mhpgp: use trusted header field copies to replace original header fields

Enigmail provides so called ``protected-headers'', which are copies
of some main mail header fields to protect them from forgery.

Mhpgp(1) works in a rough way and simply adds this MIME part
to the main header, and this resulted in a doubling of those header
fields.

Now those original headers are removed if trusted copies are
provided within the encrpyted MIME part.

diff --git a/uip/mhpgp.sh b/uip/mhpgp.sh
index ce4d2c8..1cfa274 100755 (executable)
--- a/uip/mhpgp.sh
+++ b/uip/mhpgp.sh
@@ -103,6 +103,14 @@ decrypt() {
                b a' "$FILE" > "$TEMP/outfile"
 
        if [ "$1" = "plain" ] ; then echo "" >> "$TEMP/outfile" ; fi
+
+       # Replace original header fields by secure copies that some
+       # mail clients (e.g. Enigmail) store within the encrypted and
+       # signed MIME part.
+       for i in `sed -n '/^$/q; /^[    ]/d; s,:.*,,p' "$TEMP/msg"` ; do
+               anno -delete -comp "$i" "$TEMP/outfile"
+       done
+
        sed -e 's/\r$//' $TEMP/msg >> "$TEMP/outfile" || exit 1
 
        if [ "$wflag" = "1" ] ; then