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client: Fix ssh_send_banner() to confirm with RFC 4253

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Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
This commit is contained in:
Andreas Schneider
2016-05-02 09:53:02 +02:00
parent cb52ed7b12
commit 3d1edffe77
1 changed files with 62 additions and 33 deletions
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69
src/client.c
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@@ -169,46 +169,75 @@ static int callback_receive_banner(const void *data, size_t len, void *user)
* *
* @return 0 on success, < 0 on error. * @return 0 on success, < 0 on error.
*/ */
int ssh_send_banner(ssh_session session, int server) { int ssh_send_banner(ssh_session session, int server)
{
const char *banner = NULL; const char *banner = NULL;
char buffer[128] = {0}; const char *terminator = NULL;
int err=SSH_ERROR; /* The maximum banner length is 255 for SSH2 */
char buffer[256] = {0};
size_t len;
int rc = SSH_ERROR;
banner = session->version == 1 ? CLIENTBANNER1 : CLIENTBANNER2; banner = session->version == 1 ? CLIENTBANNER1 : CLIENTBANNER2;
terminator = session->version == 1 ? "\n" : "\r\n";
if (server) { if (server == 1) {
if(session->opts.custombanner == NULL){ if (session->opts.custombanner == NULL){
len = strlen(banner);
session->serverbanner = strdup(banner); session->serverbanner = strdup(banner);
} else {
session->serverbanner = malloc(strlen(session->opts.custombanner) + 9);
if(!session->serverbanner)
goto end;
strcpy(session->serverbanner, "SSH-2.0-");
strcat(session->serverbanner, session->opts.custombanner);
}
if (session->serverbanner == NULL) { if (session->serverbanner == NULL) {
goto end; goto end;
} }
snprintf(buffer, 128, "%s\n", session->serverbanner); } else {
len = strlen(session->opts.custombanner);
session->serverbanner = malloc(len + 8 + 1);
if(session->serverbanner == NULL) {
goto end;
}
snprintf(session->serverbanner,
len + 8 + 1,
"SSH-2.0-%s",
session->opts.custombanner);
}
snprintf(buffer,
sizeof(buffer),
"%s%s",
session->serverbanner,
terminator);
} else { } else {
session->clientbanner = strdup(banner); session->clientbanner = strdup(banner);
if (session->clientbanner == NULL) { if (session->clientbanner == NULL) {
goto end; goto end;
} }
snprintf(buffer, 128, "%s\n", session->clientbanner);
/* SSH version 1 has a banner length of 128 only */
len = session->version == 1 ? 128 : 0;
snprintf(buffer,
sizeof(buffer) - len,
"%s%s",
session->clientbanner,
terminator);
} }
if (ssh_socket_write(session->socket, buffer, strlen(buffer)) == SSH_ERROR) { rc = ssh_socket_write(session->socket, buffer, strlen(buffer));
if (rc == SSH_ERROR) {
goto end; goto end;
} }
#ifdef WITH_PCAP #ifdef WITH_PCAP
if(session->pcap_ctx) if (session->pcap_ctx != NULL) {
ssh_pcap_context_write(session->pcap_ctx,SSH_PCAP_DIR_OUT,buffer,strlen(buffer),strlen(buffer)); ssh_pcap_context_write(session->pcap_ctx,
SSH_PCAP_DIR_OUT,
buffer,
strlen(buffer),
strlen(buffer));
}
#endif #endif
err=SSH_OK;
end:
return err; rc = SSH_OK;
end:
return rc;
} }
/** @internal /** @internal