Cache: reset c->body_start when reading a variant on Vary mismatch.

Previously, a variant not present in shared memory and stored on disk using a
secondary key was read using c->body_start from a variant stored with a main
key.  This could result in critical errors "cache file .. has too long header".

1 files changed, 3 insertions, 1 deletions

diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index e985f27b1..7a5b4ca5b 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -294,6 +294,8 @@ ngx_http_file_cache_open(ngx_http_request_t *r)
         cln->data = c;
     }
 
+    c->buffer_size = c->body_start;
+
     rc = ngx_http_file_cache_exists(cache, c);
 
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
@@ -1230,7 +1232,7 @@ ngx_http_file_cache_reopen(ngx_http_request_t *r, ngx_http_cache_t *c)
 
     c->secondary = 1;
     c->file.name.len = 0;
-    c->body_start = c->buf->end - c->buf->start;
+    c->body_start = c->buffer_size;
 
     ngx_memcpy(c->key, c->variant, NGX_HTTP_CACHE_KEY_LEN);