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https://github.com/moparisthebest/curl
synced 2024-12-21 23:58:49 -05:00
Modified lookup_service() to avoid the risk of a potential buffer overflow
This commit is contained in:
Yang Tse
parent
4b1a91b64f
commit
2ae67c431c
@ -70,7 +70,8 @@ struct nameinfo_query {
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#endif
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static void nameinfo_callback(void *arg, int status, struct hostent *host);
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static char *lookup_service(unsigned short port, int flags, char *buf);
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static char *lookup_service(unsigned short port, int flags,
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char *buf, size_t buflen);
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#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
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static void append_scopeid(struct sockaddr_in6 *addr6, unsigned int scopeid,
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char *buf, size_t buflen);
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@ -109,7 +110,7 @@ void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa, socklen_t
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port = addr->sin_port;
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else
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port = addr6->sin6_port;
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service = lookup_service(port, flags, buf);
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service = lookup_service(port, flags, buf, sizeof(buf));
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callback(arg, ARES_SUCCESS, NULL, service);
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return;
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}
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@ -122,7 +123,7 @@ void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa, socklen_t
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{
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unsigned int port = 0;
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char ipbuf[IPBUFSIZ];
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char srvbuf[32];
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char srvbuf[33];
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char *service = NULL;
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ipbuf[0] = 0;
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@ -150,7 +151,7 @@ void ares_getnameinfo(ares_channel channel, const struct sockaddr *sa, socklen_t
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}
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/* They also want a service */
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if (flags & ARES_NI_LOOKUPSERVICE)
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service = lookup_service(port, flags, srvbuf);
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service = lookup_service(port, flags, srvbuf, sizeof(srvbuf));
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callback(arg, ARES_SUCCESS, ipbuf, service);
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return;
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}
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@ -198,10 +199,10 @@ static void nameinfo_callback(void *arg, int status, struct hostent *host)
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{
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if (niquery->family == AF_INET)
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service = lookup_service(niquery->addr.addr4.sin_port,
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niquery->flags, srvbuf);
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niquery->flags, srvbuf, sizeof(srvbuf));
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else
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service = lookup_service(niquery->addr.addr6.sin6_port,
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niquery->flags, srvbuf);
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niquery->flags, srvbuf, sizeof(srvbuf));
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}
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/* NOFQDN means we have to strip off the domain name portion.
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We do this by determining our own domain name, then searching the string
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@ -240,10 +241,10 @@ static void nameinfo_callback(void *arg, int status, struct hostent *host)
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{
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if (niquery->family == AF_INET)
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service = lookup_service(niquery->addr.addr4.sin_port,
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niquery->flags, srvbuf);
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niquery->flags, srvbuf, sizeof(srvbuf));
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else
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service = lookup_service(niquery->addr.addr6.sin6_port,
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niquery->flags, srvbuf);
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niquery->flags, srvbuf, sizeof(srvbuf));
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}
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niquery->callback(niquery->arg, ARES_SUCCESS, ipbuf, service);
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return;
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@ -253,31 +254,21 @@ static void nameinfo_callback(void *arg, int status, struct hostent *host)
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}
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static char *lookup_service(unsigned short port, int flags,
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char *buf) /* 33 bytes buffer */
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char *buf, size_t buflen)
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{
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const char *proto;
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struct servent *sep;
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#ifdef HAVE_GETSERVBYPORT_R
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struct servent se;
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#endif
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char tmpbuf[4096];
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if (port)
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{
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/* Just return the port as a string */
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if (flags & ARES_NI_NUMERICSERV)
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sprintf(buf, "%u", ntohs(port));
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sep = NULL;
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else
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{
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struct servent *se;
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const char *proto;
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#ifdef HAVE_GETSERVBYPORT_R
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#if GETSERVBYPORT_R_ARGS == 6
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struct servent ret;
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char buf[4096];
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int len = 4096;
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#elif GETSERVBYPORT_R_ARGS == 5
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struct servent ret;
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char buf[4096];
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int len = 4096;
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#elif GETSERVBYPORT_R_ARGS == 4
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struct servent ret;
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struct servent_data sed;
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#endif
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#endif /* HAVE_GETSERVBYPORT_R */
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if (flags & ARES_NI_UDP)
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proto = "udp";
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else if (flags & ARES_NI_SCTP)
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@ -287,39 +278,40 @@ static char *lookup_service(unsigned short port, int flags,
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else
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proto = "tcp";
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#ifdef HAVE_GETSERVBYPORT_R
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sep = &se;
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memset(tmpbuf, 0, sizeof(tmpbuf));
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#if GETSERVBYPORT_R_ARGS == 6
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se = &ret;
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if (getservbyport_r(port, proto, se, buf, len, &ret))
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se = NULL;
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if (getservbyport_r(port, proto, &se, (void *)tmpbuf, sizeof(tmpbuf), &sep) != 0)
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sep = NULL;
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#elif GETSERVBYPORT_R_ARGS == 5
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se = &ret;
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se = getservbyport_r(port, proto, se, buf, len);
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sep = getservbyport_r(port, proto, &se, (void *)tmpbuf, sizeof(tmpbuf));
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#elif GETSERVBYPORT_R_ARGS == 4
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se = &ret;
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if (getservbyport_r(port, proto, se, &sed) == -1)
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se = NULL;
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if (getservbyport_r(port, proto, &se, (void *)tmpbuf) != 0)
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sep = NULL;
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#else
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/* Lets just hope the OS uses TLS! */
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se = getservbyport(port, proto);
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sep = getservbyport(port, proto);
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#endif
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#else
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/* Lets just hope the OS uses TLS! */
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se = getservbyport(port, proto);
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sep = getservbyport(port, proto);
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#endif
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if (se && se->s_name) {
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size_t len = strlen(se->s_name);
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if(len < 33) {
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strcpy(buf, se->s_name);
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}
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else
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/* too big name to fit the buffer */
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buf[0]=0;
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}
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else
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sprintf(buf, "%u", ntohs(port));
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}
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if (sep && sep->s_name)
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/* get service name */
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strcpy(tmpbuf, sep->s_name);
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else
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/* get port as a string */
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sprintf(tmpbuf, "%u", ntohs(port));
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if (strlen(tmpbuf) < buflen)
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/* return it if buffer big enough */
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strcpy(buf, tmpbuf);
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else
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/* avoid reusing previous one */
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buf[0] = '\0';
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return buf;
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}
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buf[0] = '\0';
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return NULL;
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}
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