sftp_packet_read: use 32bit variables for 32bit data

src/sftp.c

@@ -168,8 +168,9 @@ sftp_packet_read(LIBSSH2_SFTP *sftp)
     LIBSSH2_CHANNEL *channel = sftp->channel;
     LIBSSH2_SESSION *session = channel->session;
     unsigned char *packet;
-    size_t packet_len, packet_received;
+    size_t packet_received;
     ssize_t rc;
+    uint32_t packet_len; /* 32bits on the wire */
 
     _libssh2_debug(session, LIBSSH2_TRACE_SFTP, "recv packet");
 

src/sftp.h

@@ -145,7 +145,7 @@ struct _LIBSSH2_SFTP
     unsigned char partial_size[4];      /* buffer for size field   */
     size_t partial_size_len;            /* size field length       */
     unsigned char *partial_packet;      /* The data                */
-    size_t partial_len;                 /* Desired number of bytes */
+    uint32_t partial_len;               /* Desired number of bytes */
     size_t partial_received;            /* Bytes received so far   */
 
     /* Time that libssh2_sftp_packet_requirev() started reading */