pacman-key: stricter parsing for -verify

Prevents trust being spoofed by using TRUST_FULLY in the signatory's name
or in an added notation.

Fixes FS#41147.

Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/pacman-key.sh.in

@@ -482,7 +482,7 @@ verify_sig() {
 	local ret=0
 	for sig; do
 		msg "Checking %s ..." "$sig"
-		if ! "${GPG_PACMAN[@]}" --status-fd 1 --verify "$sig" | grep -qE 'TRUST_(FULLY|ULTIMATE)'; then
+		if ! "${GPG_PACMAN[@]}" --status-fd 1 --verify "$sig" | grep -qE '^\[GNUPG:\] TRUST_(FULLY|ULTIMATE)$'; then
 			error "$(gettext "The signature identified by %s could not be verified.")" "$sig"
 			ret=1
 		fi