V4 [PATCH] x86: Remove ARCH_CET_LEGACY_BITMAP [BZ #25397]
H.J. Lu
hjl.tools@gmail.com
Wed Mar 18 11:34:51 GMT 2020
On Tue, Mar 17, 2020 at 8:20 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> On 3/16/20 8:58 PM, H.J. Lu wrote:
> > On Mon, Mar 16, 2020 at 07:41:54PM -0400, Carlos O'Donell wrote:
> >> On 3/13/20 9:25 AM, H.J. Lu via Libc-alpha wrote:
> >>> On Tue, Mar 10, 2020 at 06:36:54AM -0700, H.J. Lu wrote:
> >>>> On Tue, Mar 10, 2020 at 02:13:37PM +0100, Florian Weimer wrote:
> >>>>> * H. J. Lu:
> >>>>>
> >>>>>>> I think the error message should say *where* indirect branch tracking
> >>>>>>> is not enabled. I assume this is a property of the loaded object.
> >>>>>> Fixed. Now I got
> >>>>>>
> >>>>>> .... libvirtd[1048]: internal error: Failed to load module
> >>>>>> '/usr/lib64/libvirt/storage-backend/libvirt_storage_backend_rbd.so':
> >>>>>> /usr/lib64/ceph/libceph-common.so.0: indirect branch tracking isn't
> >>>>>> enabled: Invalid argument
> >>>>> What I meant is that the error message should say that the object
> >>>>> needs to be rebuilt with IBT/SHSTK support. In the above, it's
> >>>>> unclear whether the process or the object has to enable IBT.
> >>>>>
> >>>>> (The Invalid Argument part should also be suppressed.)
> >>>> Like this? The diff against V2 patch is:
> >>>>
> >>>> diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
> >>>> index f527a1414c..b2843488be 100644
> >>>> --- a/sysdeps/x86/dl-cet.c
> >>>> +++ b/sysdeps/x86/dl-cet.c
> >>>> @@ -142,10 +142,10 @@ dl_cet_check (struct link_map *m, const char *program)
> >>>> /* When IBT is enabled, we cannot dlopen a shared
> >>>> object without IBT. */
> >>>> if (found_ibt_legacy)
> >>>> - _dl_signal_error (EINVAL,
> >>>> + _dl_signal_error (0,
> >>>> m->l_initfini[ibt_legacy]->l_name,
> >>>> "dlopen",
> >>>> - N_("indirect branch tracking isn't enabled"));
> >>>> + N_("rebuilt with IBT support needed"));
> >>>> }
> >>>>
> >>>> if (enable_shstk_type != CET_PERMISSIVE)
> >>>> @@ -153,10 +153,10 @@ dl_cet_check (struct link_map *m, const char *program)
> >>>> /* When SHSTK is enabled, we cannot dlopen a shared
> >>>> object without SHSTK. */
> >>>> if (found_shstk_legacy)
> >>>> - _dl_signal_error (EINVAL,
> >>>> + _dl_signal_error (0,
> >>>> m->l_initfini[shstk_legacy]->l_name,
> >>>> "dlopen",
> >>>> - N_("shadow stack isn't enabled"));
> >>>> + N_("rebuilt with SHSTK support needed"));
> >>>> }
> >>>>
> >>>> if (enable_ibt_type != CET_PERMISSIVE
> >>>>
> >>> PING.
> >>
> >> Please post v4 with adjusted error message, and expanded comment in new test,
> >> and I'll review that quickly.
> >>
> >>> H.J.
> >>> ---
> >>> Since legacy bitmap doesn't cover jitted code generated by legacy JIT
> >>> engine, it isn't very useful. This patch removes ARCH_CET_LEGACY_BITMAP
> >>> and treats indirect branch tracking similar to shadow stack by removing
> >>> legacy bitmap support.
> >>
> >> OK.
> >>
> >>
> >>>
> >>> * sysdeps/unix/sysv/linux/x86/dl-cet.h
> >>> (dl_cet_allocate_legacy_bitmap): Removed.
> >>> * sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> >>> (ARCH_CET_LEGACY_BITMAP): Removed.
> >>> * sysdeps/x86/Makefile (tests): Add tst-cet-legacy-7.
> >>> (CFLAGS-tst-cet-legacy-mod-5a.c): Changed to
> >>> -fcf-protection=branch.
> >>> (CFLAGS-tst-cet-legacy-mod-6a.c): Likewise.
> >>> (CFLAGS-tst-cet-legacy-7.c): New.
> >>> * sysdeps/x86/dl-cet.c (dl_cet_mark_legacy_region): Removed.
> >>> (dl_cet_check): Remove legacy bitmap support. Don't allow
> >>> dlopening legacy shared library when IBT is enabled. Set
> >>> feature_1 if IBT or SHSTK is enabled in executable.
> >>> * sysdeps/x86/dl-procruntime.c (_dl_x86_legacy_bitmap): Removed.
> >>> * sysdeps/x86/tst-cet-legacy-4.c: Include <string.h> and
> >>> <support/check.h>.
> >>> (do_test): Check indirect branch tracking error. Use
> >>> FAIL_EXIT1.
> >>> * sysdeps/x86/tst-cet-legacy-7.c: New file.
> >>
> >> Hopefully you don't plan to include this in the commit log :-)
> >>
> >
> > Leftover from my old version :-).
> >
> >>> ---
> >>> sysdeps/unix/sysv/linux/x86/dl-cet.h | 20 --
> >>> .../unix/sysv/linux/x86/include/asm/prctl.h | 5 -
> >>> sysdeps/x86/Makefile | 7 +-
> >>> sysdeps/x86/dl-cet.c | 217 +++++-------------
> >>> sysdeps/x86/dl-procruntime.c | 11 -
> >>> sysdeps/x86/tst-cet-legacy-4.c | 19 +-
> >>> sysdeps/x86/tst-cet-legacy-5.c | 2 +-
> >>> sysdeps/x86/tst-cet-legacy-6.c | 2 +-
> >>> sysdeps/x86/tst-cet-legacy-7.c | 36 +++
> >>> 9 files changed, 111 insertions(+), 208 deletions(-)
> >>> create mode 100644 sysdeps/x86/tst-cet-legacy-7.c
> >>>
> >>> diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> >>> index 9b2aaa238c..ae97a433a2 100644
> >>> --- a/sysdeps/unix/sysv/linux/x86/dl-cet.h
> >>> +++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> >>> @@ -18,26 +18,6 @@
> >>> #include <sys/prctl.h>
> >>> #include <asm/prctl.h>
> >>>
> >>> -static inline int __attribute__ ((always_inline))
> >>> -dl_cet_allocate_legacy_bitmap (unsigned long *legacy_bitmap)
> >>> -{
> >>> - /* Allocate legacy bitmap. */
> >>> -#ifdef __LP64__
> >>> - return (int) INTERNAL_SYSCALL_CALL (arch_prctl,
> >>> - ARCH_CET_LEGACY_BITMAP, legacy_bitmap);
> >>> -#else
> >>> - unsigned long long legacy_bitmap_u64[2];
> >>> - int res = INTERNAL_SYSCALL_CALL (arch_prctl,
> >>> - ARCH_CET_LEGACY_BITMAP, legacy_bitmap_u64);
> >>> - if (res == 0)
> >>> - {
> >>> - legacy_bitmap[0] = legacy_bitmap_u64[0];
> >>> - legacy_bitmap[1] = legacy_bitmap_u64[1];
> >>> - }
> >>> - return res;
> >>> -#endif
> >>> -}
> >>> -
> >>
> >> OK.
> >>
> >>> static inline int __attribute__ ((always_inline))
> >>> dl_cet_disable_cet (unsigned int cet_feature)
> >>> {
> >>> diff --git a/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h b/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> >>> index f67f3299b9..45ad0b052f 100644
> >>> --- a/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> >>> +++ b/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> >>> @@ -24,9 +24,4 @@
> >>> OUT: allocated shadow stack address: *addr.
> >>> */
> >>> # define ARCH_CET_ALLOC_SHSTK 0x3004
> >>> -/* Return legacy region bitmap info in unsigned long long *addr:
> >>> - address: addr[0].
> >>> - size: addr[1].
> >>> - */
> >>> -# define ARCH_CET_LEGACY_BITMAP 0x3005
> >>
> >> OK.
> >>
> >>> #endif /* ARCH_CET_STATUS */
> >>> diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> >>> index 95182a508c..ec96b59a78 100644
> >>> --- a/sysdeps/x86/Makefile
> >>> +++ b/sysdeps/x86/Makefile
> >>> @@ -20,7 +20,7 @@ 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-5a tst-cet-legacy-6a tst-cet-legacy-7
> >>
> >> OK.
> >>
> >>> 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 \
> >>> @@ -43,14 +43,15 @@ CFLAGS-tst-cet-legacy-4b.c += -fcf-protection
> >>> CFLAGS-tst-cet-legacy-mod-4.c += -fcf-protection=none
> >>> CFLAGS-tst-cet-legacy-5a.c += -fcf-protection
> >>> CFLAGS-tst-cet-legacy-5b.c += -fcf-protection
> >>> -CFLAGS-tst-cet-legacy-mod-5a.c += -fcf-protection=none
> >>> +CFLAGS-tst-cet-legacy-mod-5a.c += -fcf-protection=branch
> >>> CFLAGS-tst-cet-legacy-mod-5b.c += -fcf-protection
> >>> CFLAGS-tst-cet-legacy-mod-5c.c += -fcf-protection
> >>> CFLAGS-tst-cet-legacy-6a.c += -fcf-protection
> >>> CFLAGS-tst-cet-legacy-6b.c += -fcf-protection
> >>> -CFLAGS-tst-cet-legacy-mod-6a.c += -fcf-protection=none
> >>> +CFLAGS-tst-cet-legacy-mod-6a.c += -fcf-protection=branch
> >>> 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
> >>
> >> OK.
> >>
> >>>
> >>> $(objpfx)tst-cet-legacy-1: $(objpfx)tst-cet-legacy-mod-1.so \
> >>> $(objpfx)tst-cet-legacy-mod-2.so
> >>> diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
> >>> index ca3b5849bc..b2843488be 100644
> >>> --- a/sysdeps/x86/dl-cet.c
> >>> +++ b/sysdeps/x86/dl-cet.c
> >>> @@ -33,63 +33,6 @@
> >>> # error GNU_PROPERTY_X86_FEATURE_1_SHSTK != X86_FEATURE_1_SHSTK
> >>> #endif
> >>>
> >>> -static int
> >>> -dl_cet_mark_legacy_region (struct link_map *l)
> >>> -{
> >>> - /* Mark PT_LOAD segments with PF_X in legacy code page bitmap. */
> >>> - size_t i, phnum = l->l_phnum;
> >>> - const ElfW(Phdr) *phdr = l->l_phdr;
> >>> -#ifdef __x86_64__
> >>> - typedef unsigned long long word_t;
> >>> -#else
> >>> - typedef unsigned long word_t;
> >>> -#endif
> >>> - unsigned int bits_to_set;
> >>> - word_t mask_to_set;
> >>> -#define BITS_PER_WORD (sizeof (word_t) * 8)
> >>> -#define BITMAP_FIRST_WORD_MASK(start) \
> >>> - (~((word_t) 0) << ((start) & (BITS_PER_WORD - 1)))
> >>> -#define BITMAP_LAST_WORD_MASK(nbits) \
> >>> - (~((word_t) 0) >> (-(nbits) & (BITS_PER_WORD - 1)))
> >>> -
> >>> - word_t *bitmap = (word_t *) GL(dl_x86_legacy_bitmap)[0];
> >>> - word_t bitmap_size = GL(dl_x86_legacy_bitmap)[1];
> >>> - word_t *p;
> >>> - size_t page_size = GLRO(dl_pagesize);
> >>> -
> >>> - for (i = 0; i < phnum; i++)
> >>> - if (phdr[i].p_type == PT_LOAD && (phdr[i].p_flags & PF_X))
> >>> - {
> >>> - /* One bit in legacy bitmap represents a page. */
> >>> - ElfW(Addr) start = (phdr[i].p_vaddr + l->l_addr) / page_size;
> >>> - ElfW(Addr) len = (phdr[i].p_memsz + page_size - 1) / page_size;
> >>> - ElfW(Addr) end = start + len;
> >>> -
> >>> - if ((end / 8) > bitmap_size)
> >>> - return -EINVAL;
> >>> -
> >>> - p = bitmap + (start / BITS_PER_WORD);
> >>> - bits_to_set = BITS_PER_WORD - (start % BITS_PER_WORD);
> >>> - mask_to_set = BITMAP_FIRST_WORD_MASK (start);
> >>> -
> >>> - while (len >= bits_to_set)
> >>> - {
> >>> - *p |= mask_to_set;
> >>> - len -= bits_to_set;
> >>> - bits_to_set = BITS_PER_WORD;
> >>> - mask_to_set = ~((word_t) 0);
> >>> - p++;
> >>> - }
> >>> - if (len)
> >>> - {
> >>> - mask_to_set &= BITMAP_LAST_WORD_MASK (end);
> >>> - *p |= mask_to_set;
> >>> - }
> >>> - }
> >>> -
> >>> - return 0;
> >>> -}
> >>> -
> >>
> >> OK.
> >>
> >>> /* Check if object M is compatible with CET. */
> >>>
> >>> static void
> >>> @@ -117,6 +60,8 @@ dl_cet_check (struct link_map *m, const char *program)
> >>> if (ibt_enabled || shstk_enabled)
> >>> {
> >>> struct link_map *l = NULL;
> >>> + unsigned int ibt_legacy = 0, shstk_legacy = 0;
> >>> + bool found_ibt_legacy = false, found_shstk_legacy = false;
> >>
> >> OK.
> >>
> >>>
> >>> /* Check if IBT and SHSTK are enabled in object. */
> >>> bool enable_ibt = (ibt_enabled
> >>> @@ -142,10 +87,7 @@ dl_cet_check (struct link_map *m, const char *program)
> >>> support IBT nor SHSTK. */
> >>> if (enable_ibt || enable_shstk)
> >>> {
> >>> - int res;
> >>> unsigned int i;
> >>> - unsigned int first_legacy, last_legacy;
> >>> - bool need_legacy_bitmap = false;
> >>
> >> OK.
> >>
> >>>
> >>> i = m->l_searchlist.r_nlist;
> >>> while (i-- > 0)
> >>> @@ -167,91 +109,25 @@ dl_cet_check (struct link_map *m, const char *program)
> >>> continue;
> >>> #endif
> >>>
> >>> - if (enable_ibt
> >>> - && enable_ibt_type != CET_ALWAYS_ON
> >>> - && !(l->l_cet & lc_ibt))
> >>> + /* IBT is enabled only if it is enabled in executable as
> >>> + well as all shared objects. */
> >>> + enable_ibt &= (enable_ibt_type == CET_ALWAYS_ON
> >>> + || (l->l_cet & lc_ibt) != 0);
> >>> + if (!found_ibt_legacy && enable_ibt != ibt_enabled)
> >>> {
> >>> - /* Remember the first and last legacy objects. */
> >>> - if (!need_legacy_bitmap)
> >>> - last_legacy = i;
> >>> - first_legacy = i;
> >>> - need_legacy_bitmap = true;
> >>> + found_ibt_legacy = true;
> >>> + ibt_legacy = i;
> >>
> >> OK.
> >>
> >>> }
> >>>
> >>> /* SHSTK is enabled only if it is enabled in executable as
> >>> well as all shared objects. */
> >>> enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON
> >>> || (l->l_cet & lc_shstk) != 0);
> >>> - }
> >>> -
> >>> - if (need_legacy_bitmap)
> >>> - {
> >>> - if (GL(dl_x86_legacy_bitmap)[0])
> >>> - {
> >>> - /* Change legacy bitmap to writable. */
> >>> - if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
> >>> - GL(dl_x86_legacy_bitmap)[1],
> >>> - PROT_READ | PROT_WRITE) < 0)
> >>> - {
> >>> -mprotect_failure:
> >>> - if (program)
> >>> - _dl_fatal_printf ("%s: mprotect legacy bitmap failed\n",
> >>> - l->l_name);
> >>> - else
> >>> - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> >>> - N_("mprotect legacy bitmap failed"));
> >>> - }
> >>> - }
> >>> - else
> >>> + if (enable_shstk != shstk_enabled)
> >>
> >> OK.
> >>
> >>> {
> >>> - /* Allocate legacy bitmap. */
> >>> - int res = dl_cet_allocate_legacy_bitmap
> >>> - (GL(dl_x86_legacy_bitmap));
> >>> - if (res != 0)
> >>> - {
> >>> - if (program)
> >>> - _dl_fatal_printf ("%s: legacy bitmap isn't available\n",
> >>> - l->l_name);
> >>> - else
> >>> - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> >>> - N_("legacy bitmap isn't available"));
> >>> - }
> >>> + found_shstk_legacy = true;
> >>> + shstk_legacy = i;
> >>
> >> OK.
> >>
> >>> }
> >>> -
> >>> - /* Put legacy shared objects in legacy bitmap. */
> >>> - for (i = first_legacy; i <= last_legacy; i++)
> >>> - {
> >>> - l = m->l_initfini[i];
> >>> -
> >>> - if (l->l_init_called || (l->l_cet & lc_ibt))
> >>> - continue;
> >>> -
> >>> -#ifdef SHARED
> >>> - if (l == &GL(dl_rtld_map)
> >>> - || l->l_real == &GL(dl_rtld_map)
> >>> - || (program && l == m))
> >>> - continue;
> >>> -#endif
> >>> -
> >>> - /* If IBT is enabled in executable and IBT isn't enabled
> >>> - in this shard object, mark PT_LOAD segments with PF_X
> >>> - in legacy code page bitmap. */
> >>> - res = dl_cet_mark_legacy_region (l);
> >>> - if (res != 0)
> >>> - {
> >>> - if (program)
> >>> - _dl_fatal_printf ("%s: failed to mark legacy code region\n",
> >>> - l->l_name);
> >>> - else
> >>> - _dl_signal_error (-res, l->l_name, "dlopen",
> >>> - N_("failed to mark legacy code region"));
> >>> - }
> >>> - }
> >>> -
> >>> - /* Change legacy bitmap to read-only. */
> >>> - if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
> >>> - GL(dl_x86_legacy_bitmap)[1], PROT_READ) < 0)
> >>> - goto mprotect_failure;
> >>
> >> OK.
> >>
> >>> }
> >>> }
> >>>
> >>> @@ -259,23 +135,40 @@ mprotect_failure:
> >>>
> >>> if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
> >>> {
> >>> - if (!program
> >>> - && enable_shstk_type != CET_PERMISSIVE)
> >>> + if (!program)
> >>> {
> >>> - /* When SHSTK is enabled, we can't dlopening a shared
> >>> - object without SHSTK. */
> >>> - if (enable_shstk != shstk_enabled)
> >>> - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> >>> - N_("shadow stack isn't enabled"));
> >>> - return;
> >>> + if (enable_ibt_type != CET_PERMISSIVE)
> >>> + {
> >>> + /* When IBT is enabled, we cannot dlopen a shared
> >>> + object without IBT. */
> >>> + if (found_ibt_legacy)
> >>> + _dl_signal_error (0,
> >>> + m->l_initfini[ibt_legacy]->l_name,
> >>> + "dlopen",
> >>> + N_("rebuilt with IBT support needed"));
> >>> + }
> >>
> >> Suggest:
> >> "rebuild shared object with IBT support enabled"
> >
> > Fixed.
> >
> >>
> >>> +
> >>> + if (enable_shstk_type != CET_PERMISSIVE)
> >>> + {
> >>> + /* When SHSTK is enabled, we cannot dlopen a shared
> >>> + object without SHSTK. */
> >>> + if (found_shstk_legacy)
> >>> + _dl_signal_error (0,
> >>> + m->l_initfini[shstk_legacy]->l_name,
> >>> + "dlopen",
> >>> + N_("rebuilt with SHSTK support needed"));
> >>> + }
> >>
> >> Suggest:
> >> "rebuild shared object with SHSTK support enabled"
> >>
> >
> > Fixed.
> >
> >>> +
> >>> + if (enable_ibt_type != CET_PERMISSIVE
> >>> + && enable_shstk_type != CET_PERMISSIVE)
> >>> + return;
> >>> }
> >>>
> >>> /* Disable IBT and/or SHSTK if they are enabled by kernel, but
> >>> disabled in executable or shared objects. */
> >>> unsigned int cet_feature = 0;
> >>>
> >>> - /* Disable IBT only during program startup. */
> >>> - if (program && !enable_ibt)
> >>> + if (!enable_ibt)
> >>
> >> OK.
> >>
> >>> cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
> >>> if (!enable_shstk)
> >>> cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
> >>> @@ -286,8 +179,14 @@ mprotect_failure:
> >>> if (program)
> >>> _dl_fatal_printf ("%s: can't disable CET\n", program);
> >>> else
> >>> - _dl_signal_error (-res, l->l_name, "dlopen",
> >>> - N_("can't disable CET"));
> >>> + {
> >>> + if (found_ibt_legacy)
> >>> + l = m->l_initfini[ibt_legacy];
> >>> + else
> >>> + l = m->l_initfini[shstk_legacy];
> >>> + _dl_signal_error (-res, l->l_name, "dlopen",
> >>> + N_("can't disable CET"));
> >>
> >> OK.
> >>
> >>> + }
> >>> }
> >>>
> >>> /* Clear the disabled bits in dl_x86_feature_1. */
> >>> @@ -297,17 +196,21 @@ mprotect_failure:
> >>> }
> >>>
> >>> #ifdef SHARED
> >>> - if (program
> >>> - && (!shstk_enabled
> >>> - || enable_shstk_type != CET_PERMISSIVE)
> >>> - && (ibt_enabled || shstk_enabled))
> >>> + if (program && (ibt_enabled || shstk_enabled))
> >>> {
> >>> - /* Lock CET if IBT or SHSTK is enabled in executable. Don't
> >>> - lock CET if SHSTK is enabled permissively. */
> >>> - int res = dl_cet_lock_cet ();
> >>> - if (res != 0)
> >>> - _dl_fatal_printf ("%s: can't lock CET\n", program);
> >>> + if ((!ibt_enabled
> >>> + || enable_ibt_type != CET_PERMISSIVE)
> >>> + && (!shstk_enabled
> >>> + || enable_shstk_type != CET_PERMISSIVE))
> >>> + {
> >>> + /* Lock CET if IBT or SHSTK is enabled in executable unless
> >>> + IBT or SHSTK is enabled permissively. */
> >>> + int res = dl_cet_lock_cet ();
> >>> + if (res != 0)
> >>> + _dl_fatal_printf ("%s: can't lock CET\n", program);
> >>
> >> OK.
> >>
> >>> + }
> >>>
> >>> + /* Set feature_1 if IBT or SHSTK is enabled in executable. */
> >>> cet_feature_changed = true;
> >>> }
> >>> #endif
> >>> diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c
> >>> index fb36801f3e..5e39a38133 100644
> >>> --- a/sysdeps/x86/dl-procruntime.c
> >>> +++ b/sysdeps/x86/dl-procruntime.c
> >>> @@ -54,15 +54,4 @@ PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
> >>> # else
> >>> ,
> >>> # endif
> >>> -
> >>> -# if !defined PROCINFO_DECL && defined SHARED
> >>> - ._dl_x86_legacy_bitmap
> >>> -# else
> >>> -PROCINFO_CLASS unsigned long _dl_x86_legacy_bitmap[2]
> >>> -# endif
> >>> -# if !defined SHARED || defined PROCINFO_DECL
> >>> -;
> >>> -# else
> >>> -,
> >>> -# endif
> >>
> >> OK.
> >>
> >>> #endif
> >>> diff --git a/sysdeps/x86/tst-cet-legacy-4.c b/sysdeps/x86/tst-cet-legacy-4.c
> >>> index a77078afc9..a922339333 100644
> >>> --- a/sysdeps/x86/tst-cet-legacy-4.c
> >>> +++ b/sysdeps/x86/tst-cet-legacy-4.c
> >>> @@ -20,6 +20,9 @@
> >>> #include <dlfcn.h>
> >>> #include <stdio.h>
> >>> #include <stdlib.h>
> >>> +#include <string.h>
> >>> +
> >>> +#include <support/check.h>
> >>>
> >>> static int
> >>> do_test (void)
> >>> @@ -31,22 +34,18 @@ do_test (void)
> >>> h = dlopen (modname, RTLD_LAZY);
> >>> if (h == NULL)
> >>> {
> >>> - printf ("cannot open '%s': %s\n", modname, dlerror ());
> >>> - exit (1);
> >>> + const char *err = dlerror ();
> >>> + if (!strstr (err, "rebuilt with IBT support needed"))
> >>
> >> OK (needs adjustment if string is changed).
> >>
> >
> > Fixed.
> >
> >>> + FAIL_EXIT1 ("incorrect dlopen '%s' error: %s\n", modname, err);
> >>> + return 0;
> >>> }
> >>>
> >>> fp = dlsym (h, "test");
> >>> if (fp == NULL)
> >>> - {
> >>> - printf ("cannot get symbol 'test': %s\n", dlerror ());
> >>> - exit (1);
> >>> - }
> >>> + FAIL_EXIT1 ("cannot get symbol 'test': %s\n", dlerror ());
> >>>
> >>> if (fp () != 0)
> >>> - {
> >>> - puts ("test () != 0");
> >>> - exit (1);
> >>> - }
> >>> + FAIL_EXIT1 ("test () != 0");
> >>>
> >>> dlclose (h);
> >>>
> >>> diff --git a/sysdeps/x86/tst-cet-legacy-5.c b/sysdeps/x86/tst-cet-legacy-5.c
> >>> index 6c9bba06f5..350c7e41df 100644
> >>> --- a/sysdeps/x86/tst-cet-legacy-5.c
> >>> +++ b/sysdeps/x86/tst-cet-legacy-5.c
> >>> @@ -35,7 +35,7 @@ do_test_1 (const char *modname, bool fail)
> >>> if (fail)
> >>> {
> >>> const char *err = dlerror ();
> >>> - if (strstr (err, "shadow stack isn't enabled") == NULL)
> >>> + if (strstr (err, "rebuilt with SHSTK support needed") == NULL)
> >>
> >> OK (also needs adjustment)
> >
> > Fixed.
> >
> >>
> >>> {
> >>> printf ("incorrect dlopen '%s' error: %s\n", modname,
> >>> err);
> >>> diff --git a/sysdeps/x86/tst-cet-legacy-6.c b/sysdeps/x86/tst-cet-legacy-6.c
> >>> index 877e77747d..9f2748fcb6 100644
> >>> --- a/sysdeps/x86/tst-cet-legacy-6.c
> >>> +++ b/sysdeps/x86/tst-cet-legacy-6.c
> >>> @@ -35,7 +35,7 @@ do_test_1 (const char *modname, bool fail)
> >>> if (fail)
> >>> {
> >>> const char *err = dlerror ();
> >>> - if (strstr (err, "shadow stack isn't enabled") == NULL)
> >>> + if (strstr (err, "rebuilt with SHSTK support needed") == NULL)
> >>
> >> OK. (also needs adjustment)
> >
> > Fixed.
> >
> >>
> >>> {
> >>> printf ("incorrect dlopen '%s' error: %s\n", modname,
> >>> err);
> >>> diff --git a/sysdeps/x86/tst-cet-legacy-7.c b/sysdeps/x86/tst-cet-legacy-7.c
> >>> new file mode 100644
> >>> index 0000000000..cf4c2779ce
> >>> --- /dev/null
> >>> +++ b/sysdeps/x86/tst-cet-legacy-7.c
> >>> @@ -0,0 +1,36 @@
> >>> +/* Check compatibility of legacy executable with a JIT engine.
> >>> + Copyright (C) 2020 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
> >>> + <https://www.gnu.org/licenses/>. */
> >>> +
> >>> +#include <stdio.h>
> >>> +#include <sys/mman.h>
> >>> +#include <support/xunistd.h>
> >>> +
> >>
> >> Needs a pargraph explaining what this test is supposed to do.
> >>
> >
> > Done.
> >
> >> I expect this test is supposed to just pass and not fail because it's
> >> run with -fcf-protection=none.
> >
> > Yes.
> >
> >>
> >> What about the equivalent test to test for failure?
> >
> > Added.
> >
> >>
> >>> +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 0;
> >>
> >> OK.
> >>
> >>> +}
> >>> +
> >>> +#include <support/test-driver.c>
> >>> -- 2.24.1
> >>
> >>
> >
> > OK for master?
>
> Thank you for the extra test.
>
> OK if you use EXPECTED_SIGNAL for the new test.
>
> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
>
> > Thanks.
> >
> > H.J.
> > ---
> > Since legacy bitmap doesn't cover jitted code generated by legacy JIT
> > engine, it isn't very useful. This patch removes ARCH_CET_LEGACY_BITMAP
> > and treats indirect branch tracking similar to shadow stack by removing
> > legacy bitmap support.
> > ---
> > sysdeps/unix/sysv/linux/x86/dl-cet.h | 20 --
> > .../unix/sysv/linux/x86/include/asm/prctl.h | 5 -
> > sysdeps/x86/Makefile | 9 +-
> > sysdeps/x86/dl-cet.c | 217 +++++-------------
> > sysdeps/x86/dl-procruntime.c | 11 -
> > sysdeps/x86/tst-cet-legacy-4.c | 19 +-
> > sysdeps/x86/tst-cet-legacy-5.c | 3 +-
> > sysdeps/x86/tst-cet-legacy-6.c | 3 +-
> > sysdeps/x86/tst-cet-legacy-7.c | 38 +++
> > sysdeps/x86/tst-cet-legacy-8.c | 55 +++++
> > 10 files changed, 172 insertions(+), 208 deletions(-)
> > create mode 100644 sysdeps/x86/tst-cet-legacy-7.c
> > create mode 100644 sysdeps/x86/tst-cet-legacy-8.c
> >
> > diff --git a/sysdeps/unix/sysv/linux/x86/dl-cet.h b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> > index 9b2aaa238c..ae97a433a2 100644
> > --- a/sysdeps/unix/sysv/linux/x86/dl-cet.h
> > +++ b/sysdeps/unix/sysv/linux/x86/dl-cet.h
> > @@ -18,26 +18,6 @@
> > #include <sys/prctl.h>
> > #include <asm/prctl.h>
> >
> > -static inline int __attribute__ ((always_inline))
> > -dl_cet_allocate_legacy_bitmap (unsigned long *legacy_bitmap)
> > -{
> > - /* Allocate legacy bitmap. */
> > -#ifdef __LP64__
> > - return (int) INTERNAL_SYSCALL_CALL (arch_prctl,
> > - ARCH_CET_LEGACY_BITMAP, legacy_bitmap);
> > -#else
> > - unsigned long long legacy_bitmap_u64[2];
> > - int res = INTERNAL_SYSCALL_CALL (arch_prctl,
> > - ARCH_CET_LEGACY_BITMAP, legacy_bitmap_u64);
> > - if (res == 0)
> > - {
> > - legacy_bitmap[0] = legacy_bitmap_u64[0];
> > - legacy_bitmap[1] = legacy_bitmap_u64[1];
> > - }
> > - return res;
> > -#endif
> > -}
> > -
> > static inline int __attribute__ ((always_inline))
> > dl_cet_disable_cet (unsigned int cet_feature)
> > {
> > diff --git a/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h b/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> > index f67f3299b9..45ad0b052f 100644
> > --- a/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> > +++ b/sysdeps/unix/sysv/linux/x86/include/asm/prctl.h
> > @@ -24,9 +24,4 @@
> > OUT: allocated shadow stack address: *addr.
> > */
> > # define ARCH_CET_ALLOC_SHSTK 0x3004
> > -/* Return legacy region bitmap info in unsigned long long *addr:
> > - address: addr[0].
> > - size: addr[1].
> > - */
> > -# define ARCH_CET_LEGACY_BITMAP 0x3005
> > #endif /* ARCH_CET_STATUS */
> > diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
> > index 95182a508c..4ffa699e5f 100644
> > --- a/sysdeps/x86/Makefile
> > +++ b/sysdeps/x86/Makefile
> > @@ -20,7 +20,8 @@ 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-5a tst-cet-legacy-6a tst-cet-legacy-7 \
> > + tst-cet-legacy-8
> > 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 \
> > @@ -43,14 +44,16 @@ CFLAGS-tst-cet-legacy-4b.c += -fcf-protection
> > CFLAGS-tst-cet-legacy-mod-4.c += -fcf-protection=none
> > CFLAGS-tst-cet-legacy-5a.c += -fcf-protection
> > CFLAGS-tst-cet-legacy-5b.c += -fcf-protection
> > -CFLAGS-tst-cet-legacy-mod-5a.c += -fcf-protection=none
> > +CFLAGS-tst-cet-legacy-mod-5a.c += -fcf-protection=branch
> > CFLAGS-tst-cet-legacy-mod-5b.c += -fcf-protection
> > CFLAGS-tst-cet-legacy-mod-5c.c += -fcf-protection
> > CFLAGS-tst-cet-legacy-6a.c += -fcf-protection
> > CFLAGS-tst-cet-legacy-6b.c += -fcf-protection
> > -CFLAGS-tst-cet-legacy-mod-6a.c += -fcf-protection=none
> > +CFLAGS-tst-cet-legacy-mod-6a.c += -fcf-protection=branch
> > 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
>
> OK.
>
> >
> > $(objpfx)tst-cet-legacy-1: $(objpfx)tst-cet-legacy-mod-1.so \
> > $(objpfx)tst-cet-legacy-mod-2.so
> > diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
> > index ca3b5849bc..c7029f1b51 100644
> > --- a/sysdeps/x86/dl-cet.c
> > +++ b/sysdeps/x86/dl-cet.c
> > @@ -33,63 +33,6 @@
> > # error GNU_PROPERTY_X86_FEATURE_1_SHSTK != X86_FEATURE_1_SHSTK
> > #endif
> >
> > -static int
> > -dl_cet_mark_legacy_region (struct link_map *l)
> > -{
> > - /* Mark PT_LOAD segments with PF_X in legacy code page bitmap. */
> > - size_t i, phnum = l->l_phnum;
> > - const ElfW(Phdr) *phdr = l->l_phdr;
> > -#ifdef __x86_64__
> > - typedef unsigned long long word_t;
> > -#else
> > - typedef unsigned long word_t;
> > -#endif
> > - unsigned int bits_to_set;
> > - word_t mask_to_set;
> > -#define BITS_PER_WORD (sizeof (word_t) * 8)
> > -#define BITMAP_FIRST_WORD_MASK(start) \
> > - (~((word_t) 0) << ((start) & (BITS_PER_WORD - 1)))
> > -#define BITMAP_LAST_WORD_MASK(nbits) \
> > - (~((word_t) 0) >> (-(nbits) & (BITS_PER_WORD - 1)))
> > -
> > - word_t *bitmap = (word_t *) GL(dl_x86_legacy_bitmap)[0];
> > - word_t bitmap_size = GL(dl_x86_legacy_bitmap)[1];
> > - word_t *p;
> > - size_t page_size = GLRO(dl_pagesize);
> > -
> > - for (i = 0; i < phnum; i++)
> > - if (phdr[i].p_type == PT_LOAD && (phdr[i].p_flags & PF_X))
> > - {
> > - /* One bit in legacy bitmap represents a page. */
> > - ElfW(Addr) start = (phdr[i].p_vaddr + l->l_addr) / page_size;
> > - ElfW(Addr) len = (phdr[i].p_memsz + page_size - 1) / page_size;
> > - ElfW(Addr) end = start + len;
> > -
> > - if ((end / 8) > bitmap_size)
> > - return -EINVAL;
> > -
> > - p = bitmap + (start / BITS_PER_WORD);
> > - bits_to_set = BITS_PER_WORD - (start % BITS_PER_WORD);
> > - mask_to_set = BITMAP_FIRST_WORD_MASK (start);
> > -
> > - while (len >= bits_to_set)
> > - {
> > - *p |= mask_to_set;
> > - len -= bits_to_set;
> > - bits_to_set = BITS_PER_WORD;
> > - mask_to_set = ~((word_t) 0);
> > - p++;
> > - }
> > - if (len)
> > - {
> > - mask_to_set &= BITMAP_LAST_WORD_MASK (end);
> > - *p |= mask_to_set;
> > - }
> > - }
> > -
> > - return 0;
> > -}
> > -
> > /* Check if object M is compatible with CET. */
> >
> > static void
> > @@ -117,6 +60,8 @@ dl_cet_check (struct link_map *m, const char *program)
> > if (ibt_enabled || shstk_enabled)
> > {
> > struct link_map *l = NULL;
> > + unsigned int ibt_legacy = 0, shstk_legacy = 0;
> > + bool found_ibt_legacy = false, found_shstk_legacy = false;
> >
> > /* Check if IBT and SHSTK are enabled in object. */
> > bool enable_ibt = (ibt_enabled
> > @@ -142,10 +87,7 @@ dl_cet_check (struct link_map *m, const char *program)
> > support IBT nor SHSTK. */
> > if (enable_ibt || enable_shstk)
> > {
> > - int res;
> > unsigned int i;
> > - unsigned int first_legacy, last_legacy;
> > - bool need_legacy_bitmap = false;
> >
> > i = m->l_searchlist.r_nlist;
> > while (i-- > 0)
> > @@ -167,91 +109,25 @@ dl_cet_check (struct link_map *m, const char *program)
> > continue;
> > #endif
> >
> > - if (enable_ibt
> > - && enable_ibt_type != CET_ALWAYS_ON
> > - && !(l->l_cet & lc_ibt))
> > + /* IBT is enabled only if it is enabled in executable as
> > + well as all shared objects. */
> > + enable_ibt &= (enable_ibt_type == CET_ALWAYS_ON
> > + || (l->l_cet & lc_ibt) != 0);
> > + if (!found_ibt_legacy && enable_ibt != ibt_enabled)
> > {
> > - /* Remember the first and last legacy objects. */
> > - if (!need_legacy_bitmap)
> > - last_legacy = i;
> > - first_legacy = i;
> > - need_legacy_bitmap = true;
> > + found_ibt_legacy = true;
> > + ibt_legacy = i;
> > }
> >
> > /* SHSTK is enabled only if it is enabled in executable as
> > well as all shared objects. */
> > enable_shstk &= (enable_shstk_type == CET_ALWAYS_ON
> > || (l->l_cet & lc_shstk) != 0);
> > - }
> > -
> > - if (need_legacy_bitmap)
> > - {
> > - if (GL(dl_x86_legacy_bitmap)[0])
> > - {
> > - /* Change legacy bitmap to writable. */
> > - if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
> > - GL(dl_x86_legacy_bitmap)[1],
> > - PROT_READ | PROT_WRITE) < 0)
> > - {
> > -mprotect_failure:
> > - if (program)
> > - _dl_fatal_printf ("%s: mprotect legacy bitmap failed\n",
> > - l->l_name);
> > - else
> > - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> > - N_("mprotect legacy bitmap failed"));
> > - }
> > - }
> > - else
> > + if (enable_shstk != shstk_enabled)
> > {
> > - /* Allocate legacy bitmap. */
> > - int res = dl_cet_allocate_legacy_bitmap
> > - (GL(dl_x86_legacy_bitmap));
> > - if (res != 0)
> > - {
> > - if (program)
> > - _dl_fatal_printf ("%s: legacy bitmap isn't available\n",
> > - l->l_name);
> > - else
> > - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> > - N_("legacy bitmap isn't available"));
> > - }
> > + found_shstk_legacy = true;
> > + shstk_legacy = i;
> > }
> > -
> > - /* Put legacy shared objects in legacy bitmap. */
> > - for (i = first_legacy; i <= last_legacy; i++)
> > - {
> > - l = m->l_initfini[i];
> > -
> > - if (l->l_init_called || (l->l_cet & lc_ibt))
> > - continue;
> > -
> > -#ifdef SHARED
> > - if (l == &GL(dl_rtld_map)
> > - || l->l_real == &GL(dl_rtld_map)
> > - || (program && l == m))
> > - continue;
> > -#endif
> > -
> > - /* If IBT is enabled in executable and IBT isn't enabled
> > - in this shard object, mark PT_LOAD segments with PF_X
> > - in legacy code page bitmap. */
> > - res = dl_cet_mark_legacy_region (l);
> > - if (res != 0)
> > - {
> > - if (program)
> > - _dl_fatal_printf ("%s: failed to mark legacy code region\n",
> > - l->l_name);
> > - else
> > - _dl_signal_error (-res, l->l_name, "dlopen",
> > - N_("failed to mark legacy code region"));
> > - }
> > - }
> > -
> > - /* Change legacy bitmap to read-only. */
> > - if (__mprotect ((void *) GL(dl_x86_legacy_bitmap)[0],
> > - GL(dl_x86_legacy_bitmap)[1], PROT_READ) < 0)
> > - goto mprotect_failure;
> > }
> > }
> >
> > @@ -259,23 +135,40 @@ mprotect_failure:
> >
> > if (enable_ibt != ibt_enabled || enable_shstk != shstk_enabled)
> > {
> > - if (!program
> > - && enable_shstk_type != CET_PERMISSIVE)
> > + if (!program)
> > {
> > - /* When SHSTK is enabled, we can't dlopening a shared
> > - object without SHSTK. */
> > - if (enable_shstk != shstk_enabled)
> > - _dl_signal_error (EINVAL, l->l_name, "dlopen",
> > - N_("shadow stack isn't enabled"));
> > - return;
> > + if (enable_ibt_type != CET_PERMISSIVE)
> > + {
> > + /* When IBT is enabled, we cannot dlopen a shared
> > + object without IBT. */
> > + if (found_ibt_legacy)
> > + _dl_signal_error (0,
> > + m->l_initfini[ibt_legacy]->l_name,
> > + "dlopen",
> > + N_("rebuild shared object with IBT support enabled"));
> > + }
> > +
> > + if (enable_shstk_type != CET_PERMISSIVE)
> > + {
> > + /* When SHSTK is enabled, we cannot dlopen a shared
> > + object without SHSTK. */
> > + if (found_shstk_legacy)
> > + _dl_signal_error (0,
> > + m->l_initfini[shstk_legacy]->l_name,
> > + "dlopen",
> > + N_("rebuild shared object with SHSTK support enabled"));
> > + }
> > +
> > + if (enable_ibt_type != CET_PERMISSIVE
> > + && enable_shstk_type != CET_PERMISSIVE)
> > + return;
> > }
> >
> > /* Disable IBT and/or SHSTK if they are enabled by kernel, but
> > disabled in executable or shared objects. */
> > unsigned int cet_feature = 0;
> >
> > - /* Disable IBT only during program startup. */
> > - if (program && !enable_ibt)
> > + if (!enable_ibt)
> > cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
> > if (!enable_shstk)
> > cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
> > @@ -286,8 +179,14 @@ mprotect_failure:
> > if (program)
> > _dl_fatal_printf ("%s: can't disable CET\n", program);
> > else
> > - _dl_signal_error (-res, l->l_name, "dlopen",
> > - N_("can't disable CET"));
> > + {
> > + if (found_ibt_legacy)
> > + l = m->l_initfini[ibt_legacy];
> > + else
> > + l = m->l_initfini[shstk_legacy];
> > + _dl_signal_error (-res, l->l_name, "dlopen",
> > + N_("can't disable CET"));
> > + }
> > }
> >
> > /* Clear the disabled bits in dl_x86_feature_1. */
> > @@ -297,17 +196,21 @@ mprotect_failure:
> > }
> >
> > #ifdef SHARED
> > - if (program
> > - && (!shstk_enabled
> > - || enable_shstk_type != CET_PERMISSIVE)
> > - && (ibt_enabled || shstk_enabled))
> > + if (program && (ibt_enabled || shstk_enabled))
> > {
> > - /* Lock CET if IBT or SHSTK is enabled in executable. Don't
> > - lock CET if SHSTK is enabled permissively. */
> > - int res = dl_cet_lock_cet ();
> > - if (res != 0)
> > - _dl_fatal_printf ("%s: can't lock CET\n", program);
> > + if ((!ibt_enabled
> > + || enable_ibt_type != CET_PERMISSIVE)
> > + && (!shstk_enabled
> > + || enable_shstk_type != CET_PERMISSIVE))
> > + {
> > + /* Lock CET if IBT or SHSTK is enabled in executable unless
> > + IBT or SHSTK is enabled permissively. */
> > + int res = dl_cet_lock_cet ();
> > + if (res != 0)
> > + _dl_fatal_printf ("%s: can't lock CET\n", program);
> > + }
> >
> > + /* Set feature_1 if IBT or SHSTK is enabled in executable. */
> > cet_feature_changed = true;
> > }
> > #endif
> > diff --git a/sysdeps/x86/dl-procruntime.c b/sysdeps/x86/dl-procruntime.c
> > index fb36801f3e..5e39a38133 100644
> > --- a/sysdeps/x86/dl-procruntime.c
> > +++ b/sysdeps/x86/dl-procruntime.c
> > @@ -54,15 +54,4 @@ PROCINFO_CLASS unsigned int _dl_x86_feature_1[2]
> > # else
> > ,
> > # endif
> > -
> > -# if !defined PROCINFO_DECL && defined SHARED
> > - ._dl_x86_legacy_bitmap
> > -# else
> > -PROCINFO_CLASS unsigned long _dl_x86_legacy_bitmap[2]
> > -# endif
> > -# if !defined SHARED || defined PROCINFO_DECL
> > -;
> > -# else
> > -,
> > -# endif
> > #endif
> > diff --git a/sysdeps/x86/tst-cet-legacy-4.c b/sysdeps/x86/tst-cet-legacy-4.c
> > index a77078afc9..ee54b878ed 100644
> > --- a/sysdeps/x86/tst-cet-legacy-4.c
> > +++ b/sysdeps/x86/tst-cet-legacy-4.c
> > @@ -20,6 +20,9 @@
> > #include <dlfcn.h>
> > #include <stdio.h>
> > #include <stdlib.h>
> > +#include <string.h>
> > +
> > +#include <support/check.h>
> >
> > static int
> > do_test (void)
> > @@ -31,22 +34,18 @@ do_test (void)
> > h = dlopen (modname, RTLD_LAZY);
> > if (h == NULL)
> > {
> > - printf ("cannot open '%s': %s\n", modname, dlerror ());
> > - exit (1);
> > + const char *err = dlerror ();
> > + if (!strstr (err, "rebuild shared object with IBT support enabled"))
> > + FAIL_EXIT1 ("incorrect dlopen '%s' error: %s\n", modname, err);
> > + return 0;
> > }
> >
> > fp = dlsym (h, "test");
> > if (fp == NULL)
> > - {
> > - printf ("cannot get symbol 'test': %s\n", dlerror ());
> > - exit (1);
> > - }
> > + FAIL_EXIT1 ("cannot get symbol 'test': %s\n", dlerror ());
> >
> > if (fp () != 0)
> > - {
> > - puts ("test () != 0");
> > - exit (1);
> > - }
> > + FAIL_EXIT1 ("test () != 0");
> >
> > dlclose (h);
> >
> > diff --git a/sysdeps/x86/tst-cet-legacy-5.c b/sysdeps/x86/tst-cet-legacy-5.c
> > index 6c9bba06f5..e2e95b6749 100644
> > --- a/sysdeps/x86/tst-cet-legacy-5.c
> > +++ b/sysdeps/x86/tst-cet-legacy-5.c
> > @@ -35,7 +35,8 @@ do_test_1 (const char *modname, bool fail)
> > if (fail)
> > {
> > const char *err = dlerror ();
> > - if (strstr (err, "shadow stack isn't enabled") == NULL)
> > + if (strstr (err, "rebuild shared object with SHSTK support enabled")
> > + == NULL)
> > {
> > printf ("incorrect dlopen '%s' error: %s\n", modname,
> > err);
> > diff --git a/sysdeps/x86/tst-cet-legacy-6.c b/sysdeps/x86/tst-cet-legacy-6.c
> > index 877e77747d..bdbbb9075f 100644
> > --- a/sysdeps/x86/tst-cet-legacy-6.c
> > +++ b/sysdeps/x86/tst-cet-legacy-6.c
> > @@ -35,7 +35,8 @@ do_test_1 (const char *modname, bool fail)
> > if (fail)
> > {
> > const char *err = dlerror ();
> > - if (strstr (err, "shadow stack isn't enabled") == NULL)
> > + if (strstr (err, "rebuild shared object with SHSTK support enabled")
> > + == NULL)
> > {
> > printf ("incorrect dlopen '%s' error: %s\n", modname,
> > err);
> > diff --git a/sysdeps/x86/tst-cet-legacy-7.c b/sysdeps/x86/tst-cet-legacy-7.c
> > new file mode 100644
> > index 0000000000..58bcb29a5f
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-cet-legacy-7.c
> > @@ -0,0 +1,38 @@
> > +/* Check compatibility of legacy executable with a JIT engine.
> > + Copyright (C) 2020 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
> > + <https://www.gnu.org/licenses/>. */
> > +
> > +#include <stdio.h>
> > +#include <sys/mman.h>
> > +#include <support/xunistd.h>
> > +
> > +/* Check that mmapped legacy code works with -fcf-protection=none. */
> > +
> > +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 0;
> > +}
> > +
> > +#include <support/test-driver.c>
> > diff --git a/sysdeps/x86/tst-cet-legacy-8.c b/sysdeps/x86/tst-cet-legacy-8.c
> > new file mode 100644
> > index 0000000000..b14b2a7290
> > --- /dev/null
> > +++ b/sysdeps/x86/tst-cet-legacy-8.c
> > @@ -0,0 +1,55 @@
> > +/* Check incompatibility with legacy JIT engine.
> > + Copyright (C) 2020 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
> > + <https://www.gnu.org/licenses/>. */
> > +
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <x86intrin.h>
> > +#include <sys/mman.h>
> > +#include <support/test-driver.h>
> > +#include <support/xsignal.h>
> > +#include <support/xunistd.h>
> > +
> > +/* Check that mmapped legacy code trigges segfault with -fcf-protection. */
> > +
> > +static void
> > +segfault_handler (int signo)
> > +{
> > + exit (0);
> > +}
> > +
> > +static int
> > +do_test (void)
> > +{
> > + /* NB: This test should trigger SIGSEGV on CET platforms. If SHSTK
> > + is disabled, assuming IBT is also disabled. */
> > + if (_get_ssp () == 0)
> > + return EXIT_UNSUPPORTED;
> > +
> > + xsignal (SIGSEGV, segfault_handler);
>
> Please use EXPECTED_SIGNAL.
>
> > +
> > + 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_FAILURE;
> > +}
> > +
> > +#include <support/test-driver.c>
> >
This is the patch I am checking in.
Thanks.
--
H.J.
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