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authorH.J. Lu <hjl.tools@gmail.com>2023-07-28 14:06:01 -0700
committerH.J. Lu <hjl.tools@gmail.com>2023-12-20 05:03:37 -0800
commit41560a9312ce0ec7203480eef8f865076bff9edb (patch)
treed297e1204a5e6bf106610369441fd276c084d7df
parentc04035809a393c0c6f1cc523df6b316b05fdb50f (diff)
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x86/cet: Don't disable CET if not single threaded
In permissive mode, don't disable IBT nor SHSTK when dlopening a legacy shared library if not single threaded since IBT and SHSTK may be still enabled in other threads. Other threads with IBT or SHSTK enabled will crash when calling functions in the legacy shared library. Instead, an error will be issued.
-rw-r--r--sysdeps/x86/dl-cet.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
index 67c51ee..e486e54 100644
--- a/sysdeps/x86/dl-cet.c
+++ b/sysdeps/x86/dl-cet.c
@@ -20,6 +20,7 @@
#include <libintl.h>
#include <ldsodefs.h>
#include <dl-cet.h>
+#include <sys/single_threaded.h>
/* GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK
are defined in <elf.h>, which are only available for C sources.
@@ -233,7 +234,10 @@ dl_cet_check_dlopen (struct link_map *m, struct dl_cet_info *info)
&& (info->feature_1_legacy
& GNU_PROPERTY_X86_FEATURE_1_IBT) != 0)
{
- if (info->enable_ibt_type != cet_permissive)
+ /* Don't disable IBT if not single threaded since IBT may be still
+ enabled in other threads. */
+ if (info->enable_ibt_type != cet_permissive
+ || !SINGLE_THREAD_P)
{
legacy_obj = info->feature_1_legacy_ibt;
msg = N_("rebuild shared object with IBT support enabled");
@@ -249,7 +253,10 @@ dl_cet_check_dlopen (struct link_map *m, struct dl_cet_info *info)
&& (info->feature_1_legacy
& GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0)
{
- if (info->enable_shstk_type != cet_permissive)
+ /* Don't disable SHSTK if not single threaded since SHSTK may be
+ still enabled in other threads. */
+ if (info->enable_shstk_type != cet_permissive
+ || !SINGLE_THREAD_P)
{
legacy_obj = info->feature_1_legacy_shstk;
msg = N_("rebuild shared object with SHSTK support enabled");