linux-kernel - [PATCH] module/decompress: Avoid open-coded kvrealloc()

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Message-Id: <20251119225439.work.741-kees@kernel.org>
Date: Wed, 19 Nov 2025 14:54:43 -0800
From: Kees Cook <kees@...nel.org>
To: Petr Pavlu <petr.pavlu@...e.com>
Cc: Kees Cook <kees@...nel.org>,
	Luis Chamberlain <mcgrof@...nel.org>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Daniel Gomez <da.gomez@...sung.com>,
	linux-modules@...r.kernel.org,
	Daniel Gomez <da.gomez@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-hardening@...r.kernel.org
Subject: [PATCH] module/decompress: Avoid open-coded kvrealloc()

Replace open-coded allocate/copy with kvrealloc().

Signed-off-by: Kees Cook <kees@...nel.org>
---
Cc: Petr Pavlu <petr.pavlu@...e.com>
Cc: Luis Chamberlain <mcgrof@...nel.org>
Cc: Sami Tolvanen <samitolvanen@...gle.com>
Cc: Daniel Gomez <da.gomez@...sung.com>
Cc: <linux-modules@...r.kernel.org>
---
 kernel/module/decompress.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
index 474e68f0f063..36f52a232a12 100644
--- a/kernel/module/decompress.c
+++ b/kernel/module/decompress.c
@@ -17,16 +17,16 @@
 static int module_extend_max_pages(struct load_info *info, unsigned int extent)
 {
 	struct page **new_pages;
+	unsigned int new_max = info->max_pages + extent;
 
-	new_pages = kvmalloc_array(info->max_pages + extent,
-				   sizeof(info->pages), GFP_KERNEL);
+	new_pages = kvrealloc(info->pages,
+			      size_mul(new_max, sizeof(*info->pages)),
+			      GFP_KERNEL);
 	if (!new_pages)
 		return -ENOMEM;
 
-	memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages));
-	kvfree(info->pages);
 	info->pages = new_pages;
-	info->max_pages += extent;
+	info->max_pages = new_max;
 
 	return 0;
 }
-- 
2.34.1