From 674ea88294bfb8d89878a0ebbbcec38a85e118a5 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 28 Apr 2020 10:05:25 -0700 Subject: [PATCH] x86: Move CET control to _dl_x86_feature_control [BZ #25887] 1. Include to get architecture specific initializer in rtld_global. 2. Change _dl_x86_feature_1[2] to _dl_x86_feature_1. 3. Add _dl_x86_feature_control after _dl_x86_feature_1, which is a struct of 2 bitfields for IBT and SHSTK control This fixes [BZ #25887]. --- elf/rtld.c | 2 + sysdeps/i386/dl-machine.h | 2 +- sysdeps/unix/sysv/linux/x86/cpu-features.c | 2 +- sysdeps/x86/{cet-tunables.h => cet-control.h} | 34 ++++++++++----- sysdeps/x86/cpu-features.c | 12 +++--- sysdeps/x86/cpu-tunables.c | 31 +++---------- sysdeps/x86/dl-cet.c | 43 +++++++++---------- sysdeps/x86/dl-procruntime.c | 22 +++++++++- sysdeps/x86/ldsodefs.h | 1 + 9 files changed, 81 insertions(+), 68 deletions(-) rename sysdeps/x86/{cet-tunables.h => cet-control.h} (60%) diff --git a/elf/rtld.c b/elf/rtld.c index 5ccc3c2dbb..882b070cc0 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -315,6 +315,8 @@ rtld_hidden_def (_dl_starting_up) (except those which cannot be added for some reason). */ struct rtld_global _rtld_global = { + /* Get architecture specific initializer. */ +#include /* Generally the default presumption without further information is an * executable stack but this is not true for all platforms. */ ._dl_stack_flags = DEFAULT_STACK_PERMS, diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h index 8af0789a9c..0f08079e48 100644 --- a/sysdeps/i386/dl-machine.h +++ b/sysdeps/i386/dl-machine.h @@ -71,7 +71,7 @@ elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) extern void _dl_runtime_profile_shstk (Elf32_Word) attribute_hidden; /* Check if SHSTK is enabled by kernel. */ bool shstk_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; if (l->l_info[DT_JMPREL] && lazy) { diff --git a/sysdeps/unix/sysv/linux/x86/cpu-features.c b/sysdeps/unix/sysv/linux/x86/cpu-features.c index d67b300595..fc0e32827d 100644 --- a/sysdeps/unix/sysv/linux/x86/cpu-features.c +++ b/sysdeps/unix/sysv/linux/x86/cpu-features.c @@ -34,7 +34,7 @@ static inline void x86_setup_tls (void) { __libc_setup_tls (); - THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)[0]); + THREAD_SETMEM (THREAD_SELF, header.feature_1, GL(dl_x86_feature_1)); } # define ARCH_SETUP_TLS() x86_setup_tls () diff --git a/sysdeps/x86/cet-tunables.h b/sysdeps/x86/cet-control.h similarity index 60% rename from sysdeps/x86/cet-tunables.h rename to sysdeps/x86/cet-control.h index 5e1e42df10..e163a7f55b 100644 --- a/sysdeps/x86/cet-tunables.h +++ b/sysdeps/x86/cet-control.h @@ -16,14 +16,26 @@ License along with the GNU C Library; if not, see . */ -/* Valid control values: - 0: Enable CET features based on ELF property note. - 1: Always disable CET features. - 2: Always enable CET features. - 3: Enable CET features permissively. - */ -#define CET_ELF_PROPERTY 0 -#define CET_ALWAYS_OFF 1 -#define CET_ALWAYS_ON 2 -#define CET_PERMISSIVE 3 -#define CET_MAX CET_PERMISSIVE +#ifndef _CET_CONTROL_H +#define _CET_CONTROL_H + +/* For each CET feature, IBT and SHSTK, valid control values. */ +enum dl_x86_cet_control +{ + /* Enable CET features based on ELF property note. */ + cet_elf_property = 0, + /* Always enable CET features. */ + cet_always_on, + /* Always disable CET features. */ + cet_always_off, + /* Enable CET features permissively. */ + cet_permissive +}; + +struct dl_x86_feature_control +{ + enum dl_x86_cet_control ibt : 2; + enum dl_x86_cet_control shstk : 2; +}; + +#endif /* cet-control.h */ diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index bfb415f05a..b6d5d9d4b1 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -39,7 +39,6 @@ extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *) #if CET_ENABLED # include -# include #endif static void @@ -620,7 +619,7 @@ no_cpuid: if (cet_status) { - GL(dl_x86_feature_1)[0] = cet_status; + GL(dl_x86_feature_1) = cet_status; # ifndef SHARED /* Check if IBT and SHSTK are enabled by kernel. */ @@ -644,14 +643,13 @@ no_cpuid: /* Clear the disabled bits in dl_x86_feature_1. */ if (res == 0) - GL(dl_x86_feature_1)[0] &= ~cet_feature; + GL(dl_x86_feature_1) &= ~cet_feature; } /* Lock CET if IBT or SHSTK is enabled in executable. Don't - lock CET if SHSTK is enabled permissively. */ - if (((GL(dl_x86_feature_1)[1] >> CET_MAX) - & ((1 << CET_MAX) - 1)) - != CET_PERMISSIVE) + lock CET if IBT or SHSTK is enabled permissively. */ + if (GL(dl_x86_feature_control).ibt != cet_permissive + && GL(dl_x86_feature_control).shstk != cet_permissive) dl_cet_lock_cet (); } # endif diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 861bd7bcaa..38ad2c2e84 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -336,28 +336,18 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) } # if CET_ENABLED -# include attribute_hidden void TUNABLE_CALLBACK (set_x86_ibt) (tunable_val_t *valp) { if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_ALWAYS_ON; - } + GL(dl_x86_feature_control).ibt = cet_always_on; else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_ALWAYS_OFF; - } + GL(dl_x86_feature_control).ibt = cet_always_off; else if (DEFAULT_MEMCMP (valp->strval, "permissive", sizeof ("permissive")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~((1 << CET_MAX) - 1); - GL(dl_x86_feature_1)[1] |= CET_PERMISSIVE; - } + GL(dl_x86_feature_control).ibt = cet_permissive; } attribute_hidden @@ -365,21 +355,12 @@ void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *valp) { if (DEFAULT_MEMCMP (valp->strval, "on", sizeof ("on")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_ON << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_always_on; else if (DEFAULT_MEMCMP (valp->strval, "off", sizeof ("off")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_ALWAYS_OFF << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_always_off; else if (DEFAULT_MEMCMP (valp->strval, "permissive", sizeof ("permissive")) == 0) - { - GL(dl_x86_feature_1)[1] &= ~(((1 << CET_MAX) - 1) << CET_MAX); - GL(dl_x86_feature_1)[1] |= (CET_PERMISSIVE << CET_MAX); - } + GL(dl_x86_feature_control).shstk = cet_permissive; } # endif #endif diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c index c7029f1b51..5524b66038 100644 --- a/sysdeps/x86/dl-cet.c +++ b/sysdeps/x86/dl-cet.c @@ -20,7 +20,6 @@ #include #include #include -#include /* GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK are defined in , which are only available for C sources. @@ -39,23 +38,23 @@ static void dl_cet_check (struct link_map *m, const char *program) { /* Check how IBT should be enabled. */ - unsigned int enable_ibt_type - = GL(dl_x86_feature_1)[1] & ((1 << CET_MAX) - 1); + enum dl_x86_cet_control enable_ibt_type + = GL(dl_x86_feature_control).ibt; /* Check how SHSTK should be enabled. */ - unsigned int enable_shstk_type - = ((GL(dl_x86_feature_1)[1] >> CET_MAX) & ((1 << CET_MAX) - 1)); + enum dl_x86_cet_control enable_shstk_type + = GL(dl_x86_feature_control).shstk; /* No legacy object check if both IBT and SHSTK are always on. */ - if (enable_ibt_type == CET_ALWAYS_ON - && enable_shstk_type == CET_ALWAYS_ON) + if (enable_ibt_type == cet_always_on + && enable_shstk_type == cet_always_on) return; /* Check if IBT is enabled by kernel. */ bool ibt_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; /* Check if SHSTK is enabled by kernel. */ bool shstk_enabled - = (GL(dl_x86_feature_1)[0] & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; + = (GL(dl_x86_feature_1) & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0; if (ibt_enabled || shstk_enabled) { @@ -65,9 +64,9 @@ dl_cet_check (struct link_map *m, const char *program) /* Check if IBT and SHSTK are enabled in object. */ bool enable_ibt = (ibt_enabled - && enable_ibt_type != CET_ALWAYS_OFF); + && enable_ibt_type != cet_always_off); bool enable_shstk = (shstk_enabled - && enable_shstk_type != CET_ALWAYS_OFF); + && enable_shstk_type != cet_always_off); if (program) { /* Enable IBT and SHSTK only if they are enabled in executable. @@ -76,10 +75,10 @@ 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_type == CET_ALWAYS_ON + && (enable_ibt_type == cet_always_on || (m->l_cet & lc_ibt) != 0)); enable_shstk &= (HAS_CPU_FEATURE (SHSTK) - && (enable_shstk_type == CET_ALWAYS_ON + && (enable_shstk_type == cet_always_on || (m->l_cet & lc_shstk) != 0)); } @@ -111,7 +110,7 @@ dl_cet_check (struct link_map *m, const char *program) /* IBT is enabled only if it is enabled in executable as well as all shared objects. */ - enable_ibt &= (enable_ibt_type == CET_ALWAYS_ON + enable_ibt &= (enable_ibt_type == cet_always_on || (l->l_cet & lc_ibt) != 0); if (!found_ibt_legacy && enable_ibt != ibt_enabled) { @@ -121,7 +120,7 @@ dl_cet_check (struct link_map *m, const char *program) /* SHSTK is enabled only if it is enabled in executable as well as all shared objects. */ - enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON + enable_shstk &= (enable_shstk_type == cet_always_on || (l->l_cet & lc_shstk) != 0); if (enable_shstk != shstk_enabled) { @@ -137,7 +136,7 @@ dl_cet_check (struct link_map *m, const char *program) { if (!program) { - if (enable_ibt_type != CET_PERMISSIVE) + if (enable_ibt_type != cet_permissive) { /* When IBT is enabled, we cannot dlopen a shared object without IBT. */ @@ -148,7 +147,7 @@ dl_cet_check (struct link_map *m, const char *program) N_("rebuild shared object with IBT support enabled")); } - if (enable_shstk_type != CET_PERMISSIVE) + if (enable_shstk_type != cet_permissive) { /* When SHSTK is enabled, we cannot dlopen a shared object without SHSTK. */ @@ -159,8 +158,8 @@ dl_cet_check (struct link_map *m, const char *program) N_("rebuild shared object with SHSTK support enabled")); } - if (enable_ibt_type != CET_PERMISSIVE - && enable_shstk_type != CET_PERMISSIVE) + if (enable_ibt_type != cet_permissive + && enable_shstk_type != cet_permissive) return; } @@ -190,7 +189,7 @@ dl_cet_check (struct link_map *m, const char *program) } /* Clear the disabled bits in dl_x86_feature_1. */ - GL(dl_x86_feature_1)[0] &= ~cet_feature; + GL(dl_x86_feature_1) &= ~cet_feature; cet_feature_changed = true; } @@ -199,9 +198,9 @@ dl_cet_check (struct link_map *m, const char *program) if (program && (ibt_enabled || shstk_enabled)) { if ((!ibt_enabled - || enable_ibt_type != CET_PERMISSIVE) + || enable_ibt_type != cet_permissive) && (!shstk_enabled - || enable_shstk_type != CET_PERMISSIVE)) + || enable_shstk_type != cet_permissive)) { /* Lock CET if IBT or SHSTK is enabled in executable unless IBT or SHSTK is enabled permissively. */ diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c index 5e39a38133..2c3e97952b 100644 --- a/sysdeps/x86/dl-procruntime.c +++ b/sysdeps/x86/dl-procruntime.c @@ -47,7 +47,27 @@ # if !defined PROCINFO_DECL && defined SHARED ._dl_x86_feature_1 # else -PROCINFO_CLASS unsigned int _dl_x86_feature_1[2] +PROCINFO_CLASS unsigned int _dl_x86_feature_1 +# endif +# ifndef PROCINFO_DECL += 0 +# endif +# if !defined SHARED || defined PROCINFO_DECL +; +# else +, +# endif + +# if !defined PROCINFO_DECL && defined SHARED + ._dl_x86_feature_control +# else +PROCINFO_CLASS struct dl_x86_feature_control _dl_x86_feature_control +# endif +# ifndef PROCINFO_DECL += { + .ibt = cet_elf_property, + .shstk = cet_elf_property + } # endif # if !defined SHARED || defined PROCINFO_DECL ; diff --git a/sysdeps/x86/ldsodefs.h b/sysdeps/x86/ldsodefs.h index 072f826666..5b1b09dbf8 100644 --- a/sysdeps/x86/ldsodefs.h +++ b/sysdeps/x86/ldsodefs.h @@ -61,6 +61,7 @@ struct La_x32_retval; struct La_x86_64_retval *, \ const char *) +#include #include_next #endif -- 2.43.5