From 95e2b430eac97d342f49a5e20fbe914d6a0fdc76 Mon Sep 17 00:00:00 2001
From: Nick Terrell <terrelln@fb.com>
Date: Fri, 21 Jun 2019 15:22:29 -0700
Subject: [PATCH] [opt] Add asserts for corruption in ZSTD_updateTree()

---
 lib/compress/zstd_opt.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/compress/zstd_opt.c b/lib/compress/zstd_opt.c
index 39858a82..e32e542e 100644
--- a/lib/compress/zstd_opt.c
+++ b/lib/compress/zstd_opt.c
@@ -525,8 +525,13 @@ void ZSTD_updateTree_internal(
     DEBUGLOG(6, "ZSTD_updateTree_internal, from %u to %u  (dictMode:%u)",
                 idx, target, dictMode);
 
-    while(idx < target)
-        idx += ZSTD_insertBt1(ms, base+idx, iend, mls, dictMode == ZSTD_extDict);
+    while(idx < target) {
+        U32 const forward = ZSTD_insertBt1(ms, base+idx, iend, mls, dictMode == ZSTD_extDict);
+        assert(idx < (U32)(idx + forward));
+        idx += forward;
+    }
+    assert((size_t)(ip - base) <= (size_t)(U32)(-1));
+    assert((size_t)(iend - base) <= (size_t)(U32)(-1));
     ms->nextToUpdate = target;
 }