From: Kent Overstreet <kent.overstreet@linux.dev>
To: Reed Riley <reed@riley.engineer>
Cc: "linux-bcachefs@vger.kernel.org" <linux-bcachefs@vger.kernel.org>
Subject: Re: [PATCH] bcachefs: fix overflow in fiemap
Date: Sat, 4 May 2024 19:35:13 -0400 [thread overview]
Message-ID: <2x2pkl56bpo6ptinyp6kpjgrazbiwzsccw3qxb3jv7u775eesb@3bqc6om37j6f> (raw)
In-Reply-To: <7qU8xNKAHxFIkSlLrXO1B6kyf-7DvRoJRgZloXK5qHovOzUFYbbCYhe_9Tzv1J6MgiXcakyIFiovCX3HtotUEE9fsV25jYmifgyMz_wa-Ik=@riley.engineer>
On Sat, May 04, 2024 at 10:12:23PM +0000, Reed Riley wrote:
> filefrag (and potentially other utilities that call fiemap) sometimes
> pass ULONG_MAX as the length. fiemap_prep clamps excessively large
> lengths - but the calculation of end can overflow if it occurs before
> calling fiemap_prep. When this happens, filefrag assumes it has read to
> the end and exits.
>
> Signed-off-by: Reed Riley <reed@riley.engineer>
Applied!
> ---
> fs/bcachefs/fs.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
> index 4e4442bc71e3..ff01c954bff8 100644
> --- a/fs/bcachefs/fs.c
> +++ b/fs/bcachefs/fs.c
> @@ -996,7 +996,7 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
> struct btree_iter iter;
> struct bkey_s_c k;
> struct bkey_buf cur, prev;
> - struct bpos end = POS(ei->v.i_ino, (start + len) >> 9);
> + struct bpos end;
> unsigned offset_into_extent, sectors;
> bool have_extent = false;
> u32 snapshot;
> @@ -1006,6 +1006,7 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
> if (ret)
> return ret;
>
> + end = POS(ei->v.i_ino, (start + len) >> 9);
> if (start + len < start)
> return -EINVAL;
>
> --
> 2.44.0
>
prev parent reply other threads:[~2024-05-04 23:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-04 22:12 [PATCH] bcachefs: fix overflow in fiemap Reed Riley
2024-05-04 23:35 ` Kent Overstreet [this message]
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