Description

picnixz

opened on Aug 15, 2026

Issue body actions

Bug report

Bug description:

Sometimes, it's possible to read an HACL* state concurrently:

• sha3 reads the live HACL state outside the object lock at six sites
• blake2's digest_size getter reads the live HACL state outside the lock

Instead, we can (1) add this static information just after construction (2) compute it inside the lock sections. The problem is that HACL* update() functions update the entire state so reading static information is unsafe.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-155835: fix digest_size and block_size data races on SHA-3 objects #155838
• gh-155835: fix digest_size data race on BLAKE-2 objects #155839
• [3.15] gh-155835: fix digest_size and block_size data races on SHA-3 objects (GH-155838) #157038
• [3.14] gh-155835: fix digest_size and block_size data races on SHA-3 objects (GH-155838) #157039
• [3.13] gh-155835: fix digest_size and block_size data races on SHA-3 objects (GH-155838) #157041

Activity

1. picnixz

   self-assigned this

   on Aug 15, 2026
2. picnixz

   added a parent issue on Aug 15, 2026

   • Meta-issue for bugs in cryptographic extension modules #155438
3. picnixz

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   on Aug 15, 2026
4. picnixz

   added 4 commits that reference this issue on Aug 15, 2026

   pythongh-155835: fix `digest_size` and `block_size` data races on SHA…

   45ec585

   pythongh-155835: fix `digest_size` and `block_size` data races on SHA…

   3cfdc82

   pythongh-155835: fix `digest_size` and `block_size` data races on SHA…

   2b6c740

   pythongh-155835: fix `digest_size` data race on BLAKE-2 objects

   194cdab
5. picnixz

   added 2 commits that reference this issue on Sep 6, 2026

   gh-155835: fix `digest_size` and `block_size` data races on SHA-3 obj…

   90ac539

   gh-155835: fix `digest_size` data race on BLAKE-2 objects (#155839)

   878b5e2
6. clin1234

   added 2 commits that reference this issue on Sep 12, 2026

   pythongh-155835: fix `digest_size` and `block_size` data races on SHA…

   6a3f68a

   pythongh-155835: fix `digest_size` data race on BLAKE-2 objects (pyth…

   5fa935d
7. Yhg1s

   added a commit that references this issue on Sep 29, 2026

   [3.13] gh-155835: fix `digest_size` and `block_size` data races on SH…

   33a6511
8. encukou

   added a commit that references this issue on Oct 12, 2026

   [3.15] gh-155835: fix `digest_size` and `block_size` data races on SH…

   f7662fa
9. encukou

   closed this as completedon Oct 12, 2026
10. encukou

    added a commit that references this issue on Oct 12, 2026

    [3.14] gh-155835: fix `digest_size` and `block_size` data races on SH…

    1fdd1dc

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