56941fe6a2
The ssl-opt.sh test cases using session resumption tend to fail occasionally on the CI due to a race condition in how ssl_server2 and ssl_client2 handle the reconnection cycle. The server does the following in order: - S1 send application data - S2 send a close_notify alert - S3 close the client socket - S4 wait for a "new connection" (actually a new datagram) - S5 start a handshake The client does the following in order: - C1 wait for and read application data from the server - C2 send a close_notify alert - C3 close the server socket - C4 reset session data and re-open a server socket - C5 start a handshake If the client has been able to send the close_notify (C2) and if has been delivered to the server before if closes the client socket (S3), when the server reaches S4, the datagram that we start the new connection will be the ClientHello and everything will be fine. However if S3 wins the race and happens before the close_notify is delivered, in S4 the close_notify is what will be seen as the first datagram in a new connection, and then in S5 this will rightfully be rejected as not being a valid ClientHello and the server will close the connection (and go wait for another one). The client will then fail to read from the socket and exit non-zero and the ssl-opt.sh harness will correctly report this as a failure. In order to avoid this race condition in test using ssl_client2 and ssl_server2, this commits introduces a new command-line option skip_close_notify to ssl_client2 and uses it in all ssl-opt.sh tests that use session resumption with DTLS and ssl_server2. This works because ssl_server2 knows how many messages it expects in each direction and in what order, and closes the connection after that rather than relying on close_notify (which is also why there was a race in the first place). Tests that use another server (in practice there are two of them, using OpenSSL as a server) wouldn't work with skip_close_notify, as the server won't close the connection until the client sends a close_notify, but for the same reason they don't need it (there is no race between receiving close_notify and closing as the former is the cause of the later). An alternative approach would be to make ssl_server2 keep the connection open until it receives a close_notify. Unfortunately it creates problems for tests where we simulate a lossy network, as the close_notify could be lost (and the client can't retransmit it). We could modify udp_proxy with an option to never drop alert messages, but when TLS 1.3 comes that would no longer work as the type of messages will be encrypted. Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> |
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| .. | ||
| aes | ||
| fuzz | ||
| hash | ||
| pkey | ||
| random | ||
| ssl | ||
| test | ||
| util | ||
| x509 | ||
| .gitignore | ||
| CMakeLists.txt | ||
| Makefile | ||
| README.md | ||
| wince_main.c | ||
Mbed TLS sample programs
This subdirectory mostly contains sample programs that illustrate specific features of the library, as well as a few test and support programs.
Symmetric cryptography (AES) examples
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aes/aescrypt2.c: file encryption and authentication with a key derived from a low-entropy secret, demonstrating the low-level AES interface, the digest interface and HMAC.
Warning: this program illustrates how to use low-level functions in the library. It should not be taken as an example of how to build a secure encryption mechanism. To derive a key from a low-entropy secret such as a password, use a standard key stretching mechanism such as PBKDF2 (provided by thepkcs5module). To encrypt and authenticate data, use a standard mode such as GCM or CCM (both available as library module). -
aes/crypt_and_hash.c: file encryption and authentication, demonstrating the generic cipher interface and the generic hash interface.
Hash (digest) examples
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hash/generic_sum.c: file hash calculator and verifier, demonstrating the message digest (md) interface. -
hash/hello.c: hello-world program for MD5.
Public-key cryptography examples
Generic public-key cryptography (pk) examples
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pkey/gen_key.c: generates a key for any of the supported public-key algorithms (RSA or ECC) and writes it to a file that can be used by the other pk sample programs. -
pkey/key_app.c: loads a PEM or DER public key or private key file and dumps its content. -
pkey/key_app_writer.c: loads a PEM or DER public key or private key file and writes it to a new PEM or DER file. -
pkey/pk_encrypt.c,pkey/pk_decrypt.c: loads a PEM or DER public/private key file and uses the key to encrypt/decrypt a short string through the generic public-key interface. -
pkey/pk_sign.c,pkey/pk_verify.c: loads a PEM or DER private/public key file and uses the key to sign/verify a short string.
ECDSA and RSA signature examples
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pkey/ecdsa.c: generates an ECDSA key, signs a fixed message and verifies the signature. -
pkey/rsa_encrypt.c,pkey/rsa_decrypt.c: loads an RSA public/private key and uses it to encrypt/decrypt a short string through the low-level RSA interface. -
pkey/rsa_genkey.c: generates an RSA key and writes it to a file that can be used with the other RSA sample programs. -
pkey/rsa_sign.c,pkey/rsa_verify.c: loads an RSA private/public key and uses it to sign/verify a short string with the RSA PKCS#1 v1.5 algorithm. -
pkey/rsa_sign_pss.c,pkey/rsa_verify_pss.c: loads an RSA private/public key and uses it to sign/verify a short string with the RSASSA-PSS algorithm.
Diffie-Hellman key exchange examples
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pkey/dh_client.c,pkey/dh_server.c: secure channel demonstrators (client, server). This pair of programs illustrates how to set up a secure channel using RSA for authentication and Diffie-Hellman to generate a shared AES session key. -
pkey/ecdh_curve25519.c: demonstration of a elliptic curve Diffie-Hellman (ECDH) key agreement.
Bignum (mpi) usage examples
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pkey/dh_genprime.c: shows how to use the bignum (mpi) interface to generate Diffie-Hellman parameters. -
pkey/mpi_demo.c: demonstrates operations on big integers.
Random number generator (RNG) examples
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random/gen_entropy.c: shows how to use the default entropy sources to generate random data.
Note: most applications should only use the entropy generator to seed a cryptographic pseudorandom generator, as illustrated byrandom/gen_random_ctr_drbg.c. -
random/gen_random_ctr_drbg.c: shows how to use the default entropy sources to seed a pseudorandom generator, and how to use the resulting random generator to generate random data. -
random/gen_random_havege.c: demonstrates the HAVEGE entropy collector.
SSL/TLS examples
SSL/TLS sample applications
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ssl/dtls_client.c: a simple DTLS client program, which sends one datagram to the server and reads one datagram in response. -
ssl/dtls_server.c: a simple DTLS server program, which expects one datagram from the client and writes one datagram in response. This program supports DTLS cookies for hello verification. -
ssl/mini_client.c: a minimalistic SSL client, which sends a short string and disconnects. This is primarily intended as a benchmark; for a better example of a typical TLS client, seessl/ssl_client1.c. -
ssl/ssl_client1.c: a simple HTTPS client that sends a fixed request and displays the response. -
ssl/ssl_fork_server.c: a simple HTTPS server using one process per client to send a fixed response. This program requires a Unix/POSIX environment implementing theforksystem call. -
ssl/ssl_mail_client.c: a simple SMTP-over-TLS or SMTP-STARTTLS client. This client sends an email with fixed content. -
ssl/ssl_pthread_server.c: a simple HTTPS server using one thread per client to send a fixed response. This program requires the pthread library. -
ssl/ssl_server.c: a simple HTTPS server that sends a fixed response. It serves a single client at a time.
SSL/TLS feature demonstrators
Note: unlike most of the other programs under the programs/ directory, these two programs are not intended as a basis for writing an application. They combine most of the features supported by the library, and most applications require only a few features. To write a new application, we recommended that you start with ssl_client1.c or ssl_server.c, and then look inside ssl/ssl_client2.c or ssl/ssl_server2.c to see how to use the specific features that your application needs.
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ssl/ssl_client2.c: an HTTPS client that sends a fixed request and displays the response, with options to select TLS protocol features and Mbed TLS library features. -
ssl/ssl_server2.c: an HTTPS server that sends a fixed response, with options to select TLS protocol features and Mbed TLS library features.
In addition to providing options for testing client-side features, the ssl_client2 program has options that allow you to trigger certain behaviors in the server. For example, there are options to select ciphersuites, or to force a renegotiation. These options are useful for testing the corresponding features in a TLS server. Likewise, ssl_server2 has options to activate certain behaviors that are useful for testing a TLS client.
Test utilities
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test/benchmark.c: benchmark for cryptographic algorithms. -
test/selftest.c: runs the self-test function in each library module. -
test/udp_proxy.c: a UDP proxy that can inject certain failures (delay, duplicate, drop). Useful for testing DTLS. -
test/zeroize.c: a test program formbedtls_platform_zeroize, used bytests/scripts/test_zeroize.gdb.
Development utilities
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util/pem2der.c: a PEM to DER converter. Mbed TLS can read PEM files directly, but this utility can be useful for interacting with other tools or with minimal Mbed TLS builds that lack PEM support. -
util/strerror.c: prints the error description corresponding to an integer status returned by an Mbed TLS function.
X.509 certificate examples
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x509/cert_app.c: connects to a TLS server and verifies its certificate chain. -
x509/cert_req.c: generates a certificate signing request (CSR) for a private key. -
x509/cert_write.c: signs a certificate signing request, or self-signs a certificate. -
x509/crl_app.c: loads and dumps a certificate revocation list (CRL). -
x509/req_app.c: loads and dumps a certificate signing request (CSR).