From c40160f2998c897231f8454bf797558d30a20375 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 6 Apr 2022 00:28:15 +0200 Subject: gcc-plugins: latent_entropy: use /dev/urandom While the latent entropy plugin mostly doesn't derive entropy from get_random_const() for measuring the call graph, when __latent_entropy is applied to a constant, then it's initialized statically to output from get_random_const(). In that case, this data is derived from a 64-bit seed, which means a buffer of 512 bits doesn't really have that amount of compile-time entropy. This patch fixes that shortcoming by just buffering chunks of /dev/urandom output and doling it out as requested. At the same time, it's important that we don't break the use of -frandom-seed, for people who want the runtime benefits of the latent entropy plugin, while still having compile-time determinism. In that case, we detect whether gcc's set_random_seed() has been called by making a call to get_random_seed(noinit=true) in the plugin init function, which is called after set_random_seed() is called but before anything that calls get_random_seed(noinit=false), and seeing if it's zero or not. If it's not zero, we're in deterministic mode, and so we just generate numbers with a basic xorshift prng. Note that we don't detect if -frandom-seed is being used using the documented local_tick variable, because it's assigned via: local_tick = (unsigned) tv.tv_sec * 1000 + tv.tv_usec / 1000; which may well overflow and become -1 on its own, and so isn't reliable: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105171 [kees: The 256 byte rnd_buf size was chosen based on average (250), median (64), and std deviation (575) bytes of used entropy for a defconfig x86_64 build] Fixes: 38addce8b600 ("gcc-plugins: Add latent_entropy plugin") Cc: stable@vger.kernel.org Cc: PaX Team Signed-off-by: Jason A. Donenfeld Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220405222815.21155-1-Jason@zx2c4.com --- scripts/gcc-plugins/latent_entropy_plugin.c | 44 ++++++++++++++++++----------- 1 file changed, 27 insertions(+), 17 deletions(-) (limited to 'scripts/gcc-plugins/latent_entropy_plugin.c') diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c index 589454bce930..8425da41de0d 100644 --- a/scripts/gcc-plugins/latent_entropy_plugin.c +++ b/scripts/gcc-plugins/latent_entropy_plugin.c @@ -86,25 +86,31 @@ static struct plugin_info latent_entropy_plugin_info = { .help = "disable\tturn off latent entropy instrumentation\n", }; -static unsigned HOST_WIDE_INT seed; -/* - * get_random_seed() (this is a GCC function) generates the seed. - * This is a simple random generator without any cryptographic security because - * the entropy doesn't come from here. - */ +static unsigned HOST_WIDE_INT deterministic_seed; +static unsigned HOST_WIDE_INT rnd_buf[32]; +static size_t rnd_idx = ARRAY_SIZE(rnd_buf); +static int urandom_fd = -1; + static unsigned HOST_WIDE_INT get_random_const(void) { - unsigned int i; - unsigned HOST_WIDE_INT ret = 0; - - for (i = 0; i < 8 * sizeof(ret); i++) { - ret = (ret << 1) | (seed & 1); - seed >>= 1; - if (ret & 1) - seed ^= 0xD800000000000000ULL; + if (deterministic_seed) { + unsigned HOST_WIDE_INT w = deterministic_seed; + w ^= w << 13; + w ^= w >> 7; + w ^= w << 17; + deterministic_seed = w; + return deterministic_seed; } - return ret; + if (urandom_fd < 0) { + urandom_fd = open("/dev/urandom", O_RDONLY); + gcc_assert(urandom_fd >= 0); + } + if (rnd_idx >= ARRAY_SIZE(rnd_buf)) { + gcc_assert(read(urandom_fd, rnd_buf, sizeof(rnd_buf)) == sizeof(rnd_buf)); + rnd_idx = 0; + } + return rnd_buf[rnd_idx++]; } static tree tree_get_random_const(tree type) @@ -537,8 +543,6 @@ static void latent_entropy_start_unit(void *gcc_data __unused, tree type, id; int quals; - seed = get_random_seed(false); - if (in_lto_p) return; @@ -573,6 +577,12 @@ __visible int plugin_init(struct plugin_name_args *plugin_info, const struct plugin_argument * const argv = plugin_info->argv; int i; + /* + * Call get_random_seed() with noinit=true, so that this returns + * 0 in the case where no seed has been passed via -frandom-seed. + */ + deterministic_seed = get_random_seed(true); + static const struct ggc_root_tab gt_ggc_r_gt_latent_entropy[] = { { .base = &latent_entropy_decl, -- cgit v1.2.3 From 61f60bac8c05f8ecd2ae2a6360520b91a45be9a2 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 10 May 2022 16:25:54 -0700 Subject: gcc-plugins: Change all version strings match kernel It's not meaningful for the GCC plugins to track their versions separately from the rest of the kernel. Switch all versions to the kernel version. Fix mismatched indenting while we're at it. Cc: linux-hardening@vger.kernel.org Signed-off-by: Kees Cook --- scripts/gcc-plugins/Makefile | 9 +++++---- scripts/gcc-plugins/latent_entropy_plugin.c | 2 +- scripts/gcc-plugins/randomize_layout_plugin.c | 2 +- scripts/gcc-plugins/sancov_plugin.c | 2 +- scripts/gcc-plugins/stackleak_plugin.c | 2 +- scripts/gcc-plugins/structleak_plugin.c | 2 +- 6 files changed, 10 insertions(+), 9 deletions(-) (limited to 'scripts/gcc-plugins/latent_entropy_plugin.c') diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index 148f4639cf09..6f0aecad5d67 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -28,10 +28,11 @@ GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin) plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \ -include $(srctree)/include/linux/compiler-version.h \ - -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \ - -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \ - -ggdb -Wno-narrowing -Wno-unused-variable \ - -Wno-format-diag + -include $(objtree)/include/generated/utsrelease.h \ + -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \ + -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \ + -ggdb -Wno-narrowing -Wno-unused-variable \ + -Wno-format-diag plugin_ldflags = -shared diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c index 8425da41de0d..5d415b2572a8 100644 --- a/scripts/gcc-plugins/latent_entropy_plugin.c +++ b/scripts/gcc-plugins/latent_entropy_plugin.c @@ -82,7 +82,7 @@ __visible int plugin_is_GPL_compatible; static GTY(()) tree latent_entropy_decl; static struct plugin_info latent_entropy_plugin_info = { - .version = "201606141920vanilla", + .version = UTS_RELEASE, .help = "disable\tturn off latent entropy instrumentation\n", }; diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c index c2ec81b68505..19214e573137 100644 --- a/scripts/gcc-plugins/randomize_layout_plugin.c +++ b/scripts/gcc-plugins/randomize_layout_plugin.c @@ -34,7 +34,7 @@ __visible int plugin_is_GPL_compatible; static int performance_mode; static struct plugin_info randomize_layout_plugin_info = { - .version = "201402201816vanilla", + .version = UTS_RELEASE, .help = "disable\t\t\tdo not activate plugin\n" "performance-mode\tenable cacheline-aware layout randomization\n" }; diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c index 23bd023a283b..f3d629555b84 100644 --- a/scripts/gcc-plugins/sancov_plugin.c +++ b/scripts/gcc-plugins/sancov_plugin.c @@ -26,7 +26,7 @@ __visible int plugin_is_GPL_compatible; tree sancov_fndecl; static struct plugin_info sancov_plugin_info = { - .version = "20160402", + .version = UTS_RELEASE, .help = "sancov plugin\n", }; diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index 42f0252ee2a4..de817d54b8af 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -44,7 +44,7 @@ static bool verbose = false; static GTY(()) tree track_function_decl; static struct plugin_info stackleak_plugin_info = { - .version = "201707101337", + .version = UTS_RELEASE, .help = "track-min-size=nn\ttrack stack for functions with a stack frame size >= nn bytes\n" "arch=target_arch\tspecify target build arch\n" "disable\t\tdo not activate the plugin\n" diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c index 74e319288389..86b608a24ec0 100644 --- a/scripts/gcc-plugins/structleak_plugin.c +++ b/scripts/gcc-plugins/structleak_plugin.c @@ -37,7 +37,7 @@ __visible int plugin_is_GPL_compatible; static struct plugin_info structleak_plugin_info = { - .version = "20190125vanilla", + .version = UTS_RELEASE, .help = "disable\tdo not activate plugin\n" "byref\tinit structs passed by reference\n" "byref-all\tinit anything passed by reference\n" -- cgit v1.2.3 From d37aa2efc89b387cda93bf15317883519683d435 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 24 May 2022 22:55:41 +0900 Subject: gcc-plugins: use KERNELVERSION for plugin version Commit 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") broke parallel builds. Instead of adding the dependency between GCC plugins and utsrelease.h, let's use KERNELVERSION, which does not require any build artifact. Another reason why I want to avoid utsrelease.h is because it depends on CONFIG_LOCALVERSION(_AUTO) and localversion* files. (include/generated/utsrelease.h depends on include/config/kernel.release, which is generated by scripts/setlocalversion) I want to keep host tools independent of the kernel configuration. There is no good reason to rebuild GCC plugins just because of CONFIG_LOCALVERSION being changed. We just want to associate the plugin versions with the kernel source version. KERNELVERSION should be enough for our purpose. Fixes: 61f60bac8c05 ("gcc-plugins: Change all version strings match kernel") Reported-by: kernel test robot Link: https://lore.kernel.org/linux-mm/202205230239.EZxeZ3Fv-lkp@intel.com Reported-by: Guenter Roeck Signed-off-by: Masahiro Yamada Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220524135541.1453693-1-masahiroy@kernel.org --- scripts/gcc-plugins/Makefile | 2 +- scripts/gcc-plugins/latent_entropy_plugin.c | 2 +- scripts/gcc-plugins/randomize_layout_plugin.c | 2 +- scripts/gcc-plugins/sancov_plugin.c | 2 +- scripts/gcc-plugins/stackleak_plugin.c | 2 +- scripts/gcc-plugins/structleak_plugin.c | 2 +- 6 files changed, 6 insertions(+), 6 deletions(-) (limited to 'scripts/gcc-plugins/latent_entropy_plugin.c') diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index 6f0aecad5d67..b34d11e22636 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -28,7 +28,7 @@ GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin) plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \ -include $(srctree)/include/linux/compiler-version.h \ - -include $(objtree)/include/generated/utsrelease.h \ + -DPLUGIN_VERSION=$(call stringify,$(KERNELVERSION)) \ -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \ -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \ -ggdb -Wno-narrowing -Wno-unused-variable \ diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c index 5d415b2572a8..848918764174 100644 --- a/scripts/gcc-plugins/latent_entropy_plugin.c +++ b/scripts/gcc-plugins/latent_entropy_plugin.c @@ -82,7 +82,7 @@ __visible int plugin_is_GPL_compatible; static GTY(()) tree latent_entropy_decl; static struct plugin_info latent_entropy_plugin_info = { - .version = UTS_RELEASE, + .version = PLUGIN_VERSION, .help = "disable\tturn off latent entropy instrumentation\n", }; diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c index ea2aea570404..951b74ba1b24 100644 --- a/scripts/gcc-plugins/randomize_layout_plugin.c +++ b/scripts/gcc-plugins/randomize_layout_plugin.c @@ -34,7 +34,7 @@ __visible int plugin_is_GPL_compatible; static int performance_mode; static struct plugin_info randomize_layout_plugin_info = { - .version = UTS_RELEASE, + .version = PLUGIN_VERSION, .help = "disable\t\t\tdo not activate plugin\n" "performance-mode\tenable cacheline-aware layout randomization\n" }; diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c index f3d629555b84..b76cb9c42cec 100644 --- a/scripts/gcc-plugins/sancov_plugin.c +++ b/scripts/gcc-plugins/sancov_plugin.c @@ -26,7 +26,7 @@ __visible int plugin_is_GPL_compatible; tree sancov_fndecl; static struct plugin_info sancov_plugin_info = { - .version = UTS_RELEASE, + .version = PLUGIN_VERSION, .help = "sancov plugin\n", }; diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index de817d54b8af..ff91885f9470 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -44,7 +44,7 @@ static bool verbose = false; static GTY(()) tree track_function_decl; static struct plugin_info stackleak_plugin_info = { - .version = UTS_RELEASE, + .version = PLUGIN_VERSION, .help = "track-min-size=nn\ttrack stack for functions with a stack frame size >= nn bytes\n" "arch=target_arch\tspecify target build arch\n" "disable\t\tdo not activate the plugin\n" diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c index 86b608a24ec0..8bc04068ed39 100644 --- a/scripts/gcc-plugins/structleak_plugin.c +++ b/scripts/gcc-plugins/structleak_plugin.c @@ -37,7 +37,7 @@ __visible int plugin_is_GPL_compatible; static struct plugin_info structleak_plugin_info = { - .version = UTS_RELEASE, + .version = PLUGIN_VERSION, .help = "disable\tdo not activate plugin\n" "byref\tinit structs passed by reference\n" "byref-all\tinit anything passed by reference\n" -- cgit v1.2.3 From fa82cce7a6bbb35ecf7fe66231c7076052cf66d5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 7 Jun 2022 16:11:34 +0200 Subject: treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_385.RULE Based on the normalized pattern: licensed under the gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference. Reviewed-by: Allison Randal Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- arch/sparc/vdso/vdso2c.c | 2 +- arch/x86/entry/vdso/vdso2c.c | 2 +- scripts/gcc-plugins/latent_entropy_plugin.c | 2 +- scripts/gcc-plugins/stackleak_plugin.c | 2 +- scripts/gcc-plugins/structleak_plugin.c | 2 +- tools/power/cpupower/debug/i386/dump_psb.c | 6 ++---- 6 files changed, 7 insertions(+), 9 deletions(-) (limited to 'scripts/gcc-plugins/latent_entropy_plugin.c') diff --git a/arch/sparc/vdso/vdso2c.c b/arch/sparc/vdso/vdso2c.c index ab7504176a7f..dc81240aab6f 100644 --- a/arch/sparc/vdso/vdso2c.c +++ b/arch/sparc/vdso/vdso2c.c @@ -1,7 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * vdso2c - A vdso image preparation tool * Copyright (c) 2014 Andy Lutomirski and others - * Licensed under the GPL v2 * * vdso2c requires stripped and unstripped input. It would be trivial * to fully strip the input in here, but, for reasons described below, diff --git a/arch/x86/entry/vdso/vdso2c.c b/arch/x86/entry/vdso/vdso2c.c index edfe9780f6d1..90d15f2a7205 100644 --- a/arch/x86/entry/vdso/vdso2c.c +++ b/arch/x86/entry/vdso/vdso2c.c @@ -1,7 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * vdso2c - A vdso image preparation tool * Copyright (c) 2014 Andy Lutomirski and others - * Licensed under the GPL v2 * * vdso2c requires stripped and unstripped input. It would be trivial * to fully strip the input in here, but, for reasons described below, diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c index 848918764174..39e86be60dd2 100644 --- a/scripts/gcc-plugins/latent_entropy_plugin.c +++ b/scripts/gcc-plugins/latent_entropy_plugin.c @@ -1,7 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2012-2016 by the PaX Team * Copyright 2016 by Emese Revfy - * Licensed under the GPL v2 * * Note: the choice of the license means that the compilation process is * NOT 'eligible' as defined by gcc's library exception to the GPL v3, diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c index ff91885f9470..c5c2ce113c92 100644 --- a/scripts/gcc-plugins/stackleak_plugin.c +++ b/scripts/gcc-plugins/stackleak_plugin.c @@ -1,7 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2011-2017 by the PaX Team * Modified by Alexander Popov - * Licensed under the GPL v2 * * Note: the choice of the license means that the compilation process is * NOT 'eligible' as defined by gcc's library exception to the GPL v3, diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c index 8bc04068ed39..d8c744233832 100644 --- a/scripts/gcc-plugins/structleak_plugin.c +++ b/scripts/gcc-plugins/structleak_plugin.c @@ -1,6 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2013-2017 by PaX Team - * Licensed under the GPL v2 * * Note: the choice of the license means that the compilation process is * NOT 'eligible' as defined by gcc's library exception to the GPL v3, diff --git a/tools/power/cpupower/debug/i386/dump_psb.c b/tools/power/cpupower/debug/i386/dump_psb.c index 2c768cf70128..6fb81b42ea61 100644 --- a/tools/power/cpupower/debug/i386/dump_psb.c +++ b/tools/power/cpupower/debug/i386/dump_psb.c @@ -1,7 +1,5 @@ -/* - * dump_psb. (c) 2004, Dave Jones, Red Hat Inc. - * Licensed under the GPL v2. - */ +// SPDX-License-Identifier: GPL-2.0-only +// dump_psb. (c) 2004, Dave Jones, Red Hat Inc. #include #include -- cgit v1.2.3