From 04dff6fc0d4ad44fc4491f89fed6574380b78251 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 26 Jan 2021 20:48:45 -0800 Subject: x86: Properly set usable CET feature bits [BZ #26625] commit 94cd37ebb293321115a36a422b091fdb72d2fb08 Author: H.J. Lu Date: Wed Sep 16 05:27:32 2020 -0700 x86: Use HAS_CPU_FEATURE with IBT and SHSTK [BZ #26625] broke GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK since it can no longer disable IBT nor SHSTK. Handle IBT and SHSTK with: 1. Revert commit 94cd37ebb293321115a36a422b091fdb72d2fb08. 2. Clears the usable CET feature bits if kernel doesn't support CET. 3. Add GLIBC_TUNABLES tests without dlopen. 4. Add tests to verify that CPU_FEATURE_USABLE on IBT and SHSTK matches _get_ssp. 5. Update GLIBC_TUNABLES tests with dlopen to verify that CET is disabled with GLIBC_TUNABLES. Reviewed-by: Carlos O'Donell --- sysdeps/x86/Makefile | 8 ++++++- sysdeps/x86/cpu-features.c | 11 +++++++-- sysdeps/x86/dl-cet.c | 4 ++-- sysdeps/x86/tst-cet-legacy-10-static.c | 1 + sysdeps/x86/tst-cet-legacy-10.c | 43 ++++++++++++++++++++++++++++++++++ sysdeps/x86/tst-cet-legacy-5.c | 11 +++++---- sysdeps/x86/tst-cet-legacy-6.c | 11 +++++---- sysdeps/x86/tst-cet-legacy-9-static.c | 1 + sysdeps/x86/tst-cet-legacy-9.c | 41 ++++++++++++++++++++++++++++++++ sysdeps/x86/tst-get-cpu-features.c | 2 ++ 10 files changed, 120 insertions(+), 13 deletions(-) create mode 100644 sysdeps/x86/tst-cet-legacy-10-static.c create mode 100644 sysdeps/x86/tst-cet-legacy-10.c create mode 100644 sysdeps/x86/tst-cet-legacy-9-static.c create mode 100644 sysdeps/x86/tst-cet-legacy-9.c (limited to 'sysdeps/x86') diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile index 7549507..dd82674 100644 --- a/sysdeps/x86/Makefile +++ b/sysdeps/x86/Makefile @@ -82,7 +82,9 @@ sysdep-dl-routines += dl-cet tests += tst-cet-legacy-1 tst-cet-legacy-1a tst-cet-legacy-2 \ tst-cet-legacy-2a tst-cet-legacy-3 tst-cet-legacy-4 \ tst-cet-legacy-5a tst-cet-legacy-6a tst-cet-legacy-7 \ - tst-cet-legacy-8 + tst-cet-legacy-8 tst-cet-legacy-9 tst-cet-legacy-9-static \ + tst-cet-legacy-10 tst-cet-legacy-10-static +tests-static += tst-cet-legacy-9-static tst-cet-legacy-10-static tst-cet-legacy-1a-ARGS = -- $(host-test-program-cmd) ifneq (no,$(have-tunables)) tests += tst-cet-legacy-4a tst-cet-legacy-4b tst-cet-legacy-4c \ @@ -123,6 +125,8 @@ CFLAGS-tst-cet-legacy-mod-6b.c += -fcf-protection CFLAGS-tst-cet-legacy-mod-6c.c += -fcf-protection CFLAGS-tst-cet-legacy-7.c += -fcf-protection=none CFLAGS-tst-cet-legacy-8.c += -mshstk +CFLAGS-tst-cet-legacy-10.c += -mshstk +CFLAGS-tst-cet-legacy-10-static.c += -mshstk $(objpfx)tst-cet-legacy-1: $(objpfx)tst-cet-legacy-mod-1.so \ $(objpfx)tst-cet-legacy-mod-2.so @@ -163,6 +167,8 @@ $(objpfx)tst-cet-legacy-6b: $(libdl) $(objpfx)tst-cet-legacy-6b.out: $(objpfx)tst-cet-legacy-mod-6a.so \ $(objpfx)tst-cet-legacy-mod-6b.so tst-cet-legacy-6b-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK +tst-cet-legacy-9-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK +tst-cet-legacy-9-static-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK endif endif diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 6496512..73b0a4d 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -75,6 +75,7 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, PREFETCHWT1); CPU_FEATURE_SET_USABLE (cpu_features, OSPKE); CPU_FEATURE_SET_USABLE (cpu_features, WAITPKG); + CPU_FEATURE_SET_USABLE (cpu_features, SHSTK); CPU_FEATURE_SET_USABLE (cpu_features, GFNI); CPU_FEATURE_SET_USABLE (cpu_features, RDPID); CPU_FEATURE_SET_USABLE (cpu_features, RDRAND); @@ -84,6 +85,7 @@ update_usable (struct cpu_features *cpu_features) CPU_FEATURE_SET_USABLE (cpu_features, FSRM); CPU_FEATURE_SET_USABLE (cpu_features, SERIALIZE); CPU_FEATURE_SET_USABLE (cpu_features, TSXLDTRK); + CPU_FEATURE_SET_USABLE (cpu_features, IBT); CPU_FEATURE_SET_USABLE (cpu_features, LAHF64_SAHF64); CPU_FEATURE_SET_USABLE (cpu_features, LZCNT); CPU_FEATURE_SET_USABLE (cpu_features, SSE4A); @@ -705,6 +707,11 @@ no_cpuid: /* Check CET status. */ unsigned int cet_status = get_cet_status (); + if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_IBT) == 0) + CPU_FEATURE_UNSET (cpu_features, IBT) + if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_SHSTK) == 0) + CPU_FEATURE_UNSET (cpu_features, SHSTK) + if (cet_status) { GL(dl_x86_feature_1) = cet_status; @@ -720,9 +727,9 @@ no_cpuid: GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK */ unsigned int cet_feature = 0; - if (!HAS_CPU_FEATURE (IBT)) + if (!CPU_FEATURE_USABLE (IBT)) cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT; - if (!HAS_CPU_FEATURE (SHSTK)) + if (!CPU_FEATURE_USABLE (SHSTK)) cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK; if (cet_feature) diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c index a63b9c7..c74e577 100644 --- a/sysdeps/x86/dl-cet.c +++ b/sysdeps/x86/dl-cet.c @@ -77,11 +77,11 @@ dl_cet_check (struct link_map *m, const char *program) GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK */ - enable_ibt &= (HAS_CPU_FEATURE (IBT) + enable_ibt &= (CPU_FEATURE_USABLE (IBT) && (enable_ibt_type == cet_always_on || (m->l_x86_feature_1_and & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0)); - enable_shstk &= (HAS_CPU_FEATURE (SHSTK) + enable_shstk &= (CPU_FEATURE_USABLE (SHSTK) && (enable_shstk_type == cet_always_on || (m->l_x86_feature_1_and & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0)); diff --git a/sysdeps/x86/tst-cet-legacy-10-static.c b/sysdeps/x86/tst-cet-legacy-10-static.c new file mode 100644 index 0000000..ecc1208 --- /dev/null +++ b/sysdeps/x86/tst-cet-legacy-10-static.c @@ -0,0 +1 @@ +#include "tst-cet-legacy-10.c" diff --git a/sysdeps/x86/tst-cet-legacy-10.c b/sysdeps/x86/tst-cet-legacy-10.c new file mode 100644 index 0000000..a618557 --- /dev/null +++ b/sysdeps/x86/tst-cet-legacy-10.c @@ -0,0 +1,43 @@ +/* Check CPU_FEATURE_USABLE on IBT and SHSTK. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +/* Check that CPU_FEATURE_USABLE on IBT and SHSTK matches _get_ssp. */ + +static int +do_test (void) +{ + if (_get_ssp () != 0) + { + if (CPU_FEATURE_USABLE (IBT) && CPU_FEATURE_USABLE (SHSTK)) + return EXIT_SUCCESS; + } + else + { + if (!CPU_FEATURE_USABLE (IBT) && !CPU_FEATURE_USABLE (SHSTK)) + return EXIT_SUCCESS; + } + + return EXIT_FAILURE; +} + +#include diff --git a/sysdeps/x86/tst-cet-legacy-5.c b/sysdeps/x86/tst-cet-legacy-5.c index e3efeb1..d870de3 100644 --- a/sysdeps/x86/tst-cet-legacy-5.c +++ b/sysdeps/x86/tst-cet-legacy-5.c @@ -37,6 +37,12 @@ do_test_1 (const char *modname, bool fail) int (*fp) (void); void *h; + /* NB: dlopen should never fail on non-CET platforms. If SHSTK is + disabled, assuming IBT is also disabled. */ + bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; + if (!cet_enabled) + fail = false; + h = dlopen (modname, RTLD_LAZY); if (h == NULL) { @@ -53,10 +59,7 @@ do_test_1 (const char *modname, bool fail) FAIL_EXIT1 ("cannot open '%s': %s\n", modname, err); } - /* NB: dlopen should never fail on non-CET platforms. If SHSTK is - disabled, assuming IBT is also disabled. */ - bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; - if (fail && cet_enabled) + if (fail) FAIL_EXIT1 ("dlopen should have failed\n"); fp = dlsym (h, "test"); diff --git a/sysdeps/x86/tst-cet-legacy-6.c b/sysdeps/x86/tst-cet-legacy-6.c index 44b2ef5..8e82ee2 100644 --- a/sysdeps/x86/tst-cet-legacy-6.c +++ b/sysdeps/x86/tst-cet-legacy-6.c @@ -37,6 +37,12 @@ do_test_1 (const char *modname, bool fail) int (*fp) (void); void *h; + /* NB: dlopen should never fail on non-CET platforms. If SHSTK is + disabled, assuming IBT is also disabled. */ + bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; + if (!cet_enabled) + fail = false; + h = dlopen (modname, RTLD_LAZY); if (h == NULL) { @@ -53,10 +59,7 @@ do_test_1 (const char *modname, bool fail) FAIL_EXIT1 ("cannot open '%s': %s\n", modname, err); } - /* NB: dlopen should never fail on non-CET platforms. If SHSTK is - disabled, assuming IBT is also disabled. */ - bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; - if (fail && cet_enabled) + if (fail) FAIL_EXIT1 ("dlopen should have failed\n"); fp = dlsym (h, "test"); diff --git a/sysdeps/x86/tst-cet-legacy-9-static.c b/sysdeps/x86/tst-cet-legacy-9-static.c new file mode 100644 index 0000000..f9a8518 --- /dev/null +++ b/sysdeps/x86/tst-cet-legacy-9-static.c @@ -0,0 +1 @@ +#include "tst-cet-legacy-9.c" diff --git a/sysdeps/x86/tst-cet-legacy-9.c b/sysdeps/x86/tst-cet-legacy-9.c new file mode 100644 index 0000000..2b526c9 --- /dev/null +++ b/sysdeps/x86/tst-cet-legacy-9.c @@ -0,0 +1,41 @@ +/* Check CET compatibility with legacy JIT engine via GLIBC_TUNABLES. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include + +/* Check that mmapped legacy code won't trigger segfault with + -fcf-protection and GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK. */ + +static int +do_test (void) +{ + void (*funcp) (void); + funcp = xmmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1); + printf ("mmap = %p\n", funcp); + /* Write RET instruction. */ + *(char *) funcp = 0xc3; + funcp (); + return EXIT_SUCCESS; +} + +#include diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c index dcdb86b..b5e7f6e 100644 --- a/sysdeps/x86/tst-get-cpu-features.c +++ b/sysdeps/x86/tst-get-cpu-features.c @@ -301,6 +301,7 @@ do_test (void) CHECK_CPU_FEATURE_USABLE (OSPKE); CHECK_CPU_FEATURE_USABLE (WAITPKG); CHECK_CPU_FEATURE_USABLE (AVX512_VBMI2); + CHECK_CPU_FEATURE_USABLE (SHSTK); CHECK_CPU_FEATURE_USABLE (GFNI); CHECK_CPU_FEATURE_USABLE (VAES); CHECK_CPU_FEATURE_USABLE (VPCLMULQDQ); @@ -324,6 +325,7 @@ do_test (void) CHECK_CPU_FEATURE_USABLE (HYBRID); CHECK_CPU_FEATURE_USABLE (TSXLDTRK); CHECK_CPU_FEATURE_USABLE (PCONFIG); + CHECK_CPU_FEATURE_USABLE (IBT); CHECK_CPU_FEATURE_USABLE (AMX_BF16); CHECK_CPU_FEATURE_USABLE (AVX512_FP16); CHECK_CPU_FEATURE_USABLE (AMX_TILE); -- cgit v1.1