From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Mon, 26 Dec 2022 23:57:34 +0000 (+0000)
Subject: libblkid: bsd: add checksum support
X-Git-Tag: v2.39-rc1~353^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c8cc50647261cd7f8181c9390850c25e7a001d0d;p=thirdparty%2Futil-linux.git

libblkid: bsd: add checksum support
---

diff --git a/libblkid/src/partitions/bsd.c b/libblkid/src/partitions/bsd.c
index 7a0b23195e..ba120195ea 100644
--- a/libblkid/src/partitions/bsd.c
+++ b/libblkid/src/partitions/bsd.c
@@ -26,6 +26,18 @@
 #define BLKID_MAG_LASTOFFSET(_mag) \
 		 (BLKID_MAG_OFFSET(_mag) - (BLKID_MAG_SECTOR(_mag) << 9))
 
+static uint16_t bsd_checksum(const struct bsd_disklabel *l)
+{
+	uint16_t v, csum = 0;
+	const char *end = (const char *) (l + 1);
+
+	for (const char *c = (const char *) l; c < end; c += sizeof(uint16_t)) {
+		memcpy(&v, c, sizeof(v));
+		csum ^= v;
+	}
+	return csum ^ le16_to_cpu(l->d_checksum);
+}
+
 static int probe_bsd_pt(blkid_probe pr, const struct blkid_idmag *mag)
 {
 	struct bsd_disklabel *l;
@@ -52,6 +64,11 @@ static int probe_bsd_pt(blkid_probe pr, const struct blkid_idmag *mag)
 
 	l = (struct bsd_disklabel *) (data + BLKID_MAG_LASTOFFSET(mag));
 
+	if (!blkid_probe_verify_csum(pr, bsd_checksum(l), le16_to_cpu(l->d_checksum))) {
+		rc = BLKID_PROBE_NONE;
+		goto nothing;
+	}
+
 	ls = blkid_probe_get_partlist(pr);
 	if (!ls)
 		goto nothing;