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path: root/config/coreboot/default/patches/0038-Subject-PATCH-1-1-Add-a-p-option-skip-FPTR-checks.patch
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From 273fec95778f53a622ff1e2a64c15b74813f48d2 Mon Sep 17 00:00:00 2001
From: Leah Rowe <leah@libreboot.org>
Date: Sun, 28 Sep 2025 03:17:50 +0100
Subject: [PATCH 1/1] Subject: [PATCH 1/1] Add a -p option (skip FPTR checks)

if you pass -k (keep fptr modules), don't use -r, don't
use -t, you can essentially just use me_cleaner to
extract a ME image without changing it. this is useful
when for example, you just want to set the HAP bit.

however, me_cleaner still performs a FPTR check.

on some newer ME versions, it's always invalid according
to me_cleaner, because for example it doesn't handle
ME16 very well yet.

this patch adds an option to override the FPTR check

either pass -p or --pass-fptr

NOTE: we probably won't use this on coreboot's me_cleaner,
which is the corna version. we only need it on the newer
me_cleaner versions for e.g. ME16, on certain setups.
still, it's best to have the patch here too, just in case.

Signed-off-by: Leah Rowe <leah@libreboot.org>
---
 util/me_cleaner/me_cleaner.py | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/util/me_cleaner/me_cleaner.py b/util/me_cleaner/me_cleaner.py
index fae5e56732..228bac899f 100755
--- a/util/me_cleaner/me_cleaner.py
+++ b/util/me_cleaner/me_cleaner.py
@@ -246,8 +246,10 @@ def check_partition_signature(f, offset):
     return "{:#x}".format(decrypted_sig).endswith(sha256.hexdigest())   # FIXME
 
 
-def print_check_partition_signature(f, offset):
-    if check_partition_signature(f, offset):
+def print_check_partition_signature(f, offset, pass_fptr):
+    if pass_fptr:
+        print("Skipping FPTR checks because the user told us to")
+    elif check_partition_signature(f, offset):
         print("VALID")
     else:
         print("INVALID!!")
@@ -486,6 +488,8 @@ if __name__ == "__main__":
                         "--extract-me)", action="store_true")
     parser.add_argument("-k", "--keep-modules", help="don't remove the FTPR "
                         "modules, even when possible", action="store_true")
+    parser.add_argument("-p", "--pass-fptr", help="skip FTPR signature checks"
+                        "regardless of other operations", action="store_true")
     bw_list.add_argument("-w", "--whitelist", metavar="whitelist",
                          help="Comma separated list of additional partitions "
                          "to keep in the final image. This can be used to "
@@ -871,12 +875,14 @@ if __name__ == "__main__":
             print("Checking the FTPR RSA signature of the extracted ME "
                   "image... ", end="")
             print_check_partition_signature(mef_copy,
-                                            ftpr_offset + ftpr_mn2_offset)
+                                            ftpr_offset + ftpr_mn2_offset,
+                                                args.pass_fptr)
         mef_copy.close()
 
     if not me6_ignition:
         print("Checking the FTPR RSA signature... ", end="")
-        print_check_partition_signature(mef, ftpr_offset + ftpr_mn2_offset)
+        print_check_partition_signature(mef, ftpr_offset + ftpr_mn2_offset,
+                                                args.pass_fptr)
 
     f.close()
 
-- 
2.47.3