c++ - OpenSSL 内存 BIO 和部分密码 block

Question

我在需要我在本地执行加密和解密的架构中使用 OpenSSL。

解密函数获得一个缓冲区，该缓冲区在连接的另一端被加密。 加密/解密过程通常工作正常，但对于缓冲区包含部分密码 block 的情况。

我想我的问题归结为: 令 s 为 SSL 对象，buf 为内存缓冲区或加密数据。 我为解密它所做的工作(减去错误处理、线程安全、内存安全等)是按照

int decDataBufSize = 1000000; //approximation of length of decrypted data
int8_t* decData = (int8_t*)malloc(decDataBufSize*sizeof(int8_t)); //room for the decrypted data to be written into
BIO* bio = BIO_new_mem_buf(encData, decDataBufSize); //set up BIO pointing to the encrypted data
int decDataLength;
BIO_set_close(bio, BIO_NOCLOSE); //This means OpenSSL doesn't try to free the encrypted data buffer
int totalDecData = 0;
for(int remaining_length = buffie->getBuffer()->limit() ; remaining_length > 0 ; )
{
    SSL_set_bio(ssl, bio, bio);
    remaining_length -= BIO_pending(bio);
    int decDataLength = SSL_read(ssl, decData + totalDecData, decDataBufSize - totalDecData);
    totalDecData += decDataLength;
    remaining_length += BIO_pending(bio);
}
return decData;

这似乎工作正常，但对于我在缓冲区中有一部分块的情况。 我知道，如果我使用套接字而不是内存 BIO，我会得到一个 SSL_ERROR_WANT_READ，但在我的例子中，我得到一个最简洁的 SSL_ERROR_SSL(解密失败或错误记录 mac)。

有什么方法可以提前验证我是否有一个完整的 block ？

提前致谢

Answer 1

显然，解决方案在于 BIO_get_mem_data。

大致是这样的: #define DEC_BUF_SIZE 1000000 静态 int buffer_length； static int8_t* partial_block;

int8_t* decrypt(int8_t* ecnData) { 
    int decDataBufSize = 1000000; //approximation of length of decrypted data
    int8_t* decData = (int8_t*)malloc(decDataBufSize*sizeof(int8_t)); //room for the decrypted data to be written into
    if (buffer_length == 0) /*prepend the contents of partial_block to encData somehow*/;
    BIO* bio = BIO_new_mem_buf(encData, decDataBufSize); //set up BIO pointing to the encrypted data
    int decDataLength;
    BIO_set_close(bio, BIO_NOCLOSE); //This means OpenSSL doesn't try to free the encrypted data buffer
    int totalDecData = 0;
    for(int remaining_length = buffie->getBuffer()->limit() ; remaining_length > 0 ; ) {
        buffer_length = BIO_get_mem_data(bio,&partial_block);
        SSL_set_bio(ssl, bio, bio);
        remaining_length -= BIO_pending(bio);
        int decDataLength = SSL_read(ssl, decData + totalDecData, decDataBufSize - totalDecData);
        totalDecData += decDataLength;
        remaining_length += BIO_pending(bio);
    }
return decData;
}