From: Dan Carpenter <dan.carpenter@oracle.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] spi: spidev: prevent spidev->speed_hz from being zero
Date: Tue, 25 Jan 2022 09:52:02 +0300 [thread overview]
Message-ID: <20220125065202.GA8807@kili> (raw)
A zero value for spi->max_speed_hz or spidev->speed_hz does not make
sense and trying to set that can lead to divide by zero crashes in
a some of the drivers.
drivers/spi/spi-s3c64xx.c:874 s3c64xx_spi_setup() error: potential divide by zero bug '/ spi->max_speed_hz'.
drivers/spi/spi-fsl-dspi.c:613 hz_to_spi_baud() error: potential divide by zero bug '/ speed_hz'.
drivers/spi/spi-xlp.c:146 xlp_spi_setup() error: potential divide by zero bug '/ (spi->max_speed_hz)'.
drivers/spi/spi-orion.c:162 orion_spi_baudrate_set() error: potential divide by zero bug '/ speed'.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
It's hard to know which Fixes tag to use...
drivers/spi/spidev.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index a5cceca8b82b..dd824db63fbe 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -453,22 +453,29 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
dev_dbg(&spi->dev, "%d bits per word\n", tmp);
}
break;
- case SPI_IOC_WR_MAX_SPEED_HZ:
+ case SPI_IOC_WR_MAX_SPEED_HZ: {
+ u32 save;
+
retval = get_user(tmp, (__u32 __user *)arg);
- if (retval == 0) {
- u32 save = spi->max_speed_hz;
+ if (retval)
+ break;
+ if (tmp == 0) {
+ retval = -EINVAL;
+ break;
+ }
- spi->max_speed_hz = tmp;
- retval = spi_setup(spi);
- if (retval == 0) {
- spidev->speed_hz = tmp;
- dev_dbg(&spi->dev, "%d Hz (max)\n",
- spidev->speed_hz);
- }
- spi->max_speed_hz = save;
+ save = spi->max_speed_hz;
+
+ spi->max_speed_hz = tmp;
+ retval = spi_setup(spi);
+ if (retval == 0) {
+ spidev->speed_hz = tmp;
+ dev_dbg(&spi->dev, "%d Hz (max)\n", spidev->speed_hz);
}
- break;
+ spi->max_speed_hz = save;
+ break;
+ }
default:
/* segmented and/or full-duplex I/O request */
/* Check message and copy into scratch area */
--
2.20.1
next reply other threads:[~2022-01-25 6:55 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 6:52 Dan Carpenter [this message]
2022-02-08 19:00 ` [PATCH] spi: spidev: prevent spidev->speed_hz from being zero Mark Brown
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