V4 [PATCH] x86: Remove ARCH_CET_LEGACY_BITMAP [BZ #25397]
Carlos O'Donell
carlos@redhat.com
Wed Mar 18 03:20:37 GMT 2020
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>
>
--
Cheers,
Carlos.
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