Range filter: changed type for total length to off_t.

Total length of a response with multiple ranges can be larger than a size_t
variable can hold, so type changed to off_t.  Previously, an incorrect
Content-Length was returned when requesting more than 4G of ranges from
a large enough file on a 32-bit system.

An additional size_t variable introduced to calculate size of the boundary
header buffer, as off_t is not needed here and will require type casts on
win32.

Reported by Shuxin Yang,
http://mailman.nginx.org/pipermail/nginx/2017-July/054384.html.

1 files changed, 9 insertions, 8 deletions

diff --git a/src/http/modules/ngx_http_range_filter_module.c b/src/http/modules/ngx_http_range_filter_module.c
index 59d273b78..965522831 100644
--- a/src/http/modules/ngx_http_range_filter_module.c
+++ b/src/http/modules/ngx_http_range_filter_module.c
@@ -458,23 +458,24 @@ static ngx_int_t
 ngx_http_range_multipart_header(ngx_http_request_t *r,
     ngx_http_range_filter_ctx_t *ctx)
 {
-    size_t              len;
+    off_t               len;
+    size_t              size;
     ngx_uint_t          i;
     ngx_http_range_t   *range;
     ngx_atomic_uint_t   boundary;
 
-    len = sizeof(CRLF "--") - 1 + NGX_ATOMIC_T_LEN
-          + sizeof(CRLF "Content-Type: ") - 1
-          + r->headers_out.content_type.len
-          + sizeof(CRLF "Content-Range: bytes ") - 1;
+    size = sizeof(CRLF "--") - 1 + NGX_ATOMIC_T_LEN
+           + sizeof(CRLF "Content-Type: ") - 1
+           + r->headers_out.content_type.len
+           + sizeof(CRLF "Content-Range: bytes ") - 1;
 
     if (r->headers_out.content_type_len == r->headers_out.content_type.len
         && r->headers_out.charset.len)
     {
-        len += sizeof("; charset=") - 1 + r->headers_out.charset.len;
+        size += sizeof("; charset=") - 1 + r->headers_out.charset.len;
     }
 
-    ctx->boundary_header.data = ngx_pnalloc(r->pool, len);
+    ctx->boundary_header.data = ngx_pnalloc(r->pool, size);
     if (ctx->boundary_header.data == NULL) {
         return NGX_ERROR;
     }
@@ -564,7 +565,7 @@ ngx_http_range_multipart_header(ngx_http_request_t *r,
                                      - range[i].content_range.data;
 
         len += ctx->boundary_header.len + range[i].content_range.len
-                                    + (size_t) (range[i].end - range[i].start);
+                                             + (range[i].end - range[i].start);
     }
 
     r->headers_out.content_length_n = len;