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From:   Philipp Stanner <pstanner@redhat.com>
To:     Wu Hao <hao.wu@intel.com>, Tom Rix <trix@redhat.com>,
        Moritz Fischer <mdf@kernel.org>, Xu Yilun <yilun.xu@intel.com>
Cc:     linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org,
        Philipp Stanner <pstanner@redhat.com>,
        Dave Airlie <airlied@redhat.com>
Subject: [PATCH] drivers/fpga: copy userspace array safely
Date:   Thu,  2 Nov 2023 19:49:09 +0100
Message-ID: <20231102184908.49558-2-pstanner@redhat.com>
MIME-Version: 1.0
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Precedence: bulk

dfl.c utilizes memdup_user() and array_size() to copy a userspace array.
Currently, this does not check for an overflow.

Use the new wrapper memdup_array_user() to copy the array more safely.

Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
Linus recently merged this new wrapper for Kernel v6.7
---
 drivers/fpga/dfl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index dd7a783d53b5..e69b9f1f2a50 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -2008,8 +2008,8 @@ long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
 	    (hdr.start + hdr.count < hdr.start))
 		return -EINVAL;
 
-	fds = memdup_user((void __user *)(arg + sizeof(hdr)),
-			  array_size(hdr.count, sizeof(s32)));
+	fds = memdup_array_user((void __user *)(arg + sizeof(hdr)),
+				hdr.count, sizeof(s32));
 	if (IS_ERR(fds))
 		return PTR_ERR(fds);
 
-- 
2.41.0