From: Kees Cook <kees@kernel.org>
To: asmadeus@codewreck.org,
Dominique Martinet via B4 Relay
<devnull+asmadeus.codewreck.org@kernel.org>,
Eric Van Hensbergen <ericvh@kernel.org>,
Latchesar Ionkov <lucho@ionkov.net>,
Christian Schoenebeck <linux_oss@crudebyte.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Michael Grzeschik <m.grzeschik@pengutronix.de>
Cc: stable@vger.kernel.org, Yuhao Jiang <danisjiang@gmail.com>,
security@kernel.org, v9fs@lists.linux.dev,
linux-kernel@vger.kernel.org,
Dominique Martinet <asmadeus@codewreck.org>
Subject: Re: [PATCH v3] net/9p: Fix buffer overflow in USB transport layer
Date: Sun, 22 Jun 2025 13:02:20 -0700 [thread overview]
Message-ID: <659844BA-48EF-47E1-8D66-D4CA98359BBF@kernel.org> (raw)
In-Reply-To: <20250622-9p-usb_overflow-v3-1-ab172691b946@codewreck.org>
On June 22, 2025 6:39:56 AM PDT, Dominique Martinet via B4 Relay <devnull+asmadeus.codewreck.org@kernel.org> wrote:
> [...]
>Add validation in usb9pfs_rx_complete() to ensure req->actual does not
>exceed the buffer capacity before copying data.
> [...]
>+ if (req_size > p9_rx_req->rc.capacity) {
>+ dev_err(&cdev->gadget->dev,
>+ "%s received data size %u exceeds buffer capacity %zu\n",
>+ ep->name, req_size, p9_rx_req->rc.capacity);
>+ req_size = 0;
>+ status = REQ_STATUS_ERROR;
>+ }
>
>- p9_rx_req->rc.size = req->actual;
>+ memcpy(p9_rx_req->rc.sdata, req->buf, req_size);
Is rc.sdata always rc.capacity sized? If so, this world be a good first adopter of the __counted_by annotation for pointer struct members, available in Clang trunk and soon in GCC:
https://gcc.gnu.org/pipermail/gcc-patches/2025-May/683696.html
-Kees
--
Kees Cook
next prev parent reply other threads:[~2025-06-22 20:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-22 13:39 Dominique Martinet via B4 Relay
2025-06-22 20:02 ` Kees Cook [this message]
2025-06-22 20:39 ` asmadeus
2025-06-22 21:20 ` Christian Schoenebeck
2025-06-22 21:37 ` asmadeus
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