pvattest/tools: Add script to display config UID and additional data

Although the previous patch enables pvattest to display the
config UID this script enables the user to extract the config UID of
the SE-guest and the additional data if specified. This allows users of
pvattest v2.22.0 to view the config UID without examining binary blobs.

$ ./pvattest-info attresult.bin
Config UID:
1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a1a
Additional Data:
1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b1b
1b1b

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

pvattest/tools/pvattest-info

@@ -0,0 +1,88 @@
+#!/bin/bash
+#
+# pvattest-info - get additional information from an attestation measurement
+#
+# Sample:
+# ./pvattest-info attestresp.bin
+#
+# Copyright IBM Corp. 2022
+#
+# s390-tools is free software; you can redistribute it and/or modify
+# it under the terms of the MIT license. See LICENSE for details.
+
+set -o pipefail
+set -o nounset
+set -e
+
+usage() {
+	cat <<-EOF
+		Usage: $(basename "$0") FILE
+
+		Prints config UID and additional data if available.
+	EOF
+}
+
+function check_is_pvattest_binary() {
+	local input="$1"
+	local size
+	local version
+
+	size=$(wc -c <"$input")
+	if [ "$size" -lt 64 ]; then
+		echo "ERROR: Input file is too small." >&2
+		exit 1
+	fi
+
+	xxd -l 16 "${input}" | grep -q pvattest ||
+		{ echo "ERROR: ${input} does not contain a pvattest binary output." >&2 && exit 1; }
+
+	size=$(xxd -s 12 -l 4 "${input}" | awk 'NR==1 {print "0x" $2 $3}')
+	if [ $((size)) -lt 64 ]; then
+		echo "ERROR: ${input} does not contain a pvattest binary output." >&2
+		exit 1
+	fi
+
+	version=$(xxd -s 8 -l 4 "$input")
+	echo "$version" | grep -q "0000 0100" ||
+		{ echo -n "WARNING: unknown hdr version " >&2  &&
+		echo "$version" | awk '{print "0x" $2 $3}'>&2 ; }
+}
+
+function print_entry() {
+	local file_off="$1"
+	local text="$2"
+	local input="$3"
+	local size
+	local off
+
+	size=$(xxd -s $((file_off)) -l 4 "${input}" | awk 'NR==1 {print "0x" $2 $3}')
+	off=$(xxd -s $((file_off + 4)) -l 4 "${input}" | awk 'NR==1 {print "0x" $2 $3}')
+
+	if [[ $size != "0x00000000" ]] || [[ $off != "0x00000000" ]]; then
+		echo "${text}:"
+		xxd -s $((off)) -l $((size)) -p "${input}"
+	fi
+}
+
+function require_command() {
+	local cmd="$1"
+
+	command -v "$cmd" >/dev/null 2>&1 || { echo >&2 "ERROR: $cmd required but not installed."; exit 1;  }
+}
+
+require_command xxd
+require_command awk
+require_command wc
+
+if [ $# -eq 0 ]; then
+	echo "ERROR: Input not set. Use '$(basename "$0") [FILE]' to specify the Input file" >&2
+	exit 1
+fi
+
+input="$1"
+
+[ -e "$input" ] || { echo "ERROR: File '$1' not found" >&2 && exit 1; }
+check_is_pvattest_binary "$input"
+
+print_entry 0x38 "Config UID" "$input"
+print_entry 0x28 "Additional Data" "$input"