From: Petr Mladek <pmladek@suse.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
John Ogness <john.ogness@linutronix.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH printk 2/3] printk: move dictionary keys to dev_printk_info
Date: Fri, 18 Sep 2020 14:13:42 +0200 [thread overview]
Message-ID: <20200918121342.GD14605@alley> (raw)
In-Reply-To: <316cf147-0ae2-1c88-7375-07aedc58bd15@rasmusvillemoes.dk>
On Fri 2020-09-18 08:16:37, Rasmus Villemoes wrote:
> On 17/09/2020 15.16, John Ogness wrote:
>
> > if (dev->class)
> > subsys = dev->class->name;
> > else if (dev->bus)
> > subsys = dev->bus->name;
> > else
> > - return 0;
> > + return;
> >
> > - pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
> > - if (pos >= hdrlen)
> > - goto overflow;
> > + snprintf(dev_info->subsystem, sizeof(dev_info->subsystem), subsys);
>
> It's unlikely that subsys would contain a %, but this will be yet
> another place to spend brain cycles ignoring if doing static analysis.
> So can we not do this. Either of strXcpy() for X=s,l will do the same
> thing, and likely faster.
Good point! Better be on the safe size in a generic printk() API.
Well, I am afraid that this would be only small drop in a huge lake.
class->name and bus->name seems to be passed to %s in so many
*print*() calls all over the kernel code.
IMHO, this is not the right place to prevent the problem. Dangerous
names must be prevented when a new bus, class, device is added.
Best Rergards,
Petr
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WARNING: multiple messages have this Message-ID (diff)
From: Petr Mladek <pmladek@suse.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: John Ogness <john.ogness@linutronix.de>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk 2/3] printk: move dictionary keys to dev_printk_info
Date: Fri, 18 Sep 2020 14:13:42 +0200 [thread overview]
Message-ID: <20200918121342.GD14605@alley> (raw)
In-Reply-To: <316cf147-0ae2-1c88-7375-07aedc58bd15@rasmusvillemoes.dk>
On Fri 2020-09-18 08:16:37, Rasmus Villemoes wrote:
> On 17/09/2020 15.16, John Ogness wrote:
>
> > if (dev->class)
> > subsys = dev->class->name;
> > else if (dev->bus)
> > subsys = dev->bus->name;
> > else
> > - return 0;
> > + return;
> >
> > - pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys);
> > - if (pos >= hdrlen)
> > - goto overflow;
> > + snprintf(dev_info->subsystem, sizeof(dev_info->subsystem), subsys);
>
> It's unlikely that subsys would contain a %, but this will be yet
> another place to spend brain cycles ignoring if doing static analysis.
> So can we not do this. Either of strXcpy() for X=s,l will do the same
> thing, and likely faster.
Good point! Better be on the safe size in a generic printk() API.
Well, I am afraid that this would be only small drop in a huge lake.
class->name and bus->name seems to be passed to %s in so many
*print*() calls all over the kernel code.
IMHO, this is not the right place to prevent the problem. Dangerous
names must be prevented when a new bus, class, device is added.
Best Rergards,
Petr
next prev parent reply other threads:[~2020-09-18 12:13 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 13:16 [PATCH printk 0/3] printk: move dictionaries to meta data John Ogness
2020-09-17 13:16 ` John Ogness
2020-09-17 13:16 ` [PATCH printk 1/3] printk: move printk_info into separate array John Ogness
2020-09-17 13:16 ` John Ogness
2020-09-18 10:06 ` Petr Mladek
2020-09-18 10:06 ` Petr Mladek
2020-09-18 11:30 ` John Ogness
2020-09-18 11:30 ` John Ogness
2020-09-17 13:16 ` [PATCH printk 2/3] printk: move dictionary keys to dev_printk_info John Ogness
2020-09-17 13:16 ` John Ogness
2020-09-18 6:16 ` Rasmus Villemoes
2020-09-18 6:16 ` Rasmus Villemoes
2020-09-18 12:13 ` Petr Mladek [this message]
2020-09-18 12:13 ` Petr Mladek
2020-09-18 12:32 ` Rasmus Villemoes
2020-09-18 12:32 ` Rasmus Villemoes
2020-09-18 14:24 ` Petr Mladek
2020-09-18 14:24 ` Petr Mladek
2020-09-18 11:39 ` Petr Mladek
2020-09-18 11:39 ` Petr Mladek
2020-09-17 13:16 ` [PATCH printk 3/3] printk: remove dict ring John Ogness
2020-09-17 13:16 ` John Ogness
2020-09-17 17:59 ` Linus Torvalds
2020-09-17 17:59 ` Linus Torvalds
2020-09-18 14:56 ` Petr Mladek
2020-09-18 14:56 ` Petr Mladek
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