ltp epoll_wait01 fail in gramine-sgx

[LeoneChen]

Description of the problem

In epoll_wait01, setup will firstly create pipe, and in get_writesize, write n * 4096 bytes to pipe and then read to determine pipe wirtable size.

However, in gramine-sgx, pipe is implemented by socket, and mbedtls is used to encrypt data, i.e. mbedtls_ssl_write used to encrypt data to write and mbedtls_ssl_read used to decrypt data to read.

Each time in SAFE_WRITE (4096 bytes), mbedtls_ssl_write treat it as a record (including header and app-level data), thus n record is sent to socket. When read, mbedtls_ssl_read read one record (read header, determine encrypted app-level data size, read app-level data) and then it is able to decrypt and return plaintext data, while other n-1 records are ignored.

I.e. maybe a loop of mbedtls_ssl_read is needed to receive n mbedtls record from socket to successfully mimic pipe behavior, maybe should update lib_SSLRead?

Gramine commit hash

8fc123d

[mkow]

Please don't paste text as screenshots.

Also, from your description I don't see why the test fails. It tries to put a lot of data into the pipe and checks how much of it fit, which will be lower under SGX. But where's the failure?