diff options
Diffstat (limited to 'src/methods/generic_gmac/generic_gmac.c')
| -rw-r--r-- | src/methods/generic_gmac/generic_gmac.c | 41 |
1 files changed, 33 insertions, 8 deletions
diff --git a/src/methods/generic_gmac/generic_gmac.c b/src/methods/generic_gmac/generic_gmac.c index 6b84a95..546cd50 100644 --- a/src/methods/generic_gmac/generic_gmac.c +++ b/src/methods/generic_gmac/generic_gmac.c @@ -23,30 +23,41 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ +/** + \file + + generic-gmac method provider + + generic-gmac can combine any stream cipher with the GMAC authentication. +*/ + #include "../../crypto.h" #include "../../method.h" #include "../common.h" +/** A specific method provided by this provider */ struct fastd_method { - const fastd_cipher_info_t *cipher_info; - const fastd_mac_info_t *ghash_info; + const fastd_cipher_info_t *cipher_info; /**< The cipher used */ + const fastd_mac_info_t *ghash_info; /**< GHASH */ }; +/** The method-specific session state */ struct fastd_method_session_state { - fastd_method_common_t common; + fastd_method_common_t common; /**< The common method state */ - const fastd_method_t *method; + const fastd_method_t *method; /**< The specific method used */ - const fastd_cipher_t *cipher; - fastd_cipher_state_t *cipher_state; + const fastd_cipher_t *cipher; /**< The cipher implementation used */ + fastd_cipher_state_t *cipher_state; /**< The cipher state */ - const fastd_mac_t *ghash; - fastd_mac_state_t *ghash_state; + const fastd_mac_t *ghash; /**< The GHASH implementation */ + fastd_mac_state_t *ghash_state; /**< The GHASH state */ }; +/** Instanciates a method using a name of the pattern "<cipher>+gmac" (or "<cipher>-gcm" for block ciphers in counter mode, e.g. aes128-gcm instead of aes128-ctr+gmac) */ static bool method_create_by_name(const char *name, fastd_method_t **method) { fastd_method_t m; @@ -85,14 +96,17 @@ static bool method_create_by_name(const char *name, fastd_method_t **method) { return true; } +/** Frees a method */ static void method_destroy(fastd_method_t *method) { free(method); } +/** Returns the key length used by a method */ static size_t method_key_length(const fastd_method_t *method) { return method->cipher_info->key_length; } +/** Initializes a session */ static fastd_method_session_state_t* method_session_init(const fastd_method_t *method, const uint8_t *secret, bool initiator) { fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t)); @@ -121,22 +135,27 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m return session; } +/** Checks if the session is currently valid */ static bool method_session_is_valid(fastd_method_session_state_t *session) { return (session && fastd_method_session_common_is_valid(&session->common)); } +/** Checks if this side is the initator of the session */ static bool method_session_is_initiator(fastd_method_session_state_t *session) { return fastd_method_session_common_is_initiator(&session->common); } +/** Checks if the session should be refreshed */ static bool method_session_want_refresh(fastd_method_session_state_t *session) { return fastd_method_session_common_want_refresh(&session->common); } +/** Marks the session as superseded */ static void method_session_superseded(fastd_method_session_state_t *session) { fastd_method_session_common_superseded(&session->common); } +/** Frees the session state */ static void method_session_free(fastd_method_session_state_t *session) { if (session) { session->cipher->free(session->cipher_state); @@ -146,6 +165,7 @@ static void method_session_free(fastd_method_session_state_t *session) { } } +/** Writes the size of the input in bits to a block */ static inline void put_size(fastd_block128_t *out, size_t len) { memset(out, 0, sizeof(fastd_block128_t)); out->b[11] = len >> 29; @@ -155,6 +175,8 @@ static inline void put_size(fastd_block128_t *out, size_t len) { out->b[15] = len << 3; } + +/** Encrypts and authenticates a packet */ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) { fastd_buffer_pull_head_zero(&in, sizeof(fastd_block128_t)); @@ -199,6 +221,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state return true; } +/** Verifies and decrypts a packet */ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *session, fastd_buffer_t *out, fastd_buffer_t in) { if (in.len < COMMON_HEADBYTES+sizeof(fastd_block128_t)) return false; @@ -255,6 +278,8 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses return true; } + +/** The generic-gmac method provider */ const fastd_method_provider_t fastd_method_generic_gmac = { .max_overhead = COMMON_HEADBYTES + sizeof(fastd_block128_t), .min_encrypt_head_space = sizeof(fastd_block128_t), |