linux.git/lib/test_user_copy.c, branch v5.4-rc2

usercopy: Add parentheses around assignment in test_copy_struct_from_user

2019-10-03T19:13:27+00:00

Clang warns:

lib/test_user_copy.c:96:10: warning: using the result of an assignment
as a condition without parentheses [-Wparentheses]
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
            ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/test_user_copy.c:96:10: note: place parentheses around the
assignment to silence this warning
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
                ^
            (                                              )
lib/test_user_copy.c:96:10: note: use '!=' to turn this compound
assignment into an inequality comparison
        if (ret |= test(umem_src == NULL, "kmalloc failed"))
                ^~
                !=

Add the parentheses as it suggests because this is intentional.

Fixes: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
Link: https://github.com/ClangBuiltLinux/linux/issues/731
Signed-off-by: Nathan Chancellor 
Acked-by: Aleksa Sarai 
Acked-by: Christian Brauner 
Link: https://lore.kernel.org/r/20191003171121.2723619-1-natechancellor@gmail.com
Signed-off-by: Christian Brauner

lib: introduce copy_struct_from_user() helper

2019-10-01T13:45:03+00:00

A common pattern for syscall extensions is increasing the size of a
struct passed from userspace, such that the zero-value of the new fields
result in the old kernel behaviour (allowing for a mix of userspace and
kernel vintages to operate on one another in most cases).

While this interface exists for communication in both directions, only
one interface is straightforward to have reasonable semantics for
(userspace passing a struct to the kernel). For kernel returns to
userspace, what the correct semantics are (whether there should be an
error if userspace is unaware of a new extension) is very
syscall-dependent and thus probably cannot be unified between syscalls
(a good example of this problem is [1]).

Previously there was no common lib/ function that implemented
the necessary extension-checking semantics (and different syscalls
implemented them slightly differently or incompletely[2]). Future
patches replace common uses of this pattern to make use of
copy_struct_from_user().

Some in-kernel selftests that insure that the handling of alignment and
various byte patterns are all handled identically to memchr_inv() usage.

[1]: commit 1251201c0d34 ("sched/core: Fix uclamp ABI bug, clean up and
     robustify sched_read_attr() ABI logic and code")

[2]: For instance {sched_setattr,perf_event_open,clone3}(2) all do do
     similar checks to copy_struct_from_user() while rt_sigprocmask(2)
     always rejects differently-sized struct arguments.

Suggested-by: Rasmus Villemoes 
Signed-off-by: Aleksa Sarai 
Reviewed-by: Kees Cook 
Reviewed-by: Christian Brauner 
Link: https://lore.kernel.org/r/20191001011055.19283-2-cyphar@cyphar.com
Signed-off-by: Christian Brauner

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282

2019-06-05T15:36:37+00:00

Based on 1 normalized pattern(s):

  this software is licensed under the terms of the gnu general public
  license version 2 as published by the free software foundation and
  may be copied distributed and modified under those terms this
  program is distributed in the hope that it will be useful but
  without any warranty without even the implied warranty of
  merchantability or fitness for a particular purpose see the gnu
  general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 285 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Alexios Zavras 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.642774971@linutronix.de
Signed-off-by: Greg Kroah-Hartman

treewide: simplify Kconfig dependencies for removed archs

2018-03-26T13:55:57+00:00

A lot of Kconfig symbols have architecture specific dependencies.
In those cases that depend on architectures we have already removed,
they can be omitted.

Acked-by: Kalle Valo 
Acked-by: Alexandre Belloni 
Signed-off-by: Arnd Bergmann

mn10300: Remove the architecture

2018-03-09T22:19:56+00:00

Remove the MN10300 arch as the hardware is defunct.

Suggested-by: Arnd Bergmann 
Signed-off-by: David Howells 
cc: Masahiro Yamada 
cc: linux-am33-list@redhat.com
Signed-off-by: Arnd Bergmann

lib: remove check for AVR32 arch in test_user_copy

2017-05-01T07:36:30+00:00

The AVR32 architecture support has been removed from the Linux kernel,
hence remove all the check for this architecture in test_user_copy.c.

Signed-off-by: Hans-Christian Noren Egtvedt

usercopy: ARM NOMMU has no 64-bit get_user

2017-02-22T19:24:08+00:00

On a NOMMU ARM kernel, we get this link error:

ERROR: "__get_user_bad" [lib/test_user_copy.ko] undefined!

The problem is that the extended get_user/put_user definitions
were only added for the normal (MMU based) case.

We could add it for NOMMU as well, but it seems easier to just not
call it, since no other code needs it.

Fixes: 4c5d7bc63775 ("usercopy: Add tests for all get_user() sizes")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Kees Cook

usercopy: Add tests for all get_user() sizes

2017-02-21T19:59:38+00:00

The existing test was only exercising native unsigned long size
get_user(). For completeness, we should check all sizes. But we
must skip some 32-bit architectures that don't implement a 64-bit
get_user().

These new tests actually uncovered a bug in ARM's 64-bit get_user()
zeroing.

Signed-off-by: Kees Cook

usercopy: Adjust tests to deal with SMAP/PAN

2017-02-17T00:34:59+00:00

Under SMAP/PAN/etc, we cannot write directly to userspace memory, so
this rearranges the test bytes to get written through copy_to_user().
Additionally drops the bad copy_from_user() test that would trigger a
memcpy() against userspace on failure.

Signed-off-by: Kees Cook

usercopy: add testcases to check zeroing on failure

2017-02-17T00:34:59+00:00

During usercopy the destination buffer will be zeroed if copy_from_user()
or get_user() fails. This patch adds testcases for it. The destination
buffer is set with non-zero value before illegal copy_from_user() or
get_user() is executed and the buffer is compared to zero after usercopy
is done.

Signed-off-by: Hoeun Ryu 
[kees: clarified commit log, dropped second kmalloc]
Signed-off-by: Kees Cook