[v6,2/6] initramfs: make dir_entry.name a flexible array member

Commit Message

David Disseldorp Jan. 7, 2022, 1:38 p.m. UTC

dir_entry.name is currently allocated via a separate kstrdup(). Change
it to a flexible array member and allocate it along with struct
dir_entry.

Signed-off-by: David Disseldorp <[e-mail]>
---
 init/initramfs.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

Christian Brauner Jan. 7, 2022, 1:46 p.m. UTC | #1

On Fri, Jan 07, 2022 at 02:38:10PM +0100, David Disseldorp wrote:
> dir_entry.name is currently allocated via a separate kstrdup(). Change
> it to a flexible array member and allocate it along with struct
> dir_entry.
> 
> Signed-off-by: David Disseldorp <[e-mail]>
> ---

Seems good,
Acked-by: Christian Brauner <[e-mail]>

Patch

diff --git a/init/initramfs.c b/init/initramfs.c
index 2f79b3ec0b40..656d2d71349f 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -130,17 +130,20 @@  static long __init do_utime(char *filename, time64_t mtime)
 static __initdata LIST_HEAD(dir_list);
 struct dir_entry {
 	struct list_head list;
-	char *name;
 	time64_t mtime;
+	char name[];
 };
 
 static void __init dir_add(const char *name, time64_t mtime)
 {
-	struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
+	size_t nlen = strlen(name) + 1;
+	struct dir_entry *de;
+
+	de = kmalloc(sizeof(struct dir_entry) + nlen, GFP_KERNEL);
 	if (!de)
 		panic_show_mem("can't allocate dir_entry buffer");
 	INIT_LIST_HEAD(&de->list);
-	de->name = kstrdup(name, GFP_KERNEL);
+	strscpy(de->name, name, nlen);
 	de->mtime = mtime;
 	list_add(&de->list, &dir_list);
 }
@@ -151,7 +154,6 @@  static void __init dir_utime(void)
 	list_for_each_entry_safe(de, tmp, &dir_list, list) {
 		list_del(&de->list);
 		do_utime(de->name, de->mtime);
-		kfree(de->name);
 		kfree(de);
 	}
 }