From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Helge Deller <deller@gmx.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages
Date: Thu, 14 Sep 2017 15:53:41 +0900 [thread overview]
Message-ID: <20170914065341.GD599@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20170908172528.qc2vdtxzqh777k6o@intel.com>
On (09/08/17 10:25), Luck, Tony wrote:
> On Fri, Sep 08, 2017 at 03:18:30PM +0900, Sergey Senozhatsky wrote:
> > if the addr is not in kernel .text, then try dereferencing it and check
> > if the dereferenced addr is in kernel .text.
>
> If it really is a function pointer, then we know that it is safe
> to dereference. But if it isn't, then maybe not?
yes. I thought about it - we can do %pS on a pointer to a global
structure. so that simple heuristic would not work reliably. we
parse ELF sections, and we know the address range of .opd section,
so we can check if the supplied pointer is within the .opd section
or not.
.opd does exist on ia64. not sure what's the name of ELF descriptor
section on ppc64/parisc64.
if we will be able to simply do
.opd->address <= ptr <= .opd->address + .opd->size
then it mostly should work for us. I guess.
> If it is a function pointer then dereferening will indeed give
> us a .text address. But if it isn't, it might still give us a
> .text address (we could reduce the probability of a false hit
> by checking that the .text address was exactly on a symbol with
> no offset ... but data values that happen to be the addresses of
> function entry points are possible).
hm. yes, need to think more.
-ss
next prev parent reply other threads:[~2017-09-14 6:53 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-06 20:27 [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages Helge Deller
2017-09-06 20:27 ` [PATCH 01/14] arm: Use %pS printk format for symbols from direct addresses Helge Deller
2017-09-06 20:27 ` [PATCH 02/14] um: " Helge Deller
2017-09-12 12:10 ` Petr Mladek
2017-09-21 20:13 ` Richard Weinberger
2017-09-06 20:27 ` [PATCH 03/14] x86: " Helge Deller
2017-09-06 20:27 ` [PATCH 04/14] ti_sci: Use %pS printk format for " Helge Deller
2017-09-08 23:30 ` Nishanth Menon
2017-09-09 0:30 ` Santosh Shilimkar
2017-09-06 20:27 ` [PATCH 05/14] i915: " Helge Deller
2017-09-27 12:24 ` [Intel-gfx] " Daniel Vetter
2017-09-06 20:27 ` [PATCH 06/14] md/bcache: " Helge Deller
2017-09-07 4:50 ` Coly Li
2017-09-07 7:42 ` Helge Deller
2017-09-07 7:49 ` Coly Li
2017-09-07 8:05 ` Sergey Senozhatsky
2017-09-06 20:27 ` [PATCH 07/14] power/avs: " Helge Deller
2017-09-08 23:37 ` Nishanth Menon
2017-09-06 20:27 ` [PATCH 08/14] fs/f2fs: " Helge Deller
2017-09-06 20:27 ` [PATCH 09/14] fs/pstore: " Helge Deller
2018-11-29 23:26 ` Kees Cook
2018-11-29 23:49 ` Luck, Tony
2018-11-30 0:40 ` Kees Cook
2017-09-06 20:27 ` [PATCH 10/14] fs/xfs: " Helge Deller
2017-09-08 7:38 ` Christoph Hellwig
2017-09-18 18:37 ` Darrick J. Wong
2017-09-06 20:27 ` [PATCH 11/14] smp: Use %pF printk format specifier for function pointers Helge Deller
2017-09-06 20:27 ` [PATCH 12/14] mm/memblock: Use %pS printk format for direct addresses Helge Deller
2017-09-06 20:28 ` [PATCH 13/14] netfilter/ipvs: " Helge Deller
2017-10-09 5:52 ` Simon Horman
2017-11-06 13:46 ` Pablo Neira Ayuso
2017-09-06 20:28 ` [PATCH 14/14] sound/core: " Helge Deller
2017-09-07 8:36 ` Takashi Iwai
2017-09-07 0:45 ` [PATCH 00/14] Fix wrong %pF and %pS printk format specifier usages Sergey Senozhatsky
2017-09-07 6:01 ` Helge Deller
2017-09-07 7:56 ` Sergey Senozhatsky
2017-09-07 8:32 ` Sergey Senozhatsky
2017-09-07 9:12 ` Helge Deller
2017-09-07 9:36 ` Sergey Senozhatsky
2017-09-07 9:51 ` Sergey Senozhatsky
2017-09-07 12:38 ` Helge Deller
2017-09-07 16:05 ` Luck, Tony
2017-09-08 6:18 ` Sergey Senozhatsky
2017-09-08 17:25 ` Luck, Tony
2017-09-08 18:28 ` Helge Deller
2017-09-14 7:40 ` Sergey Senozhatsky
2017-09-14 8:03 ` Sergey Senozhatsky
2017-09-14 8:39 ` Helge Deller
2017-09-14 9:27 ` Sergey Senozhatsky
2017-09-14 9:47 ` Helge Deller
2017-09-14 16:01 ` Luck, Tony
2017-09-18 7:03 ` Sergey Senozhatsky
2017-09-14 6:53 ` Sergey Senozhatsky [this message]
2017-09-08 20:49 ` Helge Deller
2017-09-12 11:18 ` Petr Mladek
2017-09-14 6:44 ` Sergey Senozhatsky
2017-09-08 22:23 ` Yu, Fenghua
2017-09-14 6:35 ` Sergey Senozhatsky
2017-09-07 16:50 ` Joe Perches
2017-09-08 6:23 ` Sergey Senozhatsky
2017-09-08 20:39 ` Helge Deller
2017-09-12 12:23 ` Petr Mladek
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