From: Andrei Borzenkov <arvidjaar@gmail.com>
Date: Thu, 18 Jun 2015 17:09:47 +0000 (+0300)
Subject: fat: fix handling of "." and ".." directory entries
X-Git-Tag: 2.02-beta3~286
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7bb7140df2b6fd5c1fee6c47488724bc256e957a;p=thirdparty%2Fgrub.git

fat: fix handling of "." and ".." directory entries

Emulate dot and dotdot in root directory. For other directories do not
add separator between name and extension for these two special entries.

Closes: 45335
---

diff --git a/grub-core/fs/fat.c b/grub-core/fs/fat.c
index 71537ff44..827708c18 100644
--- a/grub-core/fs/fat.c
+++ b/grub-core/fs/fat.c
@@ -829,7 +829,9 @@ grub_fat_iterate_dir_next (grub_disk_t disk, struct grub_fat_data *data,
 	      i--;
 	    }
 
-	  *filep++ = '.';
+	  /* XXX should we check that dir position is 0 or 1? */
+	  if (i > 2 || filep[0] != '.' || (i == 2 && filep[1] != '.'))
+	    *filep++ = '.';
 
 	  for (i = 8; i < 11 && ctxt->dir.name[i]; i++)
 	    *filep++ = grub_tolower (ctxt->dir.name[i]);
@@ -871,9 +873,31 @@ grub_fat_find_dir (grub_disk_t disk, struct grub_fat_data *data,
       return 0;
     }
 
-  /* Extract a directory name.  */
-  while (*path == '/')
-    path++;
+  do
+    {
+      /* Extract a directory name.  */
+      while (*path == '/')
+	path++;
+
+      /* Emulate special "." and ".." entries in root directory */
+      if (data->file_cluster == data->root_cluster)
+	{
+	  if (*path != '.')
+	    break;
+	  if (!path[1] || path[1] == '/')
+	    {
+	      path++;
+	      continue;
+	    }
+	  if (path[1] == '.' && (!path[2] || path[2] == '/'))
+	    {
+	      path += 2;
+	      continue;
+	    }
+	}
+      break;
+    }
+  while (1);
 
   dirp = grub_strchr (path, '/');
   if (dirp)
@@ -935,6 +959,9 @@ grub_fat_find_dir (grub_disk_t disk, struct grub_fat_data *data,
 	  data->file_size = grub_le_to_cpu32 (ctxt.dir.file_size);
 	  data->file_cluster = ((grub_le_to_cpu16 (ctxt.dir.first_cluster_high) << 16)
 				| grub_le_to_cpu16 (ctxt.dir.first_cluster_low));
+	  /* If directory points to root, starting cluster is 0 */
+	  if (!data->file_cluster)
+	    data->file_cluster = data->root_cluster;
 #endif
 	  data->cur_cluster_num = ~0U;