Re: [PATCH 5.10 052/390] f2fs: fix to do sanity check on summary info

[Chao Yu]

On 2022/10/25 1:30, Pavel Machek wrote:
> Hi!
>
> > From: Chao Yu <chao@xxxxxxxxxx>
> >
> > commit c6ad7fd16657ebd34a87a97d9588195aae87597d upstream.
> >
> > As Wenqing Liu reported in bugzilla:
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=216456
> >
> > BUG: KASAN: use-after-free in recover_data+0x63ae/0x6ae0 [f2fs]
> > Read of size 4 at addr ffff8881464dcd80 by task mount/1013
>
> I believe this is missing put_page on the error path:
>
> > +++ b/fs/f2fs/gc.c
> > @@ -1003,6 +1003,14 @@ static bool is_alive(struct f2fs_sb_info
> >   		return false;
> >   	}
> >   
> > +	max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
> > +						DEF_ADDRS_PER_BLOCK;
> > +	if (ofs_in_node >= max_addrs) {
> > +		f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
> > +			ofs_in_node, dni->ino, dni->nid, max_addrs);
> > +		return false;
> > +	}
> > +
> >   	*nofs = ofs_of_node(node_page);
> >   	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
> >   	f2fs_put_page(node_page, 1);
>
> So something like this is needed. (Feel free to test/adapt/apply).
>
> Signed-off-by: Pavel Machek <pavel@xxxxxxx>
>
> Best regards,
> 								Pavel
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 4546e01b2ee0..dab794225cce 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -1110,6 +1110,7 @@ static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>   	if (ofs_in_node >= max_addrs) {
>   		f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
>   			ofs_in_node, dni->ino, dni->nid, max_addrs);
> +		f2fs_put_page(node_page, 1);
>   		return false;
>   	}

My bad, thanks for fixing this.

Reviewed-by: Chao Yu <chao@xxxxxxxxxx>

Thanks,

>