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changeset 4162:fb1375e8b68c stable-1.0

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Merging r4036, r4055, r4056, r4057, r4058, r4059, r4060, r4061, r4062, r4063, r4064: Ranges related fixes: The "max_ranges" directive. "max_ranges 0" disables ranges support at all, "max_ranges 1" allows the single range, etc. By default number of ranges is unlimited, to be precise, 2^31-1. If client requests more ranges than "max_ranges" permits, nginx disables ranges and returns just the source response. If total size of all ranges is greater than source response size, then nginx disables ranges and returns just the source response. This fix should not affect well-behaving applications but will defeat DoS attempts exploiting malicious byte ranges. Now unsatisfiable ranges are processed according to RFC 2616.
author Igor Sysoev <igor@sysoev.ru>
date Fri, 30 Sep 2011 14:06:08 +0000
parents 010a0907bc95
children b8b4766fec8c
files src/http/modules/ngx_http_range_filter_module.c src/http/ngx_http_core_module.c src/http/ngx_http_core_module.h
diffstat 3 files changed, 69 insertions(+), 51 deletions(-) [+]
line wrap: on
line diff
--- a/src/http/modules/ngx_http_range_filter_module.c
+++ b/src/http/modules/ngx_http_range_filter_module.c
@@ -58,8 +58,8 @@ typedef struct {
 } ngx_http_range_filter_ctx_t;
 
 
-ngx_int_t ngx_http_range_parse(ngx_http_request_t *r,
-    ngx_http_range_filter_ctx_t *ctx);
+static ngx_int_t ngx_http_range_parse(ngx_http_request_t *r,
+    ngx_http_range_filter_ctx_t *ctx, ngx_uint_t ranges);
 static ngx_int_t ngx_http_range_singlepart_header(ngx_http_request_t *r,
     ngx_http_range_filter_ctx_t *ctx);
 static ngx_int_t ngx_http_range_multipart_header(ngx_http_request_t *r,
@@ -146,7 +146,7 @@ static ngx_int_t
 ngx_http_range_header_filter(ngx_http_request_t *r)
 {
     time_t                        if_range;
-    ngx_int_t                     rc;
+    ngx_http_core_loc_conf_t     *clcf;
     ngx_http_range_filter_ctx_t  *ctx;
 
     if (r->http_version < NGX_HTTP_VERSION_10
@@ -158,6 +158,12 @@ ngx_http_range_header_filter(ngx_http_re
         return ngx_http_next_header_filter(r);
     }
 
+    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+    if (clcf->max_ranges == 0) {
+        return ngx_http_next_header_filter(r);
+    }
+
     if (r->headers_in.range == NULL
         || r->headers_in.range->value.len < 7
         || ngx_strncasecmp(r->headers_in.range->value.data,
@@ -192,10 +198,9 @@ ngx_http_range_header_filter(ngx_http_re
         return NGX_ERROR;
     }
 
-    rc = ngx_http_range_parse(r, ctx);
+    switch (ngx_http_range_parse(r, ctx, clcf->max_ranges)) {
 
-    if (rc == NGX_OK) {
-
+    case NGX_OK:
         ngx_http_set_ctx(r, ctx, ngx_http_range_body_filter_module);
 
         r->headers_out.status = NGX_HTTP_PARTIAL_CONTENT;
@@ -206,16 +211,17 @@ ngx_http_range_header_filter(ngx_http_re
         }
 
         return ngx_http_range_multipart_header(r, ctx);
-    }
+
+    case NGX_HTTP_RANGE_NOT_SATISFIABLE:
+        return ngx_http_range_not_satisfiable(r);
 
-    if (rc == NGX_HTTP_RANGE_NOT_SATISFIABLE) {
-        return ngx_http_range_not_satisfiable(r);
+    case NGX_ERROR:
+        return NGX_ERROR;
+
+    default: /* NGX_DECLINED */
+        break;
     }
 
-    /* rc == NGX_ERROR */
-
-    return rc;
-
 next_filter:
 
     r->headers_out.accept_ranges = ngx_list_push(&r->headers_out.headers);
@@ -231,15 +237,18 @@ next_filter:
 }
 
 
-ngx_int_t
-ngx_http_range_parse(ngx_http_request_t *r, ngx_http_range_filter_ctx_t *ctx)
+static ngx_int_t
+ngx_http_range_parse(ngx_http_request_t *r, ngx_http_range_filter_ctx_t *ctx,
+    ngx_uint_t ranges)
 {
     u_char            *p;
-    off_t              start, end;
+    off_t              start, end, size, content_length;
     ngx_uint_t         suffix;
     ngx_http_range_t  *range;
 
     p = r->headers_in.range->value.data + 6;
+    size = 0;
+    content_length = r->headers_out.content_length_n;
 
     for ( ;; ) {
         start = 0;
@@ -263,26 +272,11 @@ ngx_http_range_parse(ngx_http_request_t 
                 return NGX_HTTP_RANGE_NOT_SATISFIABLE;
             }
 
-            if (start >= r->headers_out.content_length_n) {
-                return NGX_HTTP_RANGE_NOT_SATISFIABLE;
-            }
-
             while (*p == ' ') { p++; }
 
             if (*p == ',' || *p == '\0') {
-                range = ngx_array_push(&ctx->ranges);
-                if (range == NULL) {
-                    return NGX_ERROR;
-                }
-
-                range->start = start;
-                range->end = r->headers_out.content_length_n;
-
-                if (*p++ != ',') {
-                    return NGX_OK;
-                }
-
-                continue;
+                end = content_length;
+                goto found;
             }
 
         } else {
@@ -305,36 +299,49 @@ ngx_http_range_parse(ngx_http_request_t 
         }
 
         if (suffix) {
-           start = r->headers_out.content_length_n - end;
-           end = r->headers_out.content_length_n - 1;
+            start = content_length - end;
+            end = content_length - 1;
         }
 
-        if (start > end) {
-            return NGX_HTTP_RANGE_NOT_SATISFIABLE;
+        if (end >= content_length) {
+            end = content_length;
+
+        } else {
+            end++;
         }
 
-        range = ngx_array_push(&ctx->ranges);
-        if (range == NULL) {
-            return NGX_ERROR;
-        }
+    found:
 
-        range->start = start;
+        if (start < end) {
+            range = ngx_array_push(&ctx->ranges);
+            if (range == NULL) {
+                return NGX_ERROR;
+            }
 
-        if (end >= r->headers_out.content_length_n) {
-            /*
-             * Download Accelerator sends the last byte position
-             * that equals to the file length
-             */
-            range->end = r->headers_out.content_length_n;
+            range->start = start;
+            range->end = end;
 
-        } else {
-            range->end = end + 1;
+            size += end - start;
+
+            if (ranges-- == 0) {
+                return NGX_DECLINED;
+            }
         }
 
         if (*p++ != ',') {
-            return NGX_OK;
+            break;
         }
     }
+
+    if (ctx->ranges.nelts == 0) {
+        return NGX_HTTP_RANGE_NOT_SATISFIABLE;
+    }
+
+    if (size > content_length) {
+        return NGX_DECLINED;
+    }
+
+    return NGX_OK;
 }
 
 
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -631,6 +631,13 @@ static ngx_command_t  ngx_http_core_comm
       offsetof(ngx_http_core_loc_conf_t, if_modified_since),
       &ngx_http_core_if_modified_since },
 
+    { ngx_string("max_ranges"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_num_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_core_loc_conf_t, max_ranges),
+      NULL },
+
     { ngx_string("chunked_transfer_encoding"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
       ngx_conf_set_flag_slot,
@@ -3253,6 +3260,7 @@ ngx_http_core_create_loc_conf(ngx_conf_t
     clcf->keepalive_disable = NGX_CONF_UNSET_UINT;
     clcf->satisfy = NGX_CONF_UNSET_UINT;
     clcf->if_modified_since = NGX_CONF_UNSET_UINT;
+    clcf->max_ranges = NGX_CONF_UNSET_UINT;
     clcf->client_body_in_file_only = NGX_CONF_UNSET_UINT;
     clcf->client_body_in_single_buffer = NGX_CONF_UNSET;
     clcf->internal = NGX_CONF_UNSET;
@@ -3459,6 +3467,8 @@ ngx_http_core_merge_loc_conf(ngx_conf_t 
                               NGX_HTTP_SATISFY_ALL);
     ngx_conf_merge_uint_value(conf->if_modified_since, prev->if_modified_since,
                               NGX_HTTP_IMS_EXACT);
+    ngx_conf_merge_uint_value(conf->max_ranges, prev->max_ranges,
+                              0x7fffffff);
     ngx_conf_merge_uint_value(conf->client_body_in_file_only,
                               prev->client_body_in_file_only, 0);
     ngx_conf_merge_value(conf->client_body_in_single_buffer,
--- a/src/http/ngx_http_core_module.h
+++ b/src/http/ngx_http_core_module.h
@@ -363,6 +363,7 @@ struct ngx_http_core_loc_conf_s {
     ngx_uint_t    satisfy;                 /* satisfy */
     ngx_uint_t    lingering_close;         /* lingering_close */
     ngx_uint_t    if_modified_since;       /* if_modified_since */
+    ngx_uint_t    max_ranges;              /* max_ranges */
     ngx_uint_t    client_body_in_file_only; /* client_body_in_file_only */
 
     ngx_flag_t    client_body_in_single_buffer;