Various fixes

[kareem-wolfssl]

Description

Fix multiple missing bounds and length checks.

Fixes zd#21536, zd#21537, zd#21538, zd#21540, zd#21541

Testing

Built in tests, provided reproducers

Checklist

• added tests
• updated/added doxygen
• updated appropriate READMEs
• Updated manual and documentation

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Fixes multiple missing bounds/length checks across TLS 1.3 handshake, OCSP processing, and sniffer ClientHello parsing to prevent out-of-bounds reads/writes and invalid-length parsing.

Changes:

• Added maximum certificate extension count guards in TLS 1.3 certificate/OCSP flows.
• Added minimum-length checks before reading OPAQUE16-sized fields from buffers.
• Improved error return behavior/documentation for certificate status request buffer writing.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/tls13.c	Adds MAX_CERT_EXTENSIONS bounds checks around CSR-to-buffer writing and TLS 1.3 certificate sending.
src/tls.c	Adds OPAQUE16 minimum-length validation and caps OCSP request processing to MAX_CERT_EXTENSIONS.
src/sniffer.c	Adds OPAQUE16 minimum-length validation for several ClientHello extensions.
src/internal.c	Adds MAX_CERT_EXTENSIONS bounds checks while generating/sending OCSP status responses.

Comments suppressed due to low confidence (1)

src/internal.c:1

• This loop can still read past the end of chainOcspRequest because i is incremented inside &responses[++i]. After the last valid increment, the next while condition evaluates ssl->ctx->chainOcspRequest[i] with i == MAX_CERT_EXTENSIONS, causing an out-of-bounds read before the in-loop bounds check runs. Refactor to avoid pre-increment in the call (increment i separately after a bounds check) and ensure the bounds check occurs before any chainOcspRequest[i] dereference.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/internal.c:1

• The bounds check happens after indexing ssl->ctx->chainOcspRequest[i], so if i is already >= MAX_CERT_EXTENSIONS this can read out-of-bounds before the new guard runs. Move/adjust the check to validate i < MAX_CERT_EXTENSIONS before evaluating ssl->ctx->chainOcspRequest[i] (e.g., incorporate it into the while condition or add a pre-check before the assignment).

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

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[github-actions]

MemBrowse Memory Report

gcc-arm-cortex-m4

• FLASH: .text +64 B (+0.0%, 195,275 B / 262,144 B, total: 74% used)

gcc-arm-cortex-m4-baremetal

• FLASH: .text +64 B (+0.1%, 63,539 B / 262,144 B, total: 24% used)

gcc-arm-cortex-m4-min-ecc

• FLASH: .text +64 B (+0.1%, 59,125 B / 262,144 B, total: 23% used)

gcc-arm-cortex-m4-tls12

• FLASH: .text +64 B (+0.1%, 119,418 B / 262,144 B, total: 46% used)