Bugzilla bug 96571: fixed the PL_strn* functions that may read beyond

the end of buffer if the buffer is not null-terminated.
Modified files: strchr.c strcstr.c strlen.c strpbrk.c strstr.c

nsprpub/lib/libc/src/strchr.c

@@ -70,11 +70,11 @@ PL_strnchr(const char *s, char c, PRUint32 n)
 {
     if( (const char *)0 == s ) return (char *)0;
 
-    for( ; *s && n; s++, n-- )
+    for( ; n && *s; s++, n-- )
         if( *s == c )
             return (char *)s;
 
-    if( ((char)0 == c) && ((char)0 == *s) && (n > 0)) return (char *)s;
+    if( ((char)0 == c) && (n > 0) && ((char)0 == *s) ) return (char *)s;
 
     return (char *)0;
 }
@@ -86,10 +86,10 @@ PL_strnrchr(const char *s, char c, PRUint32 n)
 
     if( (const char *)0 == s ) return (char *)0;
 
-    for( p = s; *p && n; p++, n-- )
+    for( p = s; n && *p; p++, n-- )
         ;
 
-    if( ((char)0 == c) && ((char)0 == *p) && (n > 0) ) return (char *)p;
+    if( ((char)0 == c) && (n > 0) && ((char)0 == *p) ) return (char *)p;
 
     for( p--; p >= s; p-- )
         if( *p == c )

nsprpub/lib/libc/src/strcstr.c

@@ -86,7 +86,7 @@ PL_strncasestr(const char *big, const char *little, PRUint32 max)
     max -= ll;
     max++;
 
-    for( ; *big && max; big++, max-- )
+    for( ; max && *big; big++, max-- )
         /* obvious improvement available here */
             if( 0 == PL_strncasecmp(big, little, ll) )
                 return (char *)big;
@@ -105,7 +105,7 @@ PL_strncaserstr(const char *big, const char *little, PRUint32 max)
 
     ll = PL_strlen(little);
 
-    for( p = big; *p && max; p++, max-- )
+    for( p = big; max && *p; p++, max-- )
         ;
 
     p -= ll;

nsprpub/lib/libc/src/strlen.c

@@ -59,7 +59,7 @@ PL_strnlen(const char *str, PRUint32 max)
     register const char *s;
 
     if( (const char *)0 == str ) return 0;
-    for( s = str; *s && max; s++, max-- )
+    for( s = str; max && *s; s++, max-- )
         ;
 
     return (PRUint32)(s - str);

nsprpub/lib/libc/src/strpbrk.c

@@ -75,7 +75,7 @@ PL_strnpbrk(const char *s, const char *list, PRUint32 max)
 
     if( ((const char *)0 == s) || ((const char *)0 == list) ) return (char *)0;
 
-    for( ; *s && max; s++, max-- )
+    for( ; max && *s; s++, max-- )
         for( p = list; *p; p++ )
             if( *s == *p )
                 return (char *)s;
@@ -91,7 +91,7 @@ PL_strnprbrk(const char *s, const char *list, PRUint32 max)
 
     if( ((const char *)0 == s) || ((const char *)0 == list) ) return (char *)0;
 
-    for( r = s; *r && max; r++, max-- )
+    for( r = s; max && *r; r++, max-- )
         ;
 
     for( r--; r >= s; r-- )

nsprpub/lib/libc/src/strstr.c

@@ -86,7 +86,7 @@ PL_strnstr(const char *big, const char *little, PRUint32 max)
     max -= ll;
     max++;
 
-    for( ; *big && max; big++, max-- )
+    for( ; max && *big; big++, max-- )
         if( *little == *big )
             if( 0 == PL_strncmp(big, little, ll) )
                 return (char *)big;
@@ -105,7 +105,7 @@ PL_strnrstr(const char *big, const char *little, PRUint32 max)
 
     ll = PL_strlen(little);
 
-    for( p = big; *p && max; p++, max-- )
+    for( p = big; max && *p; p++, max-- )
         ;
 
     p -= ll;