All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Tobin C. Harding" <me@tobin.cc>
To: linux-kernel@vger.kernel.org
Cc: "Tobin C. Harding" <me@tobin.cc>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Kees Cook <keescook@chromium.org>,
	Anna-Maria Gleixner <anna-maria@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Theodore Ts'o" <tytso@mit.edu>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH v3 0/4] enable early printing of hashed pointers
Date: Fri,  4 May 2018 09:07:37 +1000	[thread overview]
Message-ID: <1525388861-27018-1-git-send-email-me@tobin.cc> (raw)

Currently if an attempt is made to print a pointer before there is
enough entropy then '(____ptrval____)' is printed.  This makes debugging
stack traces during early boot difficult.

It was observed that we can relax the requirement for cryptographically
secure hashing when debugging while still maintaining pointer hashing
behaviour.  This allows kernels to be debugged without developers
relying on different pointer printing behavior.

Using the hw RNG if available solves this problem for those machines
that have a hardware RNG, we would like to solve it for _all_ machines.

Patch 1 - Whitespace fixes.
Patch 2 - Fix get_random_bytes_arch()
Patch 3 - Use hw RNG for pointer hashing if available (by default).
Patch 4 - Use insecure hashing with command line option 'debug_early_boot'.

thanks,
Tobin.


v2 -> v3
 - Add __ro_after_init (suggested by Kees).

v1 -> v2
 - Use min_t() instead of min() (thanks checkpatch).
 - Add __must_check to function declaration (thanks Steve).
 - Use hw RNG by default if available (as originally suggested by Kees).
 - Add command line option to use cryptographically insecure hashing.
   If debug_early_boot is enabled use hash_long() instead of siphash
   (as requested by Steve, and solves original problem for Anna-Maria).

Tobin C. Harding (4):
  random: Fix whitespace pre random-bytes work
  random: Return nbytes filled from hw RNG
  vsprintf: Use hw RNG for ptr_key
  vsprintf: Add command line option debug_early_boot

 Documentation/admin-guide/kernel-parameters.txt |  8 ++++++
 drivers/char/random.c                           | 19 +++++++------
 include/linux/random.h                          |  2 +-
 lib/vsprintf.c                                  | 37 +++++++++++++++++++++++--
 4 files changed, 53 insertions(+), 13 deletions(-)

-- 
2.7.4

             reply	other threads:[~2018-05-03 23:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-03 23:07 Tobin C. Harding [this message]
2018-05-03 23:07 ` [PATCH v3 1/4] random: Fix whitespace pre random-bytes work Tobin C. Harding
2018-05-03 23:07 ` [PATCH v3 2/4] random: Return nbytes filled from hw RNG Tobin C. Harding
2018-05-03 23:07 ` [PATCH v3 3/4] vsprintf: Use hw RNG for ptr_key Tobin C. Harding
2018-05-03 23:07 ` [PATCH v3 4/4] vsprintf: Add command line option debug_early_boot Tobin C. Harding
2018-05-04  0:09   ` Steven Rostedt
2018-05-04  2:23 ` [PATCH v3 0/4] enable early printing of hashed pointers Theodore Y. Ts'o
2018-05-04  3:50   ` Tobin C. Harding

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1525388861-27018-1-git-send-email-me@tobin.cc \
    --to=me@tobin.cc \
    --cc=akpm@linux-foundation.org \
    --cc=anna-maria@linutronix.de \
    --cc=arnd@arndb.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rdunlap@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=torvalds@linux-foundation.org \
    --cc=tytso@mit.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.