[U-Boot] [PATCH v2 15/15] avb_verify: support using OP-TEE TA AVB
Jens Wiklander
jens.wiklander at linaro.org
Thu Aug 23 10:43:34 UTC 2018
With CONFIG_OPTEE_TA_AVB use the trusted application AVB provided by
OP-TEE to manage rollback indexes and device lock status.
Signed-off-by: Jens Wiklander <jens.wiklander at linaro.org>
---
common/avb_verify.c | 132 ++++++++++++++++++++++++++++++++++++++++++-
doc/README.avb2 | 13 +++++
include/avb_verify.h | 4 ++
3 files changed, 148 insertions(+), 1 deletion(-)
diff --git a/common/avb_verify.c b/common/avb_verify.c
index 20e35ade3029..a50c05bf7847 100644
--- a/common/avb_verify.c
+++ b/common/avb_verify.c
@@ -10,6 +10,8 @@
#include <image.h>
#include <malloc.h>
#include <part.h>
+#include <tee.h>
+#include <tee/optee_ta_avb.h>
const unsigned char avb_root_pub[1032] = {
0x0, 0x0, 0x10, 0x0, 0x55, 0xd9, 0x4, 0xad, 0xd8, 0x4,
@@ -594,6 +596,79 @@ static AvbIOResult validate_vbmeta_public_key(AvbOps *ops,
return AVB_IO_RESULT_OK;
}
+#ifdef CONFIG_OPTEE_TA_AVB
+static void uuid_to_octets(u8 d[TEE_UUID_LEN],
+ const struct tee_optee_ta_uuid *s)
+{
+ d[0] = s->time_low >> 24;
+ d[1] = s->time_low >> 16;
+ d[2] = s->time_low >> 8;
+ d[3] = s->time_low;
+ d[4] = s->time_mid >> 8;
+ d[5] = s->time_mid;
+ d[6] = s->time_hi_and_version >> 8;
+ d[7] = s->time_hi_and_version;
+ memcpy(d + 8, s->clock_seq_and_node, sizeof(s->clock_seq_and_node));
+}
+
+static int get_open_session(struct AvbOpsData *ops_data)
+{
+ struct udevice *tee = NULL;
+
+ while (!ops_data->tee) {
+ const struct tee_optee_ta_uuid uuid = TA_AVB_UUID;
+ struct tee_open_session_arg arg;
+ int rc;
+
+ tee = tee_find_device(tee, NULL, NULL, NULL);
+ if (!tee)
+ return -ENODEV;
+
+ memset(&arg, 0, sizeof(arg));
+ uuid_to_octets(arg.uuid, &uuid);
+ rc = tee_open_session(tee, &arg, 0, NULL);
+ if (!rc) {
+ ops_data->tee = tee;
+ ops_data->session = arg.session;
+ }
+ }
+
+ return 0;
+}
+
+static AvbIOResult invoke_func(struct AvbOpsData *ops_data, u32 func,
+ ulong num_param, struct tee_param *param)
+{
+ struct tee_invoke_arg arg;
+
+ if (get_open_session(ops_data))
+ return AVB_IO_RESULT_ERROR_IO;
+
+ memset(&arg, 0, sizeof(arg));
+ arg.func = func;
+ arg.session = ops_data->session;
+
+ if (tee_invoke_func(ops_data->tee, &arg, num_param, param))
+ return AVB_IO_RESULT_ERROR_IO;
+ switch (arg.ret) {
+ case TEE_SUCCESS:
+ return AVB_IO_RESULT_OK;
+ case TEE_ERROR_OUT_OF_MEMORY:
+ return AVB_IO_RESULT_ERROR_OOM;
+ case TEE_ERROR_TARGET_DEAD:
+ /*
+ * The TA has paniced, close the session to reload the TA
+ * for the next request.
+ */
+ tee_close_session(ops_data->tee, ops_data->session);
+ ops_data->tee = NULL;
+ return AVB_IO_RESULT_ERROR_IO;
+ default:
+ return AVB_IO_RESULT_ERROR_IO;
+ }
+}
+#endif
+
/**
* read_rollback_index() - gets the rollback index corresponding to the
* location of given by @out_rollback_index.
@@ -609,6 +684,7 @@ static AvbIOResult read_rollback_index(AvbOps *ops,
size_t rollback_index_slot,
u64 *out_rollback_index)
{
+#ifndef CONFIG_OPTEE_TA_AVB
/* For now we always return 0 as the stored rollback index. */
printf("%s not supported yet\n", __func__);
@@ -616,6 +692,27 @@ static AvbIOResult read_rollback_index(AvbOps *ops,
*out_rollback_index = 0;
return AVB_IO_RESULT_OK;
+#else
+ AvbIOResult rc;
+ struct tee_param param[2];
+
+ if (rollback_index_slot >= TA_AVB_MAX_ROLLBACK_LOCATIONS)
+ return AVB_IO_RESULT_ERROR_NO_SUCH_VALUE;
+
+ memset(param, 0, sizeof(param));
+ param[0].attr = TEE_PARAM_ATTR_TYPE_VALUE_INPUT;
+ param[0].u.value.a = rollback_index_slot;
+ param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT;
+
+ rc = invoke_func(ops->user_data, TA_AVB_CMD_READ_ROLLBACK_INDEX,
+ ARRAY_SIZE(param), param);
+ if (rc)
+ return rc;
+
+ *out_rollback_index = (u64)param[1].u.value.a << 32 |
+ (u32)param[1].u.value.b;
+ return AVB_IO_RESULT_OK;
+#endif
}
/**
@@ -633,10 +730,27 @@ static AvbIOResult write_rollback_index(AvbOps *ops,
size_t rollback_index_slot,
u64 rollback_index)
{
+#ifndef CONFIG_OPTEE_TA_AVB
/* For now this is a no-op. */
printf("%s not supported yet\n", __func__);
return AVB_IO_RESULT_OK;
+#else
+ struct tee_param param[2];
+
+ if (rollback_index_slot >= TA_AVB_MAX_ROLLBACK_LOCATIONS)
+ return AVB_IO_RESULT_ERROR_NO_SUCH_VALUE;
+
+ memset(param, 0, sizeof(param));
+ param[0].attr = TEE_PARAM_ATTR_TYPE_VALUE_INPUT;
+ param[0].u.value.a = rollback_index_slot;
+ param[1].attr = TEE_PARAM_ATTR_TYPE_VALUE_INPUT;
+ param[1].u.value.a = (u32)(rollback_index >> 32);
+ param[1].u.value.b = (u32)rollback_index;
+
+ return invoke_func(ops->user_data, TA_AVB_CMD_WRITE_ROLLBACK_INDEX,
+ ARRAY_SIZE(param), param);
+#endif
}
/**
@@ -652,6 +766,7 @@ static AvbIOResult write_rollback_index(AvbOps *ops,
*/
static AvbIOResult read_is_device_unlocked(AvbOps *ops, bool *out_is_unlocked)
{
+#ifndef CONFIG_OPTEE_TA_AVB
/* For now we always return that the device is unlocked. */
printf("%s not supported yet\n", __func__);
@@ -659,6 +774,16 @@ static AvbIOResult read_is_device_unlocked(AvbOps *ops, bool *out_is_unlocked)
*out_is_unlocked = true;
return AVB_IO_RESULT_OK;
+#else
+ AvbIOResult rc;
+ struct tee_param param = { .attr = TEE_PARAM_ATTR_TYPE_VALUE_OUTPUT };
+
+ rc = invoke_func(ops->user_data, TA_AVB_CMD_READ_LOCK_STATE, 1, ¶m);
+ if (rc)
+ return rc;
+ *out_is_unlocked = !param.u.value.a;
+ return AVB_IO_RESULT_OK;
+#endif
}
/**
@@ -737,6 +862,11 @@ void avb_ops_free(AvbOps *ops)
ops_data = ops->user_data;
- if (ops_data)
+ if (ops_data) {
+#ifdef CONFIG_OPTEE_TA_AVB
+ if (ops_data->tee)
+ tee_close_session(ops_data->tee, ops_data->session);
+#endif
avb_free(ops_data);
+ }
}
diff --git a/doc/README.avb2 b/doc/README.avb2
index 120279fedbe2..a29cee1b6f50 100644
--- a/doc/README.avb2
+++ b/doc/README.avb2
@@ -18,6 +18,13 @@ Integrity of the bootloader (U-boot BLOB and environment) is out of scope.
For additional details check:
https://android.googlesource.com/platform/external/avb/+/master/README.md
+1.1. AVB using OP-TEE (optional)
+---------------------------------
+If AVB is configured to use OP-TEE (see 4. below) rollback indexes and
+device lock state are stored in RPMB. The RPMB partition is managed by
+OP-TEE (https://www.op-tee.org/) which is a secure OS leveraging ARM
+TrustZone.
+
2. AVB 2.0 U-BOOT SHELL COMMANDS
-----------------------------------
@@ -61,6 +68,12 @@ CONFIG_LIBAVB=y
CONFIG_AVB_VERIFY=y
CONFIG_CMD_AVB=y
+In addtion optionally if storing rollback indexes in RPMB with help of
+OP-TEE:
+CONFIG_TEE=y
+CONFIG_OPTEE=y
+CONFIG_OPTEE_TA_AVB=y
+CONFIG_SUPPORT_EMMC_RPMB=y
Then add `avb verify` invocation to your android boot sequence of commands,
e.g.:
diff --git a/include/avb_verify.h b/include/avb_verify.h
index eaa60f5393ef..a532a2331aea 100644
--- a/include/avb_verify.h
+++ b/include/avb_verify.h
@@ -27,6 +27,10 @@ struct AvbOpsData {
struct AvbOps ops;
int mmc_dev;
enum avb_boot_state boot_state;
+#ifdef CONFIG_OPTEE_TA_AVB
+ struct udevice *tee;
+ u32 session;
+#endif
};
struct mmc_part {
--
2.17.1
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