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client: modernize socks5 fixing heap overflow

https://github.com/warmcat/libwebsockets/issues/1583
This commit is contained in:
Andy Green 2019-05-22 15:51:04 +01:00
parent 48366de1d1
commit 8b8849e8cc
3 changed files with 62 additions and 41 deletions

View file

@ -887,8 +887,8 @@ void
lws_destroy_event_pipe(struct lws *wsi);
/* socks */
void socks_generate_msg(struct lws *wsi, enum socks_msg_type type,
ssize_t *msg_len);
int
socks_generate_msg(struct lws *wsi, enum socks_msg_type type, ssize_t *msg_len);
void

View file

@ -446,7 +446,11 @@ create_new_conn:
/* Priority 2: Connect to SOCK5 Proxy */
} else if (wsi->vhost->socks_proxy_port) {
socks_generate_msg(wsi, SOCKS_MSG_GREETING, &plen);
if (socks_generate_msg(wsi, SOCKS_MSG_GREETING, &plen)) {
cce = "socks msg too large";
goto oom4;
}
lwsl_client("Sending SOCKS Greeting\n");
ads = wsi->vhost->socks_proxy_address;
port = wsi->vhost->socks_proxy_port;
@ -1086,80 +1090,94 @@ bail1:
}
#if defined(LWS_WITH_SOCKS5)
void socks_generate_msg(struct lws *wsi, enum socks_msg_type type,
ssize_t *msg_len)
int
socks_generate_msg(struct lws *wsi, enum socks_msg_type type, ssize_t *msg_len)
{
struct lws_context *context = wsi->context;
struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
ssize_t len = 0, n, passwd_len;
uint8_t *p = pt->serv_buf, *end = &p[context->pt_serv_buf_size];
ssize_t n, passwd_len;
short net_num;
char *p;
char *cp;
switch (type) {
case SOCKS_MSG_GREETING:
if (lws_ptr_diff(end, p) < 4)
return 1;
/* socks version, version 5 only */
pt->serv_buf[len++] = SOCKS_VERSION_5;
*p++ = SOCKS_VERSION_5;
/* number of methods */
pt->serv_buf[len++] = 2;
*p++ = 2;
/* username password method */
pt->serv_buf[len++] = SOCKS_AUTH_USERNAME_PASSWORD;
*p++ = SOCKS_AUTH_USERNAME_PASSWORD;
/* no authentication method */
pt->serv_buf[len++] = SOCKS_AUTH_NO_AUTH;
*p++ = SOCKS_AUTH_NO_AUTH;
break;
case SOCKS_MSG_USERNAME_PASSWORD:
n = strlen(wsi->vhost->socks_user);
passwd_len = strlen(wsi->vhost->socks_password);
if (n > 254 || passwd_len > 254)
return 1;
if (lws_ptr_diff(end, p) < 3 + n + passwd_len)
return 1;
/* the subnegotiation version */
pt->serv_buf[len++] = SOCKS_SUBNEGOTIATION_VERSION_1;
*p++ = SOCKS_SUBNEGOTIATION_VERSION_1;
/* length of the user name */
pt->serv_buf[len++] = n;
*p++ = n;
/* user name */
lws_strncpy((char *)&pt->serv_buf[len], wsi->vhost->socks_user,
context->pt_serv_buf_size - len);
len += n;
memcpy(p, wsi->vhost->socks_user, n);
p += n;
/* length of the password */
pt->serv_buf[len++] = passwd_len;
*p++ = passwd_len;
/* password */
lws_strncpy((char *)&pt->serv_buf[len],
wsi->vhost->socks_password,
context->pt_serv_buf_size - len);
len += passwd_len;
memcpy(p, wsi->vhost->socks_password, passwd_len);
p += passwd_len;
break;
case SOCKS_MSG_CONNECT:
p = (char*)&net_num;
n = strlen(wsi->stash->address);
if (n > 254 || lws_ptr_diff(end, p) < 5 + n + 2)
return 1;
cp = (char *)&net_num;
/* socks version */
pt->serv_buf[len++] = SOCKS_VERSION_5;
*p++ = SOCKS_VERSION_5;
/* socks command */
pt->serv_buf[len++] = SOCKS_COMMAND_CONNECT;
*p++ = SOCKS_COMMAND_CONNECT;
/* reserved */
pt->serv_buf[len++] = 0;
*p++ = 0;
/* address type */
pt->serv_buf[len++] = SOCKS_ATYP_DOMAINNAME;
/* skip length, we fill it in at the end */
n = len++;
*p++ = SOCKS_ATYP_DOMAINNAME;
/* length of ---> */
*p++ = n;
/* the address we tell SOCKS proxy to connect to */
lws_strncpy((char *)&(pt->serv_buf[len]), wsi->stash->address,
context->pt_serv_buf_size - len);
len += strlen(wsi->stash->address);
memcpy(p, wsi->stash->address, n);
p += n;
net_num = htons(wsi->c_port);
/* the port we tell SOCKS proxy to connect to */
pt->serv_buf[len++] = p[0];
pt->serv_buf[len++] = p[1];
*p++ = cp[0];
*p++ = cp[1];
/* the length of the address, excluding port */
pt->serv_buf[n] = strlen(wsi->stash->address);
break;
default:
return;
return 1;
}
*msg_len = len;
*msg_len = lws_ptr_diff(p, pt->serv_buf);
return 0;
}
#endif

View file

@ -182,7 +182,8 @@ lws_client_socket_service(struct lws *wsi, struct lws_pollfd *pollfd,
if (pt->serv_buf[1] == SOCKS_AUTH_NO_AUTH) {
lwsl_client("SOCKS GR: No Auth Method\n");
socks_generate_msg(wsi, SOCKS_MSG_CONNECT, &len);
if (socks_generate_msg(wsi, SOCKS_MSG_CONNECT, &len))
goto bail3;
conn_mode = LRS_WAITING_SOCKS_CONNECT_REPLY;
pending_timeout =
PENDING_TIMEOUT_AWAITING_SOCKS_CONNECT_REPLY;
@ -191,9 +192,10 @@ lws_client_socket_service(struct lws *wsi, struct lws_pollfd *pollfd,
if (pt->serv_buf[1] == SOCKS_AUTH_USERNAME_PASSWORD) {
lwsl_client("SOCKS GR: User/Pw Method\n");
socks_generate_msg(wsi,
if (socks_generate_msg(wsi,
SOCKS_MSG_USERNAME_PASSWORD,
&len);
&len))
goto bail3;
conn_mode = LRS_WAITING_SOCKS_AUTH_REPLY;
pending_timeout =
PENDING_TIMEOUT_AWAITING_SOCKS_AUTH_REPLY;
@ -208,7 +210,8 @@ lws_client_socket_service(struct lws *wsi, struct lws_pollfd *pollfd,
goto socks_reply_fail;
lwsl_client("SOCKS password OK, sending connect\n");
socks_generate_msg(wsi, SOCKS_MSG_CONNECT, &len);
if (socks_generate_msg(wsi, SOCKS_MSG_CONNECT, &len))
goto bail3;
conn_mode = LRS_WAITING_SOCKS_CONNECT_REPLY;
pending_timeout =
PENDING_TIMEOUT_AWAITING_SOCKS_CONNECT_REPLY;