Put a recursion limit to avoid DoS attacks (Maksymilian Arciemowicz)

While there do minor KNF, and do as the manual says: exit with EXIT_FAILURE

diff --git a/strsuftoll.c b/strsuftoll.c
index 0e29a6d62722a58dc9864b112f650f8a38964d7a..80fc52fc9062aed206253edf3a4b76efe300545e 100644 (file)
--- a/strsuftoll.c
+++ b/strsuftoll.c
@@ -1,4 +1,4 @@
-/*     $NetBSD: strsuftoll.c,v 1.8 2008/04/28 20:23:00 martin Exp $    */
+/*     $NetBSD: strsuftoll.c,v 1.9 2011/10/22 22:08:47 christos Exp $  */
 /*-
  * Copyright (c) 2001-2002,2004 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -67,7 +67,7 @@
 #include <sys/cdefs.h>
 
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: strsuftoll.c,v 1.8 2008/04/28 20:23:00 martin Exp $");
+__RCSID("$NetBSD: strsuftoll.c,v 1.9 2011/10/22 22:08:47 christos Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #ifdef _LIBC
@@ -121,8 +121,8 @@ strsuftoll(const char *desc, const char *val,
 
        result = strsuftollx(desc, val, min, max, errbuf, sizeof(errbuf));
        if (*errbuf != '\0')
-               errx(1, "%s", errbuf);
-       return (result);
+               errx(EXIT_FAILURE, "%s", errbuf);
+       return result;
 }
 
 /*
@@ -130,9 +130,9 @@ strsuftoll(const char *desc, const char *val,
  * rather than exiting with it.
  */
 /* LONGLONG */
-long long
-strsuftollx(const char *desc, const char *val,
-    long long min, long long max, char *ebuf, size_t ebuflen)
+static long long
+__strsuftollx(const char *desc, const char *val,
+    long long min, long long max, char *ebuf, size_t ebuflen, size_t depth)
 {
        long long num, t;
        char    *expr;
@@ -141,12 +141,15 @@ strsuftollx(const char *desc, const char *val,
        _DIAGASSERT(val != NULL);
        _DIAGASSERT(ebuf != NULL);
 
-       errno = 0;
-       ebuf[0] = '\0';
+       if (depth > 16) {
+               snprintf(ebuf, ebuflen, "%s: Recursion limit exceeded", desc);
+               return 0;
+       }
 
        while (isspace((unsigned char)*val))    /* Skip leading space */
                val++;
 
+       errno = 0;
        num = strtoll(val, &expr, 10);
        if (errno == ERANGE)
                goto erange;                    /* Overflow */
@@ -205,36 +208,42 @@ strsuftollx(const char *desc, const char *val,
        case '*':                               /* Backward compatible */
        case 'x':
                t = num;
-               num *= strsuftollx(desc, expr + 1, min, max, ebuf, ebuflen);
+               num *= __strsuftollx(desc, expr + 1, min, max, ebuf, ebuflen,
+                       depth + 1);
                if (*ebuf != '\0')
-                       return (0);
+                       return 0;
                if (t > num) {
  erange:               
-                       snprintf(ebuf, ebuflen,
-                           "%s: %s", desc, strerror(ERANGE));
-                       return (0);
+                       errno = ERANGE;
+                       snprintf(ebuf, ebuflen, "%s: %s", desc, strerror(errno));
+                       return 0;
                }
                break;
        default:
- badnum:       snprintf(ebuf, ebuflen,
-                   "%s `%s': illegal number", desc, val);
-               return (0);
+ badnum:
+               snprintf(ebuf, ebuflen, "%s `%s': illegal number", desc, val);
+               return 0;
        }
        if (num < min) {
-                       /* LONGLONG */
+               /* LONGLONG */
                snprintf(ebuf, ebuflen, "%s %lld is less than %lld.",
                    desc, (long long)num, (long long)min);
-               return (0);
+               return 0;
        }
        if (num > max) {
-                       /* LONGLONG */
-               snprintf(ebuf, ebuflen,
-                   "%s %lld is greater than %lld.",
+               /* LONGLONG */
+               snprintf(ebuf, ebuflen, "%s %lld is greater than %lld.",
                    desc, (long long)num, (long long)max);
-               return (0);
+               return 0;
        }
        *ebuf = '\0';
-       return (num);
+       return num;
 }
 
+long long
+strsuftollx(const char *desc, const char *val,
+    long long min, long long max, char *ebuf, size_t ebuflen)
+{
+       return __strsuftollx(desc, val, min, max, ebuf, ebuflen, 0);
+}
 #endif /* !HAVE_STRSUFTOLL */