recipes: kernel/generic: Bump release number

[dragora.git] / patches / patch / Fix_arbitrary_command_execution_in_ed-style_patches.patch

From 123eaff0d5d1aebe128295959435b9ca5909c26d Mon Sep 17 00:00:00 2001
From: Andreas Gruenbacher <agruen@gnu.org>
Date: Fri, 6 Apr 2018 12:14:49 +0200
Subject: Fix arbitrary command execution in ed-style patches
 (CVE-2018-1000156)

* src/pch.c (do_ed_script): Write ed script to a temporary file instead
of piping it to ed: this will cause ed to abort on invalid commands
instead of rejecting them and carrying on.
* tests/ed-style: New test case.
* tests/Makefile.am (TESTS): Add test case.
---
 src/pch.c         | 91 ++++++++++++++++++++++++++++++++++++++++---------------
 tests/Makefile.am |  1 +
 tests/ed-style    | 41 +++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 25 deletions(-)
 create mode 100644 tests/ed-style

diff --git a/src/pch.c b/src/pch.c
index 0c5cc26..4fd5a05 100644
--- a/src/pch.c
+++ b/src/pch.c
@@ -33,6 +33,7 @@
 # include <io.h>
 #endif
 #include <safe.h>
+#include <sys/wait.h>
 
 #define INITHUNKMAX 125                        /* initial dynamic allocation size */
 
@@ -2389,24 +2390,28 @@ do_ed_script (char const *inname, char const *outname,
     static char const editor_program[] = EDITOR_PROGRAM;
 
     file_offset beginning_of_this_line;
-    FILE *pipefp = 0;
     size_t chars_read;
+    FILE *tmpfp = 0;
+    char const *tmpname;
+    int tmpfd;
+    pid_t pid;
+
+    if (! dry_run && ! skip_rest_of_patch)
+      {
+       /* Write ed script to a temporary file.  This causes ed to abort on
+          invalid commands such as when line numbers or ranges exceed the
+          number of available lines.  When ed reads from a pipe, it rejects
+          invalid commands and treats the next line as a new command, which
+          can lead to arbitrary command execution.  */
+
+       tmpfd = make_tempfile (&tmpname, 'e', NULL, O_RDWR | O_BINARY, 0);
+       if (tmpfd == -1)
+         pfatal ("Can't create temporary file %s", quotearg (tmpname));
+       tmpfp = fdopen (tmpfd, "w+b");
+       if (! tmpfp)
+         pfatal ("Can't open stream for file %s", quotearg (tmpname));
+      }
 
-    if (! dry_run && ! skip_rest_of_patch) {
-       int exclusive = *outname_needs_removal ? 0 : O_EXCL;
-       if (inerrno != ENOENT)
-         {
-           *outname_needs_removal = true;
-           copy_file (inname, outname, 0, exclusive, instat.st_mode, true);
-         }
-       sprintf (buf, "%s %s%s", editor_program,
-                verbosity == VERBOSE ? "" : "- ",
-                outname);
-       fflush (stdout);
-       pipefp = popen(buf, binary_transput ? "wb" : "w");
-       if (!pipefp)
-         pfatal ("Can't open pipe to %s", quotearg (buf));
-    }
     for (;;) {
        char ed_command_letter;
        beginning_of_this_line = file_tell (pfp);
@@ -2417,14 +2422,14 @@ do_ed_script (char const *inname, char const *outname,
        }
        ed_command_letter = get_ed_command_letter (buf);
        if (ed_command_letter) {
-           if (pipefp)
-               if (! fwrite (buf, sizeof *buf, chars_read, pipefp))
+           if (tmpfp)
+               if (! fwrite (buf, sizeof *buf, chars_read, tmpfp))
                    write_fatal ();
            if (ed_command_letter != 'd' && ed_command_letter != 's') {
                p_pass_comments_through = true;
                while ((chars_read = get_line ()) != 0) {
-                   if (pipefp)
-                       if (! fwrite (buf, sizeof *buf, chars_read, pipefp))
+                   if (tmpfp)
+                       if (! fwrite (buf, sizeof *buf, chars_read, tmpfp))
                            write_fatal ();
                    if (chars_read == 2  &&  strEQ (buf, ".\n"))
                        break;
@@ -2437,13 +2442,49 @@ do_ed_script (char const *inname, char const *outname,
            break;
        }
     }
-    if (!pipefp)
+    if (!tmpfp)
       return;
-    if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, pipefp) == 0
-       || fflush (pipefp) != 0)
+    if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, tmpfp) == 0
+       || fflush (tmpfp) != 0)
       write_fatal ();
-    if (pclose (pipefp) != 0)
-      fatal ("%s FAILED", editor_program);
+
+    if (lseek (tmpfd, 0, SEEK_SET) == -1)
+      pfatal ("Can't rewind to the beginning of file %s", quotearg (tmpname));
+
+    if (! dry_run && ! skip_rest_of_patch) {
+       int exclusive = *outname_needs_removal ? 0 : O_EXCL;
+       *outname_needs_removal = true;
+       if (inerrno != ENOENT)
+         {
+           *outname_needs_removal = true;
+           copy_file (inname, outname, 0, exclusive, instat.st_mode, true);
+         }
+       sprintf (buf, "%s %s%s", editor_program,
+                verbosity == VERBOSE ? "" : "- ",
+                outname);
+       fflush (stdout);
+
+       pid = fork();
+       if (pid == -1)
+         pfatal ("Can't fork");
+       else if (pid == 0)
+         {
+           dup2 (tmpfd, 0);
+           execl ("/bin/sh", "sh", "-c", buf, (char *) 0);
+           _exit (2);
+         }
+       else
+         {
+           int wstatus;
+           if (waitpid (pid, &wstatus, 0) == -1
+               || ! WIFEXITED (wstatus)
+               || WEXITSTATUS (wstatus) != 0)
+             fatal ("%s FAILED", editor_program);
+         }
+    }
+
+    fclose (tmpfp);
+    safe_unlink (tmpname);
 
     if (ofp)
       {
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 6b6df63..16f8693 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -32,6 +32,7 @@ TESTS = \
        crlf-handling \
        dash-o-append \
        deep-directories \
+       ed-style \
        empty-files \
        false-match \
        fifo \
diff --git a/tests/ed-style b/tests/ed-style
new file mode 100644
index 0000000..d8c0689
--- /dev/null
+++ b/tests/ed-style
@@ -0,0 +1,41 @@
+# Copyright (C) 2018 Free Software Foundation, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# in any medium, are permitted without royalty provided the copyright
+# notice and this notice are preserved.
+
+. $srcdir/test-lib.sh
+
+require cat
+use_local_patch
+use_tmpdir
+
+# ==============================================================
+
+cat > ed1.diff <<EOF
+0a
+foo
+.
+EOF
+
+check 'patch -e foo -i ed1.diff' <<EOF
+EOF
+
+check 'cat foo' <<EOF
+foo
+EOF
+
+cat > ed2.diff <<EOF
+1337a
+r !echo bar
+,p
+EOF
+
+check 'patch -e foo -i ed2.diff 2> /dev/null || echo "Status: $?"' <<EOF
+?
+Status: 2
+EOF
+
+check 'cat foo' <<EOF
+foo
+EOF
-- 
cgit v1.0-41-gc330