fs/ufs: Fix a heap OOB write

grub_strcpy() was used to copy a symlink name from the filesystem
image to a heap allocated buffer. This led to a OOB write to adjacent
heap allocations. Fix by using grub_strlcpy().

Fixes: CVE-2024-45781
Reported-by: B Horn <b@horn.uk>
Signed-off-by: B Horn <b@horn.uk>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/grub-core/fs/ufs.c b/grub-core/fs/ufs.c
index a354c92d936aa10b96e9e5b26dc57c13e2360cac..01235101b49b4a11b5a162ccc448326678957181 100644 (file)
--- a/grub-core/fs/ufs.c
+++ b/grub-core/fs/ufs.c
@@ -463,7 +463,7 @@ grub_ufs_lookup_symlink (struct grub_ufs_data *data, int ino)
   /* Check against zero is paylindromic, no need to swap.  */
   if (data->inode.nblocks == 0
       && INODE_SIZE (data) <= sizeof (data->inode.symlink))
-    grub_strcpy (symlink, (char *) data->inode.symlink);
+    grub_strlcpy (symlink, (char *) data->inode.symlink, sz);
   else
     {
       if (grub_ufs_read_file (data, 0, 0, 0, sz, symlink) < 0)