linux-kernel - [PATCH 3/4] misc: xilinx_sdfec: Prevent a divide by zero in xsdfec_reg0

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Date:   Wed, 21 Aug 2019 10:09:53 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Derek Kiernan <derek.kiernan@...inx.com>,
        Dragan Cvetic <dragan.cvetic@...inx.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Michal Simek <michal.simek@...inx.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH 3/4] misc: xilinx_sdfec: Prevent a divide by zero in
 xsdfec_reg0_write()

The "psize" value comes from the user so we need to verify that it's
non-zero before we check if "n % psize" or it will crash.

Fixes: 20ec628e8007 ("misc: xilinx_sdfec: Add ability to configure LDPC")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
The parentheses in this condition are a no-op.  They're just confusing.
Perhaps something else was intended?

 drivers/misc/xilinx_sdfec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c
index 813b82c59360..3fc53d20abf3 100644
--- a/drivers/misc/xilinx_sdfec.c
+++ b/drivers/misc/xilinx_sdfec.c
@@ -460,7 +460,7 @@ static int xsdfec_reg0_write(struct xsdfec_dev *xsdfec, u32 n, u32 k, u32 psize,
 {
 	u32 wdata;
 
-	if (n < XSDFEC_REG0_N_MIN || n > XSDFEC_REG0_N_MAX ||
+	if (n < XSDFEC_REG0_N_MIN || n > XSDFEC_REG0_N_MAX || psize == 0 ||
 	    (n > XSDFEC_REG0_N_MUL_P * psize) || n <= k || ((n % psize) != 0)) {
 		dev_dbg(xsdfec->dev, "N value is not in range");
 		return -EINVAL;
-- 
2.20.1