First, use struct_size(), which provides additional compile-time checks
for structures with flexible array members (e.g., __must_be_array()), to
calculate the number of bytes to allocate for a new 'platform_object'.

Then, since we know the length of 'name' and that it is guaranteed to be
NUL-terminated, replace the deprecated strcpy() with a simple memcpy().

Link: https://github.com/KSPP/linux/issues/88
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 drivers/base/platform.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 09450349cf32..55ec4fb023e2 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
+#include <linux/overflow.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
@@ -577,10 +578,11 @@ static void platform_device_release(struct device *dev)
 struct platform_device *platform_device_alloc(const char *name, int id)
 {
 	struct platform_object *pa;
+	size_t name_len = strlen(name);
 
-	pa = kzalloc(sizeof(*pa) + strlen(name) + 1, GFP_KERNEL);
+	pa = kzalloc(struct_size(pa, name, name_len + 1), GFP_KERNEL);
 	if (pa) {
-		strcpy(pa->name, name);
+		memcpy(pa->name, name, name_len + 1);
 		pa->pdev.name = pa->name;
 		pa->pdev.id = id;
 		device_initialize(&pa->pdev.dev);
-- 
2.51.1

On Fri, Oct 31, 2025 at 01:18:58PM +0100, Thorsten Blum wrote:
> First, use struct_size(), which provides additional compile-time checks
> for structures with flexible array members (e.g., __must_be_array()), to
> calculate the number of bytes to allocate for a new 'platform_object'.
> 
> Then, since we know the length of 'name' and that it is guaranteed to be
> NUL-terminated, replace the deprecated strcpy() with a simple memcpy().

This makes no sense.  You are saying we know the length, and we know it
is NULL terminated, so let's be complex and do a strlen() and memcpy()
instead of a normal strcpy().

Please no.  This is not ok at all.

greg k-h

On 31. Oct 2025, at 13:24, Greg Kroah-Hartman wrote:
> On Fri, Oct 31, 2025 at 01:18:58PM +0100, Thorsten Blum wrote:
>> First, use struct_size(), which provides additional compile-time checks
>> for structures with flexible array members (e.g., __must_be_array()), to
>> calculate the number of bytes to allocate for a new 'platform_object'.
>> 
>> Then, since we know the length of 'name' and that it is guaranteed to be
>> NUL-terminated, replace the deprecated strcpy() with a simple memcpy().
> 
> This makes no sense.  You are saying we know the length, and we know it
> is NULL terminated, so let's be complex and do a strlen() and memcpy()
> instead of a normal strcpy().

The current version already calculates strlen(name), and then strcpy()
does another strlen() internally, which we can safely skip by using
memcpy() directly.

The current code is correct, but by removing the deprecated strcpy(), we
also remove a redundant call to strlen() without any functional changes.