FastCGI: combining headers with identical names (ticket #1724).

FastCGI responder is expected to receive CGI/1.1 environment variables
in the parameters (see section "6.2 Responder" of the FastCGI specification).
Obviously enough, there cannot be multiple environment variables with
the same name.

Further, CGI specification (RFC 3875, section "4.1.18. Protocol-Specific
Meta-Variables") explicitly requires to combine headers: "If multiple
header fields with the same field-name are received then the server MUST
rewrite them as a single value having the same semantics".

5 files changed, 138 insertions, 13 deletions

diff --git a/src/core/ngx_hash.h b/src/core/ngx_hash.h
index abc3cbe5d..3b5709928 100644
--- a/src/core/ngx_hash.h
+++ b/src/core/ngx_hash.h
@@ -89,12 +89,15 @@ typedef struct {
 } ngx_hash_keys_arrays_t;
 
 
-typedef struct {
+typedef struct ngx_table_elt_s  ngx_table_elt_t;
+
+struct ngx_table_elt_s {
     ngx_uint_t        hash;
     ngx_str_t         key;
     ngx_str_t         value;
     u_char           *lowcase_key;
-} ngx_table_elt_t;
+    ngx_table_elt_t  *next;
+};
 
 
 void *ngx_hash_find(ngx_hash_t *hash, ngx_uint_t key, u_char *name, size_t len);
diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 4a8dc338e..17b7e83a3 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -835,14 +835,14 @@ static ngx_int_t
 ngx_http_fastcgi_create_request(ngx_http_request_t *r)
 {
     off_t                         file_pos;
-    u_char                        ch, *pos, *lowcase_key;
+    u_char                        ch, sep, *pos, *lowcase_key;
     size_t                        size, len, key_len, val_len, padding,
                                   allocated;
     ngx_uint_t                    i, n, next, hash, skip_empty, header_params;
     ngx_buf_t                    *b;
     ngx_chain_t                  *cl, *body;
     ngx_list_part_t              *part;
-    ngx_table_elt_t              *header, **ignored;
+    ngx_table_elt_t              *header, *hn, **ignored;
     ngx_http_upstream_t          *u;
     ngx_http_script_code_pt       code;
     ngx_http_script_engine_t      e, le;
@@ -900,7 +900,11 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
         allocated = 0;
         lowcase_key = NULL;
 
-        if (params->number) {
+        if (ngx_http_link_multi_headers(r) != NGX_OK) {
+            return NGX_ERROR;
+        }
+
+        if (params->number || r->headers_in.multi) {
             n = 0;
             part = &r->headers_in.headers.part;
 
@@ -930,6 +934,12 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
                 i = 0;
             }
 
+            for (n = 0; n < header_params; n++) {
+                if (&header[i] == ignored[n]) {
+                    goto next_length;
+                }
+            }
+
             if (params->number) {
                 if (allocated < header[i].key.len) {
                     allocated = header[i].key.len + 16;
@@ -959,15 +969,23 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
                     ignored[header_params++] = &header[i];
                     continue;
                 }
+            }
 
-                n += sizeof("HTTP_") - 1;
+            key_len = sizeof("HTTP_") - 1 + header[i].key.len;
 
-            } else {
-                n = sizeof("HTTP_") - 1 + header[i].key.len;
+            val_len = header[i].value.len;
+
+            for (hn = header[i].next; hn; hn = hn->next) {
+                val_len += hn->value.len + 2;
+                ignored[header_params++] = hn;
             }
 
-            len += ((n > 127) ? 4 : 1) + ((header[i].value.len > 127) ? 4 : 1)
-                + n + header[i].value.len;
+            len += ((key_len > 127) ? 4 : 1) + key_len
+                   + ((val_len > 127) ? 4 : 1) + val_len;
+
+        next_length:
+
+            continue;
         }
     }
 
@@ -1109,7 +1127,7 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
 
             for (n = 0; n < header_params; n++) {
                 if (&header[i] == ignored[n]) {
-                    goto next;
+                    goto next_value;
                 }
             }
 
@@ -1125,6 +1143,11 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
             }
 
             val_len = header[i].value.len;
+
+            for (hn = header[i].next; hn; hn = hn->next) {
+                val_len += hn->value.len + 2;
+            }
+
             if (val_len > 127) {
                 *b->last++ = (u_char) (((val_len >> 24) & 0x7f) | 0x80);
                 *b->last++ = (u_char) ((val_len >> 16) & 0xff);
@@ -1150,13 +1173,34 @@ ngx_http_fastcgi_create_request(ngx_http_request_t *r)
                 *b->last++ = ch;
             }
 
-            b->last = ngx_copy(b->last, header[i].value.data, val_len);
+            b->last = ngx_copy(b->last, header[i].value.data,
+                               header[i].value.len);
+
+            if (header[i].next) {
+
+                if (header[i].key.len == sizeof("Cookie") - 1
+                    && ngx_strncasecmp(header[i].key.data, (u_char *) "Cookie",
+                                       sizeof("Cookie") - 1)
+                       == 0)
+                {
+                    sep = ';';
+
+                } else {
+                    sep = ',';
+                }
+
+                for (hn = header[i].next; hn; hn = hn->next) {
+                    *b->last++ = sep;
+                    *b->last++ = ' ';
+                    b->last = ngx_copy(b->last, hn->value.data, hn->value.len);
+                }
+            }
 
             ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                            "fastcgi param: \"%*s: %*s\"",
                            key_len, b->last - (key_len + val_len),
                            val_len, b->last - val_len);
-        next:
+        next_value:
 
             continue;
         }
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index c7463dcdc..ad8caad19 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2802,6 +2802,80 @@ ngx_http_get_forwarded_addr_internal(ngx_http_request_t *r, ngx_addr_t *addr,
 }
 
 
+ngx_int_t
+ngx_http_link_multi_headers(ngx_http_request_t *r)
+{
+    ngx_uint_t        i, j;
+    ngx_list_part_t  *part, *ppart;
+    ngx_table_elt_t  *header, *pheader, **ph;
+
+    if (r->headers_in.multi_linked) {
+        return NGX_OK;
+    }
+
+    r->headers_in.multi_linked = 1;
+
+    part = &r->headers_in.headers.part;
+    header = part->elts;
+
+    for (i = 0; /* void */; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+
+            part = part->next;
+            header = part->elts;
+            i = 0;
+        }
+
+        header[i].next = NULL;
+
+        /*
+         * search for previous headers with the same name;
+         * if there are any, link to them
+         */
+
+        ppart = &r->headers_in.headers.part;
+        pheader = ppart->elts;
+
+        for (j = 0; /* void */; j++) {
+
+            if (j >= ppart->nelts) {
+                if (ppart->next == NULL) {
+                    break;
+                }
+
+                ppart = ppart->next;
+                pheader = ppart->elts;
+                j = 0;
+            }
+
+            if (part == ppart && i == j) {
+                break;
+            }
+
+            if (header[i].key.len == pheader[j].key.len
+                && ngx_strncasecmp(header[i].key.data, pheader[j].key.data,
+                                   header[i].key.len)
+                   == 0)
+            {
+                ph = &pheader[j].next;
+                while (*ph) { ph = &(*ph)->next; }
+                *ph = &header[i];
+
+                r->headers_in.multi = 1;
+
+                break;
+            }
+        }
+    }
+
+    return NGX_OK;
+}
+
+
 static char *
 ngx_http_core_server(ngx_conf_t *cf, ngx_command_t *cmd, void *dummy)
 {
diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
index 004a98eef..7ba64947b 100644
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -532,6 +532,8 @@ ngx_int_t ngx_http_get_forwarded_addr(ngx_http_request_t *r, ngx_addr_t *addr,
     ngx_array_t *headers, ngx_str_t *value, ngx_array_t *proxies,
     int recursive);
 
+ngx_int_t ngx_http_link_multi_headers(ngx_http_request_t *r);
+
 
 extern ngx_module_t  ngx_http_core_module;
 
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index b1269d22d..52165793a 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -242,6 +242,8 @@ typedef struct {
 
     unsigned                          connection_type:2;
     unsigned                          chunked:1;
+    unsigned                          multi:1;
+    unsigned                          multi_linked:1;
     unsigned                          msie:1;
     unsigned                          msie6:1;
     unsigned                          opera:1;