Re: [PATCH 1/2] vsprintf: Prevent crash when dereferencing invalid pointers for %pD

[Petr Mladek]

On Fri 2019-08-09 10:56:04,  Justin He (Arm Technology China)  wrote:
> 
> 
> > -----Original Message-----
> > From: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> > Sent: 2019å8æ9æ 18:52
> > To: Justin He (Arm Technology China) <Justin.He@xxxxxxx>
> > Cc: Petr Mladek <pmladek@xxxxxxxx>; Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx>; Sergey Senozhatsky
> > <sergey.senozhatsky@xxxxxxxxx>; Geert Uytterhoeven
> > <geert+renesas@xxxxxxxxx>; Linux Kernel Mailing List <linux-
> > kernel@xxxxxxxxxxxxxxx>; Thomas Gleixner <tglx@xxxxxxxxxxxxx>; Steven
> > Rostedt (VMware) <rostedt@xxxxxxxxxxx>; Kees Cook
> > <keescook@xxxxxxxxxxxx>; Shuah Khan <shuah@xxxxxxxxxx>; Tobin C.
> > Harding <tobin@xxxxxxxxxx>
> > Subject: Re: [PATCH 1/2] vsprintf: Prevent crash when dereferencing invalid
> > pointers for %pD
> >
> > On Fri, Aug 9, 2019 at 4:28 AM Jia He <justin.he@xxxxxxx> wrote:
> > >
> > > Commit 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing
> > invalid
> > > pointers") prevents most crash except for %pD.
> > > There is an additional pointer dereferencing before dentry_name.
> > >
> > > At least, vma->file can be NULL and be passed to printk %pD in
> > > print_bad_pte, which can cause crash.
> > >
> > > This patch fixes it with introducing a new file_dentry_name.
> > >
> >
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> >
> > Perhaps you need to add a Fixes tag
> Thanks, Andy
> Fixes: 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers")

I have added the Fixes tag and pushed the patch into printk.git,
branch for-5.4.

Thanks for the fix.

Best Regards,
Petr