bpo-30711: Fix port number conversion in getaddrinfo emulation

Return an error code if servname is an invalid numeric service.
python · smejkar · Jun 27, 2017 · Jun 27, 2017 · Jun 27, 2017 · Jun 27, 2017
commit 7c52c85c4c6801fe43bf2f40ba06922a06068285
diff --git a/Modules/getaddrinfo.c b/Modules/getaddrinfo.c
@@ -134,7 +134,6 @@ static int get_name(const char *, struct gai_afd *,
                          int);
 static int get_addr(const char *, int, struct addrinfo **,
                        struct addrinfo *, int);
-static int str_isnumber(const char *);

 static const char * const ai_errlist[] = {
    "success.",
@@ -220,18 +219,6 @@ freeaddrinfo(struct addrinfo *ai)
    } while ((ai = next) != NULL);
 }

-static int
-str_isnumber(const char *p)
-{
-    unsigned char *q = (unsigned char *)p;
-    while (*q) {
-        if (! isdigit(*q))
-            return NO;
-        q++;
-    }
-    return YES;
-}
-
 int
 getaddrinfo(const char*hostname, const char*servname,
            const struct addrinfo *hints, struct addrinfo **res)
@@ -333,13 +320,19 @@ getaddrinfo(const char*hostname, const char*servname,
     * service port
     */
    if (servname) {
-        if (str_isnumber(servname)) {
+        long servnum;
+        char *end;
+
+        servnum = strtol(servname, &end, 10);
+        if (*end == '\0') {  /* treat "" as 0 */
            if (pai->ai_socktype == GAI_ANY) {
                /* caller accept *GAI_ANY* socktype */
                pai->ai_socktype = SOCK_DGRAM;
                pai->ai_protocol = IPPROTO_UDP;
            }
-            port = htons((u_short)atoi(servname));
+            if (servnum < 0 || servnum > 0xffff)
+                ERR(EAI_SERVICE);
+            port = htons((u_short)servnum);
        } else {
            struct servent *sp;
            char *proto;