lib-sasl: Avoid null pointer in empty response check - #310
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The SASL request API permits a NULL data pointer when the response size is zero. Skip the NUL scan for that empty-input case so the supported no-initial-response path does not pass NULL to memchr. Signed-off-by: David Sarkisyan <david@srkyn.com>
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sasl_server_request_initial()permits a null data pointer when the response size is zero. This is the normal no-initial-response case used by mechanisms such as LOGIN and CRAM-MD5. The NUL check still passed that pointer tomemchr(), which is undefined by the C library contract even with a zero length and is reported by UBSan.Skip the scan when the response is empty. Non-empty response handling is unchanged.
Tests:
b2b2d74e0900e3e3d0ba0392fac9c4cce989aab1test-sasl-authentication: 533 tests passed with Clang UBSan, with the unrelated function-type sanitizer disabledtest-sasl-authentication: 533 tests passed with GCCAUTH LOGIN: normal challenge, no UBSan diagnostic