[nginx] Slice filter: improved memory allocation error handling.

[noreply at nginx.com]

details:   https://github.com/nginx/nginx/commit/d31305653701bd99e8e5e6aa48094599a08f9f12
branches:  master
commit:    d31305653701bd99e8e5e6aa48094599a08f9f12
user:      Sergey Kandaurov <pluknet at nginx.com>
date:      Thu, 27 Feb 2025 16:09:50 +0400
description:
Slice filter: improved memory allocation error handling.

As uncovered by recent addition in slice.t, a partially initialized
context, coupled with HTTP 206 response from stub backend, might be
accessed in the next slice subrequest.

Found by bad memory allocator simulation.

---
 src/http/modules/ngx_http_slice_filter_module.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/http/modules/ngx_http_slice_filter_module.c b/src/http/modules/ngx_http_slice_filter_module.c
index 3b0bef629..67dc14c82 100644
--- a/src/http/modules/ngx_http_slice_filter_module.c
+++ b/src/http/modules/ngx_http_slice_filter_module.c
@@ -419,13 +419,13 @@ ngx_http_slice_range_variable(ngx_http_request_t *r,
             return NGX_ERROR;
         }
 
-        ngx_http_set_ctx(r, ctx, ngx_http_slice_filter_module);
-
         p = ngx_pnalloc(r->pool, sizeof("bytes=-") - 1 + 2 * NGX_OFF_T_LEN);
         if (p == NULL) {
             return NGX_ERROR;
         }
 
+        ngx_http_set_ctx(r, ctx, ngx_http_slice_filter_module);
+
         ctx->start = slcf->size * (ngx_http_slice_get_start(r) / slcf->size);
 
         ctx->range.data = p;