15 Aug, 2019
2 commits
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Signed-off-by: Petr Mladek
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This add some additional test cases of null/invalid pointer dereference
for dentry and file (%pd and %pD)Link: http://lkml.kernel.org/r/20190809012457.56685-2-justin.he@arm.com
To: Geert Uytterhoeven
To: Sergey Senozhatsky
To: Thomas Gleixner
To: Andy Shevchenko
To: Petr Mladek
To: linux-kernel@vger.kernel.org
Cc: Kees Cook
Cc: "Steven Rostedt (VMware)"
Cc: Shuah Khan
Cc: "Tobin C. Harding"
Signed-off-by: Jia He
Reviewed-by: Andy Shevchenko
Reviewed-by: Sergey Senozhatsky
Signed-off-by: Petr Mladek
21 May, 2019
1 commit
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the fileThese files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:GPL-2.0-only
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
08 May, 2019
1 commit
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Pull printk updates from Petr Mladek:
- Allow state reset of printk_once() calls.
- Prevent crashes when dereferencing invalid pointers in vsprintf().
Only the first byte is checked for simplicity.- Make vsprintf warnings consistent and inlined.
- Treewide conversion of obsolete %pf, %pF to %ps, %pF printf
modifiers.- Some clean up of vsprintf and test_printf code.
* tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
lib/vsprintf: Make function pointer_string static
vsprintf: Limit the length of inlined error messages
vsprintf: Avoid confusion between invalid address and value
vsprintf: Prevent crash when dereferencing invalid pointers
vsprintf: Consolidate handling of unknown pointer specifiers
vsprintf: Factor out %pO handler as kobject_string()
vsprintf: Factor out %pV handler as va_format()
vsprintf: Factor out %p[iI] handler as ip_addr_string()
vsprintf: Do not check address of well-known strings
vsprintf: Consistent %pK handling for kptr_restrict == 0
vsprintf: Shuffle restricted_pointer()
printk: Tie printk_once / printk_deferred_once into .data.once for reset
treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
lib/test_printf: Switch to bitmap_zalloc()
06 May, 2019
1 commit
26 Apr, 2019
2 commits
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We already prevent crash when dereferencing some obviously broken
pointers. But the handling is not consistent. Sometimes we print "(null)"
only for pure NULL pointer, sometimes for pointers in the first
page and sometimes also for pointers in the last page (error codes).Note that printk() call this code under logbuf_lock. Any recursive
printks are redirected to the printk_safe implementation and the messages
are stored into per-CPU buffers. These buffers might be eventually flushed
in printk_safe_flush_on_panic() but it is not guaranteed.This patch adds a check using probe_kernel_read(). It is not a full-proof
test. But it should help to see the error message in 99% situations where
the kernel would silently crash otherwise.Also it makes the error handling unified for "%s" and the many %p*
specifiers that need to read the data from a given address. We print:+ (null) when accessing data on pure pure NULL address
+ (efault) when accessing data on an invalid addressIt does not affect the %p* specifiers that just print the given address
in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p.Note that we print (efault) from security reasons. In fact, the real
address can be seen only by %px or eventually %pK.Link: http://lkml.kernel.org/r/20190417115350.20479-9-pmladek@suse.com
To: Rasmus Villemoes
Cc: Linus Torvalds
Cc: "Tobin C . Harding"
Cc: Joe Perches
Cc: Andrew Morton
Cc: Michal Hocko
Cc: Steven Rostedt
Cc: Sergey Senozhatsky
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky
Reviewed-by: Andy Shevchenko
Signed-off-by: Petr Mladek -
There are few printk formats that make sense only with two or more
specifiers. Also some specifiers make sense only when a kernel feature
is enabled.The handling of unknown specifiers is inconsistent and not helpful.
Using WARN() looks like an overkill for this type of error. pr_warn()
is not good either. It would by handled via printk_safe buffer and
it might be hard to match it with the problematic string.A reasonable compromise seems to be writing the unknown format specifier
into the original string with a question mark, for example (%pC?).
It should be self-explaining enough. Note that it is in brackets
to follow the (null) style.Note that it introduces a warning about that test_hashed() function
is unused. It is going to be used again by a later patch.Link: http://lkml.kernel.org/r/20190417115350.20479-8-pmladek@suse.com
To: Rasmus Villemoes
Cc: Linus Torvalds
Cc: "Tobin C . Harding"
Cc: Joe Perches
Cc: Andrew Morton
Cc: Michal Hocko
Cc: Steven Rostedt
Cc: Sergey Senozhatsky
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky
Reviewed-by: Andy Shevchenko
Signed-off-by: Petr Mladek
09 Apr, 2019
2 commits
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We just added a new C header file for use with test modules that are
intended to be run with kselftest. We can reduce code duplication by
using this header.Use new kselftest header to reduce code duplication in test_printf and
test_bitmap test modules.Acked-by: Kees Cook
Signed-off-by: Tobin C. Harding
Signed-off-by: Shuah Khan -
Currently the test_printf module does not have an exit function, this
prevents the module from being unloaded. If we cannot unload the
module we cannot run the tests a second time.Add an empty exit function.
Acked-by: Kees Cook
Signed-off-by: Tobin C. Harding
Signed-off-by: Shuah Khan
20 Mar, 2019
1 commit
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Switch to bitmap_zalloc() to show clearly what we are allocating.
Besides that it returns pointer of bitmap type instead of opaque void *.Link: http://lkml.kernel.org/r/20190304100009.65147-1-andriy.shevchenko@linux.intel.com
To: linux-kernel@vger.kernel.org
To: Andrew Morton
To: linux@rasmusvillemoes.dk
Signed-off-by: Andy Shevchenko
Signed-off-by: Petr Mladek
11 Dec, 2018
1 commit
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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
Cc: Bartlomiej Zolnierkiewicz
Cc: Dmitry Torokhov
Cc: Geert Uytterhoeven
Cc: Guan Xuetao
Cc: Ingo Molnar
Cc: Jason Wessel
Cc: Jonathan Corbet
Cc: Jonathan Hunter
Cc: Krzysztof Kozlowski
Cc: "Rafael J. Wysocki"
Cc: Thierry Reding
Cc: Petr Mladek
Signed-off-by: Andy Shevchenko
Reviewed-by: Petr Mladek
Signed-off-by: Alexandre Belloni
15 Jun, 2018
1 commit
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If the test_printf module is loaded before the crng is initialized, the
plain 'p' tests will fail because the printed address will not be hashed
and the buffer will contain "(____ptrval____)" or "(ptrval)" instead
(64-bit vs 32-bit).
Since we cannot wait for the crng to be initialized for an undefined
time, both plain 'p' tests now accept the strings "(____ptrval____)" or
"(ptrval)" as a valid result and print a warning message.Link: http://lkml.kernel.org/r/20180613171840.29827-1-thierry.escande@linaro.org
Fixes: ad67b74d2469d9b82 ("printk: hash addresses printed with %p")
To: Andrew Morton
To: David Miller
Cc: Rasmus Villemoes
Cc: "Tobin C . Harding"
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Thierry Escande
Reviewed-by: Andy Shevchenko
Signed-off-by: Petr Mladek
11 Apr, 2018
1 commit
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Sparse complains that constant is so big for unsigned long on 64-bit
architecture.lib/test_printf.c:217:54: warning: constant 0xffff0123456789ab is so big it is unsigned long
lib/test_printf.c:246:54: warning: constant 0xffff0123456789ab is so big it is unsigned longTo satisfy everyone, mark the constant with UL.
Link: http://lkml.kernel.org/r/20180216210711.79901-1-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding"
To: linux@rasmusvillemoes.dk
To: Joe Perches
To: linux-kernel@vger.kernel.org
To: Andrew Morton
Signed-off-by: Andy Shevchenko
[pmladek@suse.com: Changed from ULL to UL as suggested by Luc Van Oostenryck ]
Signed-off-by: Petr Mladek
29 Nov, 2017
1 commit
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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 virtAdd 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
16 Mar, 2016
1 commit
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In mm we use several kinds of flags bitfields that are sometimes printed
for debugging purposes, or exported to userspace via sysfs. To make
them easier to interpret independently on kernel version and config, we
want to dump also the symbolic flag names. So far this has been done
with repeated calls to pr_cont(), which is unreliable on SMP, and not
usable for e.g. sysfs export.To get a more reliable and universal solution, this patch extends
printk() format string for pointers to handle the page flags (%pGp),
gfp_flags (%pGg) and vma flags (%pGv). Existing users of
dump_flag_names() are converted and simplified.It would be possible to pass flags by value instead of pointer, but the
%p format string for pointers already has extensions for various kernel
structures, so it's a good fit, and the extra indirection in a
non-critical path is negligible.[linux@rasmusvillemoes.dk: lots of good implementation suggestions]
Signed-off-by: Vlastimil Babka
Acked-by: Michal Hocko
Cc: Steven Rostedt
Cc: Peter Zijlstra
Cc: Arnaldo Carvalho de Melo
Cc: Ingo Molnar
Cc: Rasmus Villemoes
Cc: Joonsoo Kim
Cc: Minchan Kim
Cc: Sasha Levin
Cc: "Kirill A. Shutemov"
Cc: Mel Gorman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Jan, 2016
7 commits
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Signed-off-by: Rasmus Villemoes
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Kees Cook
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Following "lib/vsprintf.c: expand field_width to 24 bits", let's add a
test to see that we now actually support bitmaps with 65536 bits.Signed-off-by: Rasmus Villemoes
Acked-by: Kees Cook
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These should also count as performed tests.
Signed-off-by: Rasmus Villemoes
Acked-by: Kees Cook
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This adds a few tests to test_number, one of which serves to document
another deviation from POSIX/C99 (printing 0 with an explicit precision
of 0).Signed-off-by: Rasmus Villemoes
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Kees Cook
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The kernel's printf doesn't follow the standards in a few corner cases
(which are probably mostly irrelevant). Add tests that document the
current behaviour.Signed-off-by: Rasmus Villemoes
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Kees Cook
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add a few padding bytes on either side of the test buffer, and check
that these (and the part of the buffer not used) are untouched by
vsnprintf.Signed-off-by: Rasmus Villemoes
Acked-by: Kees Cook
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
BUG is a completely unnecessarily big hammer, and we're more likely to
get the internal bug reported if we just pr_err() and ensure the test
suite fails.Signed-off-by: Rasmus Villemoes
Acked-by: Kees Cook
Cc: Al Viro
Cc: Andy Shevchenko
Cc: Ingo Molnar
Cc: Joe Perches
Cc: Maurizio Lombardi
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Nov, 2015
1 commit
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This adds a simple module for testing the kernel's printf facilities.
Previously, some %p extensions have caused a wrong return value in case
the entire output didn't fit and/or been unusable in kasprintf(). This
should help catch such issues. Also, it should help ensure that changes
to the formatting algorithms don't break anything.I'm not sure if we have a struct dentry or struct file lying around at
boot time or if we can fake one, but most %p extensions should be
testable, as should the ordinary number and string formatting.The nature of vararg functions means we can't use a more conventional
table-driven approach.For now, this is mostly a skeleton; contributions are very
welcome. Some tests are/will be slightly annoying to write, since the
expected output depends on stuff like CONFIG_*, sizeof(long), runtime
values etc.Signed-off-by: Rasmus Villemoes
Reviewed-by: Kees Cook
Cc: Andy Shevchenko
Cc: Martin Kletzander
Cc: Rasmus Villemoes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds