X509: certificate authority and per-host leaf minting

Functions
int	n_x509_generate_ca (const char *cn, int days, N_STR **ca_cert_pem, N_STR **ca_key_pem)
	Generate a self-signed certificate authority (CA) keypair and cert.
int	n_x509_keypair_pem (int bits, N_STR **key_pem)
	Generate an RSA private key and return it as a PEM string.
int	n_x509_mint_host_cert (const char *host, const N_STR *ca_cert_pem, const N_STR *ca_key_pem, int days, N_STR **leaf_cert_pem, N_STR **leaf_key_pem)
	Mint a per-host leaf certificate signed by the given CA.

Detailed Description

Function Documentation

n_x509_generate_ca()

int n_x509_generate_ca	(	const char *	cn,
		int	days,
		N_STR **	ca_cert_pem,
		N_STR **	ca_key_pem
	)

Generate a self-signed certificate authority (CA) keypair and cert.

The CA is meant to be installed by the user in their browser/OS trust store so a MITM proxy can present host certificates it signs. The certificate has basicConstraints CA:TRUE and keyUsage keyCertSign,cRLSign and is signed with SHA-256.

Parameters

cn	common name for the CA subject/issuer (for example "Fissure CA").
days	validity in days from now.
ca_cert_pem	out: newly allocated CA certificate PEM, owned by the caller.
ca_key_pem	out: newly allocated CA private key PEM, owned by the caller.

Returns

0 on success, -1 on error.

Definition at line 171 of file n_x509.c.

References __n_assert, add_ext(), free_nstr, gen_rsa(), LOG_ERR, n_log, N_X509_KEY_BITS, pkey_to_pem(), set_cn(), set_random_serial(), and x509_to_pem().

Referenced by main().

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n_x509_keypair_pem()

int n_x509_keypair_pem	(	int	bits,
		N_STR **	key_pem
	)

Generate an RSA private key and return it as a PEM string.

Parameters

bits	RSA modulus size in bits (for example 2048).
key_pem	out: newly allocated PEM private key, owned by the caller.

Returns

0 on success, -1 on error.

Definition at line 155 of file n_x509.c.

References __n_assert, gen_rsa(), LOG_ERR, n_log, N_X509_KEY_BITS, and pkey_to_pem().

Referenced by main().

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n_x509_mint_host_cert()

int n_x509_mint_host_cert	(	const char *	host,
		const N_STR *	ca_cert_pem,
		const N_STR *	ca_key_pem,
		int	days,
		N_STR **	leaf_cert_pem,
		N_STR **	leaf_key_pem
	)

Mint a per-host leaf certificate signed by the given CA.

The leaf has basicConstraints CA:FALSE, extendedKeyUsage serverAuth, a subjectAltName of DNS:host (or IP:host when host is a literal IP address), a fresh random serial, and is signed with the CA key using SHA-256. Cache the result per host to avoid re-minting on every connection.

Parameters

host	the requested host name (or IP) to certify.
ca_cert_pem	the CA certificate PEM (issuer).
ca_key_pem	the CA private key PEM (signer).
days	validity in days from now.
leaf_cert_pem	out: newly allocated leaf certificate PEM, owned by the caller.
leaf_key_pem	out: newly allocated leaf private key PEM, owned by the caller.

Returns

0 on success, -1 on error.

Definition at line 229 of file n_x509.c.

References __n_assert, add_ext(), N_STR::data, free_nstr, gen_rsa(), host_is_ip(), LOG_ERR, n_log, N_X509_KEY_BITS, N_X509_SAN_BUF, pkey_to_pem(), set_cn(), set_random_serial(), N_STR::written, and x509_to_pem().

Referenced by main(), and pick_cb().

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