Commit Graph

223 Commits

Author SHA1 Message Date
Petr Mladek
1ac2f9789c vsprintf: Consistent %pK handling for kptr_restrict == 0
restricted_pointer() pretends that it prints the address when kptr_restrict
is set to zero. But it is never called in this situation. Instead,
pointer() falls back to ptr_to_id() and hashes the pointer.

This patch removes the potential confusion. klp_restrict is checked only
in restricted_pointer().

It actually fixes a small race when the address might get printed unhashed:

CPU0                            CPU1

pointer()
  if (!kptr_restrict)
     /* for example set to 2 */
  restricted_pointer()
				/* echo 0 >/proc/sys/kernel/kptr_restrict */
				proc_dointvec_minmax_sysadmin()
				  klpr_restrict = 0;
    switch(kptr_restrict)
      case 0:
	break:

    number()

Fixes: ef0010a309 ("vsprintf: don't use 'restricted_pointer()' when not restricting")
Link: http://lkml.kernel.org/r/20190417115350.20479-3-pmladek@suse.com
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-26 16:19:04 +02:00
Petr Mladek
6eea242f9b vsprintf: Shuffle restricted_pointer()
This is just a preparation step for further changes.

The patch does not change the code.

Link: http://lkml.kernel.org/r/20190417115350.20479-2-pmladek@suse.com
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-26 16:18:40 +02:00
Linus Torvalds
c4703acd6d Printk changes for 5.1
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Merge tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Allow to sort mixed lines by an extra information about the caller

 - Remove no longer used LOG_PREFIX.

 - Some clean up and documentation update.

* tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk/docs: Add extra integer types to printk-formats
  printk: Remove no longer used LOG_PREFIX.
  lib/vsprintf: Remove %pCr remnant in comment
  printk: Pass caller information to log_store().
  printk: Add caller information to printk() output.
2019-03-09 09:22:42 -08:00
Rasmus Villemoes
ef27ac18b3 lib/vsprintf.c: move sizeof(struct printf_spec) next to its definition
At the time of commit d048419311 ("lib/vsprintf.c: expand field_width
to 24 bits"), there was no compiletime_assert/BUILD_BUG/....  variant
that could be used outside function scope.  Now we have static_assert(),
so move the assertion next to the definition instead of hiding it in
some arbitrary function.

Also add the appropriate #include to avoid relying on build_bug.h being
pulled in via some arbitrary chain of includes.

Link: http://lkml.kernel.org/r/20190208203015.29702-2-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07 18:31:59 -08:00
Geert Uytterhoeven
b607066442 lib/vsprintf: Remove %pCr remnant in comment
Support for "%pCr" was removed, but a reference in a comment was
forgotten.

Fixes: 666902e42f ("lib/vsprintf: Remove atomic-unsafe support for %pCr")
Link: http://lkml.kernel.org/r/20190228105315.744-1-geert+renesas@glider.be
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-02-28 12:04:56 +01:00
Andy Shevchenko
4d42c44727 lib/vsprintf: Print time and date in human readable format via %pt
There are users which print time and date represented by content of
struct rtc_time in human readable format.

Instead of open coding that each time introduce %ptR[dt][r] specifier.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-12-10 22:39:34 +01:00
Linus Torvalds
b27186abb3 Devicetree updates for 4.20:
- Sync dtc with upstream version v1.4.7-14-gc86da84d30e4
 
 - Work to get rid of direct accesses to struct device_node name and
   type pointers in preparation for removing them. New helpers for
   parsing DT cpu nodes and conversions to use the helpers. printk
   conversions to %pOFn for printing DT node names. Most went thru
   subystem trees, so this is the remainder.
 
 - Fixes to DT child node lookups to actually be restricted to child
   nodes instead of treewide.
 
 - Refactoring of dtb targets out of arch code. This makes the support
   more uniform and enables building all dtbs on c6x, microblaze, and
   powerpc.
 
 - Various DT binding updates for Renesas r8a7744 SoC
 
 - Vendor prefixes for Facebook, OLPC
 
 - Restructuring of some ARM binding docs moving some peripheral bindings
   out of board/SoC binding files
 
 - New "secure-chosen" binding for secure world settings on ARM
 
 - Dual licensing of 2 DT IRQ binding headers
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Merge tag 'devicetree-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull Devicetree updates from Rob Herring:
 "A bit bigger than normal as I've been busy this cycle.

  There's a few things with dependencies and a few things subsystem
  maintainers didn't pick up, so I'm taking them thru my tree.

  The fixes from Johan didn't get into linux-next, but they've been
  waiting for some time now and they are what's left of what subsystem
  maintainers didn't pick up.

  Summary:

   - Sync dtc with upstream version v1.4.7-14-gc86da84d30e4

   - Work to get rid of direct accesses to struct device_node name and
     type pointers in preparation for removing them. New helpers for
     parsing DT cpu nodes and conversions to use the helpers. printk
     conversions to %pOFn for printing DT node names. Most went thru
     subystem trees, so this is the remainder.

   - Fixes to DT child node lookups to actually be restricted to child
     nodes instead of treewide.

   - Refactoring of dtb targets out of arch code. This makes the support
     more uniform and enables building all dtbs on c6x, microblaze, and
     powerpc.

   - Various DT binding updates for Renesas r8a7744 SoC

   - Vendor prefixes for Facebook, OLPC

   - Restructuring of some ARM binding docs moving some peripheral
     bindings out of board/SoC binding files

   - New "secure-chosen" binding for secure world settings on ARM

   - Dual licensing of 2 DT IRQ binding headers"

* tag 'devicetree-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (78 commits)
  ARM: dt: relicense two DT binding IRQ headers
  power: supply: twl4030-charger: fix OF sibling-node lookup
  NFC: nfcmrvl_uart: fix OF child-node lookup
  net: stmmac: dwmac-sun8i: fix OF child-node lookup
  net: bcmgenet: fix OF child-node lookup
  drm/msm: fix OF child-node lookup
  drm/mediatek: fix OF sibling-node lookup
  of: Add missing exports of node name compare functions
  dt-bindings: Add OLPC vendor prefix
  dt-bindings: misc: bk4: Add device tree binding for Liebherr's BK4 SPI bus
  dt-bindings: thermal: samsung: Add SPDX license identifier
  dt-bindings: clock: samsung: Add SPDX license identifiers
  dt-bindings: timer: ostm: Add R7S9210 support
  dt-bindings: phy: rcar-gen2: Add r8a7744 support
  dt-bindings: can: rcar_can: Add r8a7744 support
  dt-bindings: timer: renesas, cmt: Document r8a7744 CMT support
  dt-bindings: watchdog: renesas-wdt: Document r8a7744 support
  dt-bindings: thermal: rcar: Add device tree support for r8a7744
  Documentation: dt: Add binding for /secure-chosen/stdout-path
  dt-bindings: arm: zte: Move sysctrl bindings to their own doc
  ...
2018-10-26 12:09:58 -07:00
Linus Torvalds
a67eefad99 Printk changes for 4.20
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Merge tag 'printk-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Fix two more locations where printf formatting leaked pointers

 - Better log_buf_len parameter handling

 - Add prefix to messages from printk code

 - Do not miss messages on other consoles when the log is replayed on a
   new one

 - Reduce race between console registration and panic() when the log
   might get replayed on all consoles

 - Some cont buffer code clean up

 - Call console only when there is something to do (log vs cont buffer)

* tag 'printk-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  lib/vsprintf: Hash printed address for netdev bits fallback
  lib/vsprintf: Hash legacy clock addresses
  lib/vsprintf: Prepare for more general use of ptr_to_id()
  lib/vsprintf: Make ptr argument conts in ptr_to_id()
  printk: fix integer overflow in setup_log_buf()
  printk: do not preliminary split up cont buffer
  printk: lock/unlock console only for new logbuf entries
  printk: keep kernel cont support always enabled
  printk: Give error on attempt to set log buffer length to over 2G
  printk: Add KBUILD_MODNAME and remove a redundant print prefix
  printk: Correct wrong casting
  printk: Fix panic caused by passing log_buf_len to command line
  printk: CON_PRINTBUFFER console registration is a bit racy
  printk: Do not miss new messages when replaying the log
2018-10-25 17:11:52 -07:00
Linus Torvalds
01aa9d518e This is a fairly typical cycle for documentation. There's some welcome
readability improvements for the formatted output, some LICENSES updates
 including the addition of the ISC license, the removal of the unloved and
 unmaintained 00-INDEX files, the deprecated APIs document from Kees, more
 MM docs from Mike Rapoport, and the usual pile of typo fixes and
 corrections.
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Merge tag 'docs-4.20' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "This is a fairly typical cycle for documentation. There's some welcome
  readability improvements for the formatted output, some LICENSES
  updates including the addition of the ISC license, the removal of the
  unloved and unmaintained 00-INDEX files, the deprecated APIs document
  from Kees, more MM docs from Mike Rapoport, and the usual pile of typo
  fixes and corrections"

* tag 'docs-4.20' of git://git.lwn.net/linux: (41 commits)
  docs: Fix typos in histogram.rst
  docs: Introduce deprecated APIs list
  kernel-doc: fix declaration type determination
  doc: fix a typo in adding-syscalls.rst
  docs/admin-guide: memory-hotplug: remove table of contents
  doc: printk-formats: Remove bogus kobject references for device nodes
  Documentation: preempt-locking: Use better example
  dm flakey: Document "error_writes" feature
  docs/completion.txt: Fix a couple of punctuation nits
  LICENSES: Add ISC license text
  LICENSES: Add note to CDDL-1.0 license that it should not be used
  docs/core-api: memory-hotplug: add some details about locking internals
  docs/core-api: rename memory-hotplug-notifier to memory-hotplug
  docs: improve readability for people with poorer eyesight
  yama: clarify ptrace_scope=2 in Yama documentation
  docs/vm: split memory hotplug notifier description to Documentation/core-api
  docs: move memory hotplug description into admin-guide/mm
  doc: Fix acronym "FEKEK" in ecryptfs
  docs: fix some broken documentation references
  iommu: Fix passthrough option documentation
  ...
2018-10-24 18:01:11 +01:00
Geert Uytterhoeven
94ac8f2074 doc: printk-formats: Remove bogus kobject references for device nodes
When converting from text to rst, the kobjects section and its sole
subsection about device tree nodes were coalesced into a single section,
yielding an inconsistent result.

Remove all references to kobjects, as
  1. Device tree object pointers are not compatible to kobject pointers
     (the former may embed the latter, though), and
  2. there are no printk formats defined for kobject types.

Update the vsprintf() source code comments to match the above.

Fixes: b3ed23213e ("doc: convert printk-formats.txt to rst")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-10-12 11:38:18 -06:00
Geert Uytterhoeven
431bca2430 lib/vsprintf: Hash printed address for netdev bits fallback
The handler for "%pN" falls back to printing the raw pointer value when
using a different format than the (sole supported) special format
"%pNF", potentially leaking sensitive information regarding the kernel
layout in memory.

Avoid this leak by printing the hashed address instead.
Note that there are no in-tree users of the fallback.

Fixes: ad67b74d24 ("printk: hash addresses printed with %p")
Link: http://lkml.kernel.org/r/20181011084249.4520-4-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-10-12 11:26:55 +02:00
Geert Uytterhoeven
ec12bc2909 lib/vsprintf: Hash legacy clock addresses
On platforms using the Common Clock Framework, "%pC" prints the clock's
name. On legacy platforms, it prints the unhashed clock's address,
potentially leaking sensitive information regarding the kernel layout in
memory.

Avoid this leak by printing the hashed address instead.  To distinguish
between clocks, a 32-bit unique identifier is as good as an actual
pointer value.

Fixes: ad67b74d24 ("printk: hash addresses printed with %p")
Link: http://lkml.kernel.org/r/20181011084249.4520-3-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-10-12 11:24:41 +02:00
Geert Uytterhoeven
9073dac14e lib/vsprintf: Prepare for more general use of ptr_to_id()
Move the function and its dependencies up so it can be called from
special pointer type formatting routines.

Link: http://lkml.kernel.org/r/20181011084249.4520-2-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[pmladek@suse.com: Split into separate patch]
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-10-12 11:23:13 +02:00
Geert Uytterhoeven
f31b224c14 lib/vsprintf: Make ptr argument conts in ptr_to_id()
Make the ptr argument const to avoid adding casts in future callers.

Link: http://lkml.kernel.org/r/20181011084249.4520-2-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[pmladek@suse.com: split into separate patch]
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-10-12 11:14:07 +02:00
Steven Rostedt (VMware)
62165600ae vsprintf: Fix off-by-one bug in bstr_printf() processing dereferenced pointers
The functions vbin_printf() and bstr_printf() are used by trace_printk() to
try to keep the overhead down during printing. trace_printk() uses
vbin_printf() at the time of execution, as it only scans the fmt string to
record the printf values into the buffer, and then uses vbin_printf() to do
the conversions to print the string based on the format and the saved
values in the buffer.

This is an issue for dereferenced pointers, as before commit 841a915d20,
the processing of the pointer could happen some time after the pointer value
was recorded (reading the trace buffer). This means the processing of the
value at a later time could show different results, or even crash the
system, if the pointer no longer existed.

Commit 841a915d20 addressed this by processing dereferenced pointers at
the time of execution and save the result in the ring buffer as a string.
The bstr_printf() would then treat these pointers as normal strings, and
print the value. But there was an off-by-one bug here, where after
processing the argument, it move the pointer only "strlen(arg)" which made
the arg pointer not point to the next argument in the ring buffer, but
instead point to the nul character of the last argument. This causes any
values after a dereferenced pointer to be corrupted.

Cc: stable@vger.kernel.org
Fixes: 841a915d20 ("vsprintf: Do not have bprintf dereference pointers")
Reported-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-10-05 10:17:15 -04:00
Rob Herring
6d0a70a284 vsprintf: print OF node name using full_name
In preparation to remove the node name pointer from struct device_node,
convert the node name print to get the node name from the full name.

Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2018-09-07 11:04:41 -05:00
Linus Torvalds
99a2c789dd Some changes to trust cpu-based hwrng (such as RDRAND) for
initializing hashed pointers and (optionally, controlled by a config
 option) to initialize the CRNG to avoid boot hangs.
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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull random updates from Ted Ts'o:
 "Some changes to trust cpu-based hwrng (such as RDRAND) for
  initializing hashed pointers and (optionally, controlled by a config
  option) to initialize the CRNG to avoid boot hangs"

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: Make crng state queryable
  random: remove preempt disabled region
  random: add a config option to trust the CPU's hwrng
  vsprintf: Add command line option debug_boot_weak_hash
  vsprintf: Use hw RNG for ptr_key
  random: Return nbytes filled from hw RNG
  random: Fix whitespace pre random-bytes work
2018-08-15 21:16:02 -07:00
Bart Van Assche
554ec50865 lib/vsprintf: Do not handle %pO[^F] as %px
This patch avoids that gcc reports the following when building with W=1:

lib/vsprintf.c:1941:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   switch (fmt[1]) {
   ^~~~~~

Fixes: 7b1924a1d9 ("vsprintf: add printk specifier %px")
Link: http://lkml.kernel.org/r/20180806223421.11995-1-bart.vanassche@wdc.com
Cc: linux-kernel@vger.kernel.org
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Joe Perches <joe@perches.com>
Cc: Rob Herring <robh@kernel.org>
Cc: v4.15+ <stable@vger.kernel.org>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-08-07 09:20:18 +02:00
Tobin C. Harding
3672476eda vsprintf: Add command line option debug_boot_weak_hash
Currently printing [hashed] pointers requires enough entropy to be
available.  Early in the boot sequence this may not be the case
resulting in a dummy string '(____ptrval____)' being printed.  This
makes debugging the early boot sequence difficult.  We can relax the
requirement to use cryptographically secure hashing during debugging.
This enables debugging while keeping development/production kernel
behaviour the same.

If new command line option debug_boot_weak_hash is enabled use
cryptographically insecure hashing and hash pointer value immediately.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2018-07-17 21:32:48 -04:00
Tobin C. Harding
1c4facb846 vsprintf: Use hw RNG for ptr_key
Currently we must wait for enough entropy to become available before
hashed pointers can be printed.  We can remove this wait by using the
hw RNG if available.

Use hw RNG to get keying material.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2018-07-17 21:32:48 -04:00
Linus Torvalds
d75ae5bdf2 Printk changes for 4.18
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Merge tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Help userspace log daemons to catch up with a flood of messages. They
   will get woken after each message even if the console is far behind
   and handled by another process.

 - Flush printk safe buffers safely even when panic() happens in the
   normal context.

 - Fix possible va_list reuse when race happened in printk_safe().

 - Remove %pCr printf format to prevent sleeping in the atomic context.

 - Misc vsprintf code cleanup.

* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk: drop in_nmi check from printk_safe_flush_on_panic()
  lib/vsprintf: Remove atomic-unsafe support for %pCr
  serial: sh-sci: Stop using printk format %pCr
  thermal: bcm2835: Stop using printk format %pCr
  clk: renesas: cpg-mssr: Stop using printk format %pCr
  printk: fix possible reuse of va_list variable
  printk: wake up klogd in vprintk_emit
  vsprintf: Tweak pF/pf comment
  lib/vsprintf: Mark expected switch fall-through
  lib/vsprintf: Replace space with '_' before crng is ready
  lib/vsprintf: Deduplicate pointer_string()
  lib/vsprintf: Move pointer_string() upper
  lib/vsprintf: Make flag_spec global
  lib/vsprintf: Make strspec global
  lib/vsprintf: Make dec_spec global
  lib/test_printf: Mark big constant with UL
2018-06-06 16:04:55 -07:00
Petr Mladek
8bafa2a44f Merge branch 'for-4.18-vsprintf-pcr-removal' into for-4.18 2018-06-05 13:39:12 +02:00
Geert Uytterhoeven
666902e42f lib/vsprintf: Remove atomic-unsafe support for %pCr
"%pCr" formats the current rate of a clock, and calls clk_get_rate().
The latter obtains a mutex, hence it must not be called from atomic
context.

Remove support for this rarely-used format, as vsprintf() (and e.g.
printk()) must be callable from any context.

Any remaining out-of-tree users will start seeing the clock's name
printed instead of its rate.

Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Fixes: 900cca2944 ("lib/vsprintf: add %pC{,n,r} format specifiers for clocks")
Link: http://lkml.kernel.org/r/1527845302-12159-5-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Zhang Rui <rui.zhang@intel.com>
To: Eduardo Valentin <edubezval@gmail.com>
To: Eric Anholt <eric@anholt.net>
To: Stefan Wahren <stefan.wahren@i2se.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-06-05 09:43:39 +02:00
Steven Rostedt (VMware)
85f4f12d51 vsprintf: Replace memory barrier with static_key for random_ptr_key update
Reviewing Tobin's patches for getting pointers out early before
entropy has been established, I noticed that there's a lone smp_mb() in
the code. As with most lone memory barriers, this one appears to be
incorrectly used.

We currently basically have this:

	get_random_bytes(&ptr_key, sizeof(ptr_key));
	/*
	 * have_filled_random_ptr_key==true is dependent on get_random_bytes().
	 * ptr_to_id() needs to see have_filled_random_ptr_key==true
	 * after get_random_bytes() returns.
	 */
	smp_mb();
	WRITE_ONCE(have_filled_random_ptr_key, true);

And later we have:

	if (unlikely(!have_filled_random_ptr_key))
		return string(buf, end, "(ptrval)", spec);

/* Missing memory barrier here. */

	hashval = (unsigned long)siphash_1u64((u64)ptr, &ptr_key);

As the CPU can perform speculative loads, we could have a situation
with the following:

	CPU0				CPU1
	----				----
				   load ptr_key = 0
   store ptr_key = random
   smp_mb()
   store have_filled_random_ptr_key

				   load have_filled_random_ptr_key = true

				    BAD BAD BAD! (you're so bad!)

Because nothing prevents CPU1 from loading ptr_key before loading
have_filled_random_ptr_key.

But this race is very unlikely, but we can't keep an incorrect smp_mb() in
place. Instead, replace the have_filled_random_ptr_key with a static_branch
not_filled_random_ptr_key, that is initialized to true and changed to false
when we get enough entropy. If the update happens in early boot, the
static_key is updated immediately, otherwise it will have to wait till
entropy is filled and this happens in an interrupt handler which can't
enable a static_key, as that requires a preemptible context. In that case, a
work_queue is used to enable it, as entropy already took too long to
establish in the first place waiting a little more shouldn't hurt anything.

The benefit of using the static key is that the unlikely branch in
vsprintf() now becomes a nop.

Link: http://lkml.kernel.org/r/20180515100558.21df515e@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: ad67b74d24 ("printk: hash addresses printed with %p")
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-05-16 09:01:41 -04:00
Sergey Senozhatsky
cdb7e52d96 vsprintf: Tweak pF/pf comment
Reflect changes that have happened to pf/pF (deprecation)
specifiers in pointer() comment section.

Link: http://lkml.kernel.org/r/20180414030005.25831-1-sergey.senozhatsky@gmail.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-18 12:53:52 +02:00
Andrei Vagin
d1be35cb6f proc: add seq_put_decimal_ull_width to speed up /proc/pid/smaps
seq_put_decimal_ull_w(m, str, val, width) prints a decimal number with a
specified minimal field width.

It is equivalent of seq_printf(m, "%s%*d", str, width, val), but it
works much faster.

== test_smaps.py
  num = 0
  with open("/proc/1/smaps") as f:
          for x in xrange(10000):
                  data = f.read()
                  f.seek(0, 0)
==

== Before patch ==
  $ time python test_smaps.py
  real    0m4.593s
  user    0m0.398s
  sys     0m4.158s

== After patch ==
  $ time python test_smaps.py
  real    0m3.828s
  user    0m0.413s
  sys     0m3.408s

$ perf -g record python test_smaps.py
== Before patch ==
-   79.01%     3.36%  python   [kernel.kallsyms]    [k] show_smap.isra.33
   - 75.65% show_smap.isra.33
      + 48.85% seq_printf
      + 15.75% __walk_page_range
      + 9.70% show_map_vma.isra.23
        0.61% seq_puts

== After patch ==
-   75.51%     4.62%  python   [kernel.kallsyms]    [k] show_smap.isra.33
   - 70.88% show_smap.isra.33
      + 24.82% seq_put_decimal_ull_w
      + 19.78% __walk_page_range
      + 12.74% seq_printf
      + 11.08% show_map_vma.isra.23
      + 1.68% seq_puts

[akpm@linux-foundation.org: fix drivers/of/unittest.c build]
Link: http://lkml.kernel.org/r/20180212074931.7227-1-avagin@openvz.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:33 -07:00
Andy Shevchenko
7e6bd6f3dc lib/vsprintf: Mark expected switch fall-through
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Link: http://lkml.kernel.org/r/20180216210711.79901-9-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 11:19:13 +02:00
Shunyong Yang
91efafb1dd lib/vsprintf: Replace space with '_' before crng is ready
Before crng is ready, output of "%p" composes of "(ptrval)" and
left padding spaces for alignment as no random address can be
generated. This seems a little strange when default string width
is larger than strlen("(ptrval)").

For example, when irq domain names are built with "%p", the nodes
under /sys/kernel/debug/irq/domains like this on AArch64 system,

[root@y irq]# ls domains/
default                   irqchip@        (ptrval)-2
irqchip@        (ptrval)-4  \_SB_.TCS0.QIC1  \_SB_.TCS0.QIC3
irqchip@        (ptrval)  irqchip@        (ptrval)-3
\_SB_.TCS0.QIC0             \_SB_.TCS0.QIC2

The name "irqchip@        (ptrval)-2" is not so readable in console
output.

This patch replaces space with readable "_" when output needs padding.
Following is the output after applying the patch,

[root@y domains]# ls
default                   irqchip@(____ptrval____)-2
irqchip@(____ptrval____)-4  \_SB_.TCS0.QIC1  \_SB_.TCS0.QIC3
irqchip@(____ptrval____)  irqchip@(____ptrval____)-3  \_SB_.TCS0.QIC0
\_SB_.TCS0.QIC2

There is same problem in some subsystem's dmesg output. Moreover,
someone may call "%p" in a similar case. In addition, the timing of
crng initialization done may vary on different system. So, the change
is made in vsprintf.c.

Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lkml.kernel.org/r/20180216210711.79901-7-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 11:18:43 +02:00
Andy Shevchenko
496a9a5f38 lib/vsprintf: Deduplicate pointer_string()
There is an exact code at the end of ptr_to_id().
Replace it by calling pointer_string() directly.

This is followup to the commit ad67b74d24 ("printk: hash addresses
printed with %p").

Cc: Tobin C. Harding <me@tobin.cc>
Link: http://lkml.kernel.org/r/20180216210711.79901-6-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 11:17:06 +02:00
Andy Shevchenko
558594f3c2 lib/vsprintf: Move pointer_string() upper
As preparatory patch to further clean up.

No functional change.

Link: http://lkml.kernel.org/r/20180216210711.79901-5-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 10:32:42 +02:00
Andy Shevchenko
5443397308 lib/vsprintf: Make flag_spec global
There are places where default specification to print flags as number
is in use.

Make it global and convert existing users.

Link: http://lkml.kernel.org/r/20180216210711.79901-4-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 10:23:10 +02:00
Andy Shevchenko
abd4fe6276 lib/vsprintf: Make strspec global
There are places where default specification to print strings
is in use.

Make it global and convert existing users.

Link: http://lkml.kernel.org/r/20180216210711.79901-3-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 10:20:47 +02:00
Andy Shevchenko
ce0b4910bd lib/vsprintf: Make dec_spec global
There are places where default specification to print decimal numbers
is in use.

Make it global and convert existing users.

Link: http://lkml.kernel.org/r/20180216210711.79901-2-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-04-11 10:20:42 +02:00
Steven Rostedt (VMware)
1e6338cfb5 vsprintf: Do not preprocess non-dereferenced pointers for bprintf (%px and %pK)
Commit 841a915d20 ("printf: Do not have bprintf dereference pointers")
would preprocess various pointers that are dereferenced in the bprintf()
because the recording and printing are done at two different times. Some
pointers stayed dereferenced in the ring buffer because user space could
handle them (namely "%pS" and friends). Pointers that are not dereferenced
should not be processed immediately but instead just saved directly.

Cc: stable@vger.kernel.org
Fixes: 841a915d20 ("printf: Do not have bprintf dereference pointers")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-04-06 08:56:51 -04:00
Adam Borowski
3a129cc215 vsprintf: avoid misleading "(null)" for %px
Like %pK already does, print "00000000" instead.

This confused people -- the convention is that "(null)" means you tried to
dereference a null pointer as opposed to printing the address.

Link: http://lkml.kernel.org/r/20180204174521.21383-1-kilobyte@angband.pl
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Roberts, William C" <william.c.roberts@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-02-08 14:21:41 +01:00
Linus Torvalds
ab486bc9a5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:

 - Add a console_msg_format command line option:

     The value "default" keeps the old "[time stamp] text\n" format. The
     value "syslog" allows to see the syslog-like "<log
     level>[timestamp] text" format.

     This feature was requested by people doing regression tests, for
     example, 0day robot. They want to have both filtered and full logs
     at hands.

 - Reduce the risk of softlockup:

     Pass the console owner in a busy loop.

     This is a new approach to the old problem. It was first proposed by
     Steven Rostedt on Kernel Summit 2017. It marks a context in which
     the console_lock owner calls console drivers and could not sleep.
     On the other side, printk() callers could detect this state and use
     a busy wait instead of a simple console_trylock(). Finally, the
     console_lock owner checks if there is a busy waiter at the end of
     the special context and eventually passes the console_lock to the
     waiter.

     The hand-off works surprisingly well and helps in many situations.
     Well, there is still a possibility of the softlockup, for example,
     when the flood of messages stops and the last owner still has too
     much to flush.

     There is increasing number of people having problems with
     printk-related softlockups. We might eventually need to get better
     solution. Anyway, this looks like a good start and promising
     direction.

 - Do not allow to schedule in console_unlock() called from printk():

     This reverts an older controversial commit. The reschedule helped
     to avoid softlockups. But it also slowed down the console output.
     This patch is obsoleted by the new console waiter logic described
     above. In fact, the reschedule made the hand-off less effective.

 - Deprecate "%pf" and "%pF" format specifier:

     It was needed on ia64, ppc64 and parisc64 to dereference function
     descriptors and show the real function address. It is done
     transparently by "%ps" and "pS" format specifier now.

     Sergey Senozhatsky found that all the function descriptors were in
     a special elf section and could be easily detected.

 - Remove printk_symbol() API:

     It has been obsoleted by "%pS" format specifier, and this change
     helped to remove few continuous lines and a less intuitive old API.

 - Remove redundant memsets:

     Sergey removed unnecessary memset when processing printk.devkmsg
     command line option.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits)
  printk: drop redundant devkmsg_log_str memsets
  printk: Never set console_may_schedule in console_trylock()
  printk: Hide console waiter logic into helpers
  printk: Add console owner and waiter logic to load balance console writes
  kallsyms: remove print_symbol() function
  checkpatch: add pF/pf deprecation warning
  symbol lookup: introduce dereference_symbol_descriptor()
  parisc64: Add .opd based function descriptor dereference
  powerpc64: Add .opd based function descriptor dereference
  ia64: Add .opd based function descriptor dereference
  sections: split dereference_function_descriptor()
  openrisc: Fix conflicting types for _exext and _stext
  lib: do not use print_symbol()
  irq debug: do not use print_symbol()
  sysfs: do not use print_symbol()
  drivers: do not use print_symbol()
  x86: do not use print_symbol()
  unicore32: do not use print_symbol()
  sh: do not use print_symbol()
  mn10300: do not use print_symbol()
  ...
2018-02-01 13:36:15 -08:00
Linus Torvalds
27529c891b Mostly clean ups and small fixes
There's not much changes for the tracing system this release.
 Mostly small clean ups and fixes.
 
 The biggest change is to how bprintf works. bprintf is used by
 trace_printk() to just save the format and args of a printf call,
 and the formatting is done when the trace buffer is read. This is
 done to keep the formatting out of the fast path (this was recommended
 by you). The issue is when arguments are de-referenced.
 
 If a pointer is saved, and the format has something like "%*pbl",
 when the buffer is read, it will de-reference the argument then.
 The problem is if the data no longer exists. This can cause the
 kernel to oops.
 
 The fix for this was to make these de-reference pointes do
 the formatting at the time it is called (the fast path), as
 this guarantees that the data exists (and doesn't change later)
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Merge tag 'trace-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "There's not much changes for the tracing system this release. Mostly
  small clean ups and fixes.

  The biggest change is to how bprintf works. bprintf is used by
  trace_printk() to just save the format and args of a printf call, and
  the formatting is done when the trace buffer is read. This is done to
  keep the formatting out of the fast path (this was recommended by
  you). The issue is when arguments are de-referenced.

  If a pointer is saved, and the format has something like "%*pbl", when
  the buffer is read, it will de-reference the argument then. The
  problem is if the data no longer exists. This can cause the kernel to
  oops.

  The fix for this was to make these de-reference pointes do the
  formatting at the time it is called (the fast path), as this
  guarantees that the data exists (and doesn't change later)"

* tag 'trace-v4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  vsprintf: Do not have bprintf dereference pointers
  ftrace: Mark function tracer test functions noinline/noclone
  trace_uprobe: Display correct offset in uprobe_events
  tracing: Make sure the parsed string always terminates with '\0'
  tracing: Clear parser->idx if only spaces are read
  tracing: Detect the string nul character when parsing user input string
2018-02-01 13:15:23 -08:00
Steven Rostedt (VMware)
841a915d20 vsprintf: Do not have bprintf dereference pointers
When trace_printk() was introduced, it was discussed that making it be as
low overhead as possible, that the processing of the format string should be
delayed until it is read. That is, a "trace_printk()" should not convert
the %d into numbers and so on, but instead, save the fmt string and all the
args in the buffer at the time of recording. When the trace_printk() data is
read, it would then parse the format string and do the conversions of the
saved arguments in the tracing buffer.

The code to perform this was added to vsprintf where vbin_printf() would
save the arguments of a specified format string in a buffer, then
bstr_printf() could be used to convert the buffer with the same format
string into the final output, as if vsprintf() was called in one go.

The issue arises when dereferenced pointers are used. The problem is that
something like %*pbl which reads a bitmask, will save the pointer to the
bitmask in the buffer. Then the reading of the buffer via bstr_printf() will
then look at the pointer to process the final output. Obviously the value of
that pointer could have changed since the time it was recorded to the time
the buffer is read. Worse yet, the bitmask could be unmapped, and the
reading of the trace buffer could actually cause a kernel oops.

Another problem is that user space tools such as perf and trace-cmd do not
have access to the contents of these pointers, and they become useless when
the tracing buffer is extracted.

Instead of having vbin_printf() simply save the pointer in the buffer for
later processing, have it perform the formatting at the time bin_printf() is
called. This will fix the issue of dereferencing pointers at a later time,
and has the extra benefit of having user space tools understand these
values.

Since perf and trace-cmd already can handle %p[sSfF] via saving kallsyms,
their pointers are saved and not processed during vbin_printf(). If they
were converted, it would break perf and trace-cmd, as they would not know
how to deal with the conversion.

Link: http://lkml.kernel.org/r/20171228204025.14a71d8f@gandalf.local.home

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-23 15:57:30 -05:00
Sergey Senozhatsky
04b8eb7a4c symbol lookup: introduce dereference_symbol_descriptor()
dereference_symbol_descriptor() invokes appropriate ARCH specific
function descriptor dereference callbacks:
- dereference_kernel_function_descriptor() if the pointer is a
  kernel symbol;

- dereference_module_function_descriptor() if the pointer is a
  module symbol.

This is the last step needed to make '%pS/%ps' smart enough to
handle function descriptor dereference on affected ARCHs and
to retire '%pF/%pf'.

To refresh it:
  Some architectures (ia64, ppc64, parisc64) use an indirect pointer
  for C function pointers - the function pointer points to a function
  descriptor and we need to dereference it to get the actual function
  pointer.

  Function descriptors live in .opd elf section and all affected
  ARCHs (ia64, ppc64, parisc64) handle it properly for kernel and
  modules. So we, technically, can decide if the dereference is
  needed by simply looking at the pointer: if it belongs to .opd
  section then we need to dereference it.

  The kernel and modules have their own .opd sections, obviously,
  that's why we need to split dereference_function_descriptor()
  and use separate kernel and module dereference arch callbacks.

Link: http://lkml.kernel.org/r/20171206043649.GB15885@jagdpanzerIV
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: James Bottomley <jejb@parisc-linux.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-ia64@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Tony Luck <tony.luck@intel.com> #ia64
Tested-by: Santosh Sivaraj <santosh@fossix.org> #powerpc
Tested-by: Helge Deller <deller@gmx.de> #parisc64
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-01-09 10:45:38 +01:00
Jonathan Corbet
27e7c0e813 vsprintf: Fix a dangling documentation reference
A reference to printk-formats.txt didn't get updated when the file moved;
fix that.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-12-21 13:39:31 -07:00
Tobin C. Harding
b3ed23213e doc: convert printk-formats.txt to rst
Documentation/printk-formats.txt is a candidate for conversion to
ReStructuredText format. Some effort has already been made to do this
conversion even thought the suffix is currently .txt

Changes required to complete conversion

 - Move printk-formats.txt to core-api/printk-formats.rst
 - Add entry to Documentation/core-api/index.rst
 - Remove entry from Documentation/00-INDEX
 - Fix minor grammatical errors.
 - Order heading adornments as suggested by rst docs.
 - Use 'Passed by reference' uniformly.
 - Update pointer documentation around %px specifier.
 - Fix erroneous double backticks (to commas).
 - Remove extraneous double backticks (suggested by Jonathan Corbet).
 - Simplify documentation for kobject.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
[jc: downcased "kernel"]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-12-21 13:39:07 -07:00
Linus Torvalds
ef0010a309 vsprintf: don't use 'restricted_pointer()' when not restricting
Instead, just fall back on the new '%p' behavior which hashes the
pointer.

Otherwise, '%pK' - that was intended to mark a pointer as restricted -
just ends up leaking pointers that a normal '%p' wouldn't leak.  Which
just make the whole thing pointless.

I suspect we should actually get rid of '%pK' entirely, and make it just
work as '%p' regardless, but this is the minimal obvious fix.  People
who actually use 'kptr_restrict' should weigh in on which behavior they
want.

Cc: Tobin Harding <me@tobin.cc>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-29 11:28:09 -08:00
Tobin C. Harding
7b1924a1d9 vsprintf: add printk specifier %px
printk specifier %p now hashes all addresses before printing. Sometimes
we need to see the actual unmodified address. This can be achieved using
%lx but then we face the risk that if in future we want to change the
way the Kernel handles printing of pointers we will have to grep through
the already existent 50 000 %lx call sites. Let's add specifier %px as a
clear, opt-in, way to print a pointer and maintain some level of
isolation from all the other hex integer output within the Kernel.

Add printk specifier %px to print the actual unmodified address.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
2017-11-29 12:13:14 +11:00
Tobin C. Harding
ad67b74d24 printk: hash addresses printed with %p
Currently there exist approximately 14 000 places in the kernel where
addresses are being printed using an unadorned %p. This potentially
leaks sensitive information regarding the Kernel layout in memory. Many
of these calls are stale, instead of fixing every call lets hash the
address by default before printing. This will of course break some
users, forcing code printing needed addresses to be updated.

Code that _really_ needs the address will soon be able to use the new
printk specifier %px to print the address.

For what it's worth, usage of unadorned %p can be broken down as
follows (thanks to Joe Perches).

$ git grep -E '%p[^A-Za-z0-9]' | cut -f1 -d"/" | sort | uniq -c
   1084 arch
     20 block
     10 crypto
     32 Documentation
   8121 drivers
   1221 fs
    143 include
    101 kernel
     69 lib
    100 mm
   1510 net
     40 samples
      7 scripts
     11 security
    166 sound
    152 tools
      2 virt

Add function ptr_to_id() to map an address to a 32 bit unique
identifier. Hash any unadorned usage of specifier %p and any malformed
specifiers.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
2017-11-29 12:09:02 +11:00
Tobin C. Harding
57e734423a vsprintf: refactor %pK code out of pointer()
Currently code to handle %pK is all within the switch statement in
pointer(). This is the wrong level of abstraction. Each of the other switch
clauses call a helper function, pK should do the same.

Refactor code out of pointer() to new function restricted_pointer().

Signed-off-by: Tobin C. Harding <me@tobin.cc>
2017-11-29 12:03:24 +11:00
Mark Rutland
6aa7de0591 locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()
Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 11:01:08 +02:00
Linus Torvalds
dd6ec12f3b DeviceTree for 4.13:
- vsprintf format specifier %pOF for device_node's. This will enable us
   to stop storing the full node names. Conversion of users will happen
   next cycle.
 
 - Update documentation to point to DT specification instead of ePAPR.
 
 - Split out graph and property functions to a separate file.
 
 - New of-graph functions for ALSA
 
 - Add vendor prefixes for RISC-V, Linksys, iWave Systems, Roofull,
   Itead, and BananaPi.
 
 - Improve dtx_diff utility filename printing.
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Merge tag 'devicetree-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull DeviceTree updates from Rob Herring:

 - vsprintf format specifier %pOF for device_node's. This will enable us
   to stop storing the full node names. Conversion of users will happen
   next cycle.

 - Update documentation to point to DT specification instead of ePAPR.

 - Split out graph and property functions to a separate file.

 - New of-graph functions for ALSA

 - Add vendor prefixes for RISC-V, Linksys, iWave Systems, Roofull,
   Itead, and BananaPi.

 - Improve dtx_diff utility filename printing.

* tag 'devicetree-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (32 commits)
  of: document /sys/firmware/fdt
  dt-bindings: Add RISC-V vendor prefix
  vsprintf: Add %p extension "%pOF" for device tree
  of: find_node_by_full_name rewrite to compare each level
  of: use kbasename instead of open coding
  dt-bindings: thermal: add file extension to brcm,ns-thermal
  of: update ePAPR references to point to Devicetree Specification
  scripts/dtc: dtx_diff - Show real file names in diff header
  of: detect invalid phandle in overlay
  of: be consistent in form of file mode
  of: make __of_attach_node() static
  of: address.c header comment typo
  of: fdt.c header comment typo
  of: make of_fdt_is_compatible() static
  dt-bindings: display-timing.txt convert non-ascii characters to ascii
  Documentation: remove overlay-notes reference to non-existent file
  dt-bindings: usb: exynos-usb: Add missing required VDD properties
  dt-bindings: Add vendor prefix for Linksys
  MAINTAINERS: add device tree ABI documentation file
  of: Add vendor prefix for iWave Systems Technologies Pvt. Ltd
  ...
2017-07-07 10:37:54 -07:00
Pantelis Antoniou
ce4fecf1fe vsprintf: Add %p extension "%pOF" for device tree
90% of the usage of device node's full_name is printing it out in a
kernel message. However, storing the full path for every node is
wasteful and redundant. With a custom format specifier, we can generate
the full path at run-time and eventually remove the full path from every
node.

For instance typical use is:
	pr_info("Frobbing node %s\n", node->full_name);

Which can be written now as:
	pr_info("Frobbing node %pOF\n", node);

'%pO' is the base specifier to represent kobjects with '%pOF'
representing struct device_node. Currently, struct device_node is the
only supported type of kobject.

More fine-grained control of formatting includes printing the name,
flags, path-spec name and others, explained in the documentation entry.

Originally written by Pantelis, but pretty much rewrote the core
function using existing string/number functions. The 2 passes were
unnecessary and have been removed. Also, updated the checkpatch.pl
check. The unittest code was written by Grant Likely.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2017-06-27 12:36:40 -05:00
Christoph Hellwig
f9727a17db uuid: rename uuid types
Our "little endian" UUID really is a Wintel GUID, so rename it and its
helpers such (guid_t).  The big endian UUID is the only true one, so
give it the name uuid_t.  The uuid_le and uuid_be names are retained for
now, but will hopefully go away soon.  The exception to that are the _cmp
helpers that will be replaced by better primitives ASAP and thus don't
get the new names.

Also the _to_bin helpers are named to match the better named uuid_parse
routine in userspace.

Also remove the existing typedef in XFS that's now been superceeded by
the generic type name.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[andy: also update the UUID_LE/UUID_BE macros including fallout]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Signed-off-by: Christoph Hellwig <hch@lst.de>
2017-06-05 16:58:59 +02:00
Joe Perches
0b523769eb checkpatch: add ability to find bad uses of vsprintf %p<foo> extensions
%pK was at least once misused at %pk in an out-of-tree module.  This
lead to some security concerns.  Add the ability to track single and
multiple line statements for misuses of %p<foo>.

[akpm@linux-foundation.org: add helpful comment into lib/vsprintf.c]
[akpm@linux-foundation.org: text tweak]
Link: http://lkml.kernel.org/r/163a690510e636a23187c0dc9caa09ddac6d4cde.1488228427.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: William Roberts <william.c.roberts@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-08 17:15:10 -07:00