git-localedef-check-magic

commit 56ea4bed7369f32e3c7c935f9e33ee38e9f78143
Author: Aurelien Jarno <aurelien@aurel32.net>
Date:   Sun Dec 5 11:51:17 2021 +0100

    localedef: check magic value on archive load [BZ #28650]

    localedef currently blindly trust the archive header. When passed an
    archive file with the wrong endianess, this leads to a segmentation
    fault:

      $ localedef --big-endian --list-archive /usr/lib/locale/locale-archive
      Segmentation fault (core dumped)

    When passed non-archive files, asserts are reported on the best case,
    but sometimes it can lead to a segmentation fault:

      $ localedef --list-archive /bin/true
      localedef: programs/locarchive.c:1643: show_archive_content: Assertion `used < GET (head->namehash_used)' failed.
      Aborted (core dumped)

      $ localedef --list-archive /usr/lib/locale/C.utf8/LC_COLLATE
      Segmentation fault (core dumped)

    This patch improves the user experience by looking at the magic value,
    which is always written, but never checked. It should still be possible
    to trigger a segmentation fault with crafted files, but this already
    catch many cases.

Gbp-Pq: Topic any
Gbp-Pq: Name git-localedef-check-magic.patch

diff --git a/locale/programs/locarchive.c b/locale/programs/locarchive.c
index 6bb189ae375c01f567bdcf5d5b837541de2c3177..28517f2e7bf8e63b894fcbb0d85cedd13f25e1aa 100644 (file)
--- a/locale/programs/locarchive.c
+++ b/locale/programs/locarchive.c
@@ -655,6 +655,13 @@ open_archive (struct locarhandle *ah, bool readonly)
       error (EXIT_FAILURE, errno, _("cannot read archive header"));
     }
 
+  /* Check the magic value */
+  if (GET (head.magic) != AR_MAGIC)
+    {
+      (void) lockf64 (fd, F_ULOCK, sizeof (struct locarhead));
+      error (EXIT_FAILURE, 0, _("bad magic value in archive header"));
+    }
+
   ah->fd = fd;
   ah->mmaped = st.st_size;