23 Jan
2023
23 Jan
'23
8:58 a.m.
On Mon, Jan 23, 2023 at 8:05 AM Eric Biggers ebiggers@kernel.org wrote:
From: Eric Biggers ebiggers@google.com
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?