BUG/MEDIUM: h2: remove connection-specific headers from request
h2spec rightfully outlines that we used not to reject these ones, and
they may cause trouble if presented, especially "upgrade".
Must be backported to 1.8.
diff --git a/src/h2.c b/src/h2.c
index 83ef043..64f27fe 100644
--- a/src/h2.c
+++ b/src/h2.c
@@ -179,6 +179,14 @@
if (isteq(list[idx].n, ist("host")))
fields |= H2_PHDR_FND_HOST;
+ /* these ones are forbidden in requests (RFC7540#8.1.2.2) */
+ if (isteq(list[idx].n, ist("connection")) ||
+ isteq(list[idx].n, ist("proxy-connection")) ||
+ isteq(list[idx].n, ist("keep-alive")) ||
+ isteq(list[idx].n, ist("upgrade")) ||
+ isteq(list[idx].n, ist("transfer-encoding")))
+ goto fail;
+
if (isteq(list[idx].n, ist("te")) && !isteq(list[idx].v, ist("trailers")))
goto fail;