265,6 +1275,9 @@ pfioctl(struct cdev *dev, u_long cmd, ca
 #undef ERROUT
 DIOCADDRULE_error:
 		PF_RULES_WUNLOCK();
+		counter_u64_free(rule->states_cur);
+		counter_u64_free(rule->states_tot);
+		counter_u64_free(rule->src_nodes);
 		free(rule, M_PFRULE);
 		if (kif)
 			free(kif, PFI_MTYPE);
@@ -1336,6 +1349,16 @@ DIOCADDRULE_error:
 			break;
 		}
 		bcopy(rule, &pr->rule, sizeof(struct pf_rule));
+		/*
+		 * XXXGL: this is what happens when internal kernel
+		 * structures are used as ioctl API structures.
+		 */
+		pr->rule.states_cur =
+		    (counter_u64_t )counter_u64_fetch(rule->states_cur);
+		pr->rule.states_tot =
+		    (counter_u64_t )counter_u64_fetch(rule->states_tot);
+		pr->rule.src_nodes =
+		    (counter_u64_t )counter_u64_fetch(rule->src_nodes);
 		if (pf_anchor_copyout(ruleset, rule, pr)) {
 			PF_RULES_WUNLOCK();
 			error = EBUSY;
@@ -1354,7 +1377,7 @@ DIOCADDRULE_error:
 			rule->evaluations = 0;
 			rule->packets[0] = rule->packets[1] = 0;
 			rule->bytes[0] = rule->bytes[1] = 0;
-			rule->states_tot = 0;
+			counter_u64_zero(rule->states_tot);
 		}
 		PF_RULES_WUNLOCK();
 		break;
@@ -1394,15 +1417,14 @@ DIOCADDRULE_error:
 #endif /* INET6 */
 			newrule = malloc(sizeof(*newrule), M_PFRULE, M_WAITOK);
 			bcopy(&pcr->rule, newrule, sizeof(struct pf_rule));
+			if (newrule->ifname[0])
+				kif = malloc(sizeof(*kif), PFI_MTYPE, M_WAITOK);
+			newrule->states_cur = counter_u64_alloc(M_WAITOK);
+			newrule->states_tot = counter_u64_alloc(M_WAITOK);
+			newrule->src_nodes = counter_u64_alloc(M_WAITOK);
 			newrule->cuid = td->td_ucred->cr_ruid;
 			newrule->cpid = td->td_proc ? td->td_proc->p_pid : 0;
 			TAILQ_INIT(&newrule->rpool.list);
-			/* Initialize refcounting. */
-			newrule->states_cur = 0;
-			newrule->entries.tqe_prev = NULL;
-
-			if (newrule->ifname[0])
-				kif = malloc(sizeof(*kif), PFI_MTYPE, M_WAITOK);
 		}
 
 #define	ERROUT(x)	{ error = (x); goto DIOCCHANGERULE_error; }
@@ -1570,8 +1592,12 @@ DIOCADDRULE_error:
 #undef ERROUT
 DIOCCHANGERULE_error:
 		PF_RULES_WUNLOCK();
-		if (newrule != NULL)
+		if (newrule != NULL) {
+			counter_u64_free(newrule->states_cur);
+			counter_u64_free(newrule->states_tot);
+			counter_u64_free(newrule->src_nodes);
 			free(newrule, M_PFRULE);
+		}
 		if (kif != NULL)
 			free(kif, PFI_MTYPE);
 		break;
@@ -3427,6 +3453,11 @@ shutdown_pf(void)
 	char nn = '\0';
 
 	V_pf_status.running = 0;
+
+	counter_u64_free(V_pf_default_rule.states_cur);
+	counter_u64_free(V_pf_default_rule.states_tot);
+	counter_u64_free(V_pf_default_rule.src_nodes);
+
 	do {
 		if ((error = pf_begin_rules(&t[0], PF_RULESET_SCRUB, &nn))
 		    != 0) {


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