On Mon, Jan 23, 2023 at 8:05 AM Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
>
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> When converting an inline directory to a regular one, f2fs is leaking
> uninitialized memory to disk because it doesn't initialize the entire
> directory block. Fix this by zero-initializing the block.
>
> This bug was introduced by commit 4ec17d688d74 ("f2fs: avoid unneeded
> initializing when converting inline dentry"), which didn't consider the
> security implications of leaking uninitialized memory to disk.
>
> This was found by running xfstest generic/435 on a KMSAN-enabled kernel.
Out of curiosity, did you add any extra annotations to detect uninit
writes to the disk?
