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Date:   Wed, 30 Mar 2022 14:33:52 -0500
From:   "Gustavo A. R. Silva" <gustavoars@kernel.org>
To:     Nick Terrell <terrelln@fb.com>
Cc:     linux-kernel@vger.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-hardening@vger.kernel.org
Subject: [PATCH][next] lib: zstd: Fix Wstringop-overflow warning
Message-ID: <20220330193352.GA119296@embeddedor>
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Fix the following -Wstringop-overflow warning when building with GCC-11:

lib/zstd/decompress/huf_decompress.c: In function ‘HUF_readDTableX2_wksp’:
lib/zstd/decompress/huf_decompress.c:700:5: warning: ‘HUF_fillDTableX2.constprop’ accessing 624 bytes in a region of size 52 [-Wstringop-overflow=]
  700 |     HUF_fillDTableX2(dt, maxTableLog,
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  701 |                    wksp->sortedSymbol, sizeOfSort,
      |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  702 |                    wksp->rankStart0, wksp->rankVal, maxW,
      |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  703 |                    tableLog+1,
      |                    ~~~~~~~~~~~
  704 |                    wksp->calleeWksp, sizeof(wksp->calleeWksp) / sizeof(U32));
      |                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/zstd/decompress/huf_decompress.c:700:5: note: referencing argument 6 of type ‘U32 (*)[13]’ {aka ‘unsigned int (*)[13]’}
lib/zstd/decompress/huf_decompress.c:571:13: note: in a call to function ‘HUF_fillDTableX2.constprop’
  571 | static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
      |             ^~~~~~~~~~~~~~~~

by using pointer notation instead of array notation.

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 lib/zstd/decompress/huf_decompress.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/zstd/decompress/huf_decompress.c b/lib/zstd/decompress/huf_decompress.c
index 5105e59ac04a..0ea34621253a 100644
--- a/lib/zstd/decompress/huf_decompress.c
+++ b/lib/zstd/decompress/huf_decompress.c
@@ -570,7 +570,7 @@ static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 co
 
 static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
                            const sortedSymbol_t* sortedList, const U32 sortedListSize,
-                           const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
+                           const U32* rankStart, const U32* rankValOrigin, const U32 maxWeight,
                            const U32 nbBitsBaseline, U32* wksp, size_t wkspSize)
 {
     U32* rankVal = wksp;
@@ -598,7 +598,7 @@ static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
             if (minWeight < 1) minWeight = 1;
             sortedRank = rankStart[minWeight];
             HUF_fillDTableX2Level2(DTable+start, targetLog-nbBits, nbBits,
-                           rankValOrigin[nbBits], minWeight,
+                           rankValOrigin + nbBits, minWeight,
                            sortedList+sortedRank, sortedListSize-sortedRank,
                            nbBitsBaseline, symbol, wksp, wkspSize);
         } else {
@@ -699,7 +699,7 @@ size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
 
     HUF_fillDTableX2(dt, maxTableLog,
                    wksp->sortedSymbol, sizeOfSort,
-                   wksp->rankStart0, wksp->rankVal, maxW,
+                   wksp->rankStart0, (U32 *)wksp->rankVal, maxW,
                    tableLog+1,
                    wksp->calleeWksp, sizeof(wksp->calleeWksp) / sizeof(U32));
 
-- 
2.27.0