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From: sohu0106 <sohu0106@126.com>
To: vneethv@linux.ibm.com, oberpar@linux.ibm.com
Cc: linux-s390@vger.kernel.org
Subject: buffer overflow in vfio_ccw_async_region_write/vfio_ccw_async_region_read
Date: Tue, 12 Jul 2022 17:52:51 +0800 (CST)	[thread overview]
Message-ID: <255c7ef5.6bf9.181f1d3637e.Coremail.sohu0106@126.com> (raw)


In the vfio_ccw_async_region_write/vfio_ccw_async_region_read function of drivers/s390/cio/vfio_ccw_async.c, parameter "size_t count" is pass by userland, if "count" is very large, it will bypass "if (pos + count > sizeof(*region))".(such as count=0xffffffff). Then it will lead to buffer overflow in "copy_from_user((void *)region + pos, buf, count)". 




diff --git a/vfio_ccw_async.c_org b/vfio_ccw_async.c
index 7a838e3..33339ad 100644
--- a/vfio_ccw_async.c_org
+++ b/vfio_ccw_async.c
@@ -21,7 +21,7 @@ static ssize_t vfio_ccw_async_region_read(struct vfio_ccw_private *private,
        struct ccw_cmd_region *region;
        int ret;


-       if (pos + count > sizeof(*region))
+       if (pos + count > sizeof(*region) && pos + count > pos)
                return -EINVAL;


        mutex_lock(&private->io_mutex);
@@ -43,7 +43,7 @@ static ssize_t vfio_ccw_async_region_write(struct vfio_ccw_private *private,
        struct ccw_cmd_region *region;
        int ret;


-       if (pos + count > sizeof(*region))
+       if (pos + count > sizeof(*region) && pos + count > pos)
                return -EINVAL;


        if (!mutex_trylock(&private->io_mutex))


             reply	other threads:[~2022-07-12 10:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-12  9:52 sohu0106 [this message]
2022-08-30 19:13 ` buffer overflow in vfio_ccw_async_region_write/vfio_ccw_async_region_read Eric Farman

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