[rlm2002]

Description

On a 64-bit build, an outlen of exactly 2^32 is treated as 0. Add bounds check before (word32)outlen cast in wolfSSL_FIPS_drbg_generate() to prevent unintentional success.

Fixes F-10635

Testing

./configure --enable-opensslall && make && ./tests/unit.test -1814

Checklist

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

[Copilot]

🟢 Approval recommended

There are no active review issues for the output-length truncation fix.

No open issues 🎉

What changed in this PR

This PR prevents wolfSSL_FIPS_drbg_generate() from reporting unintended success when a large size_t output length truncates to zero during conversion to word32.

Changes:

• Reject output lengths that exceed the maximum word32 value before casting.
• Add a regression test for a length of 2³² on platforms with wider size_t, checking failure and an unchanged output buffer.

File	Description
tests/​api.c	Adds regression coverage for output-length truncation.
src/​ssl.c	Checks the output-length bound before conversion to word32.

_{Review effort: Balanced}

[github-actions]

MemBrowse Memory Report · Explore what changed →

zephyr-frdm_rw612

• FLASH: log_const_area -8 B, rodata -8 B, text +1,592 B (+0.6%, 284,040 B / 67,108,864 B, total: 0% used)

No memory changes detected for:

• gcc-arm-cortex-m0plus
• gcc-arm-cortex-m3
• gcc-arm-cortex-m4
• gcc-arm-cortex-m4-baremetal
• gcc-arm-cortex-m4-crypto-only
• gcc-arm-cortex-m4-dtls13
• gcc-arm-cortex-m4-min-ecc
• gcc-arm-cortex-m4-openssl-compat
• gcc-arm-cortex-m4-pkcs7
• gcc-arm-cortex-m4-pq
• gcc-arm-cortex-m4-rsa-only
• gcc-arm-cortex-m4-sp-math
• gcc-arm-cortex-m4-tls12
• gcc-arm-cortex-m4-tls13
• gcc-arm-cortex-m7
• gcc-arm-cortex-m7-pq
• gcc-arm-cortex-m7-tls13
• stm32-sim-stm32h753

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