Fix plaintext length check for UTF-8 strings#193
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check_max_message_length() used sv_len() which returns character count for UTF-8 SVs, but rsa_crypt() passes the raw bytes to OpenSSL via SvPV(). For multi-byte UTF-8 strings the byte count exceeds the character count, so the pre-validation could pass while OpenSSL rejects the oversized input with a generic error instead of our descriptive "plaintext too long" message. Switch check_max_message_length() to accept the SV directly and extract byte length via SvPV(), matching what rsa_crypt() actually sends to OpenSSL. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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What
Use byte length instead of character length in
check_max_message_length().Why
sv_len()returns character count for UTF-8-flagged SVs, butrsa_crypt()passes raw bytes to OpenSSL viaSvPV(). When a UTF-8 string has multi-byte characters, the byte count exceeds the character count — so the pre-validation could pass while OpenSSL rejects the oversized input with a generic error instead of the descriptive "plaintext too long" message.How
Changed
check_max_message_length()to acceptSV*directly and extract byte length viaSvPV(), matching whatrsa_crypt()actually sends to OpenSSL. Bothencrypt()andprivate_encrypt()callers updated.Testing
t/crypto.t: constructs a UTF-8 string where character count (120) < OAEP max (214) but byte count (240) > OAEP max, verifying the descriptive error fires.🤖 Generated with Claude Code
Quality Report
Changes: 2 files changed, 26 insertions(+), 4 deletions(-)
Code scan: clean
Tests: passed (OK)
Branch hygiene: clean
Generated by Kōan post-mission quality pipeline