syzbot report KMSAN: uninit-value in pick_link, the root cause is that squashfs_symlink_read_folio did not check the length, resulting in folio not being initialized and did not return the corresponding error code. The incorrect value of length is due to the incorrect value of inode->i_size. Reported-and-tested-by: syzbot+24ac24ff58dc5b0d26b9@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=24ac24ff58dc5b0d26b9 Signed-off-by: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx> --- fs/squashfs/symlink.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/squashfs/symlink.c b/fs/squashfs/symlink.c index 6ef735bd841a..d5fa5165ddd6 100644 --- a/fs/squashfs/symlink.c +++ b/fs/squashfs/symlink.c @@ -61,6 +61,12 @@ static int squashfs_symlink_read_folio(struct file *file, struct folio *folio) } } + if (length < 0) { + ERROR("Unable to read symlink, wrong length [%d]\n", length); + error = -EINVAL; + goto out; + } + /* * Read length bytes from symlink metadata. Squashfs_read_metadata * is not used here because it can sleep and we want to use -- 2.43.0
