SSI: handling of subrequests from other modules (ticket #1263).

As the SSI parser always uses the context from the main request for storing
variables and blocks, that context should always exist for subrequests using
SSI, even though the main request does not necessarily have SSI enabled.

However, `ngx_http_get_module_ctx(r->main, ...)` is getting NULL in such cases,
resulting in the worker crashing SIGSEGV when accessing its attributes.

This patch links the first initialized context to the main request, and
upgrades it only when main context is initialized.

diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index 6737965d14f2f43ed2399348e9e11c11f557b295..e7601b83e7232daf7b4d36782fa2c37cd59c6983 100644 (file)
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -329,7 +329,7 @@ static ngx_http_variable_t  ngx_http_ssi_vars[] = {
 static ngx_int_t
 ngx_http_ssi_header_filter(ngx_http_request_t *r)
 {
-    ngx_http_ssi_ctx_t       *ctx;
+    ngx_http_ssi_ctx_t       *ctx, *mctx;
     ngx_http_ssi_loc_conf_t  *slcf;
 
     slcf = ngx_http_get_module_loc_conf(r, ngx_http_ssi_filter_module);
@@ -341,6 +341,8 @@ ngx_http_ssi_header_filter(ngx_http_request_t *r)
         return ngx_http_next_header_filter(r);
     }
 
+    mctx = ngx_http_get_module_ctx(r->main, ngx_http_ssi_filter_module);
+
     ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_ssi_ctx_t));
     if (ctx == NULL) {
         return NGX_ERROR;
@@ -367,6 +369,26 @@ ngx_http_ssi_header_filter(ngx_http_request_t *r)
     r->filter_need_in_memory = 1;
 
     if (r == r->main) {
+
+        if (mctx) {
+
+            /*
+             * if there was a shared context previously used as main,
+             * copy variables and blocks
+             */
+
+            ctx->variables = mctx->variables;
+            ctx->blocks = mctx->blocks;
+
+#if (NGX_PCRE)
+            ctx->ncaptures = mctx->ncaptures;
+            ctx->captures = mctx->captures;
+            ctx->captures_data = mctx->captures_data;
+#endif
+
+            mctx->shared = 0;
+        }
+
         ngx_http_clear_content_length(r);
         ngx_http_clear_accept_ranges(r);
 
@@ -379,6 +401,10 @@ ngx_http_ssi_header_filter(ngx_http_request_t *r)
         } else {
             ngx_http_weak_etag(r);
         }
+
+    } else if (mctx == NULL) {
+        ngx_http_set_ctx(r->main, ctx, ngx_http_ssi_filter_module);
+        ctx->shared = 1;
     }
 
     return ngx_http_next_header_filter(r);
@@ -405,6 +431,7 @@ ngx_http_ssi_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
     ctx = ngx_http_get_module_ctx(r, ngx_http_ssi_filter_module);
 
     if (ctx == NULL
+        || (ctx->shared && r == r->main)
         || (in == NULL
             && ctx->buf == NULL
             && ctx->in == NULL

diff --git a/src/http/modules/ngx_http_ssi_filter_module.h b/src/http/modules/ngx_http_ssi_filter_module.h
index 0bd01a06775d0a694c89cb618d94e04b8c5a6abe..419bf977de7d2e551b33fba0934ce58d27b00425 100644 (file)
--- a/src/http/modules/ngx_http_ssi_filter_module.h
+++ b/src/http/modules/ngx_http_ssi_filter_module.h
@@ -71,6 +71,7 @@ typedef struct {
     u_char                   *captures_data;
 #endif
 
+    unsigned                  shared:1;
     unsigned                  conditional:2;
     unsigned                  encoding:2;
     unsigned                  block:1;