From f7e6eaf84bebac565f462e2ce48f30808cc771eb Mon Sep 17 00:00:00 2001
From: David Kalnischkies <david@kalnischkies.de>
Date: Mon, 8 Jun 2020 17:07:43 +0200
Subject: Avoid undefined pointer arithmetic while growing mmap
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The undefined behaviour sanitizer complains with:
runtime error: addition of unsigned offset to 0x… overflowed to 0x…

Compilers and runtime do the right thing in any case and it is a
codepath that can (and ideally should) be avoided for speed reasons
alone, but fixing it can't hurt (too much).
---
 apt-pkg/contrib/mmap.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'apt-pkg/contrib')

diff --git a/apt-pkg/contrib/mmap.cc b/apt-pkg/contrib/mmap.cc
index 020491172..642e20473 100644
--- a/apt-pkg/contrib/mmap.cc
+++ b/apt-pkg/contrib/mmap.cc
@@ -393,7 +393,7 @@ unsigned long DynamicMMap::Allocate(unsigned long ItemSize)
       bool const newError = _error->PendingError();
       _error->MergeWithStack();
       if (Pools != oldPools)
-	 I += Pools - oldPools;
+	 I = Pools + (I - oldPools);
 
       // Does the allocation failed ?
       if (Result == 0 && newError)
-- 
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