fix: generate_key() BIGNUM leak on OpenSSL 3.x

[Koan-Bot]

Summary

• The exponent BIGNUM e was set to NULL before calling BN_free(), making the free a no-op
• EVP_PKEY_CTX_set1_rsa_keygen_pubexp() uses set1 semantics (copies the value), so the caller retains ownership and must free the original
• Removed the dead e = NULL line so BN_free(e) actually frees the BIGNUM

Impact

Memory leak of one BIGNUM on every generate_key() call when built against OpenSSL >= 3.0.

Test plan

• All 278 existing tests pass
• generate_key() tested in rsa.t (512-bit and 2048-bit)

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🤖 Generated with Claude Code

[timlegge]

LGTM - I might add a

if (e != NULL)

before the BN_free() but otherwise LGTM

[Koan-Bot]

Rebase: fix: generate_key() BIGNUM leak on OpenSSL 3.x

Branch koan.atoomic/fix-generate-key-bn-leak has been rebased onto main and force-pushed.

Actions

• Read PR comments and review feedback
• Rebased koan.atoomic/fix-generate-key-bn-leak onto upstream/main
• Applied review feedback
• Force-pushed koan.atoomic/fix-generate-key-bn-leak to origin

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Automated by Kōan

[timlegge]

Looks fine to me

[Koan-Bot]

Rebase: fix: generate_key() BIGNUM leak on OpenSSL 3.x

Branch koan.atoomic/fix-generate-key-bn-leak rebased onto main and force-pushed.

Diff: 1 file changed, 2 insertions(+), 1 deletion(-)

Review feedback was analyzed and applied.

Actions

• Rebased koan.atoomic/fix-generate-key-bn-leak onto upstream/main
• Force-pushed koan.atoomic/fix-generate-key-bn-leak to origin

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Automated by Kōan