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17 commits

Author SHA1 Message Date
Linus Torvalds
794fe7891d Fixes a typo in sancov plugin, exposed in earlier compiler versions
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Merge tag 'gcc-plugins-v4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc-plugins fix from Kees Cook:
 "Fixes a typo in sancov plugin, exposed in earlier compiler versions"

* tag 'gcc-plugins-v4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: fix sancov_plugin for gcc-5
2017-03-09 18:05:41 -08:00
Arnd Bergmann
dcc235279a gcc-plugins: fix sancov_plugin for gcc-5
The name of the local variable was inadvertantly changed from
sancov_plugin_pass_info to sancov_pass_info:

scripts/gcc-plugins/sancov_plugin.c: In function ‘int plugin_init(plugin_name_args*, plugin_gcc_version*)’:
scripts/gcc-plugins/sancov_plugin.c:136:67: error: ‘sancov_plugin_pass_info’ was not declared in this scope

This changes the conditional reference to this variable as well.

Fixes: 5a45a4c5c3 ("gcc-plugins: consolidate on PASS_INFO macro")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-02-27 14:10:10 -08:00
Kees Cook
c054ee3bbf Merge branch 'for-next/gcc-plugin/structleak' into for-linus/gcc-plugins 2017-02-21 21:12:57 -08:00
Kees Cook
c61f13eaa1 gcc-plugins: Add structleak for more stack initialization
This plugin detects any structures that contain __user attributes and
makes sure it is being fully initialized so that a specific class of
information exposure is eliminated. (This plugin was originally designed
to block the exposure of siginfo in CVE-2013-2141.)

Ported from grsecurity/PaX. This version adds a verbose option to the
plugin and the Kconfig.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-01-18 12:02:35 -08:00
Kees Cook
5a45a4c5c3 gcc-plugins: consolidate on PASS_INFO macro
Now that PASS_INFO() exists, use it in the other existing gcc plugins,
instead of always open coding the same thing.

Based on updates to the grsecurity/PaX gcc plugins.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-01-13 14:20:03 -08:00
Kees Cook
8d4973a1c0 gcc-plugins: add PASS_INFO and build_const_char_string()
This updates the GCC plugins gcc-common.h from PaX Team to include
more helpers and header files, specifically adds the PASS_INFO()
macro to make plugin declarations nicer and a helper for proper
const string building.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-01-10 16:50:57 -08:00
Kees Cook
81d873a871 gcc-plugins: update gcc-common.h for gcc-7
This updates gcc-common.h from Emese Revfy for gcc 7. This fixes issues seen
by Kugan and Arnd. Build tested with gcc 5.4 and 7 snapshot.

Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-01-03 12:08:59 -08:00
Kees Cook
9988f4d577 latent_entropy: fix ARM build error on earlier gcc
This fixes build errors seen on gcc-4.9.3 or gcc-5.3.1 for an ARM:

arm-soc/init/initramfs.c: In function 'error':
arm-soc/init/initramfs.c:50:1: error: unrecognizable insn:
 }
 ^
(insn 26 25 27 5 (set (reg:SI 111 [ local_entropy.243 ])
        (rotatert:SI (reg:SI 116 [ local_entropy.243 ])
            (const_int -30 [0xffffffffffffffe2]))) -1
     (nil))

Patch from PaX Team <pageexec@freemail.hu>

Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Brad Spengler <spender@grsecurity.net>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-01-03 12:08:59 -08:00
Masanari Iida
9165dabb25 treewide: Fix printk() message errors
This patch fix spelling typos in printk and kconfig.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-12-14 10:54:27 +01:00
Kees Cook
58bea4144d latent_entropy: Fix wrong gcc code generation with 64 bit variables
The stack frame size could grow too large when the plugin used long long
on 32-bit architectures when the given function had too many basic blocks.

The gcc warning was:

drivers/pci/hotplug/ibmphp_ebda.c: In function 'ibmphp_access_ebda':
drivers/pci/hotplug/ibmphp_ebda.c:409:1: warning: the frame size of 1108 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This switches latent_entropy from u64 to unsigned long.

Thanks to PaX Team and Emese Revfy for the patch.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-31 11:30:41 -07:00
Kees Cook
da7389ac6c gcc-plugins: Export symbols needed by gcc
This explicitly exports symbols that gcc expects from plugins.

Based on code from Emese Revfy.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-31 10:40:13 -07:00
Emese Revfy
38addce8b6 gcc-plugins: Add latent_entropy plugin
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).

At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.

The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).

To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).

Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.

Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-10 14:51:44 -07:00
Emese Revfy
caefd8c9a9 gcc-plugins: Add support for plugin subdirectories
This adds support for building more complex gcc plugins that live in a
subdirectory instead of just in a single source file.

Reported-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: clarified commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-08-08 17:53:05 -07:00
Emese Revfy
7040c83bfb gcc-plugins: Automate make rule generation
There's no reason to repeat the same names in the Makefile when the .so
files have already been listed. The .o list can be generated from them.

Reported-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: clarified commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-08-08 17:52:20 -07:00
Emese Revfy
543c37cb16 Add sancov plugin
The sancov gcc plugin inserts a __sanitizer_cov_trace_pc() call
at the start of basic blocks.

This plugin is a helper plugin for the kcov feature. It supports
all gcc versions with plugin support (from gcc-4.5 on).
It is based on the gcc commit "Add fuzzing coverage support" by Dmitry Vyukov
(https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296).

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-06-07 22:57:10 +02:00
Emese Revfy
0dae776c6b Add Cyclomatic complexity GCC plugin
Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC
plugin computes the cyclomatic complexity of each function.

The complexity M of a function's control flow graph is defined as:
M = E - N + 2P
where
E = the number of edges
N = the number of nodes
P = the number of connected components (exit nodes).

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-06-07 22:57:10 +02:00
Emese Revfy
6b90bd4ba4 GCC plugin infrastructure
This patch allows to build the whole kernel with GCC plugins. It was ported from
grsecurity/PaX. The infrastructure supports building out-of-tree modules and
building in a separate directory. Cross-compilation is supported too.
Currently the x86, arm, arm64 and uml architectures enable plugins.

The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory
there. The plugins compile with these options:
 * -fno-rtti: gcc is compiled with this option so the plugins must use it too
 * -fno-exceptions: this is inherited from gcc too
 * -fasynchronous-unwind-tables: this is inherited from gcc too
 * -ggdb: it is useful for debugging a plugin (better backtrace on internal
    errors)
 * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h)
 * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version
    variable, plugin-version.h)

The infrastructure introduces a new Makefile target called gcc-plugins. It
supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script
chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++).
This script also checks the availability of the included headers in
scripts/gcc-plugins/gcc-common.h.

The gcc-common.h header contains frequently included headers for GCC plugins
and it has a compatibility layer for the supported gcc versions.

The gcc-generate-*-pass.h headers automatically generate the registration
structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes.

Note that 'make clean' keeps the *.so files (only the distclean or mrproper
targets clean all) because they are needed for out-of-tree modules.

Based on work created by the PaX Team.

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-06-07 22:57:10 +02:00