linux-kernel - [PATCH] dm: writecache: Use 2-factor allocator arguments

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Date:   Mon, 18 Jun 2018 10:50:33 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Mikulas Patocka <mpatocka@...hat.com>
Cc:     linux-kernel@...r.kernel.org, dm-devel@...hat.com,
        Dan Williams <dan.j.williams@...el.com>,
        Mike Snitzer <msnitzer@...hat.com>,
        Alasdair Kergon <agk@...hat.com>
Subject: [PATCH] dm: writecache: Use 2-factor allocator arguments

This adjusts the allocator calls to use the 2-factor argument style, as
already done treewide for better defense against allocator overflows.
Additionally adjusts style nit to avoid assignments in test expressions.

Signed-off-by: Kees Cook <keescook@...omium.org>
---
 drivers/md/dm-writecache.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5961c7794ef3..7773f4c75701 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
 	if (da != p) {
 		long i;
 		wc->memory_map = NULL;
-		pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
+		pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
 		if (!pages) {
 			r = -ENOMEM;
 			goto err2;
@@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
 
 	if (wc->entries)
 		return 0;
-	wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
+	wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
+					 wc->n_blocks));
 	if (!wc->entries)
 		return -ENOMEM;
 	for (b = 0; b < wc->n_blocks; b++) {
@@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
 		bio_set_dev(&wb->bio, wc->dev->bdev);
 		wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
 		wb->page_offset = PAGE_SIZE;
-		if (max_pages <= WB_LIST_INLINE ||
-		    unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
-						     GFP_NOIO | __GFP_NORETRY |
-						     __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
+		if (max_pages > WB_LIST_INLINE)
+			wb->wc_list = kmalloc_array(max_pages,
+						    sizeof(struct wc_entry *),
+						    GFP_NOIO | __GFP_NORETRY |
+						    __GFP_NOMEMALLOC |
+						    __GFP_NOWARN);
+		if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {
 			wb->wc_list = wb->wc_list_inline;
 			max_pages = WB_LIST_INLINE;
 		}
-- 
2.17.0


-- 
Kees Cook
Pixel Security