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Message-Id: <20230119135721.83345-2-alexander.shishkin@linux.intel.com>
Date: Thu, 19 Jan 2023 15:57:16 +0200
From: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To: mst@...hat.com, jasowang@...hat.com
Cc: virtualization@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org, elena.reshetova@...el.com,
kirill.shutemov@...ux.intel.com, Andi Kleen <ak@...ux.intel.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Amit Shah <amit@...nel.org>, Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH v1 1/6] virtio console: Harden multiport against invalid host input
From: Andi Kleen <ak@...ux.intel.com>
It's possible for the host to set the multiport flag, but pass in
0 multiports, which results in:
BUG: KASAN: slab-out-of-bounds in init_vqs+0x244/0x6c0 drivers/char/virtio_console.c:1878
Write of size 8 at addr ffff888001cc24a0 by task swapper/1
CPU: 0 PID: 1 Comm: swapper Not tainted 5.15.0-rc1-140273-gaab0bb9fbaa1-dirty #588
Call Trace:
init_vqs+0x244/0x6c0 drivers/char/virtio_console.c:1878
virtcons_probe+0x1a3/0x5b0 drivers/char/virtio_console.c:2042
virtio_dev_probe+0x2b9/0x500 drivers/virtio/virtio.c:263
call_driver_probe drivers/base/dd.c:515
really_probe+0x1c9/0x5b0 drivers/base/dd.c:601
really_probe_debug drivers/base/dd.c:694
__driver_probe_device+0x10d/0x1f0 drivers/base/dd.c:754
driver_probe_device+0x68/0x150 drivers/base/dd.c:786
__driver_attach+0xca/0x200 drivers/base/dd.c:1145
bus_for_each_dev+0x108/0x190 drivers/base/bus.c:301
driver_attach+0x30/0x40 drivers/base/dd.c:1162
bus_add_driver+0x325/0x3c0 drivers/base/bus.c:618
driver_register+0xf3/0x1d0 drivers/base/driver.c:171
...
Add a suitable sanity check.
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Amit Shah <amit@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/char/virtio_console.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 6a821118d553..f4fd5fe7cd3a 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1843,6 +1843,9 @@ static int init_vqs(struct ports_device *portdev)
int err;
nr_ports = portdev->max_nr_ports;
+ if (use_multiport(portdev) && nr_ports < 1)
+ return -EINVAL;
+
nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
--
2.39.0
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