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136 lines
4.2 KiB
C
136 lines
4.2 KiB
C
/*-
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* SSLproxy - transparent SSL/TLS proxy
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*
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* Copyright (c) 2017-2019, Soner Tari <sonertari@gmail.com>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "protosmtp.h"
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#include "protossl.h"
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#include <string.h>
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typedef struct protosmtp_ctx protosmtp_ctx_t;
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struct protosmtp_ctx {
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unsigned int not_valid : 1;
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unsigned int seen_command_count;
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};
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// Size = 25
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static char *protosmtp_commands[] = { "EHLO", "HELO", "AUTH", "MAIL", "MAIL FROM", "RCPT", "RCPT TO", "DATA", "SEND", "RSET", "QUIT", "ATRN", "ETRN", "TURN",
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"SAML", "SOML", "EXPN", "NOOP", "HELP", "ONEX", "BDAT", "BURL", "SUBMITTER", "VERB", "VRFY" };
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static int NONNULL(1)
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protosmtp_validate_command(char *packet, UNUSED size_t packet_size)
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{
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char *c;
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unsigned int i;
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for (i = 0; i < sizeof(protosmtp_commands)/sizeof(char *); i++) {
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c = protosmtp_commands[i];
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if (!strncasecmp(packet, c, strlen(c))) {
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#ifdef DEBUG_PROXY
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log_dbg_level_printf(LOG_DBG_MODE_FINEST, "protosmtp_validate_command: Passed command validation: %.*s\n", (int)packet_size, packet);
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#endif /* DEBUG_PROXY */
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return 0;
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}
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}
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return -1;
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}
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static int NONNULL(1,2)
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protosmtp_validate(pxy_conn_ctx_t *ctx, char *packet, size_t packet_size)
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{
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protosmtp_ctx_t *smtp_ctx = ctx->protoctx->arg;
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if (smtp_ctx->not_valid) {
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#ifdef DEBUG_PROXY
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log_dbg_level_printf(LOG_DBG_MODE_FINEST, "protosmtp_validate: Not smtp\n");
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#endif /* DEBUG_PROXY */
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return -1;
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}
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if (protosmtp_validate_command(packet, packet_size) == -1) {
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smtp_ctx->not_valid = 1;
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#ifdef DEBUG_PROXY
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log_dbg_level_printf(LOG_DBG_MODE_FINEST, "protosmtp_validate: Failed command validation: %.*s\n", (int)packet_size, packet);
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#endif /* DEBUG_PROXY */
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return -1;
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} else {
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smtp_ctx->seen_command_count++;
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}
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if (smtp_ctx->seen_command_count > 2) {
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ctx->protoctx->is_valid = 1;
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#ifdef DEBUG_PROXY
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log_dbg_level_printf(LOG_DBG_MODE_FINEST, "protosmtp_validate: Passed validation\n");
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#endif /* DEBUG_PROXY */
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}
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return 0;
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}
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protocol_t
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protosmtp_setup(pxy_conn_ctx_t *ctx)
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{
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ctx->protoctx->proto = PROTO_SMTP;
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ctx->protoctx->validatecb = protosmtp_validate;
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ctx->protoctx->arg = malloc(sizeof(protosmtp_ctx_t));
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if (!ctx->protoctx->arg) {
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return PROTO_ERROR;
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}
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memset(ctx->protoctx->arg, 0, sizeof(protosmtp_ctx_t));
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return PROTO_SMTP;
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}
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protocol_t
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protosmtps_setup(pxy_conn_ctx_t *ctx)
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{
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ctx->protoctx->proto = PROTO_SMTPS;
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ctx->protoctx->connectcb = protossl_conn_connect;
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ctx->protoctx->fd_readcb = protossl_fd_readcb;
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ctx->protoctx->bev_eventcb = protossl_bev_eventcb;
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ctx->protoctx->proto_free = protossl_free;
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ctx->protoctx->validatecb = protosmtp_validate;
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ctx->protoctx->arg = malloc(sizeof(protosmtp_ctx_t));
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if (!ctx->protoctx->arg) {
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return PROTO_ERROR;
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}
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memset(ctx->protoctx->arg, 0, sizeof(protosmtp_ctx_t));
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ctx->sslctx = malloc(sizeof(ssl_ctx_t));
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if (!ctx->sslctx) {
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free(ctx->protoctx->arg);
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return PROTO_ERROR;
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}
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memset(ctx->sslctx, 0, sizeof(ssl_ctx_t));
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return PROTO_SMTPS;
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}
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/* vim: set noet ft=c: */
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