From 1d636b4ba0bd105eaf7c2427aa6b4b147bdd3035 Mon Sep 17 00:00:00 2001
From: Yonatan Komornik <yoniko@gmail.com>
Date: Tue, 24 Jan 2023 12:54:43 -0800
Subject: [PATCH] Bug fix redzones by unpoisoning only the intended buffer and
 not the followup redzone.

---
 lib/compress/zstd_cwksp.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/compress/zstd_cwksp.h b/lib/compress/zstd_cwksp.h
index 70a359a27..97676693b 100644
--- a/lib/compress/zstd_cwksp.h
+++ b/lib/compress/zstd_cwksp.h
@@ -348,7 +348,9 @@ ZSTD_cwksp_reserve_internal(ZSTD_cwksp* ws, size_t bytes, ZSTD_cwksp_alloc_phase
     if (alloc) {
         alloc = (BYTE *)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE;
         if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
-            __asan_unpoison_memory_region(alloc, bytes);
+            /* We need to keep the redzone poisoned while unpoisoning the bytes that
+             * are actually allocated. */
+            __asan_unpoison_memory_region(alloc, bytes - 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE);
         }
     }
 #endif
-- 
2.47.2