[iot] Support reading ATAP certificate UUID from keymaster

Add API and IPC calls to read the ATAP certificate UUID from keymaster.
Also rename const local variables to the standard convention.
This cherry-picked the CL 649562 from trusty/external/trusty.

Bug: 76211194

Change-Id: I98ab68180c3855e07884994dc20b879f0b59965d
Signed-off-by: Haoran.Wang <elven.wang@nxp.com>

3 files changed, 37 insertions, 5 deletions

diff --git a/include/interface/keymaster/keymaster.h b/include/interface/keymaster/keymaster.h
index fa60a1aeb5..7b18a64f36 100644
--- a/include/interface/keymaster/keymaster.h
+++ b/include/interface/keymaster/keymaster.h
@@ -61,6 +61,7 @@ enum keymaster_command {
     KM_ATAP_SET_CA_RESPONSE_BEGIN      = (0x5000 << KEYMASTER_REQ_SHIFT),
     KM_ATAP_SET_CA_RESPONSE_UPDATE     = (0x6000 << KEYMASTER_REQ_SHIFT),
     KM_ATAP_SET_CA_RESPONSE_FINISH     = (0x7000 << KEYMASTER_REQ_SHIFT),
+    KM_ATAP_READ_UUID                  = (0x8000 << KEYMASTER_REQ_SHIFT),
 };
 
 typedef enum {
diff --git a/include/trusty/keymaster.h b/include/trusty/keymaster.h
index e69527e0fa..beb2ff9578 100644
--- a/include/trusty/keymaster.h
+++ b/include/trusty/keymaster.h
@@ -108,4 +108,13 @@ int trusty_atap_get_ca_request(const uint8_t *operation_start,
 int trusty_atap_set_ca_response(const uint8_t *ca_response,
                                 uint32_t ca_response_size);
 
+/*
+* Reads the UUID from the certificate of the last provisioned attestation
+* credentials as a c-string into |*uuid_p|. Caller takes ownership of
+* |*uuid_p|. Returns one of trusty_err.
+*
+* @uuid_p: location of newly allocated UUID c-string
+*/
+int trusty_atap_read_uuid_str(char **uuid_p);
+
 #endif /* TRUSTY_KEYMASTER_H_ */
diff --git a/lib/trusty/ql-tipc/keymaster.c b/lib/trusty/ql-tipc/keymaster.c
index d62ed4aeb2..e0b8217262 100644
--- a/lib/trusty/ql-tipc/keymaster.c
+++ b/lib/trusty/ql-tipc/keymaster.c
@@ -33,8 +33,9 @@
 static struct trusty_ipc_chan km_chan;
 static bool initialized;
 static int trusty_km_version = 2;
-static const size_t max_ca_request_size = 10000;
-static const size_t max_send_size = 4000;
+static const size_t kMaxCaRequestSize = 10000;
+static const size_t kMaxSendSize = 4000;
+static const size_t kUuidSize = 32;
 
 #ifndef MIN
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
@@ -417,11 +418,11 @@ int trusty_atap_get_ca_request(const uint8_t *operation_start,
                                uint8_t **ca_request_p,
                                uint32_t *ca_request_size_p)
 {
-    *ca_request_p = trusty_calloc(1, max_ca_request_size);
+    *ca_request_p = trusty_calloc(1, kMaxCaRequestSize);
     if (!*ca_request_p) {
         return TRUSTY_ERR_NO_MEMORY;
     }
-    *ca_request_size_p = max_ca_request_size;
+    *ca_request_size_p = kMaxCaRequestSize;
     int rc = trusty_send_raw_buffer(KM_ATAP_GET_CA_REQUEST, operation_start,
                                     operation_start_size, *ca_request_p,
                                     ca_request_size_p);
@@ -448,7 +449,7 @@ int trusty_atap_set_ca_response(const uint8_t *ca_response,
 
     /* Send the CA Response message in chunks */
     while (bytes_sent < ca_response_size) {
-        send_size = MIN(max_send_size, ca_response_size - bytes_sent);
+        send_size = MIN(kMaxSendSize, ca_response_size - bytes_sent);
         rc = trusty_send_raw_buffer(KM_ATAP_SET_CA_RESPONSE_UPDATE,
                                     ca_response + bytes_sent, send_size,
                                     NULL, NULL);
@@ -461,3 +462,24 @@ int trusty_atap_set_ca_response(const uint8_t *ca_response,
     /* Tell Trusty Keymaster to parse the CA Response message */
     return km_do_tipc(KM_ATAP_SET_CA_RESPONSE_FINISH, true, NULL, 0, NULL, NULL);
 }
+
+
+int trusty_atap_read_uuid_str(char **uuid_p)
+{
+    *uuid_p = (char*) trusty_calloc(1, kUuidSize);
+
+    uint32_t response_size = kUuidSize;
+    int rc = km_do_tipc(KM_ATAP_READ_UUID, true, NULL, 0, *uuid_p,
+                        &response_size);
+    if (rc < 0) {
+        trusty_error("failed to read uuid: %d\n", rc);
+        trusty_free(*uuid_p);
+        return rc;
+    }
+    if (response_size != kUuidSize) {
+        trusty_error("keymaster returned wrong uuid size: %d\n", response_size);
+        trusty_free(*uuid_p);
+        rc = TRUSTY_ERR_GENERIC;
+    }
+    return rc;
+}