Re: [PATCH 7/7] verifiers: Verify after decompression

[Vladimir 'phcoder' Serbinenko]

Verifying after decompression is a bad security practice. It relies on decompression having no security holes. Given how complex decompression is, this is almost guaranteed to be false.

Le mer. 13 mars 2024, 18:08, Ross Lagerwall via Grub-devel <grub-devel@gnu.org> a écrit :

It is convenient and common to have binaries stored in gzip archives
(e.g. xen.gz). Verification should be run after decompression rather
than before so reorder the file filter list as appropriate.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
---
 include/grub/file.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/grub/file.h b/include/grub/file.h
index a5bf3a792d6f..a1ef3582bc7b 100644
--- a/include/grub/file.h
+++ b/include/grub/file.h
@@ -182,10 +182,10 @@ extern grub_disk_read_hook_t EXPORT_VAR(grub_file_progress_hook);
 /* Filters with lower ID are executed first.  */
 typedef enum grub_file_filter_id
   {
-    GRUB_FILE_FILTER_VERIFY,
     GRUB_FILE_FILTER_GZIO,
     GRUB_FILE_FILTER_XZIO,
     GRUB_FILE_FILTER_LZOPIO,
+    GRUB_FILE_FILTER_VERIFY,
     GRUB_FILE_FILTER_MAX,
     GRUB_FILE_FILTER_COMPRESSION_FIRST = GRUB_FILE_FILTER_GZIO,
     GRUB_FILE_FILTER_COMPRESSION_LAST = GRUB_FILE_FILTER_LZOPIO,
--
2.43.0


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