From 2fee03637d3a1d0c9c004b958af69f4b0e4b57f3 Mon Sep 17 00:00:00 2001

From: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>

Date: Fri, 4 Nov 2022 17:41:31 +0100

Subject: [PATCH 2/2] tpm_bootlog_enrich: Get DevicePath length from

 LengthOfDevicePath

In enrich_device_path(), get the length of DevicePath from the field

LengthOfDevicePath instead of calculating the length from the bytes

array.

This avoids a segmentation fault when processing the measured boot event

log in create_mb_refstate script.

This is called for the events "EV_EFI_BOOT_SERVICES_APPLICATION",

"EV_EFI_BOOT_SERVICES_DRIVER", and "EV_EFI_RUNTIME_SERVICES_DRIVER".

Fixes: #1153

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>

---

 keylime/tpm_bootlog_enrich.py | 11 ++++++-----

 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/keylime/tpm_bootlog_enrich.py b/keylime/tpm_bootlog_enrich.py

index ef8e9f7..621bc67 100644

--- a/keylime/tpm_bootlog_enrich.py

+++ b/keylime/tpm_bootlog_enrich.py

@@ -46,14 +46,14 @@ yaml.add_representer(hexint, representer)

 efivarlib_functions = CDLL(config.LIBEFIVAR)

-def getDevicePath(b):

-    ret = efivarlib_functions.efidp_format_device_path(0, 0, b, len(b))

+def getDevicePath(b, l):

+    ret = efivarlib_functions.efidp_format_device_path(0, 0, b, l)

     if ret < 0:

         raise Exception(f"getDevicePath: efidp_format_device_path({b}) returned {ret}")

     s = create_string_buffer(ret + 1)

-    ret = efivarlib_functions.efidp_format_device_path(s, ret + 1, b, len(b))

+    ret = efivarlib_functions.efidp_format_device_path(s, ret + 1, b, l)

     if ret < 0:

         raise Exception(f"getDevicePath: efidp_format_device_path({b}) returned {ret}")

@@ -174,7 +174,7 @@ def getVar(event, b):

                     c = w.decode("utf-16", errors="ignore")

                     description += c

                 r["Description"] = description

-                devicePath = getDevicePath(b[i:])

+                devicePath = getDevicePath(b[i:], len(b[i:]))

                 r["DevicePath"] = devicePath

                 return r

     return None

@@ -184,10 +184,11 @@ def enrich_device_path(d: dict) -> None:

     if isinstance(d.get("DevicePath"), str):

         try:

             b = bytes.fromhex(d["DevicePath"])

+            l = int(d["LengthOfDevicePath"])

         except Exception:

             return

         try:

-            p = getDevicePath(b)

+            p = getDevicePath(b, l)

         # Deal with garbage devicePath

         except Exception:

             return

-- 

2.38.1