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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Timur Tabi <timur@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Matthew Wilcox <willy@infradead.org>,
	akpm@linux-foundation.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	roman.fietze@magna.com, Kees Cook <keescook@chromium.org>,
	John Ogness <john.ogness@linutronix.de>,
	akinobu.mita@gmail.com, glider@google.com,
	Andrey Konovalov <andreyknvl@google.com>,
	Marco Elver <elver@google.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Pavel Machek <pavel@ucw.cz>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/3][RESEND] add support for never printing hashed addresses
Date: Thu, 11 Feb 2021 00:46:15 +0900	[thread overview]
Message-ID: <6da0be5a-7cb0-4943-e61f-7c3275e60cb6@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20210210051814.845713-1-timur@kernel.org>

On 2021/02/10 14:18, Timur Tabi wrote:
> [accidentally sent from the wrong email address, so resending]
> 
> [The list of email addresses on CC: is getting quite lengthy,
> so I hope I've included everyone.]
> 
> Although hashing addresses printed via printk does make the
> kernel more secure, it interferes with debugging, especially
> with some functions like print_hex_dump() which always uses
> hashed addresses.

Oh, I was wishing

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3b53c73580c5..34c7e145ac3c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -802,7 +802,7 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr,
 	 * Print the real pointer value for NULL and error pointers,
 	 * as they are not actual addresses.
 	 */
-	if (IS_ERR_OR_NULL(ptr))
+	if (IS_ERR_OR_NULL(ptr) || IS_ENABLED(CONFIG_DEBUG_DONT_HASH_POINTERS))
 		return pointer_string(buf, end, ptr, spec);
 
 	/* When debugging early boot use non-cryptographically secure hash. */

change as a kernel config option, for more we try to switch using kernel command line options,
more we likely make errors with sharing appropriate kernel command line options
(e.g. https://github.com/google/syzkaller/commit/99c64d5c672700d6c0de63d11db25a0678e47a75 ).


  parent reply	other threads:[~2021-02-10 15:48 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10  5:18 [PATCH 0/3][RESEND] add support for never printing hashed addresses Timur Tabi
2021-02-10  5:18 ` [PATCH 1/3] lib/test_printf: use KSTM_MODULE_GLOBALS macro Timur Tabi
2021-02-10  5:21   ` Timur Tabi
2021-02-10 13:14   ` Petr Mladek
2021-02-10  5:18 ` [PATCH 2/3] kselftest: add support for skipped tests Timur Tabi
2021-02-10  5:18 ` [PATCH 3/3] lib/vsprintf: make-printk-non-secret printks all addresses as unhashed Timur Tabi
2021-02-10 11:03   ` Vlastimil Babka
2021-02-10 13:41   ` Petr Mladek
2021-02-10 17:27     ` Timur Tabi
2021-02-12 11:52       ` Petr Mladek
2021-02-10 11:11 ` [PATCH 0/3][RESEND] add support for never printing hashed addresses Marco Elver
2021-02-10 19:03   ` Timur Tabi
2021-02-10 11:47 ` Andy Shevchenko
2021-02-10 16:57   ` Timur Tabi
2021-02-10 15:46 ` Tetsuo Handa [this message]
2021-02-10 16:18   ` Steven Rostedt
2021-02-10 16:39     ` Tetsuo Handa
2021-02-10 16:46       ` Steven Rostedt
2021-02-10 17:07         ` Tetsuo Handa
2021-02-10 17:29           ` Steven Rostedt
2021-02-10 17:21         ` Timur Tabi
2021-02-10 16:54       ` Andy Shevchenko
2021-02-10 17:41         ` Tetsuo Handa

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