From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Sat, 19 Nov 2022 19:37:50 +0000 (+0100)
Subject: libblkid: exfat: validate more fields
X-Git-Tag: v2.39-rc1~415^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1a73b23e30cb62554d85d3bc85261b30d5bd7b27;p=thirdparty%2Futil-linux.git

libblkid: exfat: validate more fields
---

diff --git a/libblkid/src/superblocks/exfat.c b/libblkid/src/superblocks/exfat.c
index 003c08f6f4..c07054ac43 100644
--- a/libblkid/src/superblocks/exfat.c
+++ b/libblkid/src/superblocks/exfat.c
@@ -167,6 +167,16 @@ static int probe_exfat(blkid_probe pr, const struct blkid_idmag *mag)
 	if (!sb || !CLUSTER_SIZE(sb))
 		return errno ? -errno : BLKID_PROBE_NONE;
 
+	if (le16_to_cpu(sb->BootSignature) != 0xAA55)
+		return BLKID_PROBE_NONE;
+
+	if (memcmp(sb->JumpBoot, "\xEB\x76\x90", 3) != 0)
+		return BLKID_PROBE_NONE;
+
+	for (size_t i = 0; i < sizeof(sb->MustBeZero); i++)
+		if (sb->MustBeZero[i] != 0x00)
+			return BLKID_PROBE_NONE;
+
 	if (!exfat_validate_checksum(pr, sb))
 		return BLKID_PROBE_NONE;