svn commit: r313820 - head/sys/netpfil/pf

[Eric van Gyzen]

Author: vangyzen
Date: Thu Feb 16 20:44:44 2017
New Revision: 313820
URL: https://svnweb.freebsd.org/changeset/base/313820

Log:
  pf: use inet_ntoa_r() instead of inet_ntoa(); maybe fix IPv6 OS fingerprinting
  
  inet_ntoa() cannot be used safely in a multithreaded environment
  because it uses a static local buffer. Instead, use inet_ntoa_r()
  with a buffer on the caller's stack.
  
  This code had an INET6 conditional before this commit, but opt_inet6.h
  was not included, so INET6 was never defined.  Apparently, pf's OS
  fingerprinting hasn't worked with IPv6 for quite some time.
  This commit might fix it, but I didn't test that.
  
  Reviewed by:	gnn, kp
  MFC after:	2 weeks
  Relnotes:	yes (if I/someone can test pf OS fingerprinting with IPv6)
  Sponsored by:	Dell EMC
  Differential Revision:	https://reviews.freebsd.org/D9625

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

Modified: head/sys/netpfil/pf/pf_osfp.c
==============================================================================
--- head/sys/netpfil/pf/pf_osfp.c	Thu Feb 16 20:30:55 2017	(r313819)
+++ head/sys/netpfil/pf/pf_osfp.c	Thu Feb 16 20:44:44 2017	(r313820)
@@ -19,6 +19,8 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+#include "opt_inet6.h"
+
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/lock.h>
@@ -34,7 +36,9 @@ __FBSDID("$FreeBSD$");
 #include <net/vnet.h>
 #include <net/pfvar.h>
 
+#ifdef INET6
 #include <netinet/ip6.h>
+#endif
 
 static MALLOC_DEFINE(M_PFOSFP, "pf_osfp", "pf(4) operating system fingerprints");
 #define	DPFPRINTF(format, x...)		\
@@ -94,7 +98,11 @@ pf_osfp_fingerprint_hdr(const struct ip 
 	struct pf_os_fingerprint fp, *fpresult;
 	int cnt, optlen = 0;
 	const u_int8_t *optp;
-	char srcname[128];
+#ifdef INET6
+	char srcname[INET6_ADDRSTRLEN];
+#else
+	char srcname[INET_ADDRSTRLEN];
+#endif
 
 	if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN)
 		return (NULL);
@@ -110,7 +118,7 @@ pf_osfp_fingerprint_hdr(const struct ip 
 		fp.fp_ttl = ip->ip_ttl;
 		if (ip->ip_off & htons(IP_DF))
 			fp.fp_flags |= PF_OSFP_DF;
-		strlcpy(srcname, inet_ntoa(ip->ip_src), sizeof(srcname));
+		inet_ntoa_r(ip->ip_src, srcname);
 	}
 #ifdef INET6
 	else if (ip6) {
@@ -119,8 +127,7 @@ pf_osfp_fingerprint_hdr(const struct ip 
 		fp.fp_ttl = ip6->ip6_hlim;
 		fp.fp_flags |= PF_OSFP_DF;
 		fp.fp_flags |= PF_OSFP_INET6;
-		strlcpy(srcname, ip6_sprintf((struct in6_addr *)&ip6->ip6_src),
-		    sizeof(srcname));
+		ip6_sprintf(srcname, (const struct in6_addr *)&ip6->ip6_src);
 	}
 #endif
 	else