Mercurial > hg > nginx
view src/stream/ngx_stream_ssl_preread_module.c @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | 6649d4433266 |
children |
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/* * 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; size_t ext; u_char *pos; u_char *dst; u_char buf[4]; u_char version[2]; ngx_str_t host; ngx_str_t alpn; 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_protocol_variable( ngx_stream_session_t *s, ngx_stream_variable_value_t *v, uintptr_t data); 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_alpn_protocols_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_protocol"), NULL, ngx_stream_ssl_preread_protocol_variable, 0, 0, 0 }, { ngx_string("ssl_preread_server_name"), NULL, ngx_stream_ssl_preread_server_name_variable, 0, 0, 0 }, { ngx_string("ssl_preread_alpn_protocols"), NULL, ngx_stream_ssl_preread_alpn_protocols_variable, 0, 0, 0 }, ngx_stream_null_variable }; 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] & 0x80) && p[2] == 1 && (p[3] == 0 || p[3] == 3)) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: version 2 ClientHello"); ctx->version[0] = p[3]; ctx->version[1] = p[4]; return NGX_OK; } if (p[0] != 0x16) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: not a handshake"); ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module); return NGX_DECLINED; } if (p[1] != 3) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: unsupported SSL version"); ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module); 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_DECLINED) { ngx_stream_set_ctx(s, NULL, ngx_stream_ssl_preread_module); return NGX_DECLINED; } 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, ext; u_char *dst, *p; enum { sw_start = 0, sw_header, /* handshake msg_type, length */ sw_version, /* client_version */ sw_random, /* 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 */ sw_alpn_len, /* ALPN length */ sw_alpn_proto_len, /* ALPN protocol_name length */ sw_alpn_proto_data, /* ALPN protocol_name */ sw_supver_len /* supported_versions length */ } 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; ext = ctx->ext; 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_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: not a client hello"); return NGX_DECLINED; } state = sw_version; dst = ctx->version; size = 2; left = (p[1] << 16) + (p[2] << 8) + p[3]; break; case sw_version: state = sw_random; dst = NULL; size = 32; break; case sw_random: 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 && ctx->host.data == NULL) { /* SNI extension */ state = sw_sni_len; dst = p; size = 2; break; } if (p[0] == 0 && p[1] == 16 && ctx->alpn.data == NULL) { /* ALPN extension */ state = sw_alpn_len; dst = p; size = 2; break; } if (p[0] == 0 && p[1] == 43) { /* supported_versions extension */ state = sw_supver_len; dst = p; size = 1; break; } state = sw_ext; dst = NULL; size = (p[2] << 8) + p[3]; break; case sw_sni_len: ext = (p[0] << 8) + p[1]; 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; } size = (p[1] << 8) + p[2]; if (ext < 3 + size) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: SNI format error"); return NGX_DECLINED; } ext -= 3 + size; ctx->host.data = ngx_pnalloc(ctx->pool, size); if (ctx->host.data == NULL) { return NGX_ERROR; } state = sw_sni_host; dst = ctx->host.data; break; case sw_sni_host: ctx->host.len = (p[1] << 8) + p[2]; ngx_log_debug1(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: SNI hostname \"%V\"", &ctx->host); state = sw_ext; dst = NULL; size = ext; break; case sw_alpn_len: ext = (p[0] << 8) + p[1]; ctx->alpn.data = ngx_pnalloc(ctx->pool, ext); if (ctx->alpn.data == NULL) { return NGX_ERROR; } state = sw_alpn_proto_len; dst = p; size = 1; break; case sw_alpn_proto_len: size = p[0]; if (size == 0) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: ALPN empty protocol"); return NGX_DECLINED; } if (ext < 1 + size) { ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: ALPN format error"); return NGX_DECLINED; } ext -= 1 + size; state = sw_alpn_proto_data; dst = ctx->alpn.data + ctx->alpn.len; break; case sw_alpn_proto_data: ctx->alpn.len += p[0]; ngx_log_debug1(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: ALPN protocols \"%V\"", &ctx->alpn); if (ext) { ctx->alpn.data[ctx->alpn.len++] = ','; state = sw_alpn_proto_len; dst = p; size = 1; break; } state = sw_ext; dst = NULL; size = 0; break; case sw_supver_len: ngx_log_debug0(NGX_LOG_DEBUG_STREAM, ctx->log, 0, "ssl preread: supported_versions"); /* set TLSv1.3 */ ctx->version[0] = 3; ctx->version[1] = 4; state = sw_ext; dst = NULL; size = p[0]; break; } 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->ext = ext; ctx->dst = dst; return NGX_AGAIN; } static ngx_int_t ngx_stream_ssl_preread_protocol_variable(ngx_stream_session_t *s, ngx_variable_value_t *v, uintptr_t data) { ngx_str_t version; 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; } /* SSL_get_version() format */ ngx_str_null(&version); switch (ctx->version[0]) { case 0: switch (ctx->version[1]) { case 2: ngx_str_set(&version, "SSLv2"); break; } break; case 3: switch (ctx->version[1]) { case 0: ngx_str_set(&version, "SSLv3"); break; case 1: ngx_str_set(&version, "TLSv1"); break; case 2: ngx_str_set(&version, "TLSv1.1"); break; case 3: ngx_str_set(&version, "TLSv1.2"); break; case 4: ngx_str_set(&version, "TLSv1.3"); break; } } v->valid = 1; v->no_cacheable = 0; v->not_found = 0; v->len = version.len; v->data = version.data; return NGX_OK; } 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_alpn_protocols_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->alpn.len; v->data = ctx->alpn.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; }