[PATCH v2] lib: zstd: Fix -Wstringop-overflow warning

[Kees Cook]

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 is one of the last remaining warnings to be fixed before globally
enabling -Wstringop-overflow.

Co-developed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Cc: Nick Terrell <terrelln@xxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
v2: use "rankValCol_t *" instead of U32
v1: https://lore.kernel.org/lkml/20220330193352.GA119296@embeddedor/
---
 lib/zstd/decompress/huf_decompress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/zstd/decompress/huf_decompress.c b/lib/zstd/decompress/huf_decompress.c
index 89b269a641c7..60958afebc41 100644
--- a/lib/zstd/decompress/huf_decompress.c
+++ b/lib/zstd/decompress/huf_decompress.c
@@ -985,7 +985,7 @@ static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 targetLog, const U32
 
 static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
                            const sortedSymbol_t* sortedList,
-                           const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
+                           const U32* rankStart, rankValCol_t *rankValOrigin, const U32 maxWeight,
                            const U32 nbBitsBaseline)
 {
     U32* const rankVal = rankValOrigin[0];
-- 
2.34.1