From 13477d60ee3913b84298039b2d42c7832c655775 Mon Sep 17 00:00:00 2001
From: Victor Julien <victor@inliniac.net>
Date: Sun, 26 Nov 2017 11:09:19 +0100
Subject: [PATCH] ipv4: add string validation function

---
 src/util-decode-mime.c | 37 +++++--------------------------
 src/util-ip.c          | 50 ++++++++++++++++++++++++++++++++++++++++++
 src/util-ip.h          |  1 +
 3 files changed, 56 insertions(+), 32 deletions(-)

diff --git a/src/util-decode-mime.c b/src/util-decode-mime.c
index 12fac63a2f..2f5cbdfc1c 100644
--- a/src/util-decode-mime.c
+++ b/src/util-decode-mime.c
@@ -25,7 +25,7 @@
 #include "suricata-common.h"
 
 #include "util-decode-mime.h"
-
+#include "util-ip.h"
 #include "util-spm-bs.h"
 #include "util-unittest.h"
 #include "util-memcmp.h"
@@ -911,42 +911,12 @@ static int IsIpv4Host(const uint8_t *urlhost, uint32_t len)
     char tempIp[MAX_IP4_CHARS + 1];
 
     /* Cut off at '/'  */
-    int alen = 0;
-    char addr[4][4];
-    int dots = 0;
     uint32_t i = 0;
-    for (i = 0; i < len && urlhost[i] != 0; i++) {
+    for ( ; i < len && urlhost[i] != 0; i++) {
 
         if (urlhost[i] == '/') {
             break;
         }
-
-        if (!(urlhost[i] == '.' || isdigit(urlhost[i]))) {
-            return 0;
-        }
-        if (urlhost[i] == '.') {
-            if (dots == 3) {
-                SCLogDebug("too many dots");
-                return 0;
-            }
-            addr[dots][alen] = '\0';
-            dots++;
-            alen = 0;
-        } else {
-            if (alen >= 4) {
-                SCLogDebug("too long");
-                return 0;
-            }
-            addr[dots][alen++] = urlhost[i];
-        }
-    }
-    addr[dots][alen] = '\0';
-    for (int x = 0; x < 4; x++) {
-        int a = atoi(addr[x]);
-        if (a < 0 || a >= 256) {
-            SCLogDebug("out of range");
-            return 0;
-        }
     }
 
     /* Too many chars */
@@ -958,6 +928,9 @@ static int IsIpv4Host(const uint8_t *urlhost, uint32_t len)
     memcpy(tempIp, urlhost, i);
     tempIp[i] = '\0';
 
+    if (!IPv4AddressStringIsValid(tempIp))
+        return 0;
+
     return inet_pton(AF_INET, tempIp, &(sa.sin_addr));
 }
 
diff --git a/src/util-ip.c b/src/util-ip.c
index b206197a4a..908a17d918 100644
--- a/src/util-ip.c
+++ b/src/util-ip.c
@@ -27,6 +27,53 @@
 #include "suricata-common.h"
 #include "util-ip.h"
 
+/** \brief determine if a string is a valid ipv4 address
+ *  \retval bool is addr valid?
+ */
+bool IPv4AddressStringIsValid(const char *str)
+{
+    int alen = 0;
+    char addr[4][4];
+    int dots = 0;
+
+    memset(&addr, 0, sizeof(addr));
+
+    uint32_t len = strlen(str);
+    uint32_t i = 0;
+    for (i = 0; i < len; i++) {
+        if (!(str[i] == '.' || isdigit(str[i]))) {
+            return false;
+        }
+        if (str[i] == '.') {
+            if (dots == 3) {
+                SCLogDebug("too many dots");
+                return false;
+            }
+            addr[dots][alen] = '\0';
+            dots++;
+            alen = 0;
+        } else {
+            if (alen >= 4) {
+                SCLogDebug("too long");
+                return false;
+            }
+            addr[dots][alen++] = str[i];
+        }
+    }
+    if (dots != 3)
+        return false;
+
+    addr[dots][alen] = '\0';
+    for (int x = 0; x < 4; x++) {
+        int a = atoi(addr[x]);
+        if (a < 0 || a >= 256) {
+            SCLogDebug("out of range");
+            return false;
+        }
+    }
+    return true;
+}
+
 /**
  * \brief Validates an IPV4 address and returns the network endian arranged
  *        version of the IPV4 address
@@ -43,6 +90,9 @@ struct in_addr *ValidateIPV4Address(const char *addr_str)
 {
     struct in_addr *addr = NULL;
 
+    if (!IPv4AddressStringIsValid(addr_str))
+        return NULL;
+
     if ( (addr = SCMalloc(sizeof(struct in_addr))) == NULL) {
         SCLogError(SC_ERR_FATAL, "Fatal error encountered in ValidateIPV4Address. Exiting...");
         exit(EXIT_FAILURE);
diff --git a/src/util-ip.h b/src/util-ip.h
index 25ffe9ec5d..f92369ccb4 100644
--- a/src/util-ip.h
+++ b/src/util-ip.h
@@ -25,6 +25,7 @@
 #ifndef __UTIL_IP_H__
 #define __UTIL_IP_H__
 
+bool IPv4AddressStringIsValid(const char *str);
 struct in_addr *ValidateIPV4Address(const char *);
 struct in6_addr *ValidateIPV6Address(const char *);
 void MaskIPNetblock(uint8_t *, int, int);