crypto: fix return type prob reported by coverity

Coverity correctly reported that the value returned
by BIO_get_mem_data could be negative and the type
provided for the return value was unsigned.

Fix up the type and check.

Signed-off-by: Michael Dawson <mdawson@devrus.com>

PR-URL: #42135
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Darshan Sen <raisinten@gmail.com>

Author: mhdawson

src/crypto/crypto_common.cc

@@ -741,9 +741,10 @@ static bool PrintGeneralName(const BIOPointer& out, const GENERAL_NAME* gen) {
       return false;
     }
     char* oline = nullptr;
-    size_t n_bytes = BIO_get_mem_data(tmp.get(), &oline);
+    long n_bytes = BIO_get_mem_data(tmp.get(), &oline);  // NOLINT(runtime/int)
+    CHECK_GE(n_bytes, 0);
     CHECK_IMPLIES(n_bytes != 0, oline != nullptr);
-    PrintAltName(out, oline, n_bytes, true, nullptr);
+    PrintAltName(out, oline, static_cast<size_t>(n_bytes), true, nullptr);
   } else if (gen->type == GEN_IPADD) {
     BIO_printf(out.get(), "IP Address:");
     const ASN1_OCTET_STRING* ip = gen->d.ip;