Update copyright dates with scripts/update-copyrights

[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / dl-execstack.c

diff --git a/sysdeps/unix/sysv/linux/dl-execstack.c b/sysdeps/unix/sysv/linux/dl-execstack.c
index 6ef9679045a3019e152087763b5fe6d9337ef80d..3339138c422a987b73b9b2b29c3f4ec1dc7c572d 100644 (file)
--- a/sysdeps/unix/sysv/linux/dl-execstack.c
+++ b/sysdeps/unix/sysv/linux/dl-execstack.c
@@ -1,5 +1,5 @@
 /* Stack executability handling for GNU dynamic linker.  Linux version.
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003-2021 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
@@ -13,9 +13,8 @@
    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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
 
 #include <ldsodefs.h>
 #include <sys/mman.h>
@@ -23,108 +22,25 @@
 #include <libintl.h>
 #include <stdbool.h>
 #include <stackinfo.h>
-#include <caller.h>
-
-#include "kernel-features.h"
+#include <sysdep.h>
 
 
 extern int __stack_prot attribute_relro attribute_hidden;
 
 
 int
-internal_function
 _dl_make_stack_executable (void **stack_endp)
 {
   /* This gives us the highest/lowest page that needs to be changed.  */
   uintptr_t page = ((uintptr_t) *stack_endp
                    & -(intptr_t) GLRO(dl_pagesize));
+  int result = 0;
 
-  /* Challenge the caller.  */
-  if (__builtin_expect (__check_caller (RETURN_ADDRESS (0),
-                                       allow_ldso|allow_libpthread) != 0, 0)
-      || __builtin_expect (*stack_endp != __libc_stack_end, 0))
-    return EPERM;
-
-  /* Newer Linux kernels support a flag to make our job easy.  */
-#if defined  PROT_GROWSDOWN || defined PROT_GROWSUP
-# if __ASSUME_PROT_GROWSUPDOWN == 0
-  static bool no_growsupdown;
-  if (! no_growsupdown)
-# endif
-    {
-      if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
-                                       __stack_prot) == 0, 1))
-       goto return_success;
-# if __ASSUME_PROT_GROWSUPDOWN == 0
-      if (errno == EINVAL)
-       no_growsupdown = true;
-      else
-# endif
-       return errno;
-    }
-#endif
-
-  /* There is always a hole in the address space below the bottom of the
-     stack.  So when we make an mprotect call that starts below the bottom
-     of the stack, it will include the hole and fail with ENOMEM.
-
-     We start with a random guess at how deep the stack might have gotten
-     so as to have extended the GROWSDOWN mapping to lower pages.  */
-
-#if __ASSUME_PROT_GROWSUPDOWN == 0
-  size_t size = GLRO(dl_pagesize) * 8;
-
-# if _STACK_GROWS_DOWN
-  page = page + GLRO(dl_pagesize) - size;
-  while (1)
-    {
-      if (__mprotect ((void *) page, size,
-                     __stack_prot & ~PROT_GROWSDOWN) == 0)
-       /* We got this chunk changed; loop to do another chunk below.  */
-       page -= size;
-      else
-       {
-         if (errno != ENOMEM)  /* Unexpected failure mode.  */
-           return errno;
-
-         if (size == GLRO(dl_pagesize))
-           /* We just tried to mprotect the top hole page and failed.
-              We are done.  */
-           break;
-
-         /* Our mprotect call failed because it started below the lowest
-            stack page.  Try again on just the top half of that region.  */
-         size /= 2;
-         page += size;
-       }
-    }
-
-# elif _STACK_GROWS_UP
-  while (1)
-    {
-      if (__mprotect ((void *) page, size, __stack_prot & ~PROT_GROWSUP) == 0)
-       /* We got this chunk changed; loop to do another chunk below.  */
-       page += size;
-      else
-       {
-         if (errno != ENOMEM)  /* Unexpected failure mode.  */
-           return errno;
-
-         if (size == GLRO(dl_pagesize))
-           /* We just tried to mprotect the lowest hole page and failed.
-              We are done.  */
-           break;
-
-         /* Our mprotect call failed because it extended past the highest
-            stack page.  Try again on just the bottom half of that region.  */
-         size /= 2;
-       }
-    }
-
-# else
-#  error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
-# endif
-#endif
+  if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),
+                                   __stack_prot) == 0, 1))
+    goto return_success;
+  result = errno;
+  goto out;
 
  return_success:
   /* Clear the address.  */
@@ -133,6 +49,11 @@ _dl_make_stack_executable (void **stack_endp)
   /* Remember that we changed the permission.  */
   GL(dl_stack_flags) |= PF_X;
 
-  return 0;
+ out:
+#ifdef check_consistency
+  check_consistency ();
+#endif
+
+  return result;
 }
 rtld_hidden_def (_dl_make_stack_executable)