Add BCM2712 RAM authenticity check and raspinfo integration

CMakeLists.txt

@@ -18,6 +18,7 @@ add_subdirectory(piolib)
 add_subdirectory(raspinfo)
 add_subdirectory(rpieepromab)
 add_subdirectory(rpi-gpu-usage)
+add_subdirectory(rpi-ram-authenticity-check)
 add_subdirectory(vcgencmd)
 add_subdirectory(vclog)
 add_subdirectory(vcmailbox)

README.md

@@ -29,6 +29,8 @@ A collection of scripts and simple applications
     secure-boot provisioner.
 * [rpi-gpu-usage](rpi-gpu-usage/) - A tool for showing the per-process usage of the V3D GPU
     on Raspberry Pi 4 and 5.
+* [rpi-ram-authenticity-check](rpi-ram-authenticity-check/) - A read-only RAM authenticity
+    check for BCM2712 devices, comparing reported capacity with the factory configuration.
 * [splashasm](splashasm/) - A tool for writing spi & i2c dumps for fast display at boot
 * [vcgencmd](vcgencmd/) - A tool to send commands to the VideoCore firmware and
     display the results.

raspinfo/README.md

@@ -1,2 +1,7 @@
 # raspinfo
 Short script to dump information about the Pi. Use it for annotating bug reports.
+
+On BCM2712 devices, includes the output of
+[`rpi-ram-authenticity-check`](../rpi-ram-authenticity-check/) when installed.
+RAM mismatch warnings and unavailable checks are recorded in `raspinfo.txt`
+without stopping the rest of the report.

raspinfo/raspinfo

@@ -235,6 +235,19 @@ cat /proc/cpuinfo | tail -3
 
 echo "Throttled flag  : "`vcgencmd get_throttled`
 
+if grep -q bcm2712 /proc/device-tree/compatible 2>/dev/null; then
+   echo
+   echo "RAM authenticity"
+   echo "----------------"
+   echo
+   if command -v rpi-ram-authenticity-check > /dev/null; then
+      rpi-ram-authenticity-check 2>&1 || :
+   else
+      echo "rpi-ram-authenticity-check not found"
+   fi
+   echo
+fi
+
 
 echo "Camera Information"
 echo "------------------"

rpi-ram-authenticity-check/CMakeLists.txt

@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.10...3.27)
+
+include(GNUInstallDirs)
+
+project(rpi-ram-authenticity-check)
+
+install(PROGRAMS rpi-ram-authenticity-check DESTINATION ${CMAKE_INSTALL_BINDIR})

rpi-ram-authenticity-check/README.md

@@ -0,0 +1,28 @@
+# rpi-ram-authenticity-check
+
+Read-only RAM authenticity check for BCM2712 devices (the Pi 5 family).
+Compares the RAM capacity in the running board revision (from device tree or
+`/proc/cpuinfo`) with the factory revision in OTP row 32.
+
+Run `rpi-ram-authenticity-check` after installing utils, or directly from this
+repository:
+
+```sh
+./rpi-ram-authenticity-check/rpi-ram-authenticity-check
+```
+
+Requires `vcgencmd` and access to `/dev/vcio`; run with `sudo` if access is denied.
+Use `--help` for usage information.
+
+A mismatch warns of possible RAM tampering or replacement and advises contacting
+the seller to arrange a return. Matching capacity is reported as "RAM appears
+authentic", but cannot detect a replacement with the same capacity.
+
+Exit status:
+
+* `0`: capacity matches.
+* `1`: capacity differs.
+* `2`: unable to check, including unsupported hardware or missing/invalid data.
+
+When installed, the checker is also called by `raspinfo` on BCM2712 devices.
+Its output, including warnings, is included in `raspinfo.txt`.

rpi-ram-authenticity-check/rpi-ram-authenticity-check

@@ -0,0 +1,76 @@
+#!/bin/sh
+
+# Compare BCM2712's reported RAM capacity with its factory revision in OTP.
+set -ef
+
+usage() {
+   cat <<EOF
+Usage: rpi-ram-authenticity-check [-h | --help]
+
+Compare the RAM capacity in the running board revision with the factory
+capacity in BCM2712 OTP row 32. Requires vcgencmd and access to /dev/vcio.
+This is a read-only capacity check; it cannot prove that the RAM is original
+or detect a replacement with the same capacity.
+
+Exit status: 0 = capacity matches, 1 = capacity differs, 2 = unable to check.
+EOF
+}
+
+die() {
+   echo "Unable to check RAM: $*" >&2
+   exit 2
+}
+
+ramSizeFromRevision() {
+   case "$1" in
+      ''|*[!0-9a-fA-F]*) return 1 ;;
+   esac
+   [ "${#1}" -le 8 ] || return 1
+   # Require a new-style BCM2712 revision before interpreting its RAM field.
+   [ $(((0x$1 >> 23) & 1)) -eq 1 ] &&
+      [ $(((0x$1 >> 12) & 15)) -eq 4 ] || return 1
+   ram_code=$(((0x$1 >> 20) & 7))
+   # Code 7 means "Other", not 32 GiB.
+   [ "${ram_code}" -lt 7 ] || return 1
+   echo "$((256 << ram_code))"
+}
+
+if [ "$#" -ne 0 ]; then
+   if [ "$#" -eq 1 ] && { [ "$1" = -h ] || [ "$1" = --help ]; }; then
+      usage
+      exit 0
+   fi
+   usage >&2
+   exit 2
+fi
+
+# Use the same running revision sources as rpi-eeprom-update. Do not fall
+# back to OTP here: comparing the factory value with itself would miss changes.
+dt_revision=/sys/firmware/devicetree/base/system/linux,revision
+if [ -r "${dt_revision}" ]; then
+   [ "$(wc -c < "${dt_revision}")" -eq 4 ] || die "Invalid device-tree board revision."
+   board_revision=$(od -v -An -t x1 "${dt_revision}" | tr -d ' \n')
+elif [ -r /proc/cpuinfo ]; then
+   board_revision=$(sed -n '/^Revision/s/^.*: \(.*\)/\1/p' /proc/cpuinfo)
+else
+   die "No running board revision found."
+fi
+reported_mib=$(ramSizeFromRevision "${board_revision}") ||
+   die "The running board revision must describe a BCM2712 device with a known RAM capacity."
+
+command -v vcgencmd > /dev/null || die "vcgencmd is required to read the factory RAM capacity."
+otp_dump=$(vcgencmd otp_dump) || die "Failed to read OTP; check access to /dev/vcio."
+# Row 32 is the BCM2712 factory revision; BCM2711 uses row 30.
+factory_revision=$(printf '%s\n' "${otp_dump}" | sed -n 's/^32:\([0-9a-fA-F]\{8\}\)$/\1/p')
+factory_mib=$(ramSizeFromRevision "${factory_revision}") ||
+   die "OTP row 32 does not contain a valid BCM2712 revision with a known RAM capacity."
+
+echo "Factory RAM: ${factory_mib} MiB; reported RAM: ${reported_mib} MiB."
+if [ "${factory_mib}" -eq "${reported_mib}" ]; then
+   echo "RAM appears authentic: capacity matches the factory configuration."
+   exit 0
+fi
+
+echo "WARNING: RAM capacity mismatch detected: possible RAM tampering or replacement." >&2
+echo "Contact the seller to arrange a return." >&2
+exit 1