From 5f29298fba1ad1e7139381e19e09c272db337b13 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 15 Mar 2023 14:31:26 +0300 Subject: [PATCH] floppy: fix MAX_ORDER usage MAX_ORDER is not inclusive: the maximum allocation order buddy allocator can deliver is MAX_ORDER-1. Fix MAX_ORDER usage in floppy code. Also allocation buffer exactly PAGE_SIZE << MAX_ORDER bytes is okay. Fix MAX_LEN check. Link: https://lkml.kernel.org/r/20230315113133.11326-4-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Acked-by: Mike Rapoport (IBM) Cc: Denis Efremov Signed-off-by: Andrew Morton --- drivers/block/floppy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 487840e3564d..90d2dfb6448e 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3079,7 +3079,7 @@ static void raw_cmd_free(struct floppy_raw_cmd **ptr) } } -#define MAX_LEN (1UL << MAX_ORDER << PAGE_SHIFT) +#define MAX_LEN (1UL << (MAX_ORDER - 1) << PAGE_SHIFT) static int raw_cmd_copyin(int cmd, void __user *param, struct floppy_raw_cmd **rcmd) @@ -3108,7 +3108,7 @@ loop: ptr->resultcode = 0; if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) { - if (ptr->length <= 0 || ptr->length >= MAX_LEN) + if (ptr->length <= 0 || ptr->length > MAX_LEN) return -EINVAL; ptr->kernel_data = (char *)fd_dma_mem_alloc(ptr->length); fallback_on_nodma_alloc(&ptr->kernel_data, ptr->length); -- 2.11.0