Segmentation fault in create_mb_refstate script

[ansasaki]

Is your issue a feature request? If so, please raise it as an enhancement

Environment

• OS / version: N/A
• Processor architecture: N/A
• TPM Manufacturer: N/A
• Keylime version: current master (7033891)

Description

Segmentation fault in create_mb_refstate depending on the input provided.

Expected behavior vs. actual behavior

The script should run normally instead of core dump with segmentation fault

Steps to reproduce problem

1. Change directory to scripts
2. Download the mb_log_b64.txt linked below
3. Decode with base64 -d mb_log_b64.txt > mb_log.bin
4. Run ./create_mb_refstate mb_log.bin mb_refstate.json

Relevant logs

• mb_log_b64.txt
  • The input that causes the segmentation fault
• mb_parsed.txt
  • The output parsed by tpm2_eventlog --eventlog_version=2

Attach any relevant log files that can help to debug your issue.

[stefanberger]

This here seems to be a solution but I don't know whether this is the correct way of handling it? @maugustosilva , @galmasi ?

diff --git a/keylime/tpm_bootlog_enrich.py b/keylime/tpm_bootlog_enrich.py
index ef8e9f7..a817d6e 100644
--- a/keylime/tpm_bootlog_enrich.py
+++ b/keylime/tpm_bootlog_enrich.py
@@ -47,6 +47,8 @@ efivarlib_functions = CDLL(config.LIBEFIVAR)


 def getDevicePath(b):
+    if b == b'\x00' * 8:
+        return ""
     ret = efivarlib_functions.efidp_format_device_path(0, 0, b, len(b))
     if ret < 0:
         raise Exception(f"getDevicePath: efidp_format_device_path({b}) returned {ret}")