From 77618db346455129424fadbbaec596a09feaf3bb Mon Sep 17 00:00:00 2001 From: Nick Terrell Date: Thu, 12 Oct 2023 12:55:34 -0700 Subject: [PATCH] zstd: Fix array-index-out-of-bounds UBSAN warning Zstd used an array of length 1 to mean a flexible array for C89 compatibility. Switch to a C99 flexible array to fix the UBSAN warning. Tested locally by booting the kernel and writing to and reading from a BtrFS filesystem with zstd compression enabled. I was unable to reproduce the issue before the fix, however it is a trivial change. Link: https://lkml.kernel.org/r/20231012213428.1390905-1-nickrterrell@gmail.com Reported-by: syzbot+1f2eb3e8cd123ffce499@syzkaller.appspotmail.com Reported-by: Eric Biggers Reported-by: Kees Cook Signed-off-by: Nick Terrell Reviewed-by: Kees Cook --- lib/zstd/common/fse_decompress.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/zstd/common/fse_decompress.c b/lib/zstd/common/fse_decompress.c index a0d06095be83..8dcb8ca39767 100644 --- a/lib/zstd/common/fse_decompress.c +++ b/lib/zstd/common/fse_decompress.c @@ -312,7 +312,7 @@ size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size typedef struct { short ncount[FSE_MAX_SYMBOL_VALUE + 1]; - FSE_DTable dtable[1]; /* Dynamically sized */ + FSE_DTable dtable[]; /* Dynamically sized */ } FSE_DecompressWksp;