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kex: split key selection and sending

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This commit is contained in:
Aris Adamantiadis
2011-09-16 23:36:20 +02:00
parent 1b10b175fc
commit 07abc3406d
10 changed files with 118 additions and 88 deletions
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91
src/kex.c
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@@ -303,22 +303,10 @@ SSH_PACKET_CALLBACK(ssh_packet_kexinit){
/* copy the server kex info into an array of strings */
if (server_kex) {
session->client_kex.methods = malloc(10 * sizeof(char **));
if (session->client_kex.methods == NULL) {
ssh_set_error_oom(session);
goto error;
}
for (i = 0; i < 10; i++) {
session->client_kex.methods[i] = strings[i];
}
} else { /* client */
session->server_kex.methods = malloc(10 * sizeof(char **));
if (session->server_kex.methods == NULL) {
ssh_set_error_oom(session);
goto error;
}
for (i = 0; i < 10; i++) {
session->server_kex.methods[i] = strings[i];
}
@@ -355,52 +343,61 @@ void ssh_list_kex(ssh_session session, KEX *kex) {
}
}
/* set_kex basicaly look at the option structure of the session and set the output kex message */
/* it must be aware of the server kex message */
/* it can fail if option is null, not any user specified kex method matches the server one, if not any default kex matches */
int set_kex(ssh_session session){
KEX *server = &session->server_kex;
KEX *client=&session->client_kex;
/**
* @brief sets the key exchange parameters to be sent to the server,
* in function of the options and available methods.
*/
int set_client_kex(ssh_session session){
KEX *client= &session->client_kex;
int i;
const char *wanted;
enter_function();
ssh_get_random(client->cookie,16,0);
client->methods=malloc(10 * sizeof(char **));
if (client->methods == NULL) {
ssh_set_error_oom(session);
leave_function();
return -1;
}
memset(client->methods,0,10*sizeof(char **));
for (i=0;i<10;i++){
if(!(wanted=session->wanted_methods[i]))
wanted=session->wanted_methods[i];
if(wanted == NULL)
wanted=default_methods[i];
client->methods[i]=ssh_find_matching(server->methods[i],wanted);
if(!client->methods[i] && i < SSH_LANG_C_S){
ssh_set_error(session,SSH_FATAL,"kex error : did not find one of algos %s in list %s for %s",
wanted,server->methods[i],ssh_kex_nums[i]);
leave_function();
return -1;
} else {
if ((i >= SSH_LANG_C_S) && (client->methods[i] == NULL)) {
/* we can safely do that for languages */
client->methods[i] = strdup("");
if (client->methods[i] == NULL) {
return -1;
}
}
}
}
if(strcmp(client->methods[SSH_KEX], "diffie-hellman-group1-sha1") == 0){
session->next_crypto->kex_type=SSH_KEX_DH_GROUP1_SHA1;
} else if(strcmp(client->methods[SSH_KEX], "ecdh-sha2-nistp256") == 0){
session->next_crypto->kex_type=SSH_KEX_ECDH_SHA2_NISTP256;
client->methods[i]=strdup(wanted);
}
leave_function();
return 0;
return SSH_OK;
}
/** @brief Select the different methods on basis of client's and
* server's kex messages, and watches out if a match is possible.
*/
int ssh_kex_select_methods (ssh_session session){
KEX *server = &session->server_kex;
KEX *client = &session->client_kex;
int rc = SSH_ERROR;
int i;
enter_function();
for (i=0;i<10;i++){
session->kex_methods[i]=ssh_find_matching(server->methods[i],client->methods[i]);
if(session->kex_methods[i] == NULL && i < SSH_LANG_C_S){
ssh_set_error(session,SSH_FATAL,"kex error : no match for method %s: server [%s], client [%s]",
ssh_kex_nums[i],server->methods[i],client->methods[i]);
goto error;
} else if ((i >= SSH_LANG_C_S) && (session->kex_methods[i] == NULL)) {
/* we can safely do that for languages */
session->kex_methods[i] = strdup("");
}
}
if(strcmp(session->kex_methods[SSH_KEX], "diffie-hellman-group1-sha1") == 0){
session->next_crypto->kex_type=SSH_KEX_DH_GROUP1_SHA1;
} else if(strcmp(session->kex_methods[SSH_KEX], "ecdh-sha2-nistp256") == 0){
session->next_crypto->kex_type=SSH_KEX_ECDH_SHA2_NISTP256;
}
rc = SSH_OK;
error:
leave_function();
return rc;
}
/* this function only sends the predefined set of kex methods */
int ssh_send_kex(ssh_session session, int server_kex) {
KEX *kex = (server_kex ? &session->server_kex : &session->client_kex);