kcov provides code coverage collection for coverage-guided fuzzing
(randomized testing). Coverage-guided fuzzing is a testing technique
that uses coverage feedback to determine new interesting inputs to a
system. A notable user-space example is AFL
(http://lcamtuf.coredump.cx/afl/). However, this technique is not
widely used for kernel testing due to missing compiler and kernel
support.
kcov does not aim to collect as much coverage as possible. It aims to
collect more or less stable coverage that is function of syscall inputs.
To achieve this goal it does not collect coverage in soft/hard
interrupts and instrumentation of some inherently non-deterministic or
non-interesting parts of kernel is disbled (e.g. scheduler, locking).
Currently there is a single coverage collection mode (tracing), but the
API anticipates additional collection modes. Initially I also
implemented a second mode which exposes coverage in a fixed-size hash
table of counters (what Quentin used in his original patch). I've
dropped the second mode for simplicity.
This patch adds the necessary support on kernel side. The complimentary
compiler support was added in gcc revision 231296.
We've used this support to build syzkaller system call fuzzer, which has
found 90 kernel bugs in just 2 months:
https://github.com/google/syzkaller/wiki/Found-Bugs
We've also found 30+ bugs in our internal systems with syzkaller.
Another (yet unexplored) direction where kcov coverage would greatly
help is more traditional "blob mutation". For example, mounting a
random blob as a filesystem, or receiving a random blob over wire.
Why not gcov. Typical fuzzing loop looks as follows: (1) reset
coverage, (2) execute a bit of code, (3) collect coverage, repeat. A
typical coverage can be just a dozen of basic blocks (e.g. an invalid
input). In such context gcov becomes prohibitively expensive as
reset/collect coverage steps depend on total number of basic
blocks/edges in program (in case of kernel it is about 2M). Cost of
kcov depends only on number of executed basic blocks/edges. On top of
that, kernel requires per-thread coverage because there are always
background threads and unrelated processes that also produce coverage.
With inlined gcov instrumentation per-thread coverage is not possible.
kcov exposes kernel PCs and control flow to user-space which is
insecure. But debugfs should not be mapped as user accessible.
Based on a patch by Quentin Casasnovas.
[akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode']
[akpm@linux-foundation.org: unbreak allmodconfig]
[akpm@linux-foundation.org: follow x86 Makefile layout standards]
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: David Drysdale <drysdale@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Code which runs outside the kernel's normal mode of operation often does
unusual things which can cause a static analysis tool like objtool to
emit false positive warnings:
- boot image
- vdso image
- relocation
- realmode
- efi
- head
- purgatory
- modpost
Set OBJECT_FILES_NON_STANDARD for their related files and directories,
which will tell objtool to skip checking them. It's ok to skip them
because they don't affect runtime stack traces.
Also skip the following code which does the right thing with respect to
frame pointers, but is too "special" to be validated by a tool:
- entry
- mcount
Also skip the test_nx module because it modifies its exception handling
table at runtime, which objtool can't understand. Fortunately it's
just a test module so it doesn't matter much.
Currently objtool is the only user of OBJECT_FILES_NON_STANDARD, but it
might eventually be useful for other tools.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/366c080e3844e8a5b6a0327dc7e8c2b90ca3baeb.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
UBSAN uses compile-time instrumentation to catch undefined behavior
(UB). Compiler inserts code that perform certain kinds of checks before
operations that could cause UB. If check fails (i.e. UB detected)
__ubsan_handle_* function called to print error message.
So the most of the work is done by compiler. This patch just implements
ubsan handlers printing errors.
GCC has this capability since 4.9.x [1] (see -fsanitize=undefined
option and its suboptions).
However GCC 5.x has more checkers implemented [2].
Article [3] has a bit more details about UBSAN in the GCC.
[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
[3] - http://developerblog.redhat.com/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan/
Issues which UBSAN has found thus far are:
Found bugs:
* out-of-bounds access - 97840cb67f ("netfilter: nfnetlink: fix
insufficient validation in nfnetlink_bind")
undefined shifts:
* d48458d4a7 ("jbd2: use a better hash function for the revoke
table")
* 10632008b9 ("clockevents: Prevent shift out of bounds")
* 'x << -1' shift in ext4 -
http://lkml.kernel.org/r/<5444EF21.8020501@samsung.com>
* undefined rol32(0) -
http://lkml.kernel.org/r/<1449198241-20654-1-git-send-email-sasha.levin@oracle.com>
* undefined dirty_ratelimit calculation -
http://lkml.kernel.org/r/<566594E2.3050306@odin.com>
* undefined roundown_pow_of_two(0) -
http://lkml.kernel.org/r/<1449156616-11474-1-git-send-email-sasha.levin@oracle.com>
* [WONTFIX] undefined shift in __bpf_prog_run -
http://lkml.kernel.org/r/<CACT4Y+ZxoR3UjLgcNdUm4fECLMx2VdtfrENMtRRCdgHB2n0bJA@mail.gmail.com>
WONTFIX here because it should be fixed in bpf program, not in kernel.
signed overflows:
* 32a8df4e0b ("sched: Fix odd values in effective_load()
calculations")
* mul overflow in ntp -
http://lkml.kernel.org/r/<1449175608-1146-1-git-send-email-sasha.levin@oracle.com>
* incorrect conversion into rtc_time in rtc_time64_to_tm() -
http://lkml.kernel.org/r/<1449187944-11730-1-git-send-email-sasha.levin@oracle.com>
* unvalidated timespec in io_getevents() -
http://lkml.kernel.org/r/<CACT4Y+bBxVYLQ6LtOKrKtnLthqLHcw-BMp3aqP3mjdAvr9FULQ@mail.gmail.com>
* [NOTABUG] signed overflow in ktime_add_safe() -
http://lkml.kernel.org/r/<CACT4Y+aJ4muRnWxsUe1CMnA6P8nooO33kwG-c8YZg=0Xc8rJqw@mail.gmail.com>
[akpm@linux-foundation.org: fix unused local warning]
[akpm@linux-foundation.org: fix __int128 build woes]
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yury Gribov <y.gribov@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
non-modular by ripping out the module_* code since Kconfig doesn't
allow it to be built as a module anyway - Paul Gortmaker
* Make the x86 efi=debug kernel parameter, which enables EFI debug
code and output, generic and usable by arm64 - Leif Lindholm
* Add support to the x86 EFI boot stub for 64-bit Graphics Output
Protocol frame buffer addresses - Matt Fleming
* Detect when the UEFI v2.5 EFI_PROPERTIES_TABLE feature is enabled
in the firmware and set an efi.flags bit so the kernel knows when
it can apply more strict runtime mapping attributes - Ard Biesheuvel
* Auto-load the efi-pstore module on EFI systems, just like we
currently do for the efivars module - Ben Hutchings
* Add "efi_fake_mem" kernel parameter which allows the system's EFI
memory map to be updated with additional attributes for specific
memory ranges. This is useful for testing the kernel code that handles
the EFI_MEMORY_MORE_RELIABLE memmap bit even if your firmware
doesn't include support - Taku Izumi
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Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into core/efi
Pull v4.4 EFI updates from Matt Fleming:
- Make the EFI System Resource Table (ESRT) driver explicitly
non-modular by ripping out the module_* code since Kconfig doesn't
allow it to be built as a module anyway. (Paul Gortmaker)
- Make the x86 efi=debug kernel parameter, which enables EFI debug
code and output, generic and usable by arm64. (Leif Lindholm)
- Add support to the x86 EFI boot stub for 64-bit Graphics Output
Protocol frame buffer addresses. (Matt Fleming)
- Detect when the UEFI v2.5 EFI_PROPERTIES_TABLE feature is enabled
in the firmware and set an efi.flags bit so the kernel knows when
it can apply more strict runtime mapping attributes - Ard Biesheuvel
- Auto-load the efi-pstore module on EFI systems, just like we
currently do for the efivars module. (Ben Hutchings)
- Add "efi_fake_mem" kernel parameter which allows the system's EFI
memory map to be updated with additional attributes for specific
memory ranges. This is useful for testing the kernel code that handles
the EFI_MEMORY_MORE_RELIABLE memmap bit even if your firmware
doesn't include support. (Taku Izumi)
Note: there is a semantic conflict between the following two commits:
8a53554e12 ("x86/efi: Fix multiple GOP device support")
ae2ee627dc ("efifb: Add support for 64-bit frame buffer addresses")
I fixed up the interaction in the merge commit, changing the type of
current_fb_base from u32 to u64.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When multiple GOP devices exists, but none of them implements
ConOut, the code should just choose the first GOP (according to
the comments). But currently 'fb_base' will refer to the last GOP,
while other parameters to the first GOP, which will likely
result in a garbled display.
I can reliably reproduce this bug using my ASRock Z87M Extreme4
motherboard with CSM and integrated GPU disabled, and two PCIe
video cards (NVidia GT640 and GTX980), booting from efi-stub
(booting from grub works fine). On the primary display the
ASRock logo remains and on the secondary screen it is garbled
up completely.
Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1444659236-24837-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The EFI Graphics Output Protocol uses 64-bit frame buffer addresses
but these get truncated to 32-bit by the EFI boot stub when storing
the address in the 'lfb_base' field of 'struct screen_info'.
Add a 'ext_lfb_base' field for the upper 32-bits of the frame buffer
address and set VIDEO_TYPE_CAPABILITY_64BIT_BASE when the field is
useable.
It turns out that the reason no one has required this support so far
is that there's actually code in tianocore to "downgrade" PCI
resources that have option ROMs and 64-bit BARS from 64-bit to 32-bit
to cope with legacy option ROMs that can't handle 64-bit addresses.
The upshot is that basically all GOP devices in the wild use a 32-bit
frame buffer address.
Still, it is possible to build firmware that uses a full 64-bit GOP
frame buffer address. Chad did, which led to him reporting this issue.
Add support in anticipation of GOP devices using 64-bit addresses more
widely, and so that efifb works out of the box when that happens.
Reported-by: Chad Page <chad.page@znyx.com>
Cc: Pete Hawkins <pete.hawkins@znyx.com>
Acked-by: Peter Jones <pjones@redhat.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
When loading x86 64bit kernel above 4GiB with patched grub2, got kernel
gunzip error.
| early console in decompress_kernel
| decompress_kernel:
| input: [0x807f2143b4-0x807ff61aee]
| output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len
| boot via startup_64
| KASLR using RDTSC...
| new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size
| decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee]
|
| Decompressing Linux... gz...
|
| uncompression error
|
| -- System halted
the new buffer is at 0x46fe000000ULL, decompressor_gzip is using
0xffffffb901ffffff as out_len. gunzip in lib/zlib_inflate/inflate.c cap
that len to 0x01ffffff and decompress fails later.
We could hit this problem with crashkernel booting that uses kexec loading
kernel above 4GiB.
We have decompress_* support:
1. inbuf[]/outbuf[] for kernel preboot.
2. inbuf[]/flush() for initramfs
3. fill()/flush() for initrd.
This bug only affect kernel preboot path that use outbuf[].
Add __decompress and take real out_buf_len for gunzip instead of guessing
wrong buf size.
Fixes: 1431574a1c (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jon Medhurst <tixy@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull x86 boot updates from Ingo Molnar:
"The main x86 bootup related changes in this cycle were:
- more boot time optimizations. (Len Brown)
- implement hex output to allow the debugging of early bootup
parameters. (Kees Cook)
- remove obsolete MCA leftovers. (Paolo Pisati)"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/smpboot: Remove APIC.wait_for_init_deassert and atomic init_deasserted
x86/smpboot: Remove SIPI delays from cpu_up()
x86/smpboot: Remove udelay(100) when polling cpu_callin_map
x86/smpboot: Remove udelay(100) when polling cpu_initialized_map
x86/boot: Obsolete the MCA sys_desc_table
x86/boot: Add hex output for debugging
The efi_info structure stores low 32 bits of memory map
in efi_memmap and high 32 bits in efi_memmap_hi.
While constructing pointer in the setup_e820(), need
to take into account all 64 bit of the pointer.
It is because on 64bit machine the function
efi_get_memory_map() may return full 64bit pointer and before
the patch that pointer was truncated.
The issue is triggered on Parallles virtual machine and
fixed with this patch.
Signed-off-by: Dmitry Skorodumov <sdmitry@parallels.com>
Cc: Denis V. Lunev <den@openvz.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
The kernel does not support the MCA bus anymroe, so mark sys_desc_table
as obsolete: remove any reference from the code together with the remaining
of MCA logic.
bloat-o-meter output:
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-55 (-55)
function old new delta
i386_start_kernel 128 119 -9
setup_arch 1421 1375 -46
Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437409430-8491-1-git-send-email-p.pisati@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is useful for reporting various addresses or other values
while debugging early boot, for example, the recent kernel image
size vs kernel run size. For example, when
CONFIG_X86_VERBOSE_BOOTUP is set, this is now visible at boot
time:
early console in setup code
early console in decompress_kernel
input_data: 0x0000000001e1526e
input_len: 0x0000000000732236
output: 0x0000000001000000
output_len: 0x0000000001535640
run_size: 0x00000000021fb000
KASLR using RDTSC...
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20150706230620.GA17501@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that there is no paravirt TSC, the "native" is
inappropriate. The function does RDTSC, so give it the obvious
name: rdtsc().
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/fd43e16281991f096c1e4d21574d9e1402c62d39.1434501121.git.luto@kernel.org
[ Ported it to v4.2-rc1. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the ->read_tsc() paravirt hook is gone, rdtscll() is
just a wrapper around native_read_tsc(). Unwrap it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/d2449ae62c1b1fb90195bcfb19ef4a35883a04dc.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
4 drivers / enabling modules:
NFIT:
Instantiates an "nvdimm bus" with the core and registers memory devices
(NVDIMMs) enumerated by the ACPI 6.0 NFIT (NVDIMM Firmware Interface
table). After registering NVDIMMs the NFIT driver then registers
"region" devices. A libnvdimm-region defines an access mode and the
boundaries of persistent memory media. A region may span multiple
NVDIMMs that are interleaved by the hardware memory controller. In
turn, a libnvdimm-region can be carved into a "namespace" device and
bound to the PMEM or BLK driver which will attach a Linux block device
(disk) interface to the memory.
PMEM:
Initially merged in v4.1 this driver for contiguous spans of persistent
memory address ranges is re-worked to drive PMEM-namespaces emitted by
the libnvdimm-core. In this update the PMEM driver, on x86, gains the
ability to assert that writes to persistent memory have been flushed all
the way through the caches and buffers in the platform to persistent
media. See memcpy_to_pmem() and wmb_pmem().
BLK:
This new driver enables access to persistent memory media through "Block
Data Windows" as defined by the NFIT. The primary difference of this
driver to PMEM is that only a small window of persistent memory is
mapped into system address space at any given point in time. Per-NVDIMM
windows are reprogrammed at run time, per-I/O, to access different
portions of the media. BLK-mode, by definition, does not support DAX.
BTT:
This is a library, optionally consumed by either PMEM or BLK, that
converts a byte-accessible namespace into a disk with atomic sector
update semantics (prevents sector tearing on crash or power loss). The
sinister aspect of sector tearing is that most applications do not know
they have a atomic sector dependency. At least today's disk's rarely
ever tear sectors and if they do one almost certainly gets a CRC error
on access. NVDIMMs will always tear and always silently. Until an
application is audited to be robust in the presence of sector-tearing
the usage of BTT is recommended.
Thanks to: Ross Zwisler, Jeff Moyer, Vishal Verma, Christoph Hellwig,
Ingo Molnar, Neil Brown, Boaz Harrosh, Robert Elliott, Matthew Wilcox,
Andy Rudoff, Linda Knippers, Toshi Kani, Nicholas Moulin, Rafael
Wysocki, and Bob Moore.
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Merge tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm
Pull libnvdimm subsystem from Dan Williams:
"The libnvdimm sub-system introduces, in addition to the
libnvdimm-core, 4 drivers / enabling modules:
NFIT:
Instantiates an "nvdimm bus" with the core and registers memory
devices (NVDIMMs) enumerated by the ACPI 6.0 NFIT (NVDIMM Firmware
Interface table).
After registering NVDIMMs the NFIT driver then registers "region"
devices. A libnvdimm-region defines an access mode and the
boundaries of persistent memory media. A region may span multiple
NVDIMMs that are interleaved by the hardware memory controller. In
turn, a libnvdimm-region can be carved into a "namespace" device and
bound to the PMEM or BLK driver which will attach a Linux block
device (disk) interface to the memory.
PMEM:
Initially merged in v4.1 this driver for contiguous spans of
persistent memory address ranges is re-worked to drive
PMEM-namespaces emitted by the libnvdimm-core.
In this update the PMEM driver, on x86, gains the ability to assert
that writes to persistent memory have been flushed all the way
through the caches and buffers in the platform to persistent media.
See memcpy_to_pmem() and wmb_pmem().
BLK:
This new driver enables access to persistent memory media through
"Block Data Windows" as defined by the NFIT. The primary difference
of this driver to PMEM is that only a small window of persistent
memory is mapped into system address space at any given point in
time.
Per-NVDIMM windows are reprogrammed at run time, per-I/O, to access
different portions of the media. BLK-mode, by definition, does not
support DAX.
BTT:
This is a library, optionally consumed by either PMEM or BLK, that
converts a byte-accessible namespace into a disk with atomic sector
update semantics (prevents sector tearing on crash or power loss).
The sinister aspect of sector tearing is that most applications do
not know they have a atomic sector dependency. At least today's
disk's rarely ever tear sectors and if they do one almost certainly
gets a CRC error on access. NVDIMMs will always tear and always
silently. Until an application is audited to be robust in the
presence of sector-tearing the usage of BTT is recommended.
Thanks to: Ross Zwisler, Jeff Moyer, Vishal Verma, Christoph Hellwig,
Ingo Molnar, Neil Brown, Boaz Harrosh, Robert Elliott, Matthew Wilcox,
Andy Rudoff, Linda Knippers, Toshi Kani, Nicholas Moulin, Rafael
Wysocki, and Bob Moore"
* tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm: (33 commits)
arch, x86: pmem api for ensuring durability of persistent memory updates
libnvdimm: Add sysfs numa_node to NVDIMM devices
libnvdimm: Set numa_node to NVDIMM devices
acpi: Add acpi_map_pxm_to_online_node()
libnvdimm, nfit: handle unarmed dimms, mark namespaces read-only
pmem: flag pmem block devices as non-rotational
libnvdimm: enable iostat
pmem: make_request cleanups
libnvdimm, pmem: fix up max_hw_sectors
libnvdimm, blk: add support for blk integrity
libnvdimm, btt: add support for blk integrity
fs/block_dev.c: skip rw_page if bdev has integrity
libnvdimm: Non-Volatile Devices
tools/testing/nvdimm: libnvdimm unit test infrastructure
libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memory
nd_btt: atomic sector updates
libnvdimm: infrastructure for btt devices
libnvdimm: write blk label set
libnvdimm: write pmem label set
libnvdimm: blk labels and namespace instantiation
...
Linus reported the following new warning on x86 allmodconfig with GCC 5.1:
> ./arch/x86/include/asm/spinlock.h: In function ‘arch_spin_lock’:
> ./arch/x86/include/asm/spinlock.h:119:3: warning: implicit declaration
> of function ‘__ticket_lock_spinning’ [-Wimplicit-function-declaration]
> __ticket_lock_spinning(lock, inc.tail);
> ^
This warning triggers because of these hacks in misc.h:
/*
* we have to be careful, because no indirections are allowed here, and
* paravirt_ops is a kind of one. As it will only run in baremetal anyway,
* we just keep it from happening
*/
#undef CONFIG_PARAVIRT
#undef CONFIG_KASAN
But these hacks were not updated when CONFIG_PARAVIRT_SPINLOCKS was added,
and eventually (with the introduction of queued paravirt spinlocks in
recent kernels) this created an invalid Kconfig combination and broke
the build.
So add a CONFIG_PARAVIRT_SPINLOCKS #undef line as well.
Also remove the _ASM_X86_DESC_H quirk: that undocumented quirk
was originally added ages ago, in:
099e137726 ("x86: use ELF format in compressed images.")
and I went back to that kernel (and fixed up the main Makefile
which didn't build anymore) and checked what failure it
avoided: it avoided an include file dependencies related
build failure related to our old x86-platforms code.
That old code is long gone, the header dependencies got cleaned
up, and the build does not fail anymore with the totality of
asm/desc.h included - so remove the quirk.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ACPI 6.0 formalizes e820-type-7 and efi-type-14 as persistent memory.
Mark it "reserved" and allow it to be claimed by a persistent memory
device driver.
This definition is in addition to the Linux kernel's existing type-12
definition that was recently added in support of shipping platforms with
NVDIMM support that predate ACPI 6.0 (which now classifies type-12 as
OEM reserved).
Note, /proc/iomem can be consulted for differentiating legacy
"Persistent Memory (legacy)" E820_PRAM vs standard "Persistent Memory"
E820_PMEM.
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
EFI variable name - Ross Lagerwall
* Stop erroneously dropping upper 32-bits of boot command line pointer
in EFI boot stub and stash them in ext_cmd_line_ptr - Roy Franz
* Fix double-free bug in error handling code path of EFI runtime map
code - Dan Carpenter
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Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent
Pull EFI fixes from Matt Fleming:
* Avoid garbage names in efivarfs due to buggy firmware by zeroing
EFI variable name. (Ross Lagerwall)
* Stop erroneously dropping upper 32 bits of boot command line pointer
in EFI boot stub and stash them in ext_cmd_line_ptr. (Roy Franz)
* Fix double-free bug in error handling code path of EFI runtime map
code. (Dan Carpenter)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Until now, the EFI stub was only setting the 32 bit cmd_line_ptr in
the setup_header structure, so on 64 bit platforms this could be truncated.
This patch adds setting the upper bits of the buffer address in
ext_cmd_line_ptr. This case was likely never hit, as the allocation
for this buffer is done at the lowest available address. Only
x86_64 kernels have this problem, as the 1-1 mapping mandated
by EFI ensures that all memory is 32 bit addressable on 32 bit
platforms. The EFI stub does not support mixed mode, so the
32 bit kernel on 64 bit firmware case does not need to be handled.
Signed-off-by: Roy Franz <roy.franz@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Commit:
e2b32e6785 ("x86, kaslr: randomize module base load address")
made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:
f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")
In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.
Originally-From: Jiri Kosina <jkosina@suse.cz>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This reverts commit:
f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")
The main reason for the revert is that the new boot flag does not work
at all currently, and in order to make this work, we need non-trivial
changes to the x86 boot code which we didn't manage to get done in
time for merging.
And even if we did, they would've been too risky so instead of
rushing things and break booting 4.1 on boxes left and right, we
will be very strict and conservative and will take our time with
this to fix and test it properly.
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: H. Peter Anvin <hpa@linux.intel.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150316100628.GD22995@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull misc x86 fixes from Ingo Molnar:
"This contains:
- EFI fixes
- a boot printout fix
- ASLR/kASLR fixes
- intel microcode driver fixes
- other misc fixes
Most of the linecount comes from an EFI revert"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch
x86/microcode/intel: Handle truncated microcode images more robustly
x86/microcode/intel: Guard against stack overflow in the loader
x86, mm/ASLR: Fix stack randomization on 64-bit systems
x86/mm/init: Fix incorrect page size in init_memory_mapping() printks
x86/mm/ASLR: Propagate base load address calculation
Documentation/x86: Fix path in zero-page.txt
x86/apic: Fix the devicetree build in certain configs
Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
x86/efi: Avoid triple faults during EFI mixed mode calls
Pull ASLR and kASLR fixes from Borislav Petkov:
- Add a global flag announcing KASLR state so that relevant code can do
informed decisions based on its setting. (Jiri Kosina)
- Fix a stack randomization entropy decrease bug. (Hector Marco-Gisbert)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit:
e2b32e6785 ("x86, kaslr: randomize module base load address")
makes the base address for module to be unconditionally randomized in
case when CONFIG_RANDOMIZE_BASE is defined and "nokaslr" option isn't
present on the commandline.
This is not consistent with how choose_kernel_location() decides whether
it will randomize kernel load base.
Namely, CONFIG_HIBERNATION disables kASLR (unless "kaslr" option is
explicitly specified on kernel commandline), which makes the state space
larger than what module loader is looking at. IOW CONFIG_HIBERNATION &&
CONFIG_RANDOMIZE_BASE is a valid config option, kASLR wouldn't be applied
by default in that case, but module loader is not aware of that.
Instead of fixing the logic in module.c, this patch takes more generic
aproach. It introduces a new bootparam setup data_type SETUP_KASLR and
uses that to pass the information whether kaslr has been applied during
kernel decompression, and sets a global 'kaslr_enabled' variable
accordingly, so that any kernel code (module loading, livepatching, ...)
can make decisions based on its value.
x86 module loader is converted to make use of this flag.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Link: https://lkml.kernel.org/r/alpine.LNX.2.00.1502101411280.10719@pobox.suse.cz
[ Always dump correct kaslr status when panicking ]
Signed-off-by: Borislav Petkov <bp@suse.de>
There is already defined macro KEEP_SEGMENTS in
<asm/bootparam.h>, let's use it instead of hardcoded
constants.
Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1424331298-7456-1-git-send-email-kuleshovmail@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Recently instrumentation of builtin functions calls was removed from GCC
5.0. To check the memory accessed by such functions, userspace asan
always uses interceptors for them.
So now we should do this as well. This patch declares
memset/memmove/memcpy as weak symbols. In mm/kasan/kasan.c we have our
own implementation of those functions which checks memory before accessing
it.
Default memset/memmove/memcpy now now always have aliases with '__'
prefix. For files that built without kasan instrumentation (e.g.
mm/slub.c) original mem* replaced (via #define) with prefixed variants,
cause we don't want to check memory accesses there.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds arch specific code for kernel address sanitizer.
16TB of virtual addressed used for shadow memory. It's located in range
[ffffec0000000000 - fffffc0000000000] between vmemmap and %esp fixup
stacks.
At early stage we map whole shadow region with zero page. Latter, after
pages mapped to direct mapping address range we unmap zero pages from
corresponding shadow (see kasan_map_shadow()) and allocate and map a real
shadow memory reusing vmemmap_populate() function.
Also replace __pa with __pa_nodebug before shadow initialized. __pa with
CONFIG_DEBUG_VIRTUAL=y make external function call (__phys_addr)
__phys_addr is instrumented, so __asan_load could be called before shadow
area initialized.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andy pointed out that if an NMI or MCE is received while we're in the
middle of an EFI mixed mode call a triple fault will occur. This can
happen, for example, when issuing an EFI mixed mode call while running
perf.
The reason for the triple fault is that we execute the mixed mode call
in 32-bit mode with paging disabled but with 64-bit kernel IDT handlers
installed throughout the call.
At Andy's suggestion, stop playing the games we currently do at runtime,
such as disabling paging and installing a 32-bit GDT for __KERNEL_CS. We
can simply switch to the __KERNEL32_CS descriptor before invoking
firmware services, and run in compatibility mode. This way, if an
NMI/MCE does occur the kernel IDT handler will execute correctly, since
it'll jump to __KERNEL_CS automatically.
However, this change is only possible post-ExitBootServices(). Before
then the firmware "owns" the machine and expects for its 32-bit IDT
handlers to be left intact to service interrupts, etc.
So, we now need to distinguish between early boot and runtime
invocations of EFI services. During early boot, we need to restore the
GDT that the firmware expects to be present. We can only jump to the
__KERNEL32_CS code segment for mixed mode calls after ExitBootServices()
has been invoked.
A liberal sprinkling of comments in the thunking code should make the
differences in early and late environments more apparent.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Commit e6023367d7 ("x86, kaslr: Prevent .bss from overlaping initrd")
added Perl to the required build environment. This reimplements in
shell the Perl script used to find the size of the kernel with bss and
brk added.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Rob Landley <rob@landley.net>
Acked-by: Rob Landley <rob@landley.net>
Cc: Anca Emanuel <anca.emanuel@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On 64-bit, relocation is not required unless the load address gets
changed. Without this, relocations do unexpected things when the kernel
is above 4G.
Reported-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Thomas D. <whissi@whissi.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20150116005146.GA4212@www.outflux.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull EFI updates from Ingo Molnar:
"Changes in this cycle are:
- support module unload for efivarfs (Mathias Krause)
- another attempt at moving x86 to libstub taking advantage of the
__pure attribute (Ard Biesheuvel)
- add EFI runtime services section to ptdump (Mathias Krause)"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, ptdump: Add section for EFI runtime services
efi/x86: Move x86 back to libstub
efivarfs: Allow unloading when build as module
Pull x86 boot and percpu updates from Ingo Molnar:
"This tree contains a bootable images documentation update plus three
slightly misplaced x86/asm percpu changes/optimizations"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86-64: Use RIP-relative addressing for most per-CPU accesses
x86-64: Handle PC-relative relocations on per-CPU data
x86: Convert a few more per-CPU items to read-mostly ones
x86, boot: Document intermediates more clearly
commit e6023367d7 'x86, kaslr: Prevent .bss from overlaping initrd'
broke the cross compile of x86. It added a objdump invocation, which
invokes the host native objdump and ignores an active cross tool
chain.
Use $(OBJDUMP) instead which takes the CROSS_COMPILE prefix into
account.
[ tglx: Massage changelog and use $(OBJDUMP) ]
Fixes: e6023367d7 'x86, kaslr: Prevent .bss from overlaping initrd'
Signed-off-by: Chris Clayton <chris2553@googlemail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/54705C8E.1080400@googlemail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This reverts commit 84be880560, which itself reverted my original
attempt to move x86 from #include'ing .c files from across the tree
to using the EFI stub built as a static library.
The issue that affected the original approach was that splitting
the implementation into several .o files resulted in the variable
'efi_early' becoming a global with external linkage, which under
-fPIC implies that references to it must go through the GOT. However,
dealing with this additional GOT entry turned out to be troublesome
on some EFI implementations. (GCC's visibility=hidden attribute is
supposed to lift this requirement, but it turned out not to work on
the 32-bit build.)
Instead, use a pure getter function to get a reference to efi_early.
This approach results in no additional GOT entries being generated,
so there is no need for any changes in the early GOT handling.
Tested-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This adds a comment detailing the various intermediate files used to build
the bootable decompression image for the x86 kernel.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Link: http://lkml.kernel.org/r/20141031162204.GA26268@www.outflux.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When choosing a random address, the current implementation does not take into
account the reversed space for .bss and .brk sections. Thus the relocated kernel
may overlap other components in memory. Here is an example of the overlap from a
x86_64 kernel in qemu (the ranges of physical addresses are presented):
Physical Address
0x0fe00000 --+--------------------+ <-- randomized base
/ | relocated kernel |
vmlinux.bin | (from vmlinux.bin) |
0x1336d000 (an ELF file) +--------------------+--
\ | | \
0x1376d870 --+--------------------+ |
| relocs table | |
0x13c1c2a8 +--------------------+ .bss and .brk
| | |
0x13ce6000 +--------------------+ |
| | /
0x13f77000 | initrd |--
| |
0x13fef374 +--------------------+
The initrd image will then be overwritten by the memset during early
initialization:
[ 1.655204] Unpacking initramfs...
[ 1.662831] Initramfs unpacking failed: junk in compressed archive
This patch prevents the above situation by requiring a larger space when looking
for a random kernel base, so that existing logic can effectively avoids the
overlap.
[kees: switched to perl to avoid hex translation pain in mawk vs gawk]
[kees: calculated overlap without relocs table]
Fixes: 82fa9637a2 ("x86, kaslr: Select random position from e820 maps")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Junjie Mao <eternal.n08@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1414762838-13067-1-git-send-email-eternal.n08@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull x86 EFI updates from Peter Anvin:
"This patchset falls under the "maintainers that grovel" clause in the
v3.18-rc1 announcement. We had intended to push it late in the merge
window since we got it into the -tip tree relatively late.
Many of these are relatively simple things, but there are a couple of
key bits, especially Ard's and Matt's patches"
* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
rtc: Disable EFI rtc for x86
efi: rtc-efi: Export platform:rtc-efi as module alias
efi: Delete the in_nmi() conditional runtime locking
efi: Provide a non-blocking SetVariable() operation
x86/efi: Adding efi_printks on memory allocationa and pci.reads
x86/efi: Mark initialization code as such
x86/efi: Update comment regarding required phys mapped EFI services
x86/efi: Unexport add_efi_memmap variable
x86/efi: Remove unused efi_call* macros
efi: Resolve some shadow warnings
arm64: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
ia64: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
x86: efi: Format EFI memory type & attrs with efi_md_typeattr_format()
efi: Introduce efi_md_typeattr_format()
efi: Add macro for EFI_MEMORY_UCE memory attribute
x86/efi: Clear EFI_RUNTIME_SERVICES if failing to enter virtual mode
arm64/efi: Do not enter virtual mode if booting with efi=noruntime or noefi
arm64/efi: uefi_init error handling fix
efi: Add kernel param efi=noruntime
lib: Add a generic cmdline parse function parse_option_str
...
Pull x86 fixes from Ingo Molnar:
"Misc smaller fixes that missed the v3.17 cycle"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/build: Add arch/x86/purgatory/ make generated files to gitignore
x86: Fix section conflict for numachip
x86: Reject x32 executables if x32 ABI not supported
x86_64, entry: Filter RFLAGS.NT on entry from userspace
x86, boot, kaslr: Fix nuisance warning on 32-bit builds
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Merge tag 'tiny/for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux
Pull "tinification" patches from Josh Triplett.
Work on making smaller kernels.
* tag 'tiny/for-3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/josh/linux:
bloat-o-meter: Ignore syscall aliases SyS_ and compat_SyS_
mm: Support compiling out madvise and fadvise
x86: Support compiling out human-friendly processor feature names
x86: Drop support for /proc files when !CONFIG_PROC_FS
x86, boot: Don't compile early_serial_console.c when !CONFIG_EARLY_PRINTK
x86, boot: Don't compile aslr.c when !CONFIG_RANDOMIZE_BASE
x86, boot: Use the usual -y -n mechanism for objects in vmlinux
x86: Add "make tinyconfig" to configure the tiniest possible kernel
x86, platform, kconfig: move kvmconfig functionality to a helper
All other calls to allocate memory seem to make some noise already, with the
exception of two calls (for gop, uga) in the setup_graphics path.
The purpose is to be noisy on worrysome errors immediately.
commit fb86b2440d ("x86/efi: Add better error logging to EFI boot
stub") introduces printing false alarms for lots of hardware. Rather
than playing Whack a Mole with non-fatal exit conditions, try the other
way round.
This is per Matt Fleming's suggestion:
> Where I think we could improve things
> is by adding efi_printk() message in certain error paths. Clearly, not
> all error paths need such messages, e.g. the EFI_INVALID_PARAMETER path
> you highlighted above, but it makes sense for memory allocation and PCI
> read failures.
Link: http://article.gmane.org/gmane.linux.kernel.efi/4628
Signed-off-by: Andre Müller <andre.muller@web.de>
Cc: Ulf Winkelvos <ulf@winkelvos.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
We need a way to customize the behaviour of the EFI boot stub, in
particular, we need a way to disable the "chunking" workaround, used
when reading files from the EFI System Partition.
One of my machines doesn't cope well when reading files in 1MB chunks to
a buffer above the 4GB mark - it appears that the "chunking" bug
workaround triggers another firmware bug. This was only discovered with
commit 4bf7111f50 ("x86/efi: Support initrd loaded above 4G"), and
that commit is perfectly valid. The symptom I observed was a corrupt
initrd rather than any kind of crash.
efi= is now used to specify EFI parameters in two very different
execution environments, the EFI boot stub and during kernel boot.
There is also a slight performance optimization by enabling efi=nochunk,
but that's offset by the fact that you're more likely to run into
firmware issues, at least on x86. This is the rationale behind leaving
the workaround enabled by default.
Also provide some documentation for EFI_READ_CHUNK_SIZE and why we're
using the current value of 1MB.
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Building 32-bit threw a warning on kASLR enabled builds:
arch/x86/boot/compressed/aslr.c: In function ‘mem_avoid_overlap’:
arch/x86/boot/compressed/aslr.c:198:17: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
avoid.start = (u64)ptr;
^
This fixes the warning; unsigned long should have been used here.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20141001183632.GA11431@www.outflux.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Pull x86 fixes from Ingo Molnar:
"This has:
- EFI revert to fix a boot regression
- early_ioremap() fix for boot failure
- KASLR fix for possible boot failures
- EFI fix for corrupted string printing
- remove a misleading EFI bootup 'failed!' error message
Unfortunately it's all rather close to the merge window"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Truncate 64-bit values when calling 32-bit OutputString()
x86/efi: Delete misleading efi_printk() error message
Revert "efi/x86: efistub: Move shared dependencies to <asm/efi.h>"
x86/kaslr: Avoid the setup_data area when picking location
x86 early_ioremap: Increase FIX_BTMAPS_SLOTS to 8
causing issues for Macbooks and Fedora + Grub2 - Matt Fleming
* Delete the misleading "setup_efi_pci() failed!" message which some
people are seeing when booting EFI - Matt Fleming
* Fix printing strings from the 32-bit EFI boot stub by only passing
32-bit addresses to the firmware - Matt Fleming
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Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent
Pull EFI fixes from Matt Fleming:
* Revert the static library changes from the merge window since they're
causing issues for Macbooks and Fedora + Grub2 (Matt Fleming)
* Delete the misleading "setup_efi_pci() failed!" message which some
people are seeing when booting EFI (Matt Fleming)
* Fix printing strings from the 32-bit EFI boot stub by only passing
32-bit addresses to the firmware (Matt Fleming)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
