linux-kernel - [PATCH 2/2] mm, cma: use literal printf format string

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Message-Id: <20250224141120.1240534-2-arnd@kernel.org>
Date: Mon, 24 Feb 2025 15:07:36 +0100
From: Arnd Bergmann <arnd@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Nathan Chancellor <nathan@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>,
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
	Bill Wendling <morbo@...gle.com>,
	Justin Stitt <justinstitt@...gle.com>,
	Frank van der Linden <fvdl@...gle.com>,
	David Hildenbrand <david@...hat.com>,
	Zi Yan <ziy@...dia.com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	llvm@...ts.linux.dev
Subject: [PATCH 2/2] mm, cma: use literal printf format string

From: Arnd Bergmann <arnd@...db.de>

Using a variable string as a printf format can be a security issue
that clang warns about when extra warnings are enabled:

mm/cma.c:239:37: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
  239 |                 snprintf(cma->name, CMA_MAX_NAME, name);
      |                                                   ^~~~

This one does not appear to be a security issue since the string is
not user controlled, but it's better to avoid the warning.
Use "%s" as the format instead and just pass the name as the argument.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 mm/cma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/cma.c b/mm/cma.c
index ef0206c0f16d..09322b8284bd 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -236,7 +236,7 @@ static int __init cma_new_area(const char *name, phys_addr_t size,
 	cma_area_count++;
 
 	if (name)
-		snprintf(cma->name, CMA_MAX_NAME, name);
+		snprintf(cma->name, CMA_MAX_NAME, "%s", name);
 	else
 		snprintf(cma->name, CMA_MAX_NAME,  "cma%d\n", cma_area_count);
 
-- 
2.39.5