From: Alexey Dobriyan <adobriyan@gmail.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/5] proc: make /proc/*/cmdline go through LSM
Date: Wed, 21 Feb 2018 22:39:38 +0300 [thread overview]
Message-ID: <20180221193938.GA28799@avx2> (raw)
In-Reply-To: <CAHp75VdaxkMn2UxURSB4fWep=iv4CRAkmEtdKBp1HKyxtW2tTg@mail.gmail.com>
On Wed, Feb 21, 2018 at 09:28:41PM +0200, Andy Shevchenko wrote:
> On Wed, Feb 21, 2018 at 9:23 PM, Alexey Dobriyan <adobriyan@gmail.com> wrote:
> > /proc/*/cmdline is not different from /proc/*/environ as it accesses
> > target task's memory (and can access the very same region of memory)
> > but it doesn't go through ptrace_may_access() and thus doesn't go through LSM.
>
> > +static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
> > +{
> > + struct mm_struct *mm = proc_mem_open(inode, mode);
> > +
> > + if (IS_ERR(mm))
> > + return PTR_ERR(mm);
>
> So, is it possible to have it NULL?..
I haven't looked closely, but if kernel thread is accesses then yes.
Regardless, patch only moves function so that code compiles, untangling
this little mess is separate adventure.
> > +static int mem_release(struct inode *inode, struct file *file)
> > +{
> > + struct mm_struct *mm = file->private_data;
>
> > + if (mm)
>
> ...or I don't get this check.
>
> > + mmdrop(mm);
> > + return 0;
> > +}
It should trigger if kernel thread is accessed.
next prev parent reply other threads:[~2018-02-21 19:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-21 19:23 [PATCH 1/5] proc: make /proc/*/cmdline go through LSM Alexey Dobriyan
2018-02-21 19:26 ` [PATCH 2/5] proc: more "unsigned int" in /proc/*/cmdline Alexey Dobriyan
2018-02-21 19:27 ` [PATCH 3/5] proc: somewhat simpler code for /proc/*/cmdline Alexey Dobriyan
2018-02-21 19:30 ` [PATCH 4/5] proc: simpler iterations " Alexey Dobriyan
2018-02-21 19:33 ` [PATCH 5/5] proc: deduplicate /proc/*/cmdline implementation Alexey Dobriyan
2018-04-20 0:15 ` [PATCH 4/5] proc: simpler iterations for /proc/*/cmdline Andrew Morton
2018-04-20 19:46 ` Alexey Dobriyan
2018-02-21 19:28 ` [PATCH 1/5] proc: make /proc/*/cmdline go through LSM Andy Shevchenko
2018-02-21 19:39 ` Alexey Dobriyan [this message]
2018-02-21 20:06 ` Andrew Morton
2018-02-23 19:43 ` [PATCH v2 " Alexey Dobriyan
2018-04-20 0:02 ` [PATCH " Andrew Morton
2018-04-20 19:25 ` Alexey Dobriyan
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