[nginx] Stream: ssl_preread module.
Vladimir Homutov
vl at nginx.com
Thu Sep 15 11:57:54 UTC 2016
details: http://hg.nginx.org/nginx/rev/060d71292b69
branches:
changeset: 6695:060d71292b69
user: Vladimir Homutov <vl at nginx.com>
date: Thu Sep 15 14:56:51 2016 +0300
description:
Stream: ssl_preread module.
The ssl_preread module extracts information from the SSL Client Hello message
without terminating SSL. Currently, only $ssl_preread_server_name variable
is supported, which contains server name from the SNI extension.
diffstat:
auto/modules | 10 +
auto/options | 4 +
src/stream/ngx_stream_ssl_preread_module.c | 448 +++++++++++++++++++++++++++++
3 files changed, 462 insertions(+), 0 deletions(-)
diffs (500 lines):
diff -r ea9dfe2f62e7 -r 060d71292b69 auto/modules
--- a/auto/modules Thu Sep 15 14:56:02 2016 +0300
+++ b/auto/modules Thu Sep 15 14:56:51 2016 +0300
@@ -1120,6 +1120,16 @@ if [ $STREAM != NO ]; then
. auto/module
fi
+
+ if [ $STREAM_SSL_PREREAD = YES ]; then
+ ngx_module_name=ngx_stream_ssl_preread_module
+ ngx_module_deps=
+ ngx_module_srcs=src/stream/ngx_stream_ssl_preread_module.c
+ ngx_module_libs=
+ ngx_module_link=$STREAM_SSL_PREREAD
+
+ . auto/module
+ fi
fi
diff -r ea9dfe2f62e7 -r 060d71292b69 auto/options
--- a/auto/options Thu Sep 15 14:56:02 2016 +0300
+++ b/auto/options Thu Sep 15 14:56:51 2016 +0300
@@ -126,6 +126,7 @@ STREAM_RETURN=YES
STREAM_UPSTREAM_HASH=YES
STREAM_UPSTREAM_LEAST_CONN=YES
STREAM_UPSTREAM_ZONE=YES
+STREAM_SSL_PREREAD=NO
DYNAMIC_MODULES=
@@ -301,6 +302,8 @@ use the \"--with-mail_ssl_module\" optio
--with-stream_geoip_module) STREAM_GEOIP=YES ;;
--with-stream_geoip_module=dynamic)
STREAM_GEOIP=DYNAMIC ;;
+ --with-stream_ssl_preread_module)
+ STREAM_SSL_PREREAD=YES ;;
--without-stream_limit_conn_module)
STREAM_LIMIT_CONN=NO ;;
--without-stream_access_module) STREAM_ACCESS=NO ;;
@@ -508,6 +511,7 @@ cat << END
--with-stream_realip_module enable ngx_stream_realip_module
--with-stream_geoip_module enable ngx_stream_geoip_module
--with-stream_geoip_module=dynamic enable dynamic ngx_stream_geoip_module
+ --with-stream_ssl_preread_module enable ngx_stream_ssl_preread_module
--without-stream_limit_conn_module disable ngx_stream_limit_conn_module
--without-stream_access_module disable ngx_stream_access_module
--without-stream_geo_module disable ngx_stream_geo_module
diff -r ea9dfe2f62e7 -r 060d71292b69 src/stream/ngx_stream_ssl_preread_module.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/stream/ngx_stream_ssl_preread_module.c Thu Sep 15 14:56:51 2016 +0300
@@ -0,0 +1,448 @@
+
+/*
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_stream.h>
+
+
+typedef struct {
+ ngx_flag_t enabled;
+} ngx_stream_ssl_preread_srv_conf_t;
+
+
+typedef struct {
+ size_t left;
+ size_t size;
+ u_char *pos;
+ u_char *dst;
+ u_char buf[4];
+ ngx_str_t host;
+ ngx_log_t *log;
+ ngx_pool_t *pool;
+ ngx_uint_t state;
+} ngx_stream_ssl_preread_ctx_t;
+
+
+static ngx_int_t ngx_stream_ssl_preread_handler(ngx_stream_session_t *s);
+static ngx_int_t ngx_stream_ssl_preread_parse_record(
+ ngx_stream_ssl_preread_ctx_t *ctx, u_char *pos, u_char *last);
+static ngx_int_t ngx_stream_ssl_preread_server_name_variable(
+ ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data);
+static ngx_int_t ngx_stream_ssl_preread_add_variables(ngx_conf_t *cf);
+static void *ngx_stream_ssl_preread_create_srv_conf(ngx_conf_t *cf);
+static char *ngx_stream_ssl_preread_merge_srv_conf(ngx_conf_t *cf, void *parent,
+ void *child);
+static ngx_int_t ngx_stream_ssl_preread_init(ngx_conf_t *cf);
+
+
+static ngx_command_t ngx_stream_ssl_preread_commands[] = {
+
+ { ngx_string("ssl_preread"),
+ NGX_STREAM_MAIN_CONF|NGX_STREAM_SRV_CONF|NGX_CONF_FLAG,
+ ngx_conf_set_flag_slot,
+ NGX_STREAM_SRV_CONF_OFFSET,
+ offsetof(ngx_stream_ssl_preread_srv_conf_t, enabled),
+ NULL },
+
+ ngx_null_command
+};
+
+
+static ngx_stream_module_t ngx_stream_ssl_preread_module_ctx = {
+ ngx_stream_ssl_preread_add_variables, /* preconfiguration */
+ ngx_stream_ssl_preread_init, /* postconfiguration */
+
+ NULL, /* create main configuration */
+ NULL, /* init main configuration */
+
+ ngx_stream_ssl_preread_create_srv_conf, /* create server configuration */
+ ngx_stream_ssl_preread_merge_srv_conf /* merge server configuration */
+};
+
+
+ngx_module_t ngx_stream_ssl_preread_module = {
+ NGX_MODULE_V1,
+ &ngx_stream_ssl_preread_module_ctx, /* module context */
+ ngx_stream_ssl_preread_commands, /* module directives */
+ NGX_STREAM_MODULE, /* module type */
+ NULL, /* init master */
+ NULL, /* init module */
+ NULL, /* init process */
+ NULL, /* init thread */
+ NULL, /* exit thread */
+ NULL, /* exit process */
+ NULL, /* exit master */
+ NGX_MODULE_V1_PADDING
+};
+
+
+static ngx_stream_variable_t ngx_stream_ssl_preread_vars[] = {
+
+ { ngx_string("ssl_preread_server_name"), NULL,
+ ngx_stream_ssl_preread_server_name_variable, 0, 0, 0 },
+
+ { ngx_null_string, NULL, NULL, 0, 0, 0 }
+};
+
+
+static ngx_int_t
+ngx_stream_ssl_preread_handler(ngx_stream_session_t *s)
+{
+ u_char *last, *p;
+ size_t len;
+ ngx_int_t rc;
+ ngx_connection_t *c;
+ ngx_stream_ssl_preread_ctx_t *ctx;
+ ngx_stream_ssl_preread_srv_conf_t *sscf;
+
+ c = s->connection;
+
+ ngx_log_debug0(NGX_LOG_DEBUG_STREAM, c->log, 0, "ssl preread handler");
+
+ sscf = ngx_stream_get_module_srv_conf(s, ngx_stream_ssl_preread_module);
+
+ if (!sscf->enabled) {
+ return NGX_DECLINED;
+ }
+
+ if (c->type != SOCK_STREAM) {
+ return NGX_DECLINED;
+ }
+
+ if (c->buffer == NULL) {
+ return NGX_AGAIN;
+ }
+
+ ctx = ngx_stream_get_module_ctx(s, ngx_stream_ssl_preread_module);
+ if (ctx == NULL) {
+ ctx = ngx_pcalloc(c->pool, sizeof(ngx_stream_ssl_preread_ctx_t));
+ if (ctx == NULL) {
+ return NGX_ERROR;
+ }
+
+ ngx_stream_set_ctx(s, ctx, ngx_stream_ssl_preread_module);
+
+ ctx->pool = c->pool;
+ ctx->log = c->log;
+ ctx->pos = c->buffer->pos;
+ }
+
+ p = ctx->pos;
+ last = c->buffer->last;
+
+ while (last - p >= 5) {
+
+ if (p[0] != 0x16) {
+ ngx_log_debug(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: not a handshake");
+ return NGX_DECLINED;
+ }
+
+ if (p[1] != 3 || p[2] == 0) {
+ ngx_log_debug(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: unsupported SSL version");
+ return NGX_DECLINED;
+ }
+
+ len = (p[3] << 8) + p[4];
+
+ /* read the whole record before parsing */
+ if ((size_t) (last - p) < len + 5) {
+ break;
+ }
+
+ p += 5;
+
+ rc = ngx_stream_ssl_preread_parse_record(ctx, p, p + len);
+ if (rc != NGX_AGAIN) {
+ return rc;
+ }
+
+ p += len;
+ }
+
+ ctx->pos = p;
+
+ return NGX_AGAIN;
+}
+
+
+static ngx_int_t
+ngx_stream_ssl_preread_parse_record(ngx_stream_ssl_preread_ctx_t *ctx,
+ u_char *pos, u_char *last)
+{
+ size_t left, n, size;
+ u_char *dst, *p;
+
+ enum {
+ sw_start = 0,
+ sw_header, /* handshake msg_type, length */
+ sw_head_tail, /* version, random */
+ sw_sid_len, /* session_id length */
+ sw_sid, /* session_id */
+ sw_cs_len, /* cipher_suites length */
+ sw_cs, /* cipher_suites */
+ sw_cm_len, /* compression_methods length */
+ sw_cm, /* compression_methods */
+ sw_ext, /* extension */
+ sw_ext_header, /* extension_type, extension_data length */
+ sw_sni_len, /* SNI length */
+ sw_sni_host_head, /* SNI name_type, host_name length */
+ sw_sni_host /* SNI host_name */
+ } state;
+
+ ngx_log_debug2(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: state %ui left %z", ctx->state, ctx->left);
+
+ state = ctx->state;
+ size = ctx->size;
+ left = ctx->left;
+ dst = ctx->dst;
+ p = ctx->buf;
+
+ for ( ;; ) {
+ n = ngx_min((size_t) (last - pos), size);
+
+ if (dst) {
+ dst = ngx_cpymem(dst, pos, n);
+ }
+
+ pos += n;
+ size -= n;
+ left -= n;
+
+ if (size != 0) {
+ break;
+ }
+
+ switch (state) {
+
+ case sw_start:
+ state = sw_header;
+ dst = p;
+ size = 4;
+ left = size;
+ break;
+
+ case sw_header:
+ if (p[0] != 1) {
+ ngx_log_debug(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: not a client hello");
+ return NGX_DECLINED;
+ }
+
+ state = sw_head_tail;
+ dst = NULL;
+ size = 34;
+ left = (p[1] << 16) + (p[2] << 8) + p[3];
+ break;
+
+ case sw_head_tail:
+ state = sw_sid_len;
+ dst = p;
+ size = 1;
+ break;
+
+ case sw_sid_len:
+ state = sw_sid;
+ dst = NULL;
+ size = p[0];
+ break;
+
+ case sw_sid:
+ state = sw_cs_len;
+ dst = p;
+ size = 2;
+ break;
+
+ case sw_cs_len:
+ state = sw_cs;
+ dst = NULL;
+ size = (p[0] << 8) + p[1];
+ break;
+
+ case sw_cs:
+ state = sw_cm_len;
+ dst = p;
+ size = 1;
+ break;
+
+ case sw_cm_len:
+ state = sw_cm;
+ dst = NULL;
+ size = p[0];
+ break;
+
+ case sw_cm:
+ if (left == 0) {
+ /* no extensions */
+ return NGX_OK;
+ }
+
+ state = sw_ext;
+ dst = p;
+ size = 2;
+ break;
+
+ case sw_ext:
+ if (left == 0) {
+ return NGX_OK;
+ }
+
+ state = sw_ext_header;
+ dst = p;
+ size = 4;
+ break;
+
+ case sw_ext_header:
+ if (p[0] == 0 && p[1] == 0) {
+ /* SNI extension */
+ state = sw_sni_len;
+ dst = NULL;
+ size = 2;
+ break;
+ }
+
+ state = sw_ext;
+ dst = NULL;
+ size = (p[2] << 8) + p[3];
+ break;
+
+ case sw_sni_len:
+ state = sw_sni_host_head;
+ dst = p;
+ size = 3;
+ break;
+
+ case sw_sni_host_head:
+ if (p[0] != 0) {
+ ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: SNI hostname type is not DNS");
+ return NGX_DECLINED;
+ }
+
+ state = sw_sni_host;
+ size = (p[1] << 8) + p[2];
+
+ ctx->host.data = ngx_pnalloc(ctx->pool, size);
+ if (ctx->host.data == NULL) {
+ return NGX_ERROR;
+ }
+
+ ctx->host.len = size;
+ dst = ctx->host.data;
+ break;
+
+ case sw_sni_host:
+ ngx_log_debug1(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: SNI hostname \"%V\"", &ctx->host);
+ return NGX_OK;
+ }
+
+ if (left < size) {
+ ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0,
+ "ssl preread: failed to parse handshake");
+ return NGX_DECLINED;
+ }
+ }
+
+ ctx->state = state;
+ ctx->size = size;
+ ctx->left = left;
+ ctx->dst = dst;
+
+ return NGX_AGAIN;
+}
+
+
+static ngx_int_t
+ngx_stream_ssl_preread_server_name_variable(ngx_stream_session_t *s,
+ ngx_variable_value_t *v, uintptr_t data)
+{
+ ngx_stream_ssl_preread_ctx_t *ctx;
+
+ ctx = ngx_stream_get_module_ctx(s, ngx_stream_ssl_preread_module);
+
+ if (ctx == NULL) {
+ v->not_found = 1;
+ return NGX_OK;
+ }
+
+ v->valid = 1;
+ v->no_cacheable = 0;
+ v->not_found = 0;
+ v->len = ctx->host.len;
+ v->data = ctx->host.data;
+
+ return NGX_OK;
+}
+
+
+static ngx_int_t
+ngx_stream_ssl_preread_add_variables(ngx_conf_t *cf)
+{
+ ngx_stream_variable_t *var, *v;
+
+ for (v = ngx_stream_ssl_preread_vars; v->name.len; v++) {
+ var = ngx_stream_add_variable(cf, &v->name, v->flags);
+ if (var == NULL) {
+ return NGX_ERROR;
+ }
+
+ var->get_handler = v->get_handler;
+ var->data = v->data;
+ }
+
+ return NGX_OK;
+}
+
+
+static void *
+ngx_stream_ssl_preread_create_srv_conf(ngx_conf_t *cf)
+{
+ ngx_stream_ssl_preread_srv_conf_t *conf;
+
+ conf = ngx_pcalloc(cf->pool, sizeof(ngx_stream_ssl_preread_srv_conf_t));
+ if (conf == NULL) {
+ return NULL;
+ }
+
+ conf->enabled = NGX_CONF_UNSET;
+
+ return conf;
+}
+
+
+static char *
+ngx_stream_ssl_preread_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+ ngx_stream_ssl_preread_srv_conf_t *prev = parent;
+ ngx_stream_ssl_preread_srv_conf_t *conf = child;
+
+ ngx_conf_merge_value(conf->enabled, prev->enabled, 0);
+
+ return NGX_CONF_OK;
+}
+
+
+static ngx_int_t
+ngx_stream_ssl_preread_init(ngx_conf_t *cf)
+{
+ ngx_stream_handler_pt *h;
+ ngx_stream_core_main_conf_t *cmcf;
+
+ cmcf = ngx_stream_conf_get_module_main_conf(cf, ngx_stream_core_module);
+
+ h = ngx_array_push(&cmcf->phases[NGX_STREAM_PREREAD_PHASE].handlers);
+ if (h == NULL) {
+ return NGX_ERROR;
+ }
+
+ *h = ngx_stream_ssl_preread_handler;
+
+ return NGX_OK;
+}
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