# HG changeset patch # User Vladimir Homutov # Date 1473940611 -10800 # Node ID 060d71292b69beb39c744ee64569b652462201f4 # Parent ea9dfe2f62e784ece51132c8131e9764bfe73fdf 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. diff --git a/auto/modules b/auto/modules --- a/auto/modules +++ b/auto/modules @@ -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 --git a/auto/options b/auto/options --- a/auto/options +++ b/auto/options @@ -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 --git a/src/stream/ngx_stream_ssl_preread_module.c b/src/stream/ngx_stream_ssl_preread_module.c new file mode 100644 --- /dev/null +++ b/src/stream/ngx_stream_ssl_preread_module.c @@ -0,0 +1,448 @@ + +/* + * Copyright (C) Nginx, Inc. + */ + + +#include +#include +#include + + +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; +}