Fix arithmetic on void pointers in cstp.c

This is a gccism and not portable. And could have been dereferencing an
unaligned pointer too. Thanks to Florian Wobbe for pointing it out.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/cstp.c b/cstp.c
index ea67fc5..026124b 100644 (file)
--- a/cstp.c
+++ b/cstp.c
@@ -439,9 +439,11 @@ int cstp_reconnect(struct openconnect_info *vpninfo)
        return 0;
 }
 
-static int inflate_and_queue_packet(struct openconnect_info *vpninfo, void *buf, int len)
+static int inflate_and_queue_packet(struct openconnect_info *vpninfo,
+                                   unsigned char *buf, int len)
 {
        struct pkt *new = malloc(sizeof(struct pkt) + vpninfo->mtu);
+       uint32_t pkt_sum;
 
        if (!new)
                return -ENOMEM;
@@ -466,7 +468,10 @@ static int inflate_and_queue_packet(struct openconnect_info *vpninfo, void *buf,
        vpninfo->inflate_adler32 = adler32(vpninfo->inflate_adler32,
                                           new->data, new->len);
 
-       if (vpninfo->inflate_adler32 != ntohl( *(uint32_t *) (buf + len - 4) )) {
+       pkt_sum = buf[len - 1] | (buf[len - 2] << 8) |
+               (buf[len - 3] << 16) | (buf[len - 4] << 24);
+
+       if (vpninfo->inflate_adler32 != pkt_sum) {
                vpninfo->quit_reason = "Compression (inflate) adler32 failure";
        }