Commit Graph

110 Commits

Author SHA1 Message Date
Denys Vlasenko
133fd9f5cd vsprintf: further optimize decimal conversion
Previous code was using optimizations which were developed to work well
even on narrow-word CPUs (by today's standards).  But Linux runs only on
32-bit and wider CPUs.  We can use that.

First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly
divide by 10 much larger numbers, and thus we can print groups of 9 digits
instead of groups of 5 digits.

Next: there are two algorithms to print larger numbers.  One is generic:
divide by 1000000000 and repeatedly print groups of (up to) 9 digits.
It's conceptually simple, but requires an (unsigned long long) /
1000000000 division.

Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
manipulates them cleverly and generates groups of 4 decimal digits.  It so
happens that it does NOT require long long division.

If long is > 32 bits, division of 64-bit values is relatively easy, and we
will use the first algorithm.  If long long is > 64 bits (strange
architecture with VERY large long long), second algorithm can't be used,
and we again use the first one.

Else (if long is 32 bits and long long is 64 bits) we use second one.

And third: there is a simple optimization which takes fast path not only
for zero as was done before, but for all one-digit numbers.

In all tested cases new code is faster than old one, in many cases by 30%,
in few cases by more than 50% (for example, on x86-32, conversion of
12345678).  Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit
case.

This patch is based upon an original from Michal Nazarewicz.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:27 -07:00
Grant Likely
725fe002d3 vsprintf: correctly handle width when '#' flag used in %#p format
The '%p' output of the kernel's vsprintf() uses spec.field_width to
determine how many digits to output based on 2 * sizeof(void*) so that all
digits of a pointer are shown.  ie.  a pointer will be output as
"001A2B3C" instead of "1A2B3C".  However, if the '#' flag is used in the
format (%#p), then the code doesn't take into account the width of the
'0x' prefix and will end up outputing "0x1A2B3C" instead of "0x001A2B3C".

This patch reworks the "pointer()" format hook to include 2 characters for
the '0x' prefix if the '#' flag is included.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-31 17:49:27 -07:00
Pierre Carrier
7c20342230 lib/vsprintf.c: "%#o",0 becomes '0' instead of '00'
number()'s behaviour is slighly changed: 0 becomes "0" instead of "00"
when using the flag SPECIAL and base 8.

Before:
Number\Format  %o    %#o  %x    %#x
            0     0   00    0   0x0
            1     1   01    1   0x1
           16    20  020   10  0x10

After:
Number\Format  %o    %#o  %x    %#x
            0     0    0    0   0x0
            1     1   01    1   0x1
           16    20  020   10  0x10

Signed-off-by: Pierre Carrier <pierre@spotify.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:33 -07:00
Stephen Boyd
4796dd200d vsprintf: fix %ps on non symbols when using kallsyms
Using %ps in a printk format will sometimes fail silently and print the
empty string if the address passed in does not match a symbol that
kallsyms knows about.  But using %pS will fall back to printing the full
address if kallsyms can't find the symbol.  Make %ps act the same as %pS
by falling back to printing the address.

While we're here also make %ps print the module that a symbol comes from
so that it matches what %pS already does.  Take this simple function for
example (in a module):

	static void test_printk(void)
	{
		int test;
		pr_info("with pS: %pS\n", &test);
		pr_info("with ps: %ps\n", &test);
	}

Before this patch:

 with pS: 0xdff7df44
 with ps:

After this patch:

 with pS: 0xdff7df44
 with ps: 0xdff7df44

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:32 -07:00
Linus Torvalds
11bcb32848 The following text was taken from the original review request:
"[PATCH 0/3] RFC - module.h usage cleanups in fs/ and lib/"
 		https://lkml.org/lkml/2012/2/29/589
 --
 
 Fix up files in fs/ and lib/ dirs to only use module.h if they really
 need it.
 
 These are trivial in scope vs. the work done previously.  We now have
 things where any few remaining cleanups can be farmed out to arch or
 subsystem maintainers, and I have done so when possible.  What is
 remaining here represents the bits that don't clearly lie within a
 single arch/subsystem boundary, like the fs dir and the lib dir.
 
 Some duplicate includes arising from overlapping fixes from
 independent subsystem maintainer submissions are also quashed.
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Merge tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

Pull cleanup of fs/ and lib/ users of module.h from Paul Gortmaker:
 "Fix up files in fs/ and lib/ dirs to only use module.h if they really
  need it.

  These are trivial in scope vs the work done previously.  We now have
  things where any few remaining cleanups can be farmed out to arch or
  subsystem maintainers, and I have done so when possible.  What is
  remaining here represents the bits that don't clearly lie within a
  single arch/subsystem boundary, like the fs dir and the lib dir.

  Some duplicate includes arising from overlapping fixes from
  independent subsystem maintainer submissions are also quashed."

Fix up trivial conflicts due to clashes with other include file cleanups
(including some due to the previous bug.h cleanup pull).

* tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
  lib: reduce the use of module.h wherever possible
  fs: reduce the use of module.h wherever possible
  includecheck: delete any duplicate instances of module.h
2012-03-24 10:24:31 -07:00
KAMEZAWA Hiroyuki
1ac101a5d6 procfs: add num_to_str() to speed up /proc/stat
== stat_check.py
num = 0
with open("/proc/stat") as f:
        while num < 1000 :
                data = f.read()
                f.seek(0, 0)
                num = num + 1
==

perf shows

    20.39%  stat_check.py  [kernel.kallsyms]    [k] format_decode
    13.41%  stat_check.py  [kernel.kallsyms]    [k] number
    12.61%  stat_check.py  [kernel.kallsyms]    [k] vsnprintf
    10.85%  stat_check.py  [kernel.kallsyms]    [k] memcpy
     4.85%  stat_check.py  [kernel.kallsyms]    [k] radix_tree_lookup
     4.43%  stat_check.py  [kernel.kallsyms]    [k] seq_printf

This patch removes most of calls to vsnprintf() by adding num_to_str()
and seq_print_decimal_ull(), which prints decimal numbers without rich
functions provided by printf().

On my 8cpu box.
== Before patch ==
[root@bluextal test]# time ./stat_check.py

real    0m0.150s
user    0m0.026s
sys     0m0.121s

== After patch ==
[root@bluextal test]# time ./stat_check.py

real    0m0.055s
user    0m0.022s
sys     0m0.030s

[akpm@linux-foundation.org: remove incorrect comment, use less statck in num_to_str(), move comment from .h to .c, simplify seq_put_decimal_ull()]
[andrea@betterlinux.com: avoid breaking the ABI in /proc/stat]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrea Righi <andrea@betterlinux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Turner <pjt@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-23 16:58:42 -07:00
Paul Gortmaker
8bc3bcc93a lib: reduce the use of module.h wherever possible
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-07 15:04:04 -05:00
Jan Beulich
5756b76e4d vsprintf: make %pV handling compatible with kasprintf()
kasprintf() (and potentially other functions that I didn't run across so
far) want to evaluate argument lists twice.  Caring to do so for the
primary list is obviously their job, but they can't reasonably be
expected to check the format string for instances of %pV, which however
need special handling too: On architectures like x86-64 (as opposed to
e.g.  ix86), using the same argument list twice doesn't produce the
expected results, as an internally managed cursor gets updated during
the first run.

Fix the problem by always acting on a copy of the original list when
handling %pV.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06 08:22:26 -08:00
Michał Mirosław
c8f44affb7 net: introduce and use netdev_features_t for device features sets
v2:	add couple missing conversions in drivers
	split unexporting netdev_fix_features()
	implemented %pNF
	convert sock::sk_route_(no?)caps

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-16 17:43:10 -05:00
Andy Shevchenko
55036ba76b lib: rename pack_hex_byte() to hex_byte_pack()
As suggested by Andrew Morton in [1] there is better to have most
significant part first in the function name.

[1] https://lkml.org/lkml/2011/9/20/22

There is no functional change.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Mimi Zohar <zohar@us.ibm.com>
Cc: James Morris <jmorris@namei.org>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:56 -07:00
Alexey Dobriyan
1dff46d698 lib/kstrtox: common code between kstrto*() and simple_strto*() functions
Currently termination logic (\0 or \n\0) is hardcoded in _kstrtoull(),
avoid that for code reuse between kstrto*() and simple_strtoull().
Essentially, make them different only in termination logic.

simple_strtoull() (and scanf(), BTW) ignores integer overflow, that's a
bug we currently don't have guts to fix, making KSTRTOX_OVERFLOW hack
necessary.

Almost forgot: patch shrinks code size by about ~80 bytes on x86_64.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:56 -07:00
Linus Torvalds
45b583b10a Merge 'akpm' patch series
* Merge akpm patch series: (122 commits)
  drivers/connector/cn_proc.c: remove unused local
  Documentation/SubmitChecklist: add RCU debug config options
  reiserfs: use hweight_long()
  reiserfs: use proper little-endian bitops
  pnpacpi: register disabled resources
  drivers/rtc/rtc-tegra.c: properly initialize spinlock
  drivers/rtc/rtc-twl.c: check return value of twl_rtc_write_u8() in twl_rtc_set_time()
  drivers/rtc: add support for Qualcomm PMIC8xxx RTC
  drivers/rtc/rtc-s3c.c: support clock gating
  drivers/rtc/rtc-mpc5121.c: add support for RTC on MPC5200
  init: skip calibration delay if previously done
  misc/eeprom: add eeprom access driver for digsy_mtc board
  misc/eeprom: add driver for microwire 93xx46 EEPROMs
  checkpatch.pl: update $logFunctions
  checkpatch: make utf-8 test --strict
  checkpatch.pl: add ability to ignore various messages
  checkpatch: add a "prefer __aligned" check
  checkpatch: validate signature styles and To: and Cc: lines
  checkpatch: add __rcu as a sparse modifier
  checkpatch: suggest using min_t or max_t
  ...

Did this as a merge because of (trivial) conflicts in
 - Documentation/feature-removal-schedule.txt
 - arch/xtensa/include/asm/uaccess.h
that were just easier to fix up in the merge than in the patch series.
2011-07-25 21:00:19 -07:00
Andy Shevchenko
75fb8f2693 lib: make _tolower() public
This function is required by *printf and kstrto* functions that are
located in the different modules.  This patch makes _tolower() public.
However, it's good idea to not use the helper outside of mentioned
functions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:16 -07:00
Jan Engelhardt
f996f20812 lib/vsprintf: replace link to Draft by final RFC number
The draft has evolved to RFC 5952.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-07-14 20:51:40 +02:00
Joe Perches
29cf519ee0 vsprintf: Update %pI6c to not compress a single 0
RFC 5952 (http://tools.ietf.org/html/rfc5952) mandates that 2 or more
consecutive 0's are required before using :: compression.

Update ip6_compressed_string to match the RFC and update the http
reference as well.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-09 12:51:15 -07:00
Jan Beulich
d9be9b90d6 lib/vsprintf.c: fix interaction of kasprintf() and vsnprintf() when using %pV
Otherwise, the warning at the top of vsnprintf() gets triggered by
kvasprintf()'s first invocation (with NULL buffer and zero size) of
vsnprintf().

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:47 -07:00
Linus Torvalds
57d19e80f4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  b43: fix comment typo reqest -> request
  Haavard Skinnemoen has left Atmel
  cris: typo in mach-fs Makefile
  Kconfig: fix copy/paste-ism for dell-wmi-aio driver
  doc: timers-howto: fix a typo ("unsgined")
  perf: Only include annotate.h once in tools/perf/util/ui/browsers/annotate.c
  md, raid5: Fix spelling error in comment ('Ofcourse' --> 'Of course').
  treewide: fix a few typos in comments
  regulator: change debug statement be consistent with the style of the rest
  Revert "arm: mach-u300/gpio: Fix mem_region resource size miscalculations"
  audit: acquire creds selectively to reduce atomic op overhead
  rtlwifi: don't touch with treewide double semicolon removal
  treewide: cleanup continuations and remove logging message whitespace
  ath9k_hw: don't touch with treewide double semicolon removal
  include/linux/leds-regulator.h: fix syntax in example code
  tty: fix typo in descripton of tty_termios_encode_baud_rate
  xtensa: remove obsolete BKL kernel option from defconfig
  m68k: fix comment typo 'occcured'
  arch:Kconfig.locks Remove unused config option.
  treewide: remove extra semicolons
  ...
2011-05-23 09:12:26 -07:00
Ingo Molnar
411f05f123 vsprintf: Turn kptr_restrict off by default
kptr_restrict has been triggering bugs in apps such as perf, and it also makes
the system less useful by default, so turn it off by default.

This is how we generally handle security features that remove functionality,
such as firewall code or SELinux - they have to be configured and activated
from user-space.

Distributions can turn kptr_restrict on again via this line in
/etc/sysctrl.conf:

kernel.kptr_restrict = 1

( Also mark the variable __read_mostly while at it, as it's typically modified
  only once per bootup, or not at all. )

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-12 15:18:16 -07:00
Jiri Kosina
07f9479a40 Merge branch 'master' into for-next
Fast-forwarded to current state of Linus' tree as there are patches to be
applied for files that didn't exist on the old branch.
2011-04-26 10:22:59 +02:00
Uwe Kleine-König
ba1835eb30 vsprintf: make comment about vs{n,cn,}printf more understandable
"You probably want ... instead." sounds like a recommendation better
not to use the v... functions.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-06 07:49:04 -07:00
Linus Torvalds
94df491c4a Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: Fix WARN_ON() test for UP
  WARN_ON_SMP(): Allow use in if() statements on UP
  x86, dumpstack: Use %pB format specifier for stack trace
  vsprintf: Introduce %pB format specifier
  lockdep: Remove unused 'factor' variable from lockdep_stats_show()
2011-03-25 17:52:22 -07:00
Namhyung Kim
0f77a8d378 vsprintf: Introduce %pB format specifier
The %pB format specifier is for stack backtrace. Its handler
sprint_backtrace() does symbol lookup using (address-1) to
ensure the address will not point outside of the function.

If there is a tail-call to the function marked "noreturn",
gcc optimized out the code after the call then causes saved
return address points outside of the function (i.e. the start
of the next function), so pollutes call trace somewhat.

This patch adds the %pB printk mechanism that allows architecture
call-trace printout functions to improve backtrace printouts.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
LKML-Reference: <1300934550-21394-1-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-24 08:36:10 +01:00
Alexey Dobriyan
33ee3b2e2e kstrto*: converting strings to integers done (hopefully) right
1. simple_strto*() do not contain overflow checks and crufty,
   libc way to indicate failure.
2. strict_strto*() also do not have overflow checks but the name and
   comments pretend they do.
3. Both families have only "long long" and "long" variants,
   but users want strtou8()
4. Both "simple" and "strict" prefixes are wrong:
   Simple doesn't exactly say what's so simple, strict should not exist
   because conversion should be strict by default.

The solution is to use "k" prefix and add convertors for more types.
Enter
	kstrtoull()
	kstrtoll()
	kstrtoul()
	kstrtol()
	kstrtouint()
	kstrtoint()

	kstrtou64()
	kstrtos64()
	kstrtou32()
	kstrtos32()
	kstrtou16()
	kstrtos16()
	kstrtou8()
	kstrtos8()

Include runtime testsuite (somewhat incomplete) as well.

strict_strto*() become deprecated, stubbed to kstrto*() and
eventually will be removed altogether.

Use kstrto*() in code today!

Note: on some archs _kstrtoul() and _kstrtol() are left in tree, even if
      they'll be unused at runtime. This is temporarily solution,
      because I don't want to hardcode list of archs where these
      functions aren't needed. Current solution with sizeof() and
      __alignof__ at least always works.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:14 -07:00
Kees Cook
9f36e2c448 printk: use %pK for /proc/kallsyms and /proc/modules
In an effort to reduce kernel address leaks that might be used to help
target kernel privilege escalation exploits, this patch uses %pK when
displaying addresses in /proc/kallsyms, /proc/modules, and
/sys/module/*/sections/*.

Note that this changes %x to %p, so some legitimately 0 values in
/proc/kallsyms would have changed from 00000000 to "(null)".  To avoid
this, "(null)" is not used when using the "K" format.  Anything that was
already successfully parsing "(null)" in addition to full hex digits
should have no problem with this change.  (Thanks to Joe Perches for the
suggestion.) Due to the %x to %p, "void *" casts are needed since these
addresses are already "unsigned long" everywhere internally, due to their
starting life as ELF section offsets.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Cc: Eugene Teo <eugene@redhat.com>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:12 -07:00
Joe Perches
26297607e0 vsprintf: neaten %pK kptr_restrict, save a bit of code space
If kptr restrictions are on, just set the passed pointer to NULL.

$ size lib/vsprintf.o.*
   text	   data	    bss	    dec	    hex	filename
   8247	      4	      2	   8253	   203d	lib/vsprintf.o.new
   8282	      4	      2	   8288	   2060	lib/vsprintf.o.old

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:12 -07:00
Anton Arapov
b921c69fb2 lib/vsprintf.c: fix vscnprintf() if @size is == 0
vscnprintf() should return 0 if @size is == 0.  Update the comment for it,
as @size is unsigned.

This change based on the code of commit
b903c0b889 ("lib: fix scnprintf() if @size
is == 0") moves the real fix into vscnprinf() from scnprintf() and makes
scnprintf() call vscnprintf(), thus avoid code duplication.

Signed-off-by: Anton Arapov <aarapov@redhat.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:10 -08:00
Dan Rosenberg
455cd5ab30 kptr_restrict for hiding kernel pointers from unprivileged users
Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict
sysctl.

The %pK format specifier is designed to hide exposed kernel pointers,
specifically via /proc interfaces.  Exposing these pointers provides an
easy target for kernel write vulnerabilities, since they reveal the
locations of writable structures containing easily triggerable function
pointers.  The behavior of %pK depends on the kptr_restrict sysctl.

If kptr_restrict is set to 0, no deviation from the standard %p behavior
occurs.  If kptr_restrict is set to 1, the default, if the current user
(intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
(currently in the LSM tree), kernel pointers using %pK are printed as 0's.
 If kptr_restrict is set to 2, kernel pointers using %pK are printed as
0's regardless of privileges.  Replacing with 0's was chosen over the
default "(null)", which cannot be parsed by userland %p, which expects
"(nil)".

[akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/]
[akpm@linux-foundation.org: coding-style fixup]
[randy.dunlap@oracle.com: fix kernel/sysctl.c warning]
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: James Morris <jmorris@namei.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Graf <tgraf@infradead.org>
Cc: Eugene Teo <eugeneteo@kernel.org>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Eric Paris <eparis@parisplace.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:08 -08:00
Changli Gao
b903c0b889 lib: fix scnprintf() if @size is == 0
scnprintf() should return 0 if @size is == 0. Update the comment for it,
as @size is unsigned.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:16 -07:00
Joe Perches
5e05798128 vsprintf.c: use default pointer field size for "(null)" strings
It might be nicer to align the output.

For instance, ACPI messages sometimes have "(null)" pointers.

$ dmesg | grep "(null)"  -A 1 -B 1
[    0.198733] ACPI: Dynamic OEM Table Load:
[    0.198745] ACPI: SSDT (null) 00239 (v02  PmRef  Cpu0Ist 00003000 INTL 20051117)
[    0.199294] ACPI: SSDT 7f596e10 001C7 (v02  PmRef  Cpu0Cst 00003001 INTL 20051117)
[    0.200708] ACPI: Dynamic OEM Table Load:
[    0.200721] ACPI: SSDT (null) 001C7 (v02  PmRef  Cpu0Cst 00003001 INTL 20051117)
[    0.201950] ACPI: SSDT 7f597f10 000D0 (v02  PmRef  Cpu1Ist 00003000 INTL 20051117)
[    0.203386] ACPI: Dynamic OEM Table Load:
[    0.203398] ACPI: SSDT (null) 000D0 (v02  PmRef  Cpu1Ist 00003000 INTL 20051117)
[    0.203871] ACPI: SSDT 7f595f10 00083 (v02  PmRef  Cpu1Cst 00003000 INTL 20051117)
[    0.205301] ACPI: Dynamic OEM Table Load:
[    0.205315] ACPI: SSDT (null) 00083 (v02  PmRef  Cpu1Cst 00003000 INTL 20051117)

[akpm@linux-foundation.org: add code comment]
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 16:52:16 -07:00
Michal Nazarewicz
559b140a36 lib: vsprintf: useless strlen() removed
The strict_strtoul() and strict_strtoull() functions used strlen() to
check argument's length in a situation where it wasn't strictly necessary

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: "Yi Yang" <yi.y.yang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:45:09 -07:00
Joe Perches
7db6f5fb65 vsprintf: Recursive vsnprintf: Add "%pV", struct va_format
Add the ability to print a format and va_list from a structure pointer

Allows __dev_printk to be implemented as a single printk while
minimizing string space duplication.

%pV should not be used without some mechanism to verify the
format and argument use ala __attribute__(format (printf(...))).

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-07-04 10:40:17 -07:00
Joe Perches
cf3b429b03 vsprintf.c: use noinline_for_stack
Mark static functions with noinline_for_stack

Before:

  akpm:/usr/src/25> objdump -d lib/vsprintf.o | perl scripts/checkstack.pl
  0x00000e82 pointer [vsprintf.o]:                        344
  0x0000198c pointer [vsprintf.o]:                        344
  0x000025d6 scnprintf [vsprintf.o]:                      216
  0x00002648 scnprintf [vsprintf.o]:                      216
  0x00002565 snprintf [vsprintf.o]:                       208
  0x0000267c sprintf [vsprintf.o]:                        208
  0x000030a3 bprintf [vsprintf.o]:                        208
  0x00003b1e sscanf [vsprintf.o]:                         208
  0x00000608 number [vsprintf.o]:                         136
  0x00000937 number [vsprintf.o]:                         136

After:

  akpm:/usr/src/25> objdump -d lib/vsprintf.o | perl scripts/checkstack.pl
  0x00000a7c symbol_string [vsprintf.o]:                  248
  0x00000ae8 symbol_string [vsprintf.o]:                  248
  0x00002310 scnprintf [vsprintf.o]:                      216
  0x00002382 scnprintf [vsprintf.o]:                      216
  0x0000229f snprintf [vsprintf.o]:                       208
  0x000023b6 sprintf [vsprintf.o]:                        208
  0x00002ddd bprintf [vsprintf.o]:                        208
  0x00003858 sscanf [vsprintf.o]:                         208
  0x00000625 number [vsprintf.o]:                         136
  0x00000954 number [vsprintf.o]:                         136

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:04 -07:00
Alexey Dobriyan
4be929be34 kernel-wide: replace USHORT_MAX, SHORT_MAX and SHORT_MIN with USHRT_MAX, SHRT_MAX and SHRT_MIN
- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
  USHORT_MAX/SHORT_MAX/SHORT_MIN.

- Make SHRT_MIN of type s16, not int, for consistency.

[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:07:02 -07:00
Hans Verkuil
98d5ce0d00 lib/vsprintf.c: add missing EXPORT_SYMBOL(simple_strtoll)
Add a missing EXPORT_SYMBOL.

I must be the first person that wants to use this function :-)

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-24 11:31:26 -07:00
Joe Perches
4e310fda91 vsprintf: Change struct printf_spec.precision from s8 to s16
Commit ef0658f3de changed precision
from int to s8.

There is existing kernel code that uses a larger precision.

An example from the audit code:
	vsnprintf(...,..., " msg='%.1024s'", (char *)data);
which overflows precision and truncates to nothing.

Extending precision size fixes the audit system issue.

Other changes:

Change the size of the struct printf_spec.type from u16 to u8 so
sizeof(struct printf_spec) stays as small as possible.
Reorder the struct members so sizeof(struct printf_spec) remains 64 bits
without alignment holes.
Document the struct members a bit more.

Original-patch-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-14 10:32:35 -07:00
Bjorn Helgaas
9d7cca0421 resource: add window support
Add support for resource windows.  This is for bridge resources, i.e.,
regions where a bridge forwards transactions from the primary to the
secondary side.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-03-14 20:08:36 -04:00
Bjorn Helgaas
0f4050c7d3 resource: add bus number support
Add support for bus number resources.  This is for bridges with a range of
bus numbers behind them.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2010-03-14 20:08:35 -04:00
Bjorn Helgaas
4da0b66c6e vsprintf: move %pR resource printf_specs off the stack
This adds separate I/O and memory specs, so we don't have to change the
field width in a shared spec, which then lets us make all the specs const
and static, since they never change.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 17:53:07 -08:00
Bjorn Helgaas
b89dc5d6b0 vsprintf: clarify comments for printf_spec flags
Add clues about what the SMALL and SPECIAL flags do.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 17:53:07 -08:00
Joe Perches
ef0658f3de vsprintf.c: Reduce sizeof struct printf_spec from 24 to 8 bytes
Reducing the size of struct printf_spec is a good thing because multiple
instances are commonly passed on stack.

It's possible for type to be u8 and field_width to be s8, but this is
likely small enough for now.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 17:47:45 -08:00
David S. Miller
51c24aaaca Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-01-23 00:31:06 -08:00
Joe Perches
0159f24ee7 lib/vsprintf.c: Add IPV4 options %pI4[hnbl] for host, network, big and little endian
This should allow the removal of the #defines and uses
of NIPQUAD and NIPQUAD_FMT

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-13 20:23:30 -08:00
Uwe Kleine-König
3f4724027b vsnprintf: fix reference for compressed ipv6 addresses
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reported-by: Josip Rodin <joy@entuzijast.net>
Cc: Joe Perches <joe@perches.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-11 09:34:06 -08:00
Joe Perches
c8e000604b lib: Kill bit-reversed FDDI MAC output case, it's bogus.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-11 00:44:14 -08:00
Joe Perches
bc7259a2ce lib/vsprintf.c: Add %pMF to format FDDI bit reversed MAC addresses
On Mon, 2010-01-04 at 23:43 +0000, Maciej W. Rozycki wrote:
> The example below shows an address, and the sequence of bits or symbols
> that would be transmitted when the address is used in the Source Address
> or Destination Address fields on the MAC header.  The transmission line
> shows the address bits in the order transmitted, from left to right.  For
> IEEE 802 LANs these correspond to actual bits on the medium.  The FDDI
> symbols line shows how the FDDI PHY sends the address bits as encoded
> symbols.
>
>         MSB:            35:7B:12:00:00:01
>         Canonical:      AC-DE-48-00-00-80
>         Transmission:   00110101 01111011 00010010 00000000 00000000 00000001
>         FDDI Symbols:   35 7B 12 00 00 01"
>
> Please note that this address has its group bit clear.
>
>  This notation is also defined in the "FDDI MEDIA ACCESS CONTROL-2
> (MAC-2)" (X3T9/92-120) document although that book does not have a need
> to use the MSB form and it's skipped.

Adds 6 bytes to object size for x86

New:
$ size lib/vsprintf.o
   text	   data	    bss	    dec	    hex	filename
   8664	      0	      2	   8666	   21da	lib/vsprintf.o
$ size lib/vsprintf.o
   text    data     bss     dec     hex filename
   8658       0       2    8660    21d4 lib/vsprintf.o

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-07 16:58:08 -08:00
Uwe Kleine-König
8a79503aa8 lib/vsprintf.c: document more vsnprintf extensions
These were added in

9ac6e44 (lib/vsprintf.c: add %pU to print UUID/GUIDs)
c7dabef (vsprintf: use %pR, %pr instead of %pRt, %pRf)
8a27f7c (lib/vsprintf.c: Add "%pI6c" - print pointer as compressed ipv6 address)
4aa9960 (printk: add %I4, %I6, %i4, %i6 format specifiers)
dd45c9c (printk: add %pM format specifier for MAC addresses)

but only added comments to pointer() not vsnprintf() that is refered to by
printk's comments.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joe Perches <joe@perches.com>
Cc: Jens Rosenboom <jens@mcbone.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-17 15:45:31 -08:00
Joe Perches
9ac6e44ee5 lib/vsprintf.c: add %pU to print UUID/GUIDs
UUID/GUIDs are somewhat common in kernel source.

Standardize the printed style of UUID/GUIDs by using
another extension to %p.

%pUb:   01020304-0506-0708-090a-0b0c0d0e0f10
%pUB:   01020304-0506-0708-090A-0B0C0D0E0F10 (upper case)
%pUl:   04030201-0605-0807-090a-0b0c0d0e0f10
%pUL:   04030201-0605-0807-090A-0B0C0D0E0F10 (upper case)

%pU defaults to %pUb

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Jeff Garzik <jgarzik@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:33 -08:00
André Goddard Rosa
e7d2860b69 tree-wide: convert open calls to remove spaces to skip_spaces() lib function
Makes use of skip_spaces() defined in lib/string.c for removing leading
spaces from strings all over the tree.

It decreases lib.a code size by 47 bytes and reuses the function tree-wide:
   text    data     bss     dec     hex filename
  64688     584     592   65864   10148 (TOTALS-BEFORE)
  64641     584     592   65817   10119 (TOTALS-AFTER)

Also, while at it, if we see (*str && isspace(*str)), we can be sure to
remove the first condition (*str) as the second one (isspace(*str)) also
evaluates to 0 whenever *str == 0, making it redundant. In other words,
"a char equals zero is never a space".

Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below,
and found occurrences of this pattern on 3 more files:
    drivers/leds/led-class.c
    drivers/leds/ledtrig-timer.c
    drivers/video/output.c

@@
expression str;
@@

( // ignore skip_spaces cases
while (*str &&  isspace(*str)) { \(str++;\|++str;\) }
|
- *str &&
isspace(*str)
)

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: David Howells <dhowells@redhat.com>
Cc: <linux-ext4@vger.kernel.org>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:32 -08:00
André Goddard Rosa
922ac25c9f vsprintf: reuse almost identical simple_strtoulX() functions
The difference between simple_strtoul() and simple_strtoull() is just
the size of the variable used to keep track of the sum of characters
converted to numbers:

unsigned long simple_strtoul() {...}
unsigned long long simple_strtoull(){...}

Both are same size on my Core 2/gcc 4.4.1.
Overflow condition is not checked on both functions, so an extremely large
string can break these functions so that they don't even notice it.

As we do not care for overflowing on these functions, always keep the sum
using the larger variable around (unsigned long long) on simple_strtoull()
and cast it to (unsigned long) on simple_strtoul(), which then becomes
just a wrapper around simple_strtoull().

Code size decreases by 304 bytes:
   text    data     bss     dec     hex filename
  15534       0       8   15542    3cb6 vsprintf.o (ex lib/lib.a-BEFORE)
  15230       0       8   15238    3b86 vsprintf.o (ex lib/lib.a-AFTER)

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:32 -08:00
André Goddard Rosa
c5484d7c0a vsprintf: factor out skip_space code in a separate function
When converting more caller sites, the inline decision will be left up to gcc.

It decreases code size:
 text    data     bss     dec     hex filename
15710       0       8   15718    3d66 vsprintf.o (ex lib/lib.a-BEFORE)
15534       0       8   15542    3cb6 vsprintf.o (ex lib/lib.a-AFTER)

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:32 -08:00