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 <<EOF
+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: $?"' <<EOF
+patching symbolic link dir/foo
+EOF
+
+cat > bad-symlink-target1.diff <<EOF
+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: $?"' <<EOF
+patching symbolic link bar
+symbolic link target '/bar' is invalid
+Status: 2
+EOF
+
+cat > bad-symlink-target2.diff <<EOF
+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: $?"' <<EOF
+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: $?"' <<EOF