Fix regressions (fast math MAX_ENCODED_SIG_SZ; DTLS export IV buffer size)#10229
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SparkiDev merged 2 commits intowolfSSL:masterfrom Apr 15, 2026
Merged
Fix regressions (fast math MAX_ENCODED_SIG_SZ; DTLS export IV buffer size)#10229SparkiDev merged 2 commits intowolfSSL:masterfrom
SparkiDev merged 2 commits intowolfSSL:masterfrom
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FP_MAX_BITS is the largest possible size of any intermediate operand. RSA requires multiplying together integers with the size of signatures (N), resulting in a size of 2N. So we must assume FP_MAX_BITS is 2N, not N (in bits: 16N, not 8N).
ExportKeyState was writing ssl->specs.iv_size bytes from keys->aead_enc_imp_IV (always sized AEAD_MAX_IMP_SZ). ssl->specs.iv_size carries a different meaning depending on the cipher suite: in AEAD suites it's the implicit IV / nonce size, but in CBC it's the block cipher's IV size (16). In CBC this overran the size of aead_enc_imp_IV (12).
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Pull request overview
Fixes two regressions affecting (1) fastmath builds’ computed maximum encoded signature size and (2) DTLS/TLS session export when exporting implicit IV material.
Changes:
- Adjust
MAX_ENCODED_SIG_SZforUSE_FAST_MATH && FP_MAX_BITSto match the effective max key size (FP_MAX_BITS/2) rather than the rawFP_MAX_BITS. - Clamp exported implicit-IV length to
AEAD_MAX_IMP_SZto prevent exporting/importing an implicit-IV size larger than the backing buffers.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
wolfssl/wolfcrypt/types.h |
Corrects fastmath-derived MAX_ENCODED_SIG_SZ to align with the library’s “FP supports up to FP_MAX_BITS/2 bits” convention. |
src/internal.c |
Prevents session-export implicit IV serialization from exceeding AEAD_MAX_IMP_SZ (and from producing exports that the importer would reject). |
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Fenrir Automated Review — PR #10229
Scan targets checked: wolfssl-bugs, wolfssl-compliance, wolfssl-consttime, wolfssl-defaults, wolfssl-mutation, wolfssl-proptest, wolfssl-src, wolfssl-zeroize
No new issues found in the changed files. ✅
|
SparkiDev
approved these changes
Apr 15, 2026
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Description
(see commit messages)
Fixes zd#21621
Testing