Add the __counted_by() compiler attribute to the flexible array member 'wksp' to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE.
Use struct_size(), which provides additional compile-time checks for structures with flexible array members (e.g., __must_be_array()), for the allocation size for a new 'zstd_ctx' while we're at it. Signed-off-by: Thorsten Blum <[email protected]> --- crypto/zstd.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/crypto/zstd.c b/crypto/zstd.c index ac318d333b68..ace7a82ea45a 100644 --- a/crypto/zstd.c +++ b/crypto/zstd.c @@ -10,6 +10,7 @@ #include <linux/mm.h> #include <linux/module.h> #include <linux/net.h> +#include <linux/overflow.h> #include <linux/vmalloc.h> #include <linux/zstd.h> #include <crypto/internal/acompress.h> @@ -25,7 +26,7 @@ struct zstd_ctx { zstd_dctx *dctx; size_t wksp_size; zstd_parameters params; - u8 wksp[] __aligned(8); + u8 wksp[] __aligned(8) __counted_by(wksp_size); }; static DEFINE_MUTEX(zstd_stream_lock); @@ -44,7 +45,7 @@ static void *zstd_alloc_stream(void) if (!wksp_size) return ERR_PTR(-EINVAL); - ctx = kvmalloc(sizeof(*ctx) + wksp_size, GFP_KERNEL); + ctx = kvmalloc(struct_size(ctx, wksp, wksp_size), GFP_KERNEL); if (!ctx) return ERR_PTR(-ENOMEM); -- 2.51.1
