1From b88a82e78cdd0ab8e0339c1c3f9564c4d8c0c969 Mon Sep 17 00:00:00 2001
2From: Daniel Axtens <dja@axtens.net>
3Date: Mon, 18 Jan 2021 17:17:16 +1100
4Subject: [PATCH] fs/btrfs: Validate the number of stripes/parities in RAID5/6
5
6This prevents a divide by zero if nstripes == nparities, and
7also prevents propagation of invalid values if nstripes ends up
8less than nparities.
9
10Signed-off-by: Daniel Axtens <dja@axtens.net>
11Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
12Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
13---
14 grub-core/fs/btrfs.c | 3 +++
15 1 file changed, 3 insertions(+)
16
17diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
18index 2b65bd5..e4e87ba 100644
19--- a/grub-core/fs/btrfs.c
20+++ b/grub-core/fs/btrfs.c
21@@ -1076,6 +1076,9 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr,
22 	       * stripen is computed without the parities
23 	       * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.).
24 	       */
25+	      if (nparities >= nstripes)
26+		return grub_error (GRUB_ERR_BAD_FS,
27+				   "invalid RAID5/6: nparities >= nstripes");
28 	      high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen);
29
30 	      /*
31--
322.14.2
33
34