From: Greg KH <gregkh@linuxfoundation.org>
To: Dragan Cvetic <dragan.cvetic@xilinx.com>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, arnd@arndb.de,
michal.simek@xilinx.com, linux-kernel@vger.kernel.org,
robh+dt@kernel.org, Derek Kiernan <derek.kiernan@xilinx.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V4 04/12] misc: xilinx_sdfec: Add open, close and ioctl
Date: Thu, 6 Jun 2019 15:28:42 +0200 [thread overview]
Message-ID: <20190606132842.GC7943@kroah.com> (raw)
In-Reply-To: <1558784245-108751-5-git-send-email-dragan.cvetic@xilinx.com>
On Sat, May 25, 2019 at 12:37:17PM +0100, Dragan Cvetic wrote:
> +static int xsdfec_dev_open(struct inode *iptr, struct file *fptr)
> +{
> + return 0;
> +}
> +
> +static int xsdfec_dev_release(struct inode *iptr, struct file *fptr)
> +{
> + return 0;
> +}
empty open/close functions are never needed, just drop them.
> +
> +static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd,
> + unsigned long data)
> +{
> + struct xsdfec_dev *xsdfec;
> + void __user *arg = NULL;
> + int rval = -EINVAL;
> +
> + xsdfec = container_of(fptr->private_data, struct xsdfec_dev, miscdev);
> + if (!xsdfec)
> + return rval;
It is impossible for container_of() to return NULL, unless something
very magical and rare just happened. It's just doing pointer math, you
can never check the return value of it.
> +
> + if (_IOC_TYPE(cmd) != XSDFEC_MAGIC)
> + return -ENOTTY;
How can this happen?
> +
> + /* check if ioctl argument is present and valid */
> + if (_IOC_DIR(cmd) != _IOC_NONE) {
> + arg = (void __user *)data;
> + if (!arg)
> + return rval;
> + }
> +
> + switch (cmd) {
> + default:
> + /* Should not get here */
> + dev_warn(xsdfec->dev, "Undefined SDFEC IOCTL");
Nice that userspace has a way to fill up the kernel log :(
Just return the correct error here, don't log it.
thanks,
greg k-h
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WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <gregkh@linuxfoundation.org>
To: Dragan Cvetic <dragan.cvetic@xilinx.com>
Cc: arnd@arndb.de, michal.simek@xilinx.com,
linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org,
mark.rutland@arm.com, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
Derek Kiernan <derek.kiernan@xilinx.com>
Subject: Re: [PATCH V4 04/12] misc: xilinx_sdfec: Add open, close and ioctl
Date: Thu, 6 Jun 2019 15:28:42 +0200 [thread overview]
Message-ID: <20190606132842.GC7943@kroah.com> (raw)
In-Reply-To: <1558784245-108751-5-git-send-email-dragan.cvetic@xilinx.com>
On Sat, May 25, 2019 at 12:37:17PM +0100, Dragan Cvetic wrote:
> +static int xsdfec_dev_open(struct inode *iptr, struct file *fptr)
> +{
> + return 0;
> +}
> +
> +static int xsdfec_dev_release(struct inode *iptr, struct file *fptr)
> +{
> + return 0;
> +}
empty open/close functions are never needed, just drop them.
> +
> +static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd,
> + unsigned long data)
> +{
> + struct xsdfec_dev *xsdfec;
> + void __user *arg = NULL;
> + int rval = -EINVAL;
> +
> + xsdfec = container_of(fptr->private_data, struct xsdfec_dev, miscdev);
> + if (!xsdfec)
> + return rval;
It is impossible for container_of() to return NULL, unless something
very magical and rare just happened. It's just doing pointer math, you
can never check the return value of it.
> +
> + if (_IOC_TYPE(cmd) != XSDFEC_MAGIC)
> + return -ENOTTY;
How can this happen?
> +
> + /* check if ioctl argument is present and valid */
> + if (_IOC_DIR(cmd) != _IOC_NONE) {
> + arg = (void __user *)data;
> + if (!arg)
> + return rval;
> + }
> +
> + switch (cmd) {
> + default:
> + /* Should not get here */
> + dev_warn(xsdfec->dev, "Undefined SDFEC IOCTL");
Nice that userspace has a way to fill up the kernel log :(
Just return the correct error here, don't log it.
thanks,
greg k-h
next prev parent reply other threads:[~2019-06-06 13:28 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-25 11:37 [PATCH V4 00/12] misc: xilinx sd-fec drive Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 01/12] dt-bindings: xilinx-sdfec: Add SDFEC binding Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 02/12] misc: xilinx-sdfec: add core driver Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-06-06 13:25 ` Greg KH
2019-06-06 13:25 ` Greg KH
2019-06-06 18:16 ` Dragan Cvetic
2019-06-06 18:16 ` Dragan Cvetic
2019-06-06 19:04 ` Greg KH
2019-06-06 19:04 ` Greg KH
2019-05-25 11:37 ` [PATCH V4 03/12] misc: xilinx_sdfec: Add CCF support Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 04/12] misc: xilinx_sdfec: Add open, close and ioctl Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-06-06 13:26 ` Greg KH
2019-06-06 13:26 ` Greg KH
2019-06-06 18:18 ` Dragan Cvetic
2019-06-06 18:18 ` Dragan Cvetic
2019-06-06 13:28 ` Greg KH [this message]
2019-06-06 13:28 ` Greg KH
2019-06-06 18:22 ` Dragan Cvetic
2019-06-06 18:22 ` Dragan Cvetic
2019-06-07 10:58 ` Dragan Cvetic
2019-06-07 10:58 ` Dragan Cvetic
2019-06-07 15:57 ` Greg KH
2019-06-07 15:57 ` Greg KH
2019-06-08 19:40 ` Dragan Cvetic
2019-06-08 19:40 ` Dragan Cvetic
2019-06-08 19:40 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 05/12] misc: xilinx_sdfec: Store driver config and state Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 06/12] misc: xilinx_sdfec: Add ability to configure turbo Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 07/12] misc: xilinx_sdfec: Add ability to configure LDPC Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 08/12] misc: xilinx_sdfec: Add ability to get/set config Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 09/12] misc: xilinx_sdfec: Support poll file operation Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 10/12] misc: xilinx_sdfec: Add stats & status ioctls Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-06-06 14:11 ` Greg KH
2019-06-06 14:11 ` Greg KH
2019-06-06 18:27 ` Dragan Cvetic
2019-06-06 18:27 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 11/12] Docs: misc: xilinx_sdfec: Add documentation Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` [PATCH V4 12/12] MAINTAINERS: add maintainer for SD-FEC Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
2019-05-25 11:37 ` Dragan Cvetic
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