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authorUlrich Drepper <drepper@myware66.akkadia.org>2009-05-15 08:01:09 -0700
committerUlrich Drepper <drepper@redhat.com>2009-05-15 08:48:00 -0700
commit774f5a3082b9b55a7668e3a92dc847de577c4946 (patch)
tree1d3ee2c0284923bd69b4db4f9eab2c433efa2af0 /elf
parentdeb84c43b1bb0958d942e6739f136d4c11189b3b (diff)
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Test DSOs for executable stack.
Add a text program, built to run on the host, to check all newly
built DSOs for executable stacks and fail if the stack information
is missing or indicates executable stacks.
Diffstat (limited to 'elf')
-rw-r--r--elf/Makefile14
-rw-r--r--elf/check-execstack.c158
2 files changed, 170 insertions, 2 deletions
diff --git a/elf/Makefile b/elf/Makefile
index e44ff1d382..94b9d069bf 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -93,7 +93,7 @@ distribute	:= rtld-Rules \
 		   order2mod1.c order2mod2.c order2mod3.c order2mod4.c \
 		   tst-stackguard1.c tst-stackguard1-static.c \
 		   tst-array5.c tst-array5-static.c tst-array5dep.c \
-		   tst-array5.exp tst-leaks1.c
+		   tst-array5.exp tst-leaks1.c check-execstack.c
 
 CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables
 CFLAGS-dl-lookup.c = -fexceptions -fasynchronous-unwind-tables
@@ -842,12 +842,16 @@ check-textrel-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE
 $(objpfx)check-textrel: check-textrel.c
 	$(native-compile)
 
+check-execstack-CFLAGS = -O -Wall -D_XOPEN_SOURCE=600 -D_BSD_SOURCE -std=gnu99
+$(objpfx)check-execstack: check-execstack.c
+	$(native-compile)
+
 check-localplt-CFLAGS = -O -Wall -D_GNU_SOURCE -std=gnu99
 $(objpfx)check-localplt: check-localplt.c
 	$(native-compile)
 
 ifeq (yes,$(build-shared))
-tests: $(objpfx)check-textrel.out
+tests: $(objpfx)check-textrel.out $(objpfx)check-execstack.out
 
 $(objpfx)check-textrel.out: $(objpfx)check-textrel
 	$(dir $<)$(notdir $<) $(common-objpfx)libc.so \
@@ -855,6 +859,12 @@ $(objpfx)check-textrel.out: $(objpfx)check-textrel
 			    $(common-objpfx)iconvdata/*.so)) > $@
 generated += check-textrel check-textrel.out
 
+$(objpfx)check-execstack.out: $(objpfx)check-execstack
+	$(dir $<)$(notdir $<) $(common-objpfx)libc.so \
+	  $(sort $(wildcard $(common-objpfx)*/lib*.so \
+			    $(common-objpfx)iconvdata/*.so)) > $@
+generated += check-execstack check-execstack.out
+
 $(objpfx)tst-dlmodcount: $(libdl)
 $(objpfx)tst-dlmodcount.out: $(test-modules)
 
diff --git a/elf/check-execstack.c b/elf/check-execstack.c
new file mode 100644
index 0000000000..55cf48721a
--- /dev/null
+++ b/elf/check-execstack.c
@@ -0,0 +1,158 @@
+/* Check for executable stacks in DSOs.
+   Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contribute by Ulrich Drepper <drepper@redhat.com>. 2009.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <byteswap.h>
+#include <elf.h>
+#include <endian.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+
+#ifdef BITS
+
+# define AB(name) _AB (name, BITS)
+# define _AB(name, bits) __AB (name, bits)
+# define __AB(name, bits) name##bits
+# define E(name) _E (name, BITS)
+# define _E(name, bits) __E (name, bits)
+# define __E(name, bits) Elf##bits##_##name
+# define SWAP(val) \
+  ({ __typeof (val) __res;						      \
+     if (((ehdr.e_ident[EI_DATA] == ELFDATA2MSB				      \
+	   && BYTE_ORDER == LITTLE_ENDIAN)				      \
+	  || (ehdr.e_ident[EI_DATA] == ELFDATA2LSB			      \
+	      && BYTE_ORDER == BIG_ENDIAN))				      \
+	 && sizeof (val) != 1)						      \
+       {								      \
+	 if (sizeof (val) == 2)						      \
+	   __res = bswap_16 (val);					      \
+	 else if (sizeof (val) == 4)					      \
+	   __res = bswap_32 (val);					      \
+	 else								      \
+	   __res = bswap_64 (val);					      \
+       }								      \
+     else								      \
+       __res = (val);							      \
+     __res; })
+
+
+static int
+AB(handle_file) (const char *fname, int fd)
+{
+  E(Ehdr) ehdr;
+
+  if (pread (fd, &ehdr, sizeof (ehdr), 0) != sizeof (ehdr))
+    {
+    read_error:
+      printf ("%s: read error: %m\n", fname);
+      return 1;
+    }
+
+  const size_t phnum = SWAP (ehdr.e_phnum);
+  const size_t phentsize = SWAP (ehdr.e_phentsize);
+
+  /* Read the program header.  */
+  E(Phdr) *phdr = alloca (phentsize * phnum);
+  if (pread (fd, phdr, phentsize * phnum, SWAP (ehdr.e_phoff))
+      != phentsize * phnum)
+    goto read_error;
+
+  /* Search for the PT_GNU_STACK entry.  */
+  for (size_t cnt = 0; cnt < phnum; ++cnt)
+    if (SWAP (phdr[cnt].p_type) == PT_GNU_STACK)
+      {
+	unsigned int flags = SWAP(phdr[cnt].p_flags);
+	if (flags & PF_X)
+	  {
+	    printf ("%s: executable stack signaled\n", fname);
+	    return 1;
+	  }
+
+	return 0;
+      }
+
+  printf ("%s: no PT_GNU_STACK entry\n", fname);
+  return 1;
+}
+
+# undef BITS
+#else
+
+# define BITS 32
+# include "check-execstack.c"
+
+# define BITS 64
+# include "check-execstack.c"
+
+
+static int
+handle_file (const char *fname)
+{
+  int fd = open (fname, O_RDONLY);
+  if (fd == -1)
+    {
+      printf ("cannot open %s: %m\n", fname);
+      return 1;
+    }
+
+  /* Read was is supposed to be the ELF header.  Read the initial
+     bytes to determine whether this is a 32 or 64 bit file.  */
+  char ident[EI_NIDENT];
+  if (read (fd, ident, EI_NIDENT) != EI_NIDENT)
+    {
+      printf ("%s: read error: %m\n", fname);
+      close (fd);
+      return 1;
+    }
+
+  if (memcmp (&ident[EI_MAG0], ELFMAG, SELFMAG) != 0)
+    {
+      printf ("%s: not an ELF file\n", fname);
+      close (fd);
+      return 1;
+    }
+
+  int result;
+  if (ident[EI_CLASS] == ELFCLASS64)
+    result = handle_file64 (fname, fd);
+  else
+    result = handle_file32 (fname, fd);
+
+  close (fd);
+
+  return result;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  int cnt;
+  int result = 0;
+
+  for (cnt = 1; cnt < argc; ++cnt)
+    result |= handle_file (argv[cnt]);
+
+  return result;
+}
+#endif