From eab3c580f955c571253ab0ebd062b5f8c8d2b82f Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Wed, 4 Sep 2019 23:49:30 +0200 Subject: urlapi: verify the IPv6 numerical address It needs to parse correctly. Otherwise it could be tricked into letting through a-f using host names that libcurl would then resolve. Like '[ab.be]'. Reported-by: Thomas Vegas Closes #4315 --- lib/urlapi.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'lib/urlapi.c') diff --git a/lib/urlapi.c b/lib/urlapi.c index d07e4f5df..03efccd7b 100644 --- a/lib/urlapi.c +++ b/lib/urlapi.c @@ -29,6 +29,7 @@ #include "url.h" #include "escape.h" #include "curl_ctype.h" +#include "inet_pton.h" /* The last 3 #include files should be in this order */ #include "curl_printf.h" @@ -591,20 +592,22 @@ static CURLUcode junkscan(char *part) static CURLUcode hostname_check(struct Curl_URL *u, char *hostname) { - const char *l = NULL; /* accepted characters */ size_t len; size_t hlen = strlen(hostname); if(hostname[0] == '[') { + char dest[16]; /* fits a binary IPv6 address */ + const char *l = "0123456789abcdefABCDEF::."; hostname++; - l = "0123456789abcdefABCDEF::."; hlen -= 2; - } - if(l) { + if(hostname[hlen] != ']') + return CURLUE_MALFORMED_INPUT; + /* only valid letters are ok */ len = strspn(hostname, l); if(hlen != len) { + hlen = len; if(hostname[len] == '%') { /* this could now be '%[zone id]' */ char zoneid[16]; @@ -628,6 +631,12 @@ static CURLUcode hostname_check(struct Curl_URL *u, char *hostname) return CURLUE_MALFORMED_INPUT; /* hostname is fine */ } +#ifdef ENABLE_IPV6 + hostname[hlen] = 0; /* end the address there */ + if(1 != Curl_inet_pton(AF_INET6, hostname, dest)) + return CURLUE_MALFORMED_INPUT; + hostname[hlen] = ']'; /* restore ending bracket */ +#endif } else { /* letters from the second string is not ok */ -- cgit v1.2.3