libphobos: Fix segfault at run-time when using custom Fibers (PR 98025)

When libphobos is configured with --enable-cet, this adds extra fields to the Fiber class to support the ucontext_t fallback implementation. These fields get omitted when compiling user code unless they also used `-fversion=CET' to build their project, which resulted in data being overwritten from within swapcontext(). On reviewing the ucontext_t definitions, it was found that the shadow stack fields were missing, and the struct size didn't match up on X32. This has been fixed in upstream druntime and merged down here. Reviewed-on: https://github.com/dlang/druntime/pull/3293 libphobos/ChangeLog: PR d/98025 * Makefile.in: Regenerate. * configure: Regenerate. * configure.ac (DCFG_ENABLE_CET): Substitute. * libdruntime/MERGE: Merge upstream druntime 0fe7974c. * libdruntime/Makefile.in: Regenerate. * libdruntime/core/thread.d: Import gcc.config. (class Fiber): Add ucontext_t fields when GNU_Enable_CET is true. * libdruntime/gcc/config.d.in (GNU_Enable_CET): Define. * src/Makefile.in: Regenerate. * testsuite/Makefile.in: Regenerate.
2020-11-27 13:15:44 +01:00 · 2020-11-27 13:15:44 +01:00 · 5dbab7b3f4
parent 6b2f370fa9
commit 5dbab7b3f4
10 changed files with 43 additions and 9 deletions
--- a/libphobos/Makefile.in
+++ b/libphobos/Makefile.in
@ -217,6 +217,7 @@ CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
 DCFG_ARM_EABI_UNWINDER = @DCFG_ARM_EABI_UNWINDER@
 DCFG_DLPI_TLS_MODID = @DCFG_DLPI_TLS_MODID@
+DCFG_ENABLE_CET = @DCFG_ENABLE_CET@
 DCFG_HAVE_64BIT_ATOMICS = @DCFG_HAVE_64BIT_ATOMICS@
 DCFG_HAVE_ATOMIC_BUILTINS = @DCFG_HAVE_ATOMIC_BUILTINS@
 DCFG_HAVE_LIBATOMIC = @DCFG_HAVE_LIBATOMIC@
--- a/libphobos/configure
+++ b/libphobos/configure
@ -722,6 +722,7 @@ LIBTOOL
 CFLAGS_FOR_BUILD
 CC_FOR_BUILD
 AR
+DCFG_ENABLE_CET
 CET_DFLAGS
 CET_FLAGS
 RANLIB
@ -5652,11 +5653,20 @@ fi


 # To ensure that runtime code for CET is compiled in, add in D version flags.
-if test "$enable_cet" = yes; then
+if test x$enable_cet = xyes; then :
+
  CET_DFLAGS="$CET_FLAGS -fversion=CET"
+  DCFG_ENABLE_CET=true
+
+else
+
+  CET_DFLAGS=
+  DCFG_ENABLE_CET=false

 fi

+
+
 # This should be inherited in the recursive make, but ensure it is defined.
 test "$AR" || AR=ar

@ -11744,7 +11754,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 11747 "configure"
+#line 11757 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@ -11850,7 +11860,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 11853 "configure"
+#line 11863 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
--- a/libphobos/configure.ac
+++ b/libphobos/configure.ac
@ -69,10 +69,15 @@ AC_PROG_MAKE_SET
 GCC_CET_FLAGS(CET_FLAGS)
 AC_SUBST(CET_FLAGS)
 # To ensure that runtime code for CET is compiled in, add in D version flags.
-if test "$enable_cet" = yes; then
+AS_IF([test x$enable_cet = xyes], [
  CET_DFLAGS="$CET_FLAGS -fversion=CET"
-  AC_SUBST(CET_DFLAGS)
-fi
+  DCFG_ENABLE_CET=true
+], [
+  CET_DFLAGS=
+  DCFG_ENABLE_CET=false
+])
+AC_SUBST(CET_DFLAGS)
+AC_SUBST(DCFG_ENABLE_CET)

 # This should be inherited in the recursive make, but ensure it is defined.
 test "$AR" || AR=ar
--- a/libphobos/libdruntime/MERGE
+++ b/libphobos/libdruntime/MERGE
@ -1,4 +1,4 @@
-d37ef985a97eb446371ab4b2315a52b87233fbf3
+0fe7974cf53b75db59461de2a3d6e53ce933d297

 The first line of this file holds the git revision number of the last
 merge done from the dlang/druntime repository.
--- a/libphobos/libdruntime/Makefile.in
+++ b/libphobos/libdruntime/Makefile.in
@ -577,6 +577,7 @@ CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
 DCFG_ARM_EABI_UNWINDER = @DCFG_ARM_EABI_UNWINDER@
 DCFG_DLPI_TLS_MODID = @DCFG_DLPI_TLS_MODID@
+DCFG_ENABLE_CET = @DCFG_ENABLE_CET@
 DCFG_HAVE_64BIT_ATOMICS = @DCFG_HAVE_64BIT_ATOMICS@
 DCFG_HAVE_ATOMIC_BUILTINS = @DCFG_HAVE_ATOMIC_BUILTINS@
 DCFG_HAVE_LIBATOMIC = @DCFG_HAVE_LIBATOMIC@
--- a/libphobos/libdruntime/core/sys/posix/ucontext.d
+++ b/libphobos/libdruntime/core/sys/posix/ucontext.d
@ -114,7 +114,7 @@ version (CRuntime_Glibc)

            enum NGREG = 23;

-            alias c_long            greg_t;
+            alias long              greg_t;
            alias greg_t[NGREG]     gregset_t;
            alias _libc_fpstate*    fpregset_t;
        }
@ -123,7 +123,7 @@ version (CRuntime_Glibc)
        {
            gregset_t   gregs;
            fpregset_t  fpregs;
-            c_ulong[8]  __reserved1;
+            ulong[8]    __reserved1;
        }

        struct ucontext_t
@ -134,6 +134,7 @@ version (CRuntime_Glibc)
            mcontext_t      uc_mcontext;
            sigset_t        uc_sigmask;
            _libc_fpstate   __fpregs_mem;
+            ulong[4]        __ssp;
        }
    }
    else version (X86)
@ -205,6 +206,7 @@ version (CRuntime_Glibc)
            mcontext_t      uc_mcontext;
            sigset_t        uc_sigmask;
            _libc_fpstate   __fpregs_mem;
+            c_ulong[4]      __ssp;
        }
    }
    else version (HPPA)
--- a/libphobos/libdruntime/core/thread.d
+++ b/libphobos/libdruntime/core/thread.d
@ -52,6 +52,7 @@ version (Solaris)
 version (GNU)
 {
    import gcc.builtins;
+    import gcc.config;
    version (GNU_StackGrowsDown)
        version = StackGrowsDown;
 }
@ -5123,6 +5124,15 @@ private:
        ucontext_t              m_utxt  = void;
        ucontext_t*             m_ucur  = null;
    }
+    else static if (GNU_Enable_CET)
+    {
+        // When libphobos was built with --enable-cet, these fields need to
+        // always be present in the Fiber class layout.
+        import core.sys.posix.ucontext;
+        static ucontext_t       sm_utxt = void;
+        ucontext_t              m_utxt  = void;
+        ucontext_t*             m_ucur  = null;
+    }


 private:
--- a/libphobos/libdruntime/gcc/config.d.in
+++ b/libphobos/libdruntime/gcc/config.d.in
@ -49,3 +49,6 @@ enum GNU_Have_LibAtomic = @DCFG_HAVE_LIBATOMIC@;

 // Do we have qsort_r function
 enum Have_Qsort_R = @DCFG_HAVE_QSORT_R@;
+
+// Whether libphobos been configured with --enable-cet.
+enum GNU_Enable_CET = @DCFG_ENABLE_CET@;
--- a/libphobos/src/Makefile.in
+++ b/libphobos/src/Makefile.in
@ -333,6 +333,7 @@ CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
 DCFG_ARM_EABI_UNWINDER = @DCFG_ARM_EABI_UNWINDER@
 DCFG_DLPI_TLS_MODID = @DCFG_DLPI_TLS_MODID@
+DCFG_ENABLE_CET = @DCFG_ENABLE_CET@
 DCFG_HAVE_64BIT_ATOMICS = @DCFG_HAVE_64BIT_ATOMICS@
 DCFG_HAVE_ATOMIC_BUILTINS = @DCFG_HAVE_ATOMIC_BUILTINS@
 DCFG_HAVE_LIBATOMIC = @DCFG_HAVE_LIBATOMIC@
--- a/libphobos/testsuite/Makefile.in
+++ b/libphobos/testsuite/Makefile.in
@ -161,6 +161,7 @@ CPPFLAGS = @CPPFLAGS@
 CYGPATH_W = @CYGPATH_W@
 DCFG_ARM_EABI_UNWINDER = @DCFG_ARM_EABI_UNWINDER@
 DCFG_DLPI_TLS_MODID = @DCFG_DLPI_TLS_MODID@
+DCFG_ENABLE_CET = @DCFG_ENABLE_CET@
 DCFG_HAVE_64BIT_ATOMICS = @DCFG_HAVE_64BIT_ATOMICS@
 DCFG_HAVE_ATOMIC_BUILTINS = @DCFG_HAVE_ATOMIC_BUILTINS@
 DCFG_HAVE_LIBATOMIC = @DCFG_HAVE_LIBATOMIC@