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* treewide: Fix printk() message errorsMasanari Iida2016-12-142-2/+2
| | | | | | | | 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>
* latent_entropy: Fix wrong gcc code generation with 64 bit variablesKees Cook2016-10-311-10/+9
| | | | | | | | | | | | | | | | 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>
* gcc-plugins: Export symbols needed by gccKees Cook2016-10-314-7/+8
| | | | | | | | This explicitly exports symbols that gcc expects from plugins. Based on code from Emese Revfy. Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: Add latent_entropy pluginEmese Revfy2016-10-101-0/+640
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* gcc-plugins: Add support for plugin subdirectoriesEmese Revfy2016-08-081-3/+6
| | | | | | | | | | 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>
* gcc-plugins: Automate make rule generationEmese Revfy2016-08-081-2/+1
| | | | | | | | | | 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>
* Add sancov pluginEmese Revfy2016-06-072-0/+150
| | | | | | | | | | | | | | 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>
* Add Cyclomatic complexity GCC pluginEmese Revfy2016-06-072-0/+74
| | | | | | | | | | | | | | | | 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>
* GCC plugin infrastructureEmese Revfy2016-06-076-0/+1664
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>