elfedit: Add --enable-x86-feature/--disable-x86-feature

Add --enable-x86-feature and --disable-x86-feature options to elfedit
to set and clear the IBT and SHSTK bits in program property in ELF
executables and shared objects.

binutils/

	* doc/binutils.texi: Document --enable-x86-feature and
	--disable-x86-feature options for elfedit.
	* elfedit.c: Include "config.h" and <sys/mman.h>.
	(enable_x86_features): New.
	(disable_x86_features): Likewise.
	(update_gnu_property): Likewise.
	(elf_x86_feature): Likewise.
	(process_file): Call update_gnu_property on ET_EXEC or ET_DYN
	file.
	(command_line_switch): Add OPTION_ENABLE_X86_FEATURE and
	OPTION_DISABLE_X86_FEATURE.
	(options): Add--enable-x86-feature and --disable-x86-feature.
	(usage): Likewise.
	(main): Handle OPTION_ENABLE_X86_FEATURE and
	OPTION_DISABLE_X86_FEATURE.

ld/

	* testsuite/config/default.exp (ELFEDIT): New.
	* testsuite/ld-elf/linux-x86.exp (elfedit_test): New proc.
	Run elfedit tests.
	* testsuite/ld-elf/x86-feature-1a.rd: New file.
	* testsuite/ld-elf/x86-feature-1b.rd: Likewise.
	* testsuite/ld-elf/x86-feature-1c.rd: Likewise.
	* testsuite/ld-elf/x86-feature-1d.rd: Likewise.
	* testsuite/ld-elf/x86-feature-1e.rd: Likewise.

1 files changed, 254 insertions, 2 deletions

diff --git a/binutils/elfedit.c b/binutils/elfedit.c
index a9f7c9d..98d4fd7 100644
--- a/binutils/elfedit.c
+++ b/binutils/elfedit.c
@@ -18,6 +18,7 @@
    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
    02110-1301, USA.  */
 
+#include "config.h"
 #include "sysdep.h"
 #include <assert.h>
 
@@ -65,6 +66,217 @@ enum elfclass
 static enum elfclass input_elf_class = ELF_CLASS_UNKNOWN;
 static enum elfclass output_elf_class = ELF_CLASS_BOTH;
 
+#ifdef HAVE_MMAP
+#include <sys/mman.h>
+
+static unsigned int enable_x86_features;
+static unsigned int disable_x86_features;
+
+static int
+update_gnu_property (const char *file_name, FILE *file)
+{
+  char *map;
+  Elf_Internal_Phdr *phdrs;
+  struct stat st_buf;
+  unsigned int i;
+  int ret;
+
+  if (!enable_x86_features && !disable_x86_features)
+    return 0;
+
+  if (elf_header.e_machine != EM_386
+      && elf_header.e_machine != EM_X86_64)
+    {
+      error (_("%s: Not an i386 nor x86-64 ELF file\n"), file_name);
+      return 0;
+    }
+
+  if (fstat (fileno (file), &st_buf) < 0)
+    {
+      error (_("%s: stat () failed\n"), file_name);
+      return 1;
+    }
+
+  map = mmap (NULL, st_buf.st_size, PROT_READ | PROT_WRITE,
+	      MAP_SHARED, fileno (file), 0);
+  if (map == MAP_FAILED)
+    {
+      error (_("%s: mmap () failed\n"), file_name);
+      return 0;
+    }
+
+  phdrs = xmalloc (elf_header.e_phnum * sizeof (*phdrs));
+
+  if (elf_header.e_ident[EI_CLASS] == ELFCLASS32)
+    {
+      Elf32_External_Phdr *phdrs32
+	= (Elf32_External_Phdr *) (map + elf_header.e_phoff);
+      for (i = 0; i < elf_header.e_phnum; i++)
+	{
+	  phdrs[i].p_type = BYTE_GET (phdrs32[i].p_type);
+	  phdrs[i].p_offset = BYTE_GET (phdrs32[i].p_offset);
+	  phdrs[i].p_vaddr = BYTE_GET (phdrs32[i].p_vaddr);
+	  phdrs[i].p_paddr = BYTE_GET (phdrs32[i].p_paddr);
+	  phdrs[i].p_filesz = BYTE_GET (phdrs32[i].p_filesz);
+	  phdrs[i].p_memsz = BYTE_GET (phdrs32[i].p_memsz);
+	  phdrs[i].p_flags = BYTE_GET (phdrs32[i].p_flags);
+	  phdrs[i].p_align = BYTE_GET (phdrs32[i].p_align);
+	}
+    }
+  else
+    {
+      Elf64_External_Phdr *phdrs64
+	= (Elf64_External_Phdr *) (map + elf_header.e_phoff);
+      for (i = 0; i < elf_header.e_phnum; i++)
+	{
+	  phdrs[i].p_type = BYTE_GET (phdrs64[i].p_type);
+	  phdrs[i].p_offset = BYTE_GET (phdrs64[i].p_offset);
+	  phdrs[i].p_vaddr = BYTE_GET (phdrs64[i].p_vaddr);
+	  phdrs[i].p_paddr = BYTE_GET (phdrs64[i].p_paddr);
+	  phdrs[i].p_filesz = BYTE_GET (phdrs64[i].p_filesz);
+	  phdrs[i].p_memsz = BYTE_GET (phdrs64[i].p_memsz);
+	  phdrs[i].p_flags = BYTE_GET (phdrs64[i].p_flags);
+	  phdrs[i].p_align = BYTE_GET (phdrs64[i].p_align);
+	}
+    }
+
+  ret = 0;
+  for (i = 0; i < elf_header.e_phnum; i++)
+    if (phdrs[i].p_type == PT_NOTE)
+      {
+	size_t offset = phdrs[i].p_offset;
+	size_t size = phdrs[i].p_filesz;
+	size_t align = phdrs[i].p_align;
+	char *buf = map + offset;
+	char *p = buf;
+
+	while (p < buf + size)
+	  {
+	    Elf_External_Note *xnp = (Elf_External_Note *) p;
+	    Elf_Internal_Note in;
+
+	    if (offsetof (Elf_External_Note, name) > buf - p + size)
+	      {
+		ret = 1;
+		goto out;
+	      }
+
+	    in.type = BYTE_GET (xnp->type);
+	    in.namesz = BYTE_GET (xnp->namesz);
+	    in.namedata = xnp->name;
+	    if (in.namesz > buf - in.namedata + size)
+	      {
+		ret = 1;
+		goto out;
+	      }
+
+	    in.descsz = BYTE_GET (xnp->descsz);
+	    in.descdata = p + ELF_NOTE_DESC_OFFSET (in.namesz, align);
+	    in.descpos = offset + (in.descdata - buf);
+	    if (in.descsz != 0
+		&& (in.descdata >= buf + size
+		    || in.descsz > buf - in.descdata + size))
+	      {
+		ret = 1;
+		goto out;
+	      }
+
+	    if (in.namesz == sizeof "GNU"
+		&& strcmp (in.namedata, "GNU") == 0
+		&& in.type == NT_GNU_PROPERTY_TYPE_0)
+	      {
+		unsigned char *ptr;
+		unsigned char *ptr_end;
+
+		if (in.descsz < 8 || (in.descsz % align) != 0)
+		  {
+		    ret = 1;
+		    goto out;
+		  }
+
+		ptr = (unsigned char *) in.descdata;
+		ptr_end = ptr + in.descsz;
+
+		do
+		  {
+		    unsigned int type = byte_get (ptr, 4);
+		    unsigned int datasz = byte_get (ptr + 4, 4);
+		    unsigned int bitmask, old_bitmask;
+
+		    ptr += 8;
+		    if ((ptr + datasz) > ptr_end)
+		      {
+			ret = 1;
+			goto out;
+		      }
+
+		    if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
+		      {
+			if (datasz != 4)
+			  {
+			    ret = 1;
+			    goto out;
+			  }
+
+			old_bitmask = byte_get (ptr, 4);
+			bitmask = old_bitmask;
+			if (enable_x86_features)
+			  bitmask |= enable_x86_features;
+			if (disable_x86_features)
+			  bitmask &= ~disable_x86_features;
+			if (old_bitmask != bitmask)
+			  BYTE_PUT (ptr, bitmask);
+			goto out;
+		      }
+
+		    ptr += ELF_ALIGN_UP (datasz, align);
+		  }
+		while ((ptr_end - ptr) >= 8);
+	      }
+
+	    p += ELF_NOTE_NEXT_OFFSET (in.namesz, in.descsz, align);
+	  }
+      }
+
+out:
+  if (ret != 0)
+    error (_("%s: Invalid PT_NOTE segment\n"), file_name);
+
+  free (phdrs);
+  munmap (map, st_buf.st_size);
+
+  return ret;
+}
+
+/* Set enable_x86_features and disable_x86_features for a feature
+   string, FEATURE.  */
+
+static int
+elf_x86_feature (const char *feature, int enable)
+{
+  unsigned int x86_feature;
+  if (strcasecmp (feature, "ibt") == 0)
+    x86_feature = GNU_PROPERTY_X86_FEATURE_1_IBT;
+  else if (strcasecmp (feature, "shstk") == 0)
+    x86_feature = GNU_PROPERTY_X86_FEATURE_1_SHSTK;
+  else
+    return -1;
+
+  if (enable)
+    {
+      enable_x86_features |= x86_feature;
+      disable_x86_features &= ~x86_feature;
+    }
+  else
+    {
+      disable_x86_features |= x86_feature;
+      enable_x86_features &= ~x86_feature;
+    }
+
+  return 0;
+}
+#endif
+
 /* Return ELF class for a machine type, MACH.  */
 
 static enum elfclass
@@ -533,6 +745,12 @@ process_file (const char *file_name)
       rewind (file);
       archive_file_size = archive_file_offset = 0;
       ret = process_object (file_name, file);
+#ifdef HAVE_MMAP
+      if (!ret
+	  && (elf_header.e_type == ET_EXEC
+	      || elf_header.e_type == ET_DYN))
+	ret = update_gnu_property (file_name, file);
+#endif
     }
 
   fclose (file);
@@ -632,7 +850,11 @@ enum command_line_switch
     OPTION_INPUT_TYPE,
     OPTION_OUTPUT_TYPE,
     OPTION_INPUT_OSABI,
-    OPTION_OUTPUT_OSABI
+    OPTION_OUTPUT_OSABI,
+#ifdef HAVE_MMAP
+    OPTION_ENABLE_X86_FEATURE,
+    OPTION_DISABLE_X86_FEATURE,
+#endif
   };
 
 static struct option options[] =
@@ -643,6 +865,12 @@ static struct option options[] =
   {"output-type",	required_argument, 0, OPTION_OUTPUT_TYPE},
   {"input-osabi",	required_argument, 0, OPTION_INPUT_OSABI},
   {"output-osabi",	required_argument, 0, OPTION_OUTPUT_OSABI},
+#ifdef HAVE_MMAP
+  {"enable-x86-feature",
+			required_argument, 0, OPTION_ENABLE_X86_FEATURE},
+  {"disable-x86-feature",
+			required_argument, 0, OPTION_DISABLE_X86_FEATURE},
+#endif
   {"version",		no_argument, 0, 'v'},
   {"help",		no_argument, 0, 'h'},
   {0,			no_argument, 0, 0}
@@ -661,7 +889,15 @@ usage (FILE *stream, int exit_status)
   --input-type <type>         Set input file type to <type>\n\
   --output-type <type>        Set output file type to <type>\n\
   --input-osabi <osabi>       Set input OSABI to <osabi>\n\
-  --output-osabi <osabi>      Set output OSABI to <osabi>\n\
+  --output-osabi <osabi>      Set output OSABI to <osabi>\n"));
+#ifdef HAVE_MMAP
+  fprintf (stream, _("\
+  --enable-x86-feature <feature>\n\
+                              Enable x86 feature <feature>\n\
+  --disable-x86-feature <feature>\n\
+                              Disable x86 feature <feature>\n"));
+#endif
+  fprintf (stream, _("\
   -h --help                   Display this information\n\
   -v --version                Display the version number of %s\n\
 "),
@@ -734,6 +970,18 @@ main (int argc, char ** argv)
 	    return 1;
 	  break;
 
+#ifdef HAVE_MMAP
+	case OPTION_ENABLE_X86_FEATURE:
+	  if (elf_x86_feature (optarg, 1) < 0)
+	    return 1;
+	  break;
+
+	case OPTION_DISABLE_X86_FEATURE:
+	  if (elf_x86_feature (optarg, 0) < 0)
+	    return 1;
+	  break;
+#endif
+
 	case 'h':
 	  usage (stdout, 0);
 
@@ -748,6 +996,10 @@ main (int argc, char ** argv)
 
   if (optind == argc
       || (output_elf_machine == -1
+#ifdef HAVE_MMAP
+	 && ! enable_x86_features
+	 && ! disable_x86_features
+#endif
 	  && output_elf_type == -1
 	  && output_elf_osabi == -1))
     usage (stderr, 1);