ima: platform-independent hash value

For remote attestion it is important for the ima measurement values to
be platform-independent.  Therefore integer fields to be hashed must be
converted to canonical format.

Link: http://lkml.kernel.org/r/1480554346-29071-11-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Andreas Steffen <andreas.steffen@strongswan.org>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

security/integrity/ima/ima_crypto.c

@@ -477,11 +477,13 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 		u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
 		u8 *data_to_hash = field_data[i].data;
 		u32 datalen = field_data[i].len;
+		u32 datalen_to_hash =
+		    !ima_canonical_fmt ? datalen : cpu_to_le32(datalen);
 
 		if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 			rc = crypto_shash_update(shash,
-						(const u8 *) &field_data[i].len,
-						sizeof(field_data[i].len));
+						(const u8 *) &datalen_to_hash,
+						sizeof(datalen_to_hash));
 			if (rc)
 				break;
 		} else if (strcmp(td->fields[i]->field_id, "n") == 0) {