From: Richard Weinberger <richard@nod.at>
Date: Tue, 14 Jun 2016 08:12:16 +0000 (+0200)
Subject: ubi: Check whether the Fastmap anchor matches the super block
X-Git-Tag: v4.8-rc1~39^2~2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=5283ec72b0cca44ccea63070f6954fd8675b9ac4;p=linux.git

ubi: Check whether the Fastmap anchor matches the super block

This helps to detect cases where an user copies an UBI image to
another target with different bad blocks.

Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 12bdb0902327..b66cb3e2a5f0 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -975,6 +975,13 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
 			goto free_hdr;
 		}
 
+		if (i == 0 && pnum != fm_anchor) {
+			ubi_err(ubi, "Fastmap anchor PEB mismatch: PEB: %i vs. %i",
+				pnum, fm_anchor);
+			ret = UBI_BAD_FASTMAP;
+			goto free_hdr;
+		}
+
 		ret = ubi_io_read_ec_hdr(ubi, pnum, ech, 0);
 		if (ret && ret != UBI_IO_BITFLIPS) {
 			ubi_err(ubi, "unable to read fastmap block# %i EC (PEB: %i)",