linux-toradex.git/lib/vsprintf.c, branch v5.9-rc6

lib: Revert use of fallthrough pseudo-keyword in lib/

2020-08-24T21:17:44+00:00

The following build error for powerpc64 was reported by Nathan Chancellor:

  "$ scripts/config --file arch/powerpc/configs/powernv_defconfig -e KERNEL_XZ

   $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux- distclean powernv_defconfig zImage
   ...
   In file included from arch/powerpc/boot/../../../lib/decompress_unxz.c:234,
                    from arch/powerpc/boot/decompress.c:38:
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c: In function 'dec_main':
   arch/powerpc/boot/../../../lib/xz/xz_dec_stream.c:586:4: error: 'fallthrough' undeclared (first use in this function)
     586 |    fallthrough;
         |    ^~~~~~~~~~~

   This will end up affecting distribution configurations such as Debian
   and OpenSUSE according to my testing. I am not sure what the solution
   is, the PowerPC wrapper does not set -D__KERNEL__ so I am not sure
   that compiler_attributes.h can be safely included."

In order to avoid these sort of problems, it seems that the best
solution is to use /* fall through */ comments instead of the
fallthrough pseudo-keyword macro in lib/, for now.

Reported-by: Nathan Chancellor 
Fixes: df561f6688fe ("treewide: Use fallthrough pseudo-keyword")
Signed-off-by: Gustavo A. R. Silva 
Reviewed-and-tested-by: Nathan Chancellor 
Signed-off-by: Linus Torvalds

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

lib/vsprintf: Force type of flags value for gfp_t

2020-08-01T03:52:57+00:00

Sparse is not happy about restricted type being assigned:
  lib/vsprintf.c:1940:23: warning: incorrect type in assignment (different base types)
  lib/vsprintf.c:1940:23:    expected unsigned long [assigned] flags
  lib/vsprintf.c:1940:23:    got restricted gfp_t [usertype]

Force type of flags value to make sparse happy.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Steven Rostedt (VMware) 
Link: https://lore.kernel.org/r/20200731180825.30575-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Sergey Senozhatsky

lib/vsprintf: Replace custom spec to print decimals with generic one

2020-08-01T03:52:36+00:00

When printing phandle via %pOFp the custom spec is used. First of all,
it has a SMALL flag which makes no sense for decimal numbers. Second,
we have already default spec for decimal numbers. Use the latter in
the %pOFp case as well.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Steven Rostedt (VMware) 
Reviewed-by: Sergey Senozhatsky 
Cc: Pantelis Antoniou 
Cc: Rob Herring 
Cc: Joe Perches 
Cc: Grant Likely 
Link: https://lore.kernel.org/r/20200731180825.30575-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Sergey Senozhatsky

lib/vsprintf: Replace hidden BUILD_BUG_ON() with static_assert()

2020-08-01T03:52:32+00:00

First of all, there is no compile time check for the SMALL
to be ' ' (0x20, i.e. space). Second, for ZEROPAD the check
is hidden in the code.

For better maintenance replace BUILD_BUG_ON() with static_assert()
for ZEROPAD and move it closer to the definition. While at it,
introduce check for SMALL.

Signed-off-by: Andy Shevchenko 
Reviewed-by: Steven Rostedt (VMware) 
Reviewed-by: Sergey Senozhatsky 
Link: https://lore.kernel.org/r/20200731180825.30575-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Sergey Senozhatsky

Replace HTTP links with HTTPS ones: vsprintf

2020-07-03T12:07:00+00:00

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
          If both the HTTP and HTTPS versions
          return 200 OK and serve the same content:
            Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov 
Reviewed-by: Petr Mladek 
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20200702200536.13389-1-grandmaster@al2klimov.de

Merge tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2020-06-01T19:13:30+00:00

Pull printk updates from Petr Mladek:

 - Benjamin Herrenschmidt solved a problem with non-matched console
   aliases by first checking consoles defined on the command line. It is
   a more conservative approach than the previous attempts.

 - Benjamin also made sure that the console accessible via /dev/console
   always has CON_CONSDEV flag.

 - Andy Shevchenko added the %ptT modifier for printing struct time64_t.
   It extends the existing %ptR handling for struct rtc_time.

 - Bruno Meneguele fixed /dev/kmsg error value returned by unsupported
   SEEK_CUR.

 - Tetsuo Handa removed unused pr_cont_once().

... and a few small fixes.

* tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Remove pr_cont_once()
  printk: handle blank console arguments passed in.
  kernel/printk: add kmsg SEEK_CUR handling
  printk: Fix a typo in comment "interator"->"iterator"
  usb: pulse8-cec: Switch to use %ptT
  ARM: bcm2835: Switch to use %ptT
  lib/vsprintf: Print time64_t in human readable format
  lib/vsprintf: update comment about simple_strto() functions
  printk: Correctly set CON_CONSDEV even when preferred console was not registered
  printk: Fix preferred console selection with multiple matches
  printk: Move console matching logic into a separate function
  printk: Convert a use of sprintf to snprintf in console_unlock

Merge branch 'for-5.8-printf-time64_t' into for-linus

2020-06-01T08:15:43+00:00

lib/vsprintf: Print time64_t in human readable format

2020-05-20T12:54:18+00:00

There are users which print time and date represented by content of
time64_t type in human readable format.

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

Few test cases for %ptT specifier has been added as well.

Link: https://lore.kernel.org/r/20200415170046.33374-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Reviewed-by: Alexandre Belloni 
Acked-by: Sergey Senozhatsky 
Rewieved-by: Petr Mladek 
Signed-off-by: Petr Mladek

vsprintf: don't obfuscate NULL and error pointers

2020-05-19T18:35:38+00:00

I don't see what security concern is addressed by obfuscating NULL
and IS_ERR() error pointers, printed with %p/%pK.  Given the number
of sites where %p is used (over 10000) and the fact that NULL pointers
aren't uncommon, it probably wouldn't take long for an attacker to
find the hash that corresponds to 0.  Although harder, the same goes
for most common error values, such as -1, -2, -11, -14, etc.

The NULL part actually fixes a regression: NULL pointers weren't
obfuscated until commit 3e5903eb9cff ("vsprintf: Prevent crash when
dereferencing invalid pointers") which went into 5.2.  I'm tacking
the IS_ERR() part on here because error pointers won't leak kernel
addresses and printing them as pointers shouldn't be any different
from e.g. %d with PTR_ERR_OR_ZERO().  Obfuscating them just makes
debugging based on existing pr_debug and friends excruciating.

Note that the "always print 0's for %pK when kptr_restrict == 2"
behaviour which goes way back is left as is.

Example output with the patch applied:

                             ptr         error-ptr              NULL
 %p:            0000000001f8cc5b  fffffffffffffff2  0000000000000000
 %pK, kptr = 0: 0000000001f8cc5b  fffffffffffffff2  0000000000000000
 %px:           ffff888048c04020  fffffffffffffff2  0000000000000000
 %pK, kptr = 1: ffff888048c04020  fffffffffffffff2  0000000000000000
 %pK, kptr = 2: 0000000000000000  0000000000000000  0000000000000000

Fixes: 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers")
Signed-off-by: Ilya Dryomov 
Reviewed-by: Petr Mladek 
Reviewed-by: Sergey Senozhatsky 
Reviewed-by: Andy Shevchenko 
Acked-by: Steven Rostedt (VMware) 
Signed-off-by: Linus Torvalds