From: Daniel Lenski <dlenski@gmail.com>
Date: Thu, 14 May 2020 21:41:19 +0000 (-0700)
Subject: n != ppp.hlen for HDLC (will only work by coincidence if PPP header is uncompressed... 
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ce48e5544971f9a153279b47161996cb0be6c067;p=users%2Fdwmw2%2Fopenconnect.git

n != ppp.hlen for HDLC (will only work by coincidence if PPP header is uncompressed/4 bytes)

See https://gitlab.com/openconnect/openconnect/-/commit/c060e713f7aba546ccc3a1e729dd6e2e21e0e43b#note_342889873

Signed-off-by: Daniel Lenski <dlenski@gmail.com>
---

diff --git a/ppp.c b/ppp.c
index 0c840073..265506ce 100644
--- a/ppp.c
+++ b/ppp.c
@@ -1001,9 +1001,11 @@ int ppp_mainloop(struct openconnect_info *vpninfo, int *timeout, int readable)
 						 proto == PPP_LCP ? ASYNCMAP_LCP : ppp->out_asyncmap);
 			if (!this)
 				return 1; /* XX */
-			store_be32(this->data + n - 4, this->len - n);
+
+			/* XX: header is simply the number of bytes on the wire (excluding itself) */
+			store_be32(this->data - this->ppp.hlen - 4, this->len + this->ppp.hlen);
+			this->ppp.hlen += 4;
 			free(vpninfo->current_ssl_pkt);
-			this->ppp.hlen = -n + 4;
 			vpninfo->current_ssl_pkt = this;
 			break;
 		default: