libblkid: luks: add checksum support

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>

diff --git a/libblkid/src/superblocks/luks.c b/libblkid/src/superblocks/luks.c
index 0230b349267081966641122a0dbbecc57df47e6d..a3aa84c5ea6df21e72f2ec7738e78d63f388dbfd 100644 (file)
--- a/libblkid/src/superblocks/luks.c
+++ b/libblkid/src/superblocks/luks.c
@@ -17,6 +17,7 @@
 #include <stdint.h>
 
 #include "superblocks.h"
+#include "sha256.h"
 
 #define LUKS_CIPHERNAME_L              32
 #define LUKS_CIPHERMODE_L              32
@@ -96,6 +97,23 @@ static int luks_attributes(blkid_probe pr, struct luks2_phdr *header, uint64_t o
        return BLKID_PROBE_OK;
 }
 
+static int luks_verify_csum(blkid_probe pr, struct luks2_phdr *header)
+{
+       if (strncmp(header->checksum_alg, "sha256", sizeof(header->checksum_alg)))
+               return 1;
+
+       uint64_t header_size = be64_to_cpu(header->hdr_size);
+       unsigned char *checksummed = blkid_probe_get_buffer(pr, 0, header_size);
+       if (!checksummed)
+               return 0;
+       memset(checksummed + offsetof(struct luks2_phdr, csum), 0, LUKS2_CHECKSUM_L);
+
+       unsigned char csum[32];
+       ul_SHA256(csum, checksummed, header_size);
+
+       return blkid_probe_verify_csum(pr, 1, !memcmp(header->csum, csum, 32));
+}
+
 static int probe_luks(blkid_probe pr, const struct blkid_idmag *mag __attribute__((__unused__)))
 {
        struct luks2_phdr *header;
@@ -106,6 +124,8 @@ static int probe_luks(blkid_probe pr, const struct blkid_idmag *mag __attribute_
                return errno ? -errno : BLKID_PROBE_NONE;
 
        if (!memcmp(header->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
+               if (!luks_verify_csum(pr, header))
+                       return BLKID_PROBE_NONE;
                /* LUKS primary header was found. */
                return luks_attributes(pr, header, 0);
        }

diff --git a/tests/ts/blkid/images-fs/luks2.img.xz b/tests/ts/blkid/images-fs/luks2.img.xz
index 997fb0483d6e1f4827543f9267e8cf830898144f..311a4e865608e81dcc79f1e0351558c0d1a9f796 100644 (file)
Binary files a/tests/ts/blkid/images-fs/luks2.img.xz and b/tests/ts/blkid/images-fs/luks2.img.xz differ