Pull strscpy string copy function implementation from Chris Metcalf. Chris sent this during the merge window, but I waffled back and forth on the pull request, which is why it's going in only now. The new "strscpy()" function is definitely easier to use and more secure than either strncpy() or strlcpy(), both of which are horrible nasty interfaces that have serious and irredeemable problems. strncpy() has a useless return value, and doesn't NUL-terminate an overlong result. To make matters worse, it pads a short result with zeroes, which is a performance disaster if you have big buffers. strlcpy(), by contrast, is a mis-designed "fix" for strlcpy(), lacking the insane NUL padding, but having a differently broken return value which returns the original length of the source string. Which means that it will read characters past the count from the source buffer, and you have to trust the source to be properly terminated. It also makes error handling fragile, since the test for overflow is unnecessarily subtle. strscpy() avoids both these problems, guaranteeing the NUL termination (but not excessive padding) if the destination size wasn't zero, and making the overflow condition very obvious by returning -E2BIG. It also doesn't read past the size of the source, and can thus be used for untrusted source data too. So why did I waffle about this for so long? Every time we introduce a new-and-improved interface, people start doing these interminable series of trivial conversion patches. And every time that happens, somebody does some silly mistake, and the conversion patch to the improved interface actually makes things worse. Because the patch is mindnumbing and trivial, nobody has the attention span to look at it carefully, and it's usually done over large swatches of source code which means that not every conversion gets tested. So I'm pulling the strscpy() support because it *is* a better interface. But I will refuse to pull mindless conversion patches. Use this in places where it makes sense, but don't do trivial patches to fix things that aren't actually known to be broken. * 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: tile: use global strscpy() rather than private copy string: provide strscpy() Make asm/word-at-a-time.h available on all architectures
Pull MIPS updates from Ralf Baechle: "This week's round of MIPS fixes: - Fix JZ4740 build - Fix fallback to GFP_DMA - FP seccomp in case of ENOSYS - Fix bootmem panic - A number of FP and CPS fixes - Wire up new syscalls - Make sure BPF assembler objects can properly be disassembled - Fix BPF assembler code for MIPS I" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: MIPS: scall: Always run the seccomp syscall filters MIPS: Octeon: Fix kernel panic on startup from memory corruption MIPS: Fix R2300 FP context switch handling MIPS: Fix octeon FP context switch handling MIPS: BPF: Fix load delay slots. MIPS: BPF: Do all exports of symbols with FEXPORT(). MIPS: Fix the build on jz4740 after removing the custom gpio.h MIPS: CPS: #ifdef on CONFIG_MIPS_MT_SMP rather than CONFIG_MIPS_MT MIPS: CPS: Don't include MT code in non-MT kernels. MIPS: CPS: Stop dangling delay slot from has_mt. MIPS: dma-default: Fix 32-bit fall back to GFP_DMA MIPS: Wire up userfaultfd and membarrier syscalls.
The MIPS syscall handler code used to return -ENOSYS on invalid syscalls. Whilst this is expected, it caused problems for seccomp filters because the said filters never had the change to run since the code returned -ENOSYS before triggering them. This caused problems on the chromium testsuite for filters looking for invalid syscalls. This has now changed and the seccomp filters are always run even if the syscall is invalid. We return -ENOSYS once we return from the seccomp filters. Moreover, similar codepaths have been merged in the process which simplifies somewhat the overall syscall code. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11236/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull x86 fixes from Ingo Molnar: "Fixes all around the map: W+X kernel mapping fix, WCHAN fixes, two build failure fixes for corner case configs, x32 header fix and a speling fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds x86/mm: Set NX on gap between __ex_table and rodata x86/kexec: Fix kexec crash in syscall kexec_file_load() x86/process: Unify 32bit and 64bit implementations of get_wchan() x86/process: Add proper bound checks in 64bit get_wchan() x86, efi, kasan: Fix build failure on !KASAN && KMEMCHECK=y kernels x86/hyperv: Fix the build in the !CONFIG_KEXEC_CORE case x86/cpufeatures: Correct spelling of the HWP_NOTIFY flag
Pull EFI fixes from Ingo Molnar: "Two EFI fixes: one for x86, one for ARM, fixing a boot crash bug that can trigger under newer EFI firmware" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down
Pull arm64 fixes from Catalin Marinas: - Fix for transparent huge page change_protection() logic which was inadvertently changing a huge pmd page into a pmd table entry. - Function graph tracer panic fix caused by the return_to_handler code corrupting the multi-regs function return value (composite types). * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: ftrace: fix function_graph tracer panic arm64: Fix THP protection change logic
Pull m68k updates from Geert Uytterhoeven: "Summary: - Fix for accidental modification of arguments of syscall functions - Wire up new syscalls - Update defconfigs" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k: m68k/defconfig: Update defconfigs for v4.3-rc1 m68k: Define asmlinkage_protect m68k: Wire up membarrier m68k: Wire up userfaultfd m68k: Wire up direct socket calls
During development it was found that a number of builds would panic
during the kernel init process, more specifically in 'delayed_fput()'.
The panic showed the kernel trying to access a memory address of
'0xb7fdc00' while traversing the 'delayed_fput_list' structure.
Comparing this memory address to the value of the pointer used on
builds that did not panic confirmed that the pointer on crashing
builds must have been corrupted at some stage earlier in the init
process.
By traversing the list earlier and earlier in the code it was found
that 'plat_mem_setup()' was responsible for corrupting the list.
Specifically the line:
memory = cvmx_bootmem_phy_alloc(mem_alloc_size,
__pa_symbol(&__init_end), -1,
0x100000,
CVMX_BOOTMEM_FLAG_NO_LOCKING);
Which would eventually call:
cvmx_bootmem_phy_set_size(new_ent_addr,
cvmx_bootmem_phy_get_size
(ent_addr) -
(desired_min_addr -
ent_addr));
Where 'new_ent_addr'=0x4800000 (the address of 'delayed_fput_list')
and the second argument (size)=0xb7fdc00 (the address causing the
kernel panic). The job of this part of 'plat_mem_setup()' is to
allocate chunks of memory for the kernel to use. At the start of
each chunk of memory the size of the chunk is written, hence the
value 0xb7fdc00 is written onto memory at 0x4800000, therefore the
kernel panics when it goes back to access 'delayed_fput_list' later
on in the initialisation process.
On builds that were not crashing it was found that the compiler had
placed 'delayed_fput_list' at 0x4800008, meaning it wasn't corrupted
(but something else in memory was overwritten).
As can be seen in the first function call above the code begins to
allocate chunks of memory beginning from the symbol '__init_end'.
The MIPS linker script (vmlinux.lds.S) however defines the .bss
section to begin after '__init_end'. Therefore memory within the
.bss section is allocated to the kernel to use (System.map shows
'delayed_fput_list' and other kernel structures to be in .bss).
To stop the kernel panic (and the .bss section being corrupted)
memory should begin being allocated from the symbol '_end'.
Signed-off-by: Matt Bennett <matt.bennett@alliedtelesis.co.nz>
Acked-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: aleksey.makarov@auriga.com
Patchwork: https://patchwork.linux-mips.org/patch/11251/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit 1a3d59579b9f ("MIPS: Tidy up FPU context switching") removed FP
context saving from the asm-written resume function in favour of reusing
existing code to perform the same task. However it only removed the FP
context saving code from the r4k_switch.S implementation of resume.
Remove it from the r2300_switch.S implementation too in order to prevent
attempting to save the FP context twice, which would likely lead to an
exception from the second save because the FPU had already been disabled
by the first save.
This patch has only been build tested, using rbtx49xx_defconfig.
Fixes: 1a3d59579b9f ("MIPS: Tidy up FPU context switching")
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/11167/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit 1a3d59579b9f ("MIPS: Tidy up FPU context switching") removed FP
context saving from the asm-written resume function in favour of reusing
existing code to perform the same task. However it only removed the FP
context saving code from the r4k_switch.S implementation of resume.
Octeon uses its own implementation in octeon_switch.S, so remove FP
context saving there too in order to prevent attempting to save context
twice. That formerly led to an exception from the second save as follows
because the FPU had already been disabled by the first save:
do_cpu invoked from kernel context![#1]:
CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.3.0-rc2-dirty #2
task: 800000041f84a008 ti: 800000041f864000 task.ti: 800000041f864000
$ 0 : 0000000000000000 0000000010008ce1 0000000000100000 ffffffffbfffffff
$ 4 : 800000041f84a008 800000041f84ac08 800000041f84c000 0000000000000004
$ 8 : 0000000000000001 0000000000000000 0000000000000000 0000000000000001
$12 : 0000000010008ce3 0000000000119c60 0000000000000036 800000041f864000
$16 : 800000041f84ac08 800000000792ce80 800000041f84a008 ffffffff81758b00
$20 : 0000000000000000 ffffffff8175ae50 0000000000000000 ffffffff8176c740
$24 : 0000000000000006 ffffffff81170300
$28 : 800000041f864000 800000041f867d90 0000000000000000 ffffffff815f3fa0
Hi : 0000000000fa8257
Lo : ffffffffe15cfc00
epc : ffffffff8112821c resume+0x9c/0x200
ra : ffffffff815f3fa0 __schedule+0x3f0/0x7d8
Status: 10008ce2 KX SX UX KERNEL EXL
Cause : 1080002c (ExcCode 0b)
PrId : 000d0601 (Cavium Octeon+)
Modules linked in:
Process kthreadd (pid: 2, threadinfo=800000041f864000, task=800000041f84a008, tls=0000000000000000)
Stack : ffffffff81604218 ffffffff815f7e08 800000041f84a008 ffffffff811681b0
800000041f84a008 ffffffff817e9878 0000000000000000 ffffffff81770000
ffffffff81768340 ffffffff81161398 0000000000000001 0000000000000000
0000000000000000 ffffffff815f4424 0000000000000000 ffffffff81161d68
ffffffff81161be8 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 ffffffff8111e16c
0000000000000000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000 0000000000000000
...
Call Trace:
[<ffffffff8112821c>] resume+0x9c/0x200
[<ffffffff815f3fa0>] __schedule+0x3f0/0x7d8
[<ffffffff815f4424>] schedule+0x34/0x98
[<ffffffff81161d68>] kthreadd+0x180/0x198
[<ffffffff8111e16c>] ret_from_kernel_thread+0x14/0x1c
Tested using cavium_octeon_defconfig on an EdgeRouter Lite.
Fixes: 1a3d59579b9f ("MIPS: Tidy up FPU context switching")
Reported-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-kernel@vger.kernel.org
Cc: Chandrakala Chavva <cchavva@caviumnetworks.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Leonid Rosenboim <lrosenboim@caviumnetworks.com>
Patchwork: https://patchwork.linux-mips.org/patch/11166/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>