diff -up patch-2.7.1/NEWS.CVE-2015-1196 patch-2.7.1/NEWS

diff -up patch-2.7.1/src/pch.c.CVE-2015-1196 patch-2.7.1/src/pch.c

--- patch-2.7.1/src/pch.c.CVE-2015-1196	2015-01-20 12:23:34.808516117 +0000

+++ patch-2.7.1/src/pch.c	2015-01-20 12:24:15.763652714 +0000

@@ -454,6 +454,60 @@ name_is_valid (char const *name)

   return is_valid;

 }

+bool

+symlink_target_is_valid (char const *target, char const *to)

+{

+  bool is_valid;

+

+  if (IS_ABSOLUTE_FILE_NAME (to))

+    is_valid = true;

+  else if (IS_ABSOLUTE_FILE_NAME (target))

+    is_valid = false;

+  else

+    {

+      unsigned int depth = 0;

+      char const *t;

+

+      is_valid = true;

+      t = to;

+      while (*t)

+	{

+	  while (*t && ! ISSLASH (*t))

+	    t++;

+	  if (ISSLASH (*t))

+	    {

+	      while (ISSLASH (*t))

+		t++;

+	      depth++;

+	    }

+	}

+

+      t = target;

+      while (*t)

+	{

+	  if (*t == '.' && *++t == '.' && (! *++t || ISSLASH (*t)))

+	    {

+	      if (! depth--)

+		{

+		  is_valid = false;

+		  break;

+		}

+	    }

+	  else

+	    {

+	      while (*t && ! ISSLASH (*t))

+		t++;

+	      depth++;

+	    }

+	  while (ISSLASH (*t))

+	    t++;

+	}

+    }

+

+  /* Allow any symlink target if we are in the filesystem root.  */

+  return is_valid || cwd_is_root (to);

+}

+

 /* Determine what kind of diff is in the remaining part of the patch file. */

 static enum diff

diff -up patch-2.7.1/src/pch.h.CVE-2015-1196 patch-2.7.1/src/pch.h

--- patch-2.7.1/src/pch.h.CVE-2015-1196	2012-09-22 18:37:21.000000000 +0100

+++ patch-2.7.1/src/pch.h	2015-01-20 12:24:15.763652714 +0000

@@ -37,6 +37,7 @@ bool pch_write_line (lin, FILE *);

 bool there_is_another_patch (bool, mode_t *);

 char *pfetch (lin) _GL_ATTRIBUTE_PURE;

 char pch_char (lin) _GL_ATTRIBUTE_PURE;

+bool symlink_target_is_valid (char const *, char const *);

 int another_hunk (enum diff, bool);

 int pch_says_nonexistent (bool) _GL_ATTRIBUTE_PURE;

 size_t pch_line_len (lin) _GL_ATTRIBUTE_PURE;

diff -up patch-2.7.1/src/util.c.CVE-2015-1196 patch-2.7.1/src/util.c

--- patch-2.7.1/src/util.c.CVE-2015-1196	2015-01-20 12:23:34.808516117 +0000

+++ patch-2.7.1/src/util.c	2015-01-20 12:24:15.764652717 +0000

@@ -478,6 +478,13 @@ move_file (char const *from, bool *from_

 	    read_fatal ();

 	  buffer[size] = 0;

+	  if (! symlink_target_is_valid (buffer, to))

+	    {

+	      fprintf (stderr, "symbolic link target '%s' is invalid\n",

+		       buffer);

+	      fatal_exit (0);

+	    }

+

 	  if (! backup)

 	    {

 	      if (unlink (to) == 0)

diff -up patch-2.7.1/tests/symlinks.CVE-2015-1196 patch-2.7.1/tests/symlinks

--- patch-2.7.1/tests/symlinks.CVE-2015-1196	2012-09-19 02:18:42.000000000 +0100

+++ patch-2.7.1/tests/symlinks	2015-01-20 12:24:15.764652717 +0000

@@ -146,6 +146,59 @@ ncheck 'test ! -L symlink'

 # --------------------------------------------------------------

+# Patch should not create symlinks which point outside the working directory.

+

+cat > symlink-target.diff <

+diff --git a/dir/foo b/dir/foo

+new file mode 120000

+index 0000000..cad2309

+--- /dev/null

++++ b/dir/foo

+@@ -0,0 +1 @@

++../foo

+\ No newline at end of file

+EOF

+

+check 'patch -p1 < symlink-target.diff || echo "Status: $?"' <

+patching symbolic link dir/foo

+EOF

+

+cat > bad-symlink-target1.diff <

+diff --git a/bar b/bar

+new file mode 120000

+index 0000000..cad2309

+--- /dev/null

++++ b/bar

+@@ -0,0 +1 @@

++/bar

+\ No newline at end of file

+EOF

+

+check 'patch -p1 < bad-symlink-target1.diff || echo "Status: $?"' <

+patching symbolic link bar

+symbolic link target '/bar' is invalid

+Status: 2

+EOF

+

+cat > bad-symlink-target2.diff <

+diff --git a/baz b/baz

+new file mode 120000

+index 0000000..cad2309

+--- /dev/null

++++ b/baz

+@@ -0,0 +1 @@

++../baz

+\ No newline at end of file

+EOF

+

+check 'patch -p1 < bad-symlink-target2.diff || echo "Status: $?"' <

+patching symbolic link baz

+symbolic link target '../baz' is invalid

+Status: 2

+EOF

+

+# --------------------------------------------------------------

+

 # The backup file of a new symlink is an empty regular file.

 check 'patch -p1 --backup < create-symlink.diff || echo "Status: $?"' <