From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Mon, 24 Oct 2022 14:48:18 +0000 (+0200)
Subject: libblkid: cramfs: handle cross-endianess for checksums
X-Git-Tag: v2.39-rc1~456^2~3
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3d074d422131f3758b3a4b3923097ba602ba665f;p=thirdparty%2Futil-linux.git

libblkid: cramfs: handle cross-endianess for checksums
---

diff --git a/libblkid/src/superblocks/cramfs.c b/libblkid/src/superblocks/cramfs.c
index 094367d4c6..76b5611e9a 100644
--- a/libblkid/src/superblocks/cramfs.c
+++ b/libblkid/src/superblocks/cramfs.c
@@ -37,16 +37,31 @@ struct cramfs_super
 
 #define CRAMFS_FLAG_FSID_VERSION_2	0x00000001	/* fsid version #2 */
 
+static int cramfs_is_little_endian(const struct blkid_idmag *mag)
+{
+	assert(mag->len == 4);
+	return memcmp(mag->magic, "\x45\x3d\xcd\x28", 4) == 0;
+}
+
+static uint32_t cfs32_to_cpu(int le, uint32_t value)
+{
+	if (le)
+		return le32_to_cpu(value);
+	else
+		return be32_to_cpu(value);
+}
+
 static int cramfs_verify_csum(blkid_probe pr, const struct blkid_idmag *mag, struct cramfs_super *cs)
 {
 	uint32_t crc, expected, csummed_size;
 	unsigned char *csummed;
+	int le = cramfs_is_little_endian(mag);
 
-	if (!(cs->flags & CRAMFS_FLAG_FSID_VERSION_2))
+	if (!(cfs32_to_cpu(le, cs->flags) & CRAMFS_FLAG_FSID_VERSION_2))
 		return 1;
 
-	expected = le32_to_cpu(cs->info.crc);
-	csummed_size = le32_to_cpu(cs->size);
+	expected = cfs32_to_cpu(le, cs->info.crc);
+	csummed_size = cfs32_to_cpu(le, cs->size);
 
 	if (csummed_size > (1 << 16)
 	    || csummed_size < sizeof(struct cramfs_super))