crypto,lib: read WebCrypto inputs through primordials by panva · Pull Request #65115 · nodejs/node · GitHub

A pass over the Web Crypto implementation from a primordials perspective, continuing where #63363 left off. That one covered the promise/thenable side, this covers input validation and normalization.

Per our threat model, prototype pollution requiring control over user input is not a vulnerability so this is hardening and spec-fidelity work rather than a security fix.

Three things covered:

internal tables null prototype
BufferSource.{byteLength,buffer,byteOffset}
new SafeSet(usages) usages %Array.prototype%` iterator

The obvious (__proto__: null) fix regresses badly: V8 creates __proto__: null object literals in dictionary mode and constant-folds absent-property loads through a stable %Object.prototype% chain. Applied naively that cost -88% on webidl-dict-null and -24% on normalizeAlgorithm-string. Instead, tables are detached with ObjectSetPrototypeOf() after construction, options and descriptors spell out every key they read, and dictionaries needing no missing-member handling skip those reads.

benchmark/misc/webcrypto-webidl, 25 runs, medians:

benchmark	delta
normalizeAlgorithm-string	+2.78%
normalizeAlgorithm-dict	+0.57%
webidl-dict	-0.97%
webidl-dict-null	+0.59%
webidl-dict-enforce-range	-1.81%
webidl-dict-ensure-sha	+1.50%

All within noise.

Member descriptors are plain object literals that spell out only the members they need, so createDictionaryConverter() reading the optional validator, defaultValue and required members off them resolves through %Object.prototype%. Copy each descriptor once at construction time with every key present. They keep an ordinary prototype because a null-prototype object literal lands in V8 dictionary mode, and dictionaries with no defaults and no required members now skip steps 4.1.5 and 4.1.6. Signed-off-by: Filip Skokan <panva.ip@gmail.com>

BufferSource conversion hands over the caller's own object uncopied, so byteLength, byteOffset, buffer and length reads on it run user-replaceable prototype accessors. Internal lookup tables are indexed with computed keys, so a polluted %Object.prototype% key answers a miss. The %Set% constructor iterates its argument through the user-mutable %Array.prototype% iterator. The algorithm registry and the hash name tables are detached from %Object.prototype% after construction rather than declared `__proto__: null`, which V8 places in dictionary mode. Signed-off-by: Filip Skokan <panva.ip@gmail.com>

Review requested:

@nodejs/crypto

Codecov Report

❌ Patch coverage is 98.96907% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.30%. Comparing base (6c862f4) to head (e0ce135).
⚠️ Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/crypto/util.js	98.55%	1 Missing ⚠️
lib/internal/crypto/webidl.js	96.29%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #65115    +/-   ##
========================================
  Coverage   90.29%   90.30%            
========================================
  Files         759      759            
  Lines      248295   248404   +109     
  Branches    46861    46872    +11     
========================================
+ Hits       224205   224328   +123     
+ Misses      15517    15509     -8     
+ Partials     8573     8567     -6

Files with missing lines	Coverage Δ
lib/internal/crypto/aes.js	93.75% <100.00%> (+0.02%)	⬆️
lib/internal/crypto/cfrg.js	95.89% <100.00%> (ø)
lib/internal/crypto/diffiehellman.js	97.73% <100.00%> (+<0.01%)	⬆️
lib/internal/crypto/ec.js	96.89% <100.00%> (+0.01%)	⬆️
lib/internal/crypto/hash.js	98.14% <100.00%> (+<0.01%)	⬆️
lib/internal/crypto/hashnames.js	100.00% <100.00%> (ø)
lib/internal/crypto/keys.js	98.04% <100.00%> (ø)
lib/internal/crypto/ml_dsa.js	97.37% <100.00%> (+0.01%)	⬆️
lib/internal/crypto/ml_kem.js	95.33% <100.00%> (+0.01%)	⬆️
lib/internal/crypto/rsa.js	94.89% <100.00%> (ø)
... and 5 more

... and 30 files with indirect coverage changes

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❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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CI: https://ci.nodejs.org/job/node-test-pull-request/75630/

Landed in abbf086...e04663a

Member descriptors are plain object literals that spell out only the members they need, so createDictionaryConverter() reading the optional validator, defaultValue and required members off them resolves through %Object.prototype%. Copy each descriptor once at construction time with every key present. They keep an ordinary prototype because a null-prototype object literal lands in V8 dictionary mode, and dictionaries with no defaults and no required members now skip steps 4.1.5 and 4.1.6. Signed-off-by: Filip Skokan <panva.ip@gmail.com> PR-URL: #65115 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Aviv Keller <me@aviv.sh>

BufferSource conversion hands over the caller's own object uncopied, so byteLength, byteOffset, buffer and length reads on it run user-replaceable prototype accessors. Internal lookup tables are indexed with computed keys, so a polluted %Object.prototype% key answers a miss. The %Set% constructor iterates its argument through the user-mutable %Array.prototype% iterator. The algorithm registry and the hash name tables are detached from %Object.prototype% after construction rather than declared `__proto__: null`, which V8 places in dictionary mode. Signed-off-by: Filip Skokan <panva.ip@gmail.com> PR-URL: #65115 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Aviv Keller <me@aviv.sh>

Member descriptors are plain object literals that spell out only the members they need, so createDictionaryConverter() reading the optional validator, defaultValue and required members off them resolves through %Object.prototype%. Copy each descriptor once at construction time with every key present. They keep an ordinary prototype because a null-prototype object literal lands in V8 dictionary mode, and dictionaries with no defaults and no required members now skip steps 4.1.5 and 4.1.6. Signed-off-by: Filip Skokan <panva.ip@gmail.com> PR-URL: #65115 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Aviv Keller <me@aviv.sh>

BufferSource conversion hands over the caller's own object uncopied, so byteLength, byteOffset, buffer and length reads on it run user-replaceable prototype accessors. Internal lookup tables are indexed with computed keys, so a polluted %Object.prototype% key answers a miss. The %Set% constructor iterates its argument through the user-mutable %Array.prototype% iterator. The algorithm registry and the hash name tables are detached from %Object.prototype% after construction rather than declared `__proto__: null`, which V8 places in dictionary mode. Signed-off-by: Filip Skokan <panva.ip@gmail.com> PR-URL: #65115 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Aviv Keller <me@aviv.sh>

panva added 2 commits August 7, 2026 20:14

panva requested a review from RafaelGSS August 7, 2026 18:26

panva added webcrypto commit-queue-rebase Add this label to allow the Commit Queue to land a PR in several commits. web-standards Issues and PRs related to Web APIs labels Aug 7, 2026

nodejs-github-bot added lib / src Issues and PRs related to general changes in the lib or src directory. needs-ci PRs that need a full CI run. labels Aug 7, 2026

fixup! crypto: read WebCrypto inputs through primordials

e0ce135

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panva deleted the proto-pass-webcrypto branch August 9, 2026 19:12

panva mentioned this pull request Aug 9, 2026

test: account for [EnforceRange] in test-webcrypto-prototype-pollution #65173

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crypto,lib: read WebCrypto inputs through primordials by panva · Pull Request #65115 · nodejs/node · GitHub

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