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/dl-cet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'sysdeps/x86/dl-cet.c') diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c index a63b9c7164..c74e577289 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)); -- cgit v1.2.3