Adjust default_print() to not run over snapend.

Kill default_print_unaligned() and adjust default_print() to also work
with unaligned buffers. There is no need for two functions doing the
same thing.

Pass the right length in nsh_print to default_print(). Fixes on place
that makes tcpdump crash.
Reported by Peter J. Philipp (pjp at delphinusdns dot org)
OK mbuhl@

5 files changed, 21 insertions, 51 deletions

diff --git a/usr.sbin/tcpdump/interface.h b/usr.sbin/tcpdump/interface.h
index 602be405723..4e055f3eb80 100644
--- a/usr.sbin/tcpdump/interface.h
+++ b/usr.sbin/tcpdump/interface.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: interface.h,v 1.86 2020/08/17 06:29:29 dlg Exp $	*/
+/*	$OpenBSD: interface.h,v 1.87 2023/02/28 10:04:50 claudio Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -20,7 +20,7 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * @(#) $Id: interface.h,v 1.86 2020/08/17 06:29:29 dlg Exp $ (LBL)
+ * @(#) $Id: interface.h,v 1.87 2023/02/28 10:04:50 claudio Exp $ (LBL)
  */
 
 #ifndef tcpdump_interface_h
@@ -199,7 +199,6 @@ extern void bootp_print(const u_char *, u_int, u_short, u_short);
 extern void bgp_print(const u_char *, int);
 extern void decnet_print(const u_char *, u_int, u_int);
 extern void default_print(const u_char *, u_int);
-extern void default_print_unaligned(const u_char *, u_int);
 extern void dvmrp_print(const u_char *, u_int);
 extern void egp_print(const u_char *, u_int, const u_char *);
 extern void enc_if_print(u_char *, const struct pcap_pkthdr *, const u_char *);
diff --git a/usr.sbin/tcpdump/print-isoclns.c b/usr.sbin/tcpdump/print-isoclns.c
index 0c94a02ff2c..ea2edac3d7a 100644
--- a/usr.sbin/tcpdump/print-isoclns.c
+++ b/usr.sbin/tcpdump/print-isoclns.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-isoclns.c,v 1.15 2021/12/01 18:28:46 deraadt Exp $	*/
+/*	$OpenBSD: print-isoclns.c,v 1.16 2023/02/28 10:04:50 claudio Exp $	*/
 
 /*
  * Copyright (c) 1992, 1993, 1994, 1995, 1996
@@ -88,7 +88,7 @@ isoclns_print(const u_char *p, u_int length, u_int caplen,
 		/* isis_print(&p, &length); */
 		printf(" len=%d ", length);
 		if (caplen > 1)
-			default_print_unaligned(p, caplen);
+			default_print(p, caplen);
 		break;
 
 	case NULLNS:
@@ -107,7 +107,7 @@ isoclns_print(const u_char *p, u_int length, u_int caplen,
 			    etheraddr_string(edst));
 		printf(" len=%d ", length);
 		if (caplen > 1)
-			default_print_unaligned(p, caplen);
+			default_print(p, caplen);
 		break;
 	}
 }
diff --git a/usr.sbin/tcpdump/print-llc.c b/usr.sbin/tcpdump/print-llc.c
index 14829688033..ed48dc46a25 100644
--- a/usr.sbin/tcpdump/print-llc.c
+++ b/usr.sbin/tcpdump/print-llc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-llc.c,v 1.22 2020/01/24 22:46:37 procter Exp $	*/
+/*	$OpenBSD: print-llc.c,v 1.23 2023/02/28 10:04:50 claudio Exp $	*/
 
 /*
  * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
@@ -219,7 +219,7 @@ llc_print(const u_char *p, u_int length, u_int caplen,
 		printf("%s/%c", m, f);
 
 		if (caplen < 6) {
-			default_print_unaligned(p, caplen);
+			default_print(p, caplen);
 			return (0);
 		}
 		p += 3;
@@ -248,7 +248,7 @@ llc_print(const u_char *p, u_int length, u_int caplen,
 	} else {
 		char f;
 		if (caplen < 4) {
-			default_print_unaligned(p, caplen);
+			default_print(p, caplen);
 			return (0);
 		}
 		llc.llcis = ntohs(llc.llcis);
diff --git a/usr.sbin/tcpdump/print-nsh.c b/usr.sbin/tcpdump/print-nsh.c
index f21fe690119..9d66bf114dc 100644
--- a/usr.sbin/tcpdump/print-nsh.c
+++ b/usr.sbin/tcpdump/print-nsh.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-nsh.c,v 1.1 2019/12/03 01:43:33 dlg Exp $ */
+/*	$OpenBSD: print-nsh.c,v 1.2 2023/02/28 10:04:50 claudio Exp $ */
 
 /*
  * Copyright (c) 2019 David Gwynne <dlg@openbsd.org>
@@ -214,7 +214,7 @@ nsh_print(const u_char *p, u_int length)
 	}
 
 	if (vflag)
-		default_print_unaligned(p, length);
+		default_print(p, l);
 
 	return;
 trunc:
diff --git a/usr.sbin/tcpdump/tcpdump.c b/usr.sbin/tcpdump/tcpdump.c
index fccccd46473..336f4efbf3d 100644
--- a/usr.sbin/tcpdump/tcpdump.c
+++ b/usr.sbin/tcpdump/tcpdump.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcpdump.c,v 1.97 2022/07/09 23:24:44 halex Exp $	*/
+/*	$OpenBSD: tcpdump.c,v 1.98 2023/02/28 10:04:50 claudio Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
@@ -632,44 +632,15 @@ default_print_ascii(const u_char *cp, unsigned int length)
 	}
 }
 
-/* Like default_print() but data need not be aligned */
-void
-default_print_unaligned(const u_char *cp, u_int length)
-{
-	u_int i, s;
-	int nshorts;
-
-	if (Xflag) {
-		/* dump the buffer in `emacs-hexl' style */
-		default_print_hexl(cp, length);
-	} else if (Aflag) {
-		/* dump the text in the buffer */
-		default_print_ascii(cp, length);
-	} else {
-		/* dump the buffer in old tcpdump style */
-		nshorts = (u_int) length / sizeof(u_short);
-		i = 0;
-		while (--nshorts >= 0) {
-			if ((i++ % 8) == 0)
-				printf("\n\t\t\t");
-			s = *cp++;
-			printf(" %02x%02x", s, *cp++);
-		}
-		if (length & 1) {
-			if ((i % 8) == 0)
-				printf("\n\t\t\t");
-			printf(" %02x", *cp);
-		}
-	}
-}
-
 void
 default_print(const u_char *bp, u_int length)
 {
-	const u_short *sp;
 	u_int i;
 	int nshorts;
 
+	if (snapend - bp < length)
+		length = snapend - bp;
+
 	if (Xflag) {
 		/* dump the buffer in `emacs-hexl' style */
 		default_print_hexl(bp, length);
@@ -677,23 +648,23 @@ default_print(const u_char *bp, u_int length)
 		/* dump the text in the buffer */
 		default_print_ascii(bp, length);
 	} else {
+		u_short sp;
+
 		/* dump the buffer in old tcpdump style */
-		if ((long)bp & 1) {
-			default_print_unaligned(bp, length);
-			return;
-		}
-		sp = (u_short *)bp;
 		nshorts = (u_int) length / sizeof(u_short);
 		i = 0;
 		while (--nshorts >= 0) {
 			if ((i++ % 8) == 0)
 				printf("\n\t\t\t");
-			printf(" %04x", ntohs(*sp++));
+
+			sp = (u_short)*bp++ << 8;
+			sp |= *bp++;
+			printf(" %04x", sp);
 		}
 		if (length & 1) {
 			if ((i % 8) == 0)
 				printf("\n\t\t\t");
-			printf(" %02x", *(u_char *)sp);
+			printf(" %02x", *bp);
 		}
 	}
 }