From 5a418352f3a1ca4f049396d7892d6e74f4011197 Mon Sep 17 00:00:00 2001
From: Guy Harris <guy@alum.mit.edu>
Date: Sat, 31 Aug 2019 17:54:51 -0700
Subject: Don't use ctype.h macros.

Some of them are locale-dependent, and all of them run the risk of
failing if you hand them a char with the 8th bit set.

Define our own locale-independent macros that can be handed any integral
value.

Don't include <ctype.h>.

This should address the issue in GitHub pull request #839, and should
also catch any (highly unlikely) cases in which something other than
Boring Old Space And Tab and, sometimes, CR and LF are treated as white
space.  (No, we don't want FF or VT treated as white space.)
---
 etherent.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

(limited to 'etherent.c')

diff --git a/etherent.c b/etherent.c
index 5f499613..e883a9c7 100644
--- a/etherent.c
+++ b/etherent.c
@@ -25,7 +25,6 @@
 
 #include <pcap-types.h>
 
-#include <ctype.h>
 #include <memory.h>
 #include <stdio.h>
 #include <string.h>
@@ -45,14 +44,18 @@ static inline int skip_line(FILE *);
 static inline u_char
 xdtoi(u_char c)
 {
-	if (isdigit(c))
+	if (c >= '0' && c < '9')
 		return (u_char)(c - '0');
-	else if (islower(c))
+	else if (c >= 'a' && c <= 'f')
 		return (u_char)(c - 'a' + 10);
 	else
 		return (u_char)(c - 'A' + 10);
 }
 
+/*
+ * Skip linear white space (space and tab) and any CRs before LF.
+ * Stop when we hit a non-white-space character or an end-of-line LF.
+ */
 static inline int
 skip_space(FILE *f)
 {
@@ -60,7 +63,7 @@ skip_space(FILE *f)
 
 	do {
 		c = getc(f);
-	} while (isspace(c) && c != '\n');
+	} while (PCAP_ISLWSP(c) || c == '\r');
 
 	return c;
 }
@@ -97,7 +100,7 @@ pcap_next_etherent(FILE *fp)
 
 		/* If this is a comment, or first thing on line
 		   cannot be Ethernet address, skip the line. */
-		if (!isxdigit(c)) {
+		if (!PCAP_ISXDIGIT(c)) {
 			c = skip_line(fp);
 			if (c == EOF)
 				return (NULL);
@@ -110,7 +113,7 @@ pcap_next_etherent(FILE *fp)
 			c = getc(fp);
 			if (c == EOF)
 				return (NULL);
-			if (isxdigit(c)) {
+			if (PCAP_ISXDIGIT(c)) {
 				d <<= 4;
 				d |= xdtoi((u_char)c);
 				c = getc(fp);
@@ -126,7 +129,7 @@ pcap_next_etherent(FILE *fp)
 		}
 
 		/* Must be whitespace */
-		if (!isspace(c)) {
+		if (!PCAP_ISSPACE(c)) {
 			c = skip_line(fp);
 			if (c == EOF)
 				return (NULL);
@@ -156,7 +159,7 @@ pcap_next_etherent(FILE *fp)
 			c = getc(fp);
 			if (c == EOF)
 				return (NULL);
-		} while (!isspace(c) && --namesize != 0);
+		} while (!PCAP_ISSPACE(c) && --namesize != 0);
 		*bp = '\0';
 
 		/* Eat trailing junk */
-- 
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