Fixes to delta updates, reinforced size checks, improved hardening

[danielinux]

F/220 - Improved PSA & PKCS11 store write boundary checks
F/222 - Fixed bug in bmdiff
F/229 - GPT: Verify CRC32 in header
F/230 - Self update improved size check
F/231 - Constant time public key lookup
F/235 - Fix delta wb_patch double escape corner case
F/93 - RSA: validate key size buffer when decoding signature
F/233 - Re-calculate hash before extending PCR
F/445 - Forcezero secrets from stack
F/232 - PCI: prevent loops on malformed trees
F/436 - NIT: parentheses around macro
F/368 - Fix uart printf digit count on large representation
F/221 - Fix QSPI write page, enforcing actual remaining bytes count
F/369 - Don't rely on assumption of alignment when loading RSA exponent

[Copilot]

Pull request overview

Improves robustness and hardening across delta updates, storage writes, TPM/GPT handling, and self-update validation, with new/updated unit tests to cover regressions.

Changes:

• Adds/expands unit tests covering TPM RSA exponent decoding, QSPI page writes, PSA/PKCS11 cross-sector writes, GPT CRC validation, PCI capability loop protection, and delta escape corner cases.
• Hardens runtime code paths: CRC32 verification for GPT headers, constant-time key hint matching, safer ASN.1 tag decoding bounds, improved size checks for self header, and secure zeroization of encryption material.
• Fixes concrete bugs in tools/runtime (e.g., bmdiff mmap error check, UART printf maxdigits parsing, QSPI remaining-byte calculation).

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tools/unit-tests/unit-tpm-rsa-exp.c	Adds a unit test validating DER exponent byte decoding for TPM RSA public key loading.
tools/unit-tests/unit-qspi-flash.c	Adds unit test ensuring QSPI writes split the last page based on remaining bytes.
tools/unit-tests/unit-psa_store.c	Adds PSA store cross-sector write test to verify size/offset bookkeeping.
tools/unit-tests/unit-pkcs11_store.c	Tightens read-length expectations and adds PKCS11 cross-sector write size test.
tools/unit-tests/unit-image.c	Adds self-header oversize rejection test and guards tests by signing configuration; adds RSA ASN.1 bounds test.
tools/unit-tests/unit-disk.c	Adds helpers and tests to validate GPT header CRC behavior in parser.
tools/unit-tests/unit-delta.c	Adds regression test for trailing escape byte in delta patch stream.
tools/unit-tests/unit-boot-x86_fsp.c	Adds tests for PCI capability traversal (find target, reject cycles/loops).
tools/unit-tests/Makefile	Adds new unit test targets and a wolfPSA include path configuration.
tools/delta/test-bmdiff.c	Adds a standalone test to validate bmdiff behavior on mmap failure.
tools/delta/bmdiff.c	Fixes incorrect variable used in mmap failure check.
tools/delta/Makefile	Adds build/run targets for bmdiff-test and updates clean.
src/update_flash.c	Ensures encryption secrets are zeroed on all exits; refactors returns via goto out.
src/tpm.c	Safely decodes RSA exponent bytes into a uint32_t (avoids unaligned dereference).
src/string.c	Fixes digit parsing logic for UART printf width/maxdigits calculation.
src/qspi_flash.c	Fixes per-page transfer sizing to use remaining bytes, not total length.
src/psa_store.c	Fixes in-sector write length computation using remaining bytes (len - written).
src/pkcs11_store.c	Fixes in-sector write length computation using remaining bytes (len - written).
src/libwolfboot.c	Adds parentheses to macro to avoid precedence surprises.
src/image.c	Adds constant-time comparisons, improves ASN.1 tag bounds check, and adds self-header size enforcement under fixed partitions.
src/gpt.c	Adds GPT header CRC32 verification to reject corrupted headers.
src/delta.c	Adds bounds checks to prevent reading past end of patch stream on escape sequences.
src/boot_x86_fsp.c	Recomputes hash before PCR extend and caps PCI capability traversal to prevent loops.

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Pull request overview

Copilot reviewed 25 out of 25 changed files in this pull request and generated 1 comment.

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[dgarske]

LGTM