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cryptocb: add AES CryptoCB key import support and tests#9658

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douzzer merged 1 commit intowolfSSL:masterfrom
sameehj:aes-offload
Feb 3, 2026
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cryptocb: add AES CryptoCB key import support and tests#9658
douzzer merged 1 commit intowolfSSL:masterfrom
sameehj:aes-offload

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@sameehj sameehj commented Jan 14, 2026 •
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Add CryptoCB-based AES key import support to enable Secure Element
offload without exposing raw AES key material to wolfCrypt.

This change introduces a new optional CryptoCB hook
(WOLF_CRYPTO_CB_AES_SETKEY) that allows AES keys to be imported into
external devices (e.g. Secure Elements or HSMs) and referenced via an
opaque handle stored in aes->devCtx. When this mode is active, wolfCrypt
stores only key metadata and routes AES-GCM operations through CryptoCB,
bypassing software key storage and GCM table generation.

Key points:
- Add wc_CryptoCb_AesSetKey() callback for AES key import
- Update AES SetKey paths to support key import mode with graceful
  fallback to software when CryptoCB is unavailable
- Skip GCM H/M table generation when AES-GCM is handled by the device
- Preserve existing software AES behavior when devId is INVALID_DEVID

Testing:
- Add unit test for CryptoCB AES SetKey behavior
- Add end-to-end AES-GCM offload unit test that verifies:
  * SetKey, Encrypt, Decrypt, and Free are routed via CryptoCB
  * Correct ciphertext/auth tag generation
  * Correct plaintext recovery after decrypt
  * Proper lifecycle handling of device context handles
- Tests use a mock Secure Element that internally performs software AES
  to validate routing without requiring hardware

@sameehj sameehj requested a review from douzzer January 14, 2026 14:35
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devin-ai-integration bot commented Jan 14, 2026

🛟 Devin Lifeguard found 2 likely issues in this PR

  • check-all-return-codes snippet snippet: Capture the return value of wc_CryptoCb_UnRegisterDevice() in each test (e.g., ret = wc_CryptoCb_UnRegisterDevice(TEST_CRYPTOCB_AES_DEVID); ExpectIntEQ(ret, 0);) to ensure any error is detected.
  • limit-stack-usage snippet snippet: Use the WOLFSSL_SMALL_STACK pattern in the two newly added test functions: dynamically allocate the large local objects (Aes aes, the plaintext/ciphertext/authTag buffers, etc.) with XMALLOC/XFREE (guarded by #ifdef WOLFSSL_SMALL_STACK) instead of placing them on the stack.

@sameehj
please take a look at the above issues which Devin flagged. Devin will not fix these issues automatically.

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sameehj commented Jan 14, 2026

retest this please

@sameehj sameehj force-pushed the aes-offload branch 2 times, most recently from b3bcd1c to fd6d469 Compare January 15, 2026 16:17
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I see "proxy-key" appearing multiple times in the PR. What does it mean?
The ORIGINAL: comments should be cleaned up.

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julek-wolfssl commented Jan 15, 2026

Is it possible to setup a gh action that tests this with wolfHSM? At the very least this new config should be added to os-check.yml.

@sameehj sameehj force-pushed the aes-offload branch 4 times, most recently from be96866 to ea7e61d Compare January 16, 2026 17:05
@sameehj sameehj changed the title cryptocb: add AES proxy-key support and end-to-end CryptoCB AES-GCM t… cryptocb: add AES CryptoCB key import support and tests Jan 16, 2026
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sameehj commented Jan 16, 2026

I see "proxy-key" appearing multiple times in the PR. What does it mean? The ORIGINAL: comments should be cleaned up.

Dropped proxy-key terminology
and dropped 'ORIGINAL" comments

@sameehj sameehj force-pushed the aes-offload branch 10 times, most recently from 5e03e8f to b02f16b Compare January 22, 2026 18:23
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douzzer commented Jan 23, 2026

retest this please

@sameehj sameehj force-pushed the aes-offload branch 4 times, most recently from a7d4524 to 39d2c2a Compare January 26, 2026 18:18
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sameehj commented Jan 27, 2026

retest this please

@sameehj sameehj force-pushed the aes-offload branch 2 times, most recently from ece931c to 6e377c0 Compare January 30, 2026 11:32
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this implementation looks really strong.

I left comments with reconciliation suggestions for the conflicts, and a comment on a stray linefeed that snuck in. otherwise, LGTM!

@sameehj
cryptocb: add AES CryptoCB key import support and tests
425dc13 
Add CryptoCB-based AES key import support to enable Secure Element
offload without exposing raw AES key material to wolfCrypt.

When WOLF_CRYPTO_CB_AES_SETKEY is defined, wolfCrypt invokes a CryptoCB
callback during AES key setup. Behavior is determined by the callback
return value:

- If callback returns 0: Key is imported to the device (aes->devCtx).
  Key is NOT copied to wolfCrypt RAM; GCM H/M tables are NOT generated.
  Full hardware offload is assumed.

- If callback returns CRYPTOCB_UNAVAILABLE: Device does not support
  SetKey. Normal software path is used; key is copied to devKey for
  optional encrypt/decrypt acceleration.

- Any other error: Propagated to the caller.

Key points:
- Add wc_CryptoCb_AesSetKey() callback for AES key import
- Update AES SetKey paths to call CryptoCB and branch on return value
- Skip GCM H/M table generation when callback succeeded (devCtx set)
- Preserve existing behavior when devId is INVALID_DEVID or
  WOLF_CRYPTO_CB_AES_SETKEY is not defined

Testing:
- Add unit test for CryptoCB AES SetKey (verifies key isolation when
  callback succeeds)
- Add end-to-end AES-GCM offload test (SetKey, Encrypt, Decrypt, Free
  via CryptoCB)
- Tests use a mock SE with software AES to validate routing

Enable with: CPPFLAGS="-DWOLF_CRYPTO_CB_AES_SETKEY -DWOLF_CRYPTO_CB_FREE"

Signed-off-by: Sameeh Jubran <sameeh@wolfssl.com>
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sameehj commented Feb 3, 2026

retest this please

@douzzer douzzer self-requested a review February 3, 2026 18:20
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wolfssl-multi-test.sh ... pr-check:

final tally for 425dc1372d with build env c2c7829175: all 51 selected checks succeeded.

@douzzer douzzer merged commit 492ff38 into wolfSSL:master Feb 3, 2026
419 checks passed
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