summaryrefslogtreecommitdiffstats
path: root/src/methods/xsalsa20_poly1305
diff options
context:
space:
mode:
authorMatthias Schiffer <mschiffer@universe-factory.net>2014-05-29 05:00:11 +0200
committerMatthias Schiffer <mschiffer@universe-factory.net>2014-05-29 05:00:11 +0200
commit2fe678653b7dd9f61dbbcd5e7d862360882bd7e8 (patch)
tree38c9dabad94845e848373b15788fcd7ae089218e /src/methods/xsalsa20_poly1305
parentefcafca969d2e789cdf106609b04a86ef9b53a3d (diff)
downloadfastd-2fe678653b7dd9f61dbbcd5e7d862360882bd7e8.tar
fastd-2fe678653b7dd9f61dbbcd5e7d862360882bd7e8.zip
Document *everything*
Diffstat (limited to 'src/methods/xsalsa20_poly1305')
-rw-r--r--src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c39
1 files changed, 36 insertions, 3 deletions
diff --git a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
index f06e0f8..9f2d61c 100644
--- a/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
+++ b/src/methods/xsalsa20_poly1305/xsalsa20_poly1305.c
@@ -23,6 +23,16 @@
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+/**
+ \file
+
+ The xsalsa20-poly1305 method provider (deprecated)
+
+ This provider is included for compatiblity reasons as pre-v11
+ xsalsa20-poly1305 was the recommended method. In new setups salsa20+poly1305
+ provided by the generic-poly1305 provider should be used as a replacement.
+*/
+
#include "../../crypto.h"
#include "../../method.h"
@@ -31,24 +41,29 @@
#include <crypto_secretbox_xsalsa20poly1305.h>
+/** The session state */
struct fastd_method_session_state {
- fastd_method_common_t common;
+ fastd_method_common_t common; /**< The common method state */
- uint8_t key[crypto_secretbox_xsalsa20poly1305_KEYBYTES] __attribute__((aligned(8)));
+ uint8_t key[crypto_secretbox_xsalsa20poly1305_KEYBYTES] __attribute__((aligned(8))); /**< The encryption key */
};
+/** Matches the method name "xsalsa20-poly1305" */
static bool method_create_by_name(const char *name, fastd_method_t **method UNUSED) {
return !strcmp(name, "xsalsa20-poly1305");
}
+/** Does nothing as this provider has only a single method */
static void method_destroy(fastd_method_t *method UNUSED) {
}
+/** Returns the key length used by xsalsa20-poly1305 */
static size_t method_key_length(const fastd_method_t *method UNUSED) {
return crypto_secretbox_xsalsa20poly1305_KEYBYTES;
}
+/** Initializes the session state */
static fastd_method_session_state_t* method_session_init(const fastd_method_t *method UNUSED, const uint8_t *secret, bool initiator) {
fastd_method_session_state_t *session = malloc(sizeof(fastd_method_session_state_t));
@@ -59,6 +74,7 @@ static fastd_method_session_state_t* method_session_init(const fastd_method_t *m
return session;
}
+/** Initializes the session state (pre-v11 compat handshake) */
static fastd_method_session_state_t* method_session_init_compat(const fastd_method_t *method, const uint8_t *secret, size_t length, bool initiator) {
if (length < crypto_secretbox_xsalsa20poly1305_KEYBYTES)
exit_bug("xsalsa20-poly1305: tried to init with short secret");
@@ -66,22 +82,27 @@ static fastd_method_session_state_t* method_session_init_compat(const fastd_meth
return method_session_init(method, secret, initiator);
}
+/** Checks if a 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 initiator 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) {
secure_memzero(session, sizeof(fastd_method_session_state_t));
@@ -90,12 +111,19 @@ static void method_session_free(fastd_method_session_state_t *session) {
}
+/**
+ Copies a nonce of length COMMON_NONCEBYTES to a buffer, reversing its byte order
+
+ To maintain compability with pre-v11 versions, which used a little-endian nonce,
+ the xsalsa20-poly1305 keeps using the old nonce format.
+*/
static inline void memcpy_nonce(uint8_t *dst, const uint8_t *src) {
size_t i;
for (i = 0; i < COMMON_NONCEBYTES; i++)
dst[i] = src[COMMON_NONCEBYTES-i-1];
}
+/** Adds the xsalsa20-poly1305 header to the head of a packet */
static inline void put_header(fastd_buffer_t *buffer, const uint8_t nonce[COMMON_NONCEBYTES], uint8_t flags) {
fastd_buffer_pull_head_from(buffer, &flags, 1);
@@ -103,19 +131,22 @@ static inline void put_header(fastd_buffer_t *buffer, const uint8_t nonce[COMMON
memcpy_nonce(buffer->data, nonce);
}
+/** Removes the xsalsa20-poly1305 header from the head of a packet */
static inline void take_header(fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags) {
- memcpy_nonce(nonce, buffer->data );
+ memcpy_nonce(nonce, buffer->data);
fastd_buffer_push_head(buffer, COMMON_NONCEBYTES);
fastd_buffer_push_head_to(buffer, flags, 1);
}
+/** Removes and handles the xsalsa20-poly1305 header from the head of a packet */
static inline bool handle_header(const fastd_method_common_t *session, fastd_buffer_t *buffer, uint8_t nonce[COMMON_NONCEBYTES], uint8_t *flags, int64_t *age) {
take_header(buffer, nonce, flags);
return fastd_method_is_nonce_valid(session, nonce, age);
}
+/** Performs encryption and authentication of 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, crypto_secretbox_xsalsa20poly1305_ZEROBYTES);
@@ -135,6 +166,7 @@ static bool method_encrypt(fastd_peer_t *peer UNUSED, fastd_method_session_state
return true;
}
+/** Performs validation and decryption of 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)
return false;
@@ -180,6 +212,7 @@ static bool method_decrypt(fastd_peer_t *peer, fastd_method_session_state_t *ses
}
+/** The xsalsa20-poly1305 method provider */
const fastd_method_provider_t fastd_method_xsalsa20_poly1305 = {
.max_overhead = COMMON_HEADBYTES + crypto_secretbox_xsalsa20poly1305_ZEROBYTES - crypto_secretbox_xsalsa20poly1305_BOXZEROBYTES,