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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-27 11:19:07 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-27 11:19:07 -0800 |
commit | c6f1b355d451680a45d63ce66cea67057c938a87 (patch) | |
tree | 413ed05d88e6a59d33a8b2034cfffdae1862e7b8 /scripts | |
parent | c06e9ef6918b1a6d183f1fef78ebc66f054a7b5a (diff) | |
parent | 189af4657186da08a2e79fb8e906cfd82b2ccddc (diff) | |
download | linux-c6f1b355d451680a45d63ce66cea67057c938a87.tar.gz |
Merge tag 'gcc-plugins-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc-plugins update from Kees Cook:
"Both arm and arm64 are gaining per-task stack canaries (to match x86),
but arm is being done with a gcc plugin, hence it going through the
gcc-plugins tree.
New gcc-plugin:
- Enable per-task stack protector for ARM (Ard Biesheuvel)"
* tag 'gcc-plugins-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
ARM: smp: add support for per-task stack canaries
Diffstat (limited to 'scripts')
-rw-r--r-- | scripts/Makefile.gcc-plugins | 6 | ||||
-rw-r--r-- | scripts/gcc-plugins/Kconfig | 4 | ||||
-rw-r--r-- | scripts/gcc-plugins/arm_ssp_per_task_plugin.c | 103 |
3 files changed, 113 insertions, 0 deletions
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 46c5c6809806..048179d8c07f 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -36,6 +36,12 @@ ifdef CONFIG_GCC_PLUGIN_STACKLEAK endif export DISABLE_STACKLEAK_PLUGIN +gcc-plugin-$(CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK) += arm_ssp_per_task_plugin.so +ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK + DISABLE_ARM_SSP_PER_TASK_PLUGIN += -fplugin-arg-arm_ssp_per_task_plugin-disable +endif +export DISABLE_ARM_SSP_PER_TASK_PLUGIN + # All the plugin CFLAGS are collected here in case a build target needs to # filter them out of the KBUILD_CFLAGS. GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index 0d5c799688f0..d45f7f36b859 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -190,4 +190,8 @@ config STACKLEAK_RUNTIME_DISABLE runtime to control kernel stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK. +config GCC_PLUGIN_ARM_SSP_PER_TASK + bool + depends on GCC_PLUGINS && ARM + endif diff --git a/scripts/gcc-plugins/arm_ssp_per_task_plugin.c b/scripts/gcc-plugins/arm_ssp_per_task_plugin.c new file mode 100644 index 000000000000..de70b8470971 --- /dev/null +++ b/scripts/gcc-plugins/arm_ssp_per_task_plugin.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "gcc-common.h" + +__visible int plugin_is_GPL_compatible; + +static unsigned int sp_mask, canary_offset; + +static unsigned int arm_pertask_ssp_rtl_execute(void) +{ + rtx_insn *insn; + + for (insn = get_insns(); insn; insn = NEXT_INSN(insn)) { + const char *sym; + rtx body; + rtx masked_sp; + + /* + * Find a SET insn involving a SYMBOL_REF to __stack_chk_guard + */ + if (!INSN_P(insn)) + continue; + body = PATTERN(insn); + if (GET_CODE(body) != SET || + GET_CODE(SET_SRC(body)) != SYMBOL_REF) + continue; + sym = XSTR(SET_SRC(body), 0); + if (strcmp(sym, "__stack_chk_guard")) + continue; + + /* + * Replace the source of the SET insn with an expression that + * produces the address of the copy of the stack canary value + * stored in struct thread_info + */ + masked_sp = gen_reg_rtx(Pmode); + + emit_insn_before(gen_rtx_SET(masked_sp, + gen_rtx_AND(Pmode, + stack_pointer_rtx, + GEN_INT(sp_mask))), + insn); + + SET_SRC(body) = gen_rtx_PLUS(Pmode, masked_sp, + GEN_INT(canary_offset)); + } + return 0; +} + +#define PASS_NAME arm_pertask_ssp_rtl + +#define NO_GATE +#include "gcc-generate-rtl-pass.h" + +__visible int plugin_init(struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + const int argc = plugin_info->argc; + const struct plugin_argument *argv = plugin_info->argv; + int tso = 0; + int i; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + for (i = 0; i < argc; ++i) { + if (!strcmp(argv[i].key, "disable")) + return 0; + + /* all remaining options require a value */ + if (!argv[i].value) { + error(G_("no value supplied for option '-fplugin-arg-%s-%s'"), + plugin_name, argv[i].key); + return 1; + } + + if (!strcmp(argv[i].key, "tso")) { + tso = atoi(argv[i].value); + continue; + } + + if (!strcmp(argv[i].key, "offset")) { + canary_offset = atoi(argv[i].value); + continue; + } + error(G_("unknown option '-fplugin-arg-%s-%s'"), + plugin_name, argv[i].key); + return 1; + } + + /* create the mask that produces the base of the stack */ + sp_mask = ~((1U << (12 + tso)) - 1); + + PASS_INFO(arm_pertask_ssp_rtl, "expand", 1, PASS_POS_INSERT_AFTER); + + register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, + NULL, &arm_pertask_ssp_rtl_pass_info); + + return 0; +} |