linux-stable.git/lib, branch v5.4.44

vsprintf: don't obfuscate NULL and error pointers

2020-05-27T15:46:43+00:00

commit 7bd57fbc4a4ddedc664cad0bbced1b469e24e921 upstream.

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 
Signed-off-by: Greg Kroah-Hartman

lib: devres: add a helper function for ioremap_uc

2020-05-10T08:31:30+00:00

[ Upstream commit e537654b7039aacfe8ae629d49655c0e5692ad44 ]

Implement a resource managed strongly uncachable ioremap function.

Cc:  # v4.19+
Tested-by: AceLan Kao 
Signed-off-by: Tuowen Zhao 
Acked-by: Mika Westerberg 
Acked-by: Andy Shevchenko 
Acked-by: Luis Chamberlain 
Signed-off-by: Lee Jones 
Signed-off-by: Sasha Levin

lib/mpi: Fix building for powerpc with clang

2020-05-10T08:31:28+00:00

[ Upstream commit 5990cdee689c6885b27c6d969a3d58b09002b0bc ]

0day reports over and over on an powerpc randconfig with clang:

lib/mpi/generic_mpih-mul1.c:37:13: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions

Remove the superfluous casts, which have been done previously for x86
and arm32 in commit dea632cadd12 ("lib/mpi: fix build with clang") and
commit 7b7c1df2883d ("lib/mpi/longlong.h: fix building with 32-bit
x86").

Reported-by: kbuild test robot 
Signed-off-by: Nathan Chancellor 
Acked-by: Herbert Xu 
Signed-off-by: Michael Ellerman 
Link: https://github.com/ClangBuiltLinux/linux/issues/991
Link: https://lore.kernel.org/r/20200413195041.24064-1-natechancellor@gmail.com
Signed-off-by: Sasha Levin

lib/raid6/test: fix build on distros whose /bin/sh is not bash

2020-04-29T14:33:00+00:00

[ Upstream commit 06bd48b6cd97ef3889b68c8e09014d81dbc463f1 ]

You can build a user-space test program for the raid6 library code,
like this:

  $ cd lib/raid6/test
  $ make

The command in $(shell ...) function is evaluated by /bin/sh by default.
(or, you can specify the shell by passing SHELL= from command line)

Currently '>&/dev/null' is used to sink both stdout and stderr. Because
this code is bash-ism, it only works when /bin/sh is a symbolic link to
bash (this is the case on RHEL etc.)

This does not work on Ubuntu where /bin/sh is a symbolic link to dash.

I see lots of

  /bin/sh: 1: Syntax error: Bad fd number

and

  warning "your version of binutils lacks ... support"

Replace it with portable '>/dev/null 2>&1'.

Fixes: 4f8c55c5ad49 ("lib/raid6: build proper files on corresponding arch")
Signed-off-by: Masahiro Yamada 
Acked-by: H. Peter Anvin (Intel) 
Reviewed-by: Jason A. Donenfeld 
Acked-by: Ingo Molnar 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Sasha Levin

kbuild, btf: Fix dependencies for DEBUG_INFO_BTF

2020-04-23T08:36:18+00:00

commit 7d32e69310d67e6b04af04f26193f79dfc2f05c7 upstream.

Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
enabled will produce invalid btf file, since gen_btf function in
link-vmlinux.sh script doesn't handle *.dwo files.

Enabling DEBUG_INFO_REDUCED will also produce invalid btf file,
and using GCC_PLUGIN_RANDSTRUCT with BTF makes no sense.

Fixes: e83b9f55448a ("kbuild: add ability to generate BTF type info for vmlinux")
Reported-by: Jann Horn 
Reported-by: Liu Yiding 
Signed-off-by: Slava Bacherikov 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Kees Cook 
Acked-by: KP Singh 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20200402204138.408021-1-slava@bacher09.org
Signed-off-by: Greg Kroah-Hartman

xarray: Fix early termination of xas_for_each_marked

2020-04-17T08:50:18+00:00

commit 7e934cf5ace1dceeb804f7493fa28bb697ed3c52 upstream.

xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:

TASK1                                   TASK2
page_cache_delete()         	        find_get_pages_range_tag()
                                          xas_for_each_marked()
                                            xas_find_marked()
                                              off = xas_find_chunk()

  xas_store(&xas, NULL)
    xas_init_marks(&xas);
    ...
    rcu_assign_pointer(*slot, NULL);
                                              entry = xa_entry(off);

And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).

If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).

Reported-by: Jan Kara 
CC: stable@vger.kernel.org
Fixes: ef8e5717db01 ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Greg Kroah-Hartman

XArray: Fix xas_pause for large multi-index entries

2020-04-17T08:50:18+00:00

commit c36d451ad386b34f452fc3c8621ff14b9eaa31a6 upstream.

Inspired by the recent Coverity report, I looked for other places where
the offset wasn't being converted to an unsigned long before being
shifted, and I found one in xas_pause() when the entry being paused is
of order >32.

Fixes: b803b42823d0 ("xarray: Add XArray iterators")
Signed-off-by: Matthew Wilcox (Oracle) 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

uapi: rename ext2_swab() to swab() and share globally in swab.h

2020-04-13T08:48:07+00:00

commit d5767057c9a76a29f073dad66b7fa12a90e8c748 upstream.

ext2_swab() is defined locally in lib/find_bit.c However it is not
specific to ext2, neither to bitmaps.

There are many potential users of it, so rename it to just swab() and
move to include/uapi/linux/swab.h

ABI guarantees that size of unsigned long corresponds to BITS_PER_LONG,
therefore drop unneeded cast.

Link: http://lkml.kernel.org/r/20200103202846.21616-1-yury.norov@gmail.com
Signed-off-by: Yury Norov 
Cc: Allison Randal 
Cc: Joe Perches 
Cc: Thomas Gleixner 
Cc: William Breathitt Gray 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

XArray: Fix xa_find_next for large multi-index entries

2020-04-08T07:08:40+00:00

[ Upstream commit bd40b17ca49d7d110adf456e647701ce74de2241 ]

Coverity pointed out that xas_sibling() was shifting xa_offset without
promoting it to an unsigned long first, so the shift could cause an
overflow and we'd get the wrong answer.  The fix is obvious, and the
new test-case provokes UBSAN to report an error:
runtime error: shift exponent 60 is too large for 32-bit type 'int'

Fixes: 19c30f4dd092 ("XArray: Fix xa_find_after with multi-index entries")
Reported-by: Bjorn Helgaas 
Reported-by: Kees Cook 
Signed-off-by: Matthew Wilcox (Oracle) 
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin

kbuild: move headers_check rule to usr/include/Makefile

2020-03-05T15:43:47+00:00

commit 7ecaf069da52e472d393f03e79d721aabd724166 upstream.

Currently, some sanity checks for uapi headers are done by
scripts/headers_check.pl, which is wired up to the 'headers_check'
target in the top Makefile.

It is true compiling headers has better test coverage, but there
are still several headers excluded from the compile test. I like
to keep headers_check.pl for a while, but we can delete a lot of
code by moving the build rule to usr/include/Makefile.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman