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Date:      Sun, 26 Apr 2020 16:16:40 +0000 (UTC)
From:      Kristof Provost <kp@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r360344 - head/sys/netpfil/pf
Message-ID:  <202004261616.03QGGeBf095624@repo.freebsd.org>
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Author: kp
Date: Sun Apr 26 16:16:39 2020
New Revision: 360344
URL: https://svnweb.freebsd.org/changeset/base/360344

Log:
  pf: Improve input validation
  
  If we pass an anchor name which doesn't exist pfr_table_count() returns
  -1, which leads to an overflow in mallocarray() and thus a panic.
  
  Explicitly check that pfr_table_count() does not return an error.
  
  Reported-by:	syzbot+bd09d55d897d63d5f4f4@syzkaller.appspotmail.com
  Reviewed by:	melifaro
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D24539

Modified:
  head/sys/netpfil/pf/pf_ioctl.c

Modified: head/sys/netpfil/pf/pf_ioctl.c
==============================================================================
--- head/sys/netpfil/pf/pf_ioctl.c	Sun Apr 26 16:13:51 2020	(r360343)
+++ head/sys/netpfil/pf/pf_ioctl.c	Sun Apr 26 16:16:39 2020	(r360344)
@@ -3008,7 +3008,8 @@ DIOCCHANGEADDR_error:
 	case DIOCRGETTABLES: {
 		struct pfioc_table *io = (struct pfioc_table *)addr;
 		struct pfr_table *pfrts;
-		size_t totlen, n;
+		size_t totlen;
+		int n;
 
 		if (io->pfrio_esize != sizeof(struct pfr_table)) {
 			error = ENODEV;
@@ -3016,6 +3017,11 @@ DIOCCHANGEADDR_error:
 		}
 		PF_RULES_RLOCK();
 		n = pfr_table_count(&io->pfrio_table, io->pfrio_flags);
+		if (n < 0) {
+			PF_RULES_RUNLOCK();
+			error = EINVAL;
+			break;
+		}
 		io->pfrio_size = min(io->pfrio_size, n);
 
 		totlen = io->pfrio_size * sizeof(struct pfr_table);
@@ -3039,7 +3045,8 @@ DIOCCHANGEADDR_error:
 	case DIOCRGETTSTATS: {
 		struct pfioc_table *io = (struct pfioc_table *)addr;
 		struct pfr_tstats *pfrtstats;
-		size_t totlen, n;
+		size_t totlen;
+		int n;
 
 		if (io->pfrio_esize != sizeof(struct pfr_tstats)) {
 			error = ENODEV;
@@ -3047,6 +3054,11 @@ DIOCCHANGEADDR_error:
 		}
 		PF_RULES_WLOCK();
 		n = pfr_table_count(&io->pfrio_table, io->pfrio_flags);
+		if (n < 0) {
+			PF_RULES_WUNLOCK();
+			error = EINVAL;
+			break;
+		}
 		io->pfrio_size = min(io->pfrio_size, n);
 
 		totlen = io->pfrio_size * sizeof(struct pfr_tstats);
@@ -3069,7 +3081,8 @@ DIOCCHANGEADDR_error:
 	case DIOCRCLRTSTATS: {
 		struct pfioc_table *io = (struct pfioc_table *)addr;
 		struct pfr_table *pfrts;
-		size_t totlen, n;
+		size_t totlen;
+		int n;
 
 		if (io->pfrio_esize != sizeof(struct pfr_table)) {
 			error = ENODEV;
@@ -3078,6 +3091,11 @@ DIOCCHANGEADDR_error:
 
 		PF_RULES_WLOCK();
 		n = pfr_table_count(&io->pfrio_table, io->pfrio_flags);
+		if (n < 0) {
+			PF_RULES_WUNLOCK();
+			error = EINVAL;
+			break;
+		}
 		io->pfrio_size = min(io->pfrio_size, n);
 
 		totlen = io->pfrio_size * sizeof(struct pfr_table);
@@ -3104,7 +3122,8 @@ DIOCCHANGEADDR_error:
 	case DIOCRSETTFLAGS: {
 		struct pfioc_table *io = (struct pfioc_table *)addr;
 		struct pfr_table *pfrts;
-		size_t totlen, n;
+		size_t totlen;
+		int n;
 
 		if (io->pfrio_esize != sizeof(struct pfr_table)) {
 			error = ENODEV;
@@ -3113,6 +3132,12 @@ DIOCCHANGEADDR_error:
 
 		PF_RULES_RLOCK();
 		n = pfr_table_count(&io->pfrio_table, io->pfrio_flags);
+		if (n < 0) {
+			PF_RULES_RUNLOCK();
+			error = EINVAL;
+			break;
+		}
+
 		io->pfrio_size = min(io->pfrio_size, n);
 		PF_RULES_RUNLOCK();

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