[PATCH] alpha: Replace sprintf()/strcpy() with scnprintf()/strscpy()

[PATCH] alpha: Replace sprintf()/strcpy() with scnprintf()/strscpy()

[Thorsten Blum]

Replace sprintf() with the safer variant scnprintf() and use its return
value instead of calculating the string length again using strlen().

Use strscpy() instead of the deprecated strcpy().

No functional changes intended.

Link: https://github.com/KSPP/linux/issues/88
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 arch/alpha/kernel/core_marvel.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/alpha/kernel/core_marvel.c b/arch/alpha/kernel/core_marvel.c
index b1bfbd11980d..d38f4d6759e4 100644
--- a/arch/alpha/kernel/core_marvel.c
+++ b/arch/alpha/kernel/core_marvel.c
@@ -17,6 +17,7 @@
 #include <linux/vmalloc.h>
 #include <linux/mc146818rtc.h>
 #include <linux/rtc.h>
+#include <linux/string.h>
 #include <linux/module.h>
 #include <linux/memblock.h>
 
@@ -79,10 +80,12 @@ mk_resource_name(int pe, int port, char *str)
 {
 	char tmp[80];
 	char *name;
-	
-	sprintf(tmp, "PCI %s PE %d PORT %d", str, pe, port);
-	name = memblock_alloc_or_panic(strlen(tmp) + 1, SMP_CACHE_BYTES);
-	strcpy(name, tmp);
+	size_t sz;
+
+	sz = scnprintf(tmp, sizeof(tmp), "PCI %s PE %d PORT %d", str, pe, port);
+	sz += 1; /* NUL terminator */
+	name = memblock_alloc_or_panic(sz, SMP_CACHE_BYTES);
+	strscpy(name, tmp, sz);
 
 	return name;
 }
-- 
2.49.0

Re: [PATCH] alpha: Replace sprintf()/strcpy() with scnprintf()/strscpy()

[Al Viro]

On Sat, Apr 19, 2025 at 01:40:11PM +0200, Thorsten Blum wrote:
> Replace sprintf() with the safer variant scnprintf() and use its return
> value instead of calculating the string length again using strlen().
> 
> Use strscpy() instead of the deprecated strcpy().

FWIW, an idiomatic variant would be
	size = snprintf(NULL, 0, <....>);
	buffer = <allocate size + 1 bytes>
	if succeeded
		snprintf(buffer, size + 1, <....>);