Introduce strtonum(), which works like string_to_number(), but passes
back the 'end' pointer. It is useful where you want to do boundary
checking yet work with strings that are not entirely slurped by
strtoul(), e.g.:
s = "1/2";
if (!strtonum(s, &end, &value, 0, 5))
error("Zero-length string, or value out of bounds");
if (*end != '/')
error("Malformed string");
info->param1 = value;
if (!strtonum(end + 1, &end, &value, 2, 4))
error("..");
if (*end != '\0')
error("Malformed string");
info->param2 = value;
Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxxxxxxx>
---
include/xtables.h | 5 +++++
xtables.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 49 insertions(+)
Index: iptables-modules/include/xtables.h
===================================================================
--- iptables-modules.orig/include/xtables.h
+++ iptables-modules/include/xtables.h
@@ -5,6 +5,7 @@
#include <linux/types.h>
#include <linux/netfilter/x_tables.h>
#include <libiptc/libxtc.h>
+#include <stdbool.h>
#ifndef XT_LIB_DIR
#define XT_LIB_DIR "/usr/local/lib/iptables"
@@ -206,6 +207,10 @@ extern int string_to_number(const char *
unsigned int min,
unsigned int max,
unsigned int *ret);
+extern bool strtonuml(const char *, char **, unsigned long *,
+ unsigned long, unsigned long);
+extern bool strtonum(const char *, char **, unsigned int *,
+ unsigned int, unsigned int);
extern int service_to_port(const char *name, const char *proto);
extern u_int16_t parse_port(const char *port, const char *proto);
extern void
Index: iptables-modules/xtables.c
===================================================================
--- iptables-modules.orig/xtables.c
+++ iptables-modules/xtables.c
@@ -19,6 +19,7 @@
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
+#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -199,6 +200,49 @@ int string_to_number(const char *s, unsi
return result;
}
+/*
+ * strtonum{,l} - string to number conversion
+ *
+ * If @end is NULL, we assume the caller does not want
+ * a case like "15a", so reject it.
+ */
+bool strtonuml(const char *s, char **end, unsigned long *value,
+ unsigned long min, unsigned long max)
+{
+ unsigned long v;
+ char *my_end;
+
+ errno = 0;
+ v = strtoul(s, &my_end, 0);
+
+ if (my_end == s)
+ return false;
+ if (end != NULL)
+ *end = my_end;
+
+ if (errno != ERANGE && min <= v && (max == 0 || v <= max)) {
+ if (value != NULL)
+ *value = v;
+ if (end == NULL)
+ return *my_end == '\0';
+ return true;
+ }
+
+ return false;
+}
+
+bool strtonum(const char *s, char **end, unsigned int *value,
+ unsigned int min, unsigned int max)
+{
+ unsigned long v;
+ bool ret;
+
+ ret = strtonuml(s, end, &v, min, max);
+ if (value != NULL)
+ *value = v;
+ return ret;
+}
+
int service_to_port(const char *name, const char *proto)
{
struct servent *service;
-
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