linux-kernel - [PATCH 0/3][v3] add support for never printing hashed addresses

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Message-Id: <20210210213453.1504219-1-timur@kernel.org>
Date:   Wed, 10 Feb 2021 15:34:50 -0600
From:   Timur Tabi <timur@...nel.org>
To:     Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        akpm@...ux-foundation.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        roman.fietze@...na.com, Kees Cook <keescook@...omium.org>,
        John Ogness <john.ogness@...utronix.de>,
        akinobu.mita@...il.com, glider@...gle.com,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Pavel Machek <pavel@....cz>,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 0/3][v3] add support for never printing hashed addresses

[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.

To avoid having to choose between %p and %px, it's easier to
add a kernel command line that treats all %p as %px.  This
encourages developers to use %p more without making debugging
more difficult.

Patches #1 and #2 upgrade the kselftest framework so that
it can report on tests that were skipped outright.  This
is needed for the test_printf module which will now skip
%p hashing tests if hashing is disabled.

Patch #2 upgrades the printf library to check the command
line.  It also updates test_printf().

Full series:

Acked-by: Marco Elver <elver@...gle.com>

Timur Tabi (3):
  [v3] lib: use KSTM_MODULE_GLOBALS macro in kselftest drivers
  [v3] kselftest: add support for skipped tests
  [v3] lib/vsprintf: debug_never_hash_pointers prints all addresses as
    unhashed

 .../admin-guide/kernel-parameters.txt         | 15 ++++++++
 lib/test_bitmap.c                             |  3 +-
 lib/test_printf.c                             | 12 +++++-
 lib/vsprintf.c                                | 38 ++++++++++++++++++-
 tools/testing/selftests/kselftest_module.h    | 18 ++++++---
 5 files changed, 74 insertions(+), 12 deletions(-)

-- 
2.25.1