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Tsirkin" To: Fang Xieyan Cc: Jason Wang , Eugenio =?iso-8859-1?Q?P=E9rez?= , Stefano Garzarella , virtualization@lists.linux.dev, kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Guanglei Zhu Subject: Re: [PATCH] vhost/vringh: reject zero-length indirect descriptor tables Message-ID: <20261102122942-mutt-send-email-mst@kernel.org> References: <20261021070242.75009-1-fangxy@xiaopeng.com> X-Mailing-List: kvm@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261021070242.75009-1-fangxy@xiaopeng.com> On Wed, Oct 21, 2026 at 03:02:42PM +0800, Fang Xieyan wrote: > move_to_indirect() accepts an indirect descriptor with a zero length, > setting desc_max to 0. __vringh_iov() then reads descs[0] before > checking the descriptor bounds, resulting in an out-of-bounds read. > > Reject a zero-length indirect table in move_to_indirect() so the > caller returns -EINVAL before dereferencing the table. Also use the > converted length in the warning to report invalid lengths correctly > when the vring byte order differs from the CPU byte order. > > Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") > Cc: stable@vger.kernel.org > Reviewed-by: Guanglei Zhu > Signed-off-by: Fang Xieyan Isn't this already addressed by Subject: [PATCH v2] vringh: reject empty / undersized indirect descriptor tables that you posted previously? > --- > drivers/vhost/vringh.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c > index 9066f9f12ba1..ce4f5a02c8d2 100644 > --- a/drivers/vhost/vringh.c > +++ b/drivers/vhost/vringh.c > @@ -197,8 +197,8 @@ static int move_to_indirect(const struct vringh *vrh, > } > > len = vringh32_to_cpu(vrh, desc->len); > - if (unlikely(len % sizeof(struct vring_desc))) { > - vringh_bad("Strange indirect len %u", desc->len); > + if (unlikely(!len || len % sizeof(struct vring_desc))) { > + vringh_bad("Strange indirect len %u", len); > return -EINVAL; > } > > -- > 2.50.1