From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v4 3/6] sysctl: Warn when a clamped sysctl parameter is set out of range
Date: Mon, 12 Mar 2018 20:50:01 +0000 [thread overview]
Message-ID: <20180312205001.GA4449@wotan.suse.de> (raw)
In-Reply-To: <1520885744-1546-4-git-send-email-longman@redhat.com>
On Mon, Mar 12, 2018 at 04:15:41PM -0400, Waiman Long wrote:
> Even with clamped sysctl parameters, it is still not that straight
> forward to figure out the exact range of those parameters. One may
> try to write extreme parameter values to see if they get clamped.
> To make it easier, a warning with the expected range will now be
> printed into the kernel ring buffer when a clamped sysctl parameter
> receives an out of range value.
>
> The pr_warn_ratelimited() macro is used to limit the number of warning
> messages that can be printed within a given period of time.
>
> Signed-off-by: Waiman Long <longman@redhat.com>
> ---
> kernel/sysctl.c | 48 ++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 40 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 3d65f41..14aca92 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -2505,6 +2505,7 @@ static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
> * @min: pointer to minimum allowable value
> * @max: pointer to maximum allowable value
> * @flags: pointer to flags
> + * @name: sysctl parameter name
> *
> * The do_proc_dointvec_minmax_conv_param structure provides the
> * minimum and maximum values for doing range checking for those sysctl
> @@ -2514,31 +2515,48 @@ struct do_proc_dointvec_minmax_conv_param {
> int *min;
> int *max;
> unsigned int *flags;
> + const char *name;
> };
>
> +#ifdef pr_fmt
> +#undef pr_fmt
> +#endif
> +#define pr_fmt(fmt) "sysctl: " fmt
No. This needs to be defined at the top of the file, please look
at other uses on kernel/*.c and just use:
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
The filename already provides the name we want.
> +
> static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
> int *valp,
> int write, void *data)
> {
> struct do_proc_dointvec_minmax_conv_param *param = data;
> +
> if (write) {
> int val = *negp ? -*lvalp : *lvalp;
> + bool clamped = false;
> bool clamp = param->flags &&
> (*param->flags & CTL_FLAGS_CLAMP_RANGE);
>
> if (param->min && *param->min > val) {
> - if (clamp)
> + if (clamp) {
> val = *param->min;
> - else
> + clamped = true;
> + } else {
> return -EINVAL;
> + }
> }
> if (param->max && *param->max < val) {
> - if (clamp)
> + if (clamp) {
> val = *param->max;
> - else
> + clamped = true;
> + } else {
> return -EINVAL;
> + }
> }
> *valp = val;
> + if (clamped && param->name)
> + pr_warn_ratelimited("\"%s\" was set out of range [%d, %d], clamped to %d.\n",
> + param->name,
> + param->min ? *param->min : -INT_MAX,
> + param->max ? *param->max : INT_MAX, val);
We already warn here but I see you also add yet-another warning for the driver....
Luis
next prev parent reply other threads:[~2018-03-12 20:50 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 20:15 [PATCH v4 0/6] ipc: Clamp *mni to the real IPCMNI limit Waiman Long
2018-03-12 20:15 ` [PATCH v4 1/6] sysctl: Add flags to support min/max range clamping Waiman Long
2018-03-12 20:44 ` Luis R. Rodriguez
2018-03-12 20:48 ` Waiman Long
2018-03-13 17:46 ` Eric W. Biederman
2018-03-13 18:49 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 2/6] proc/sysctl: Check for invalid flags bits Waiman Long
2018-03-12 20:46 ` Luis R. Rodriguez
2018-03-12 20:54 ` Waiman Long
2018-03-12 20:59 ` Luis R. Rodriguez
2018-03-12 21:02 ` Waiman Long
2018-03-12 20:52 ` Andrew Morton
2018-03-12 22:12 ` Waiman Long
2018-03-12 22:42 ` Andrew Morton
2018-03-12 20:15 ` [PATCH v4 3/6] sysctl: Warn when a clamped sysctl parameter is set out of range Waiman Long
2018-03-12 20:50 ` Luis R. Rodriguez [this message]
2018-03-12 21:07 ` Waiman Long
2018-03-12 21:00 ` Andrew Morton
2018-03-12 21:04 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 4/6] ipc: Clamp msgmni and shmmni to the real IPCMNI limit Waiman Long
2018-03-13 18:17 ` Eric W. Biederman
2018-03-13 18:39 ` Waiman Long
2018-03-13 20:29 ` Eric W. Biederman
2018-03-13 21:06 ` Waiman Long
2018-03-15 0:49 ` [RFC][PATCH] ipc: Remove IPCMNI Eric W. Biederman
2018-03-15 17:02 ` Waiman Long
2018-03-15 19:00 ` Eric W. Biederman
2018-03-15 21:46 ` Waiman Long
2018-03-29 2:14 ` Davidlohr Bueso
2018-03-29 8:47 ` Manfred Spraul
2018-03-29 10:56 ` Matthew Wilcox
2018-03-29 18:07 ` Manfred Spraul
2018-03-29 18:52 ` Eric W. Biederman
2018-03-29 19:32 ` Matthew Wilcox
2018-03-29 20:08 ` Eric W. Biederman
2018-03-15 19:45 ` Matthew Wilcox
2018-03-12 20:15 ` [PATCH v4 5/6] ipc: Clamp semmni to the real IPCMNI limit Waiman Long
2018-03-12 20:52 ` Luis R. Rodriguez
2018-03-12 20:59 ` Waiman Long
2018-03-12 20:15 ` [PATCH v4 6/6] test_sysctl: Add range clamping test Waiman Long
2018-03-12 20:53 ` Luis R. Rodriguez
2018-03-12 21:00 ` Waiman Long
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