Skip the redundant signature verification for normal CAs. by yosuke-wolfssl · Pull Request #11892 · wolfSSL/wolfssl

yosuke-wolfssl · 2026-10-26T01:48:54Z

Problem

PR #11334 introduced selfSigned and its verifier ConfirmSelfSignature.
It increased the memory usage for CA loads unconditionally.
The PR recognized the runtime cost only.

Fix

a CA_TYPE cert now skips ConfirmSelfSignature() only when its AKID is set and equals its SKID, and Key Usage allows keyCertSign.
Also, ProcessPeerCertParse() sets selfSigned on the small-cert path when the signature verified with the certificate's own key. wc_CheckCertSignature_ex() is added for the purpose.

Test

make check with --enable-all: pass.

Verification (peak heap)

Configs are the low_ecc and low_rsa2048 lines from nightly-memusage-v2,
plus --enable-trackmemory (prints peak Bytes on exit) and
--disable-shared:

# low_ecc
./configure --enable-singlethreaded --enable-lowresource --disable-sha512 \
  --disable-sha3 --disable-sha --disable-aescbc --enable-smallstack \
  --disable-tls13 --disable-eccshamir --disable-dh --disable-rsa \
  --enable-ecc --enable-curve25519 --disable-ed25519 \
  CFLAGS=-DSP_INT_BITS=256 C_EXTRA_FLAGS=-DFP_MAX_BITS=512 \
  --enable-trackmemory --disable-shared
# low_rsa2048
./configure --enable-singlethreaded --enable-lowresource --disable-sha512 \
  --disable-sha3 --disable-sha --disable-aescbc --enable-smallstack \
  --disable-tls13 --enable-dh --enable-rsa --disable-ecc \
  --disable-curve25519 --disable-ed25519 \
  CFLAGS=-DSP_INT_BITS=2048 C_EXTRA_FLAGS=-DFP_MAX_BITS=4096 \
  --enable-trackmemory --disable-shared
make examples/client/client examples/server/server

One mutual-auth TLS 1.2 handshake between examples/server/server and
examples/client/client; numbers are each process's peak Bytes (whole
process, CA load included). Repeated runs gave identical numbers.

ECC: server -c certs/server-ecc.pem -k certs/ecc-key.pem -A certs/client-ecc-cert.pem,
client -A certs/ca-ecc-cert.pem -c certs/client-ecc-cert.pem -k certs/ecc-client-key.pem
RSA: default certs on both sides (DHE-RSA)

Peak bytes	before (`1625c65a1e`)	after
low_ecc client	10313	9123
low_ecc server	11241	9425
low_rsa2048 client	19895	17355
low_rsa2048 server	21513	21169

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github-actions · 2026-10-26T01:52:21Z

MemBrowse Memory Report · Explore what changed →

gcc-arm-cortex-m0plus

FLASH: .text +68 B (+0.1%, 70,527 B / 262,144 B, total: 27% used)

gcc-arm-cortex-m3

FLASH: .text +48 B (+0.0%, 130,817 B / 262,144 B, total: 50% used)

gcc-arm-cortex-m4-baremetal

FLASH: .text +64 B (+0.1%, 73,079 B / 262,144 B, total: 28% used)

gcc-arm-cortex-m4-crypto-only

FLASH: .text +64 B (+0.0%, 179,859 B / 262,144 B, total: 69% used)

gcc-arm-cortex-m4-min-ecc

FLASH: .text +64 B (+0.1%, 67,737 B / 262,144 B, total: 26% used)

gcc-arm-cortex-m4-openssl-compat

FLASH: .text +128 B (+0.0%, 793,564 B / 1,048,576 B, total: 76% used)

gcc-arm-cortex-m4-pkcs7

FLASH: .text +64 B (+0.0%, 220,884 B / 262,144 B, total: 84% used)

gcc-arm-cortex-m4-pq

FLASH: .text +64 B (+0.0%, 309,072 B / 1,048,576 B, total: 29% used)

gcc-arm-cortex-m4-rsa-only

FLASH: .text +64 B (+0.0%, 340,424 B / 1,048,576 B, total: 32% used)

gcc-arm-cortex-m4-sp-math

FLASH: .text +64 B (+0.1%, 67,737 B / 262,144 B, total: 26% used)

gcc-arm-cortex-m4-tls12

FLASH: .text +64 B (+0.0%, 131,601 B / 262,144 B, total: 50% used)

gcc-arm-cortex-m4-tls13

FLASH: .text +64 B (+0.0%, 246,562 B / 262,144 B, total: 94% used)

gcc-arm-cortex-m7-pq

FLASH: .text +64 B (+0.0%, 309,968 B / 1,048,576 B, total: 30% used)

gcc-arm-cortex-m7-tls13

FLASH: .text +64 B (+0.0%, 246,562 B / 262,144 B, total: 94% used)

stm32-sim-stm32h753

FLASH: .text +128 B (+0.1%, 203,116 B / 2,097,152 B, total: 10% used)

zephyr-frdm_rw612

FLASH: rodata +100 B, text +256 B (+0.1%, 282,608 B / 67,108,864 B, total: 0% used)

No memory changes detected for:

_{Catch memory regressions in CI with MemBrowse. Free for open source.}

wolfSSL-Fenrir-bot

Fenrir Automated Review — PR #11892

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs
Coverage: 1 of 1 in-scope changed file(s) opened by the reviewer

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

wolfSSL-Fenrir-bot

Fenrir Automated Review — PR #11892

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-src, wolfssl-bugs
Coverage: 1 of 3 in-scope changed file(s) opened by the reviewer; not opened: tests/api.c, wolfssl/wolfcrypt/asn.h

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

wolfSSL-Fenrir-bot

Fenrir Automated Review — PR #11892

Scan targets checked: wolfssl-src, wolfssl-bugs
Unchanged since last review (not re-run): wolfcrypt-src, wolfcrypt-bugs
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: tests/api.c

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

Frauschi

Thanks for chasing down the memory cost from #11334. Skipping the self-signature check for AKID == SKID roots looks sound for the common case. A few comments: the VERIFY_NAME change sets selfSigned from a key that isn't guaranteed to be the one that verified the signature, the skip is a bit broader than the root case it targets, and the new tests don't exercise the changed path yet.

wolfSSL-Fenrir-bot

Fenrir Automated Review — PR #11892

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-src, wolfssl-bugs
Not reviewed (no scan target covers them): doc/dox_comments/header_files/asn.h
Coverage: 5 of 5 in-scope changed file(s) opened by the reviewer

Fenrir result: Approved ✅

No new issues found in the changed files.

Advisory only — this automated result does not count as a GitHub approval.

Review tier: Lite

Fenrir's latest completed scan found no issues; clearing the prior automated change request.

yosuke-wolfssl · 2026-10-27T04:06:56Z

Hi @Frauschi ,
Thank you for reviewing. I addressed all issues you mentioned.

Frauschi

LGTM

- a CA_TYPE cert now skips ConfirmSelfSignature() only when its AKID is set and equals its SKID, and Key Usage allows keyCertSign - wc_CheckCertSignature_ex() reports the key of the CA that verified the signature; wc_CheckCertSignature() calls it without one. - CheckCertSignature_ex() in asn.c and asn_orig.c fills that key. - ProcessPeerCertParse() sets selfSigned on the small-cert path when the signature verified with the certificate's own key.

philljj · 2026-10-29T04:08:55Z

tests good with multi-test with gcc-c89, c89-clang-tidy, wolfssl-all, asn-original, asn-template, smallstack, openssl-extra-coexist, etc scenarios.

yosuke-wolfssl self-assigned this Oct 26, 2026

Copilot AI balanced review requested due to automatic review settings October 26, 2026 01:48

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yosuke-wolfssl force-pushed the fix/ConfirmSelfSignature branch from b64333d to b147ee5 Compare October 26, 2026 02:05

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yosuke-wolfssl changed the title ~~Skip the full signature verification for normal CAs.~~ Skip the redundant signature verification for normal CAs. Oct 26, 2026

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Frauschi assigned yosuke-wolfssl Oct 26, 2026

yosuke-wolfssl force-pushed the fix/ConfirmSelfSignature branch from 15797c4 to 300fce8 Compare October 27, 2026 02:30

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yosuke-wolfssl dismissed Frauschi’s stale review via 5532670 October 29, 2026 00:14

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philljj merged commit ca357b7 into wolfSSL:master Oct 29, 2026
438 of 439 checks passed

yosuke-wolfssl deleted the fix/ConfirmSelfSignature branch October 29, 2026 04:28

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Verification (peak heap)

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