From 8062d40755bc42b068f506920f3ce33234cdfaca Mon Sep 17 00:00:00 2001
From: Juha Ylinen <juha.ylinen@nordicsemi.no>
Date: Tue, 13 Jun 2023 16:02:12 +0300
Subject: [PATCH] net: lib: nrf_provisioning: Fix AT command

Fix error when AT%KEYGEN command is retried after increasing
buffer size. Security tag must be cleared before new KEYGEN
command.

Add command to delete credential
Update documentation in nrf_provisioning_at.h

Signed-off-by: Juha Ylinen <juha.ylinen@nordicsemi.no>
---
 .../include/nrf_provisioning_at.h             | 21 ++++++++++++-------
 .../src/nrf_provisioning_at.c                 |  5 +++++
 .../src/nrf_provisioning_codec.c              | 12 ++++++++++-
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/subsys/net/lib/nrf_provisioning/include/nrf_provisioning_at.h b/subsys/net/lib/nrf_provisioning/include/nrf_provisioning_at.h
index 13c420583c34..26d39ba08a9f 100644
--- a/subsys/net/lib/nrf_provisioning/include/nrf_provisioning_at.h
+++ b/subsys/net/lib/nrf_provisioning/include/nrf_provisioning_at.h
@@ -53,7 +53,7 @@ bool nrf_provisioning_at_cmee_is_active(void);
 /**
  * @brief Sets mobile termination error reporting to a given state.
  *
- * @param state Buffer to receive the time into.
+ * @param state State for error reporting.
  *
  * @returns  Zero on success, negative error code on failure.
  */
@@ -62,9 +62,6 @@ int nrf_provisioning_at_cmee_control(enum nrf_provisioning_at_cmee_state state);
 /**
  * @brief Enables mobile termination error reporting state.
  *
- * @param buff Buffer to receive the time into.
- * @param size Buffer size.
- *
  * @returns  Previous state
  */
 bool nrf_provisioning_at_cmee_enable(void);
@@ -72,15 +69,25 @@ bool nrf_provisioning_at_cmee_enable(void);
 /**
  * @brief Send any AT command.
  *
- * @param buff Buffer to receive the response into.
- * @param size Buffer size.
- * @param size Command to be send.
+ * @param resp Buffer to receive the response into.
+ * @param resp_sz Buffer size.
+ * @param cmd AT command to be send.
  *
  * @returns Zero on success, negative error code on failure or positive error code when CMEE code
  * needs to be checked.
  */
 int nrf_provisioning_at_cmd(void *resp, size_t resp_sz, const char *cmd);
 
+/**
+ * @brief Delete credential.
+ *
+ * @param tag The security tag of the credential.
+ * @param type The credential type.
+ *
+ * @returns  Zero on success, negative error code on failure.
+ */
+int nrf_provisioning_at_del_credential(int sec_tag, int type);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_at.c b/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_at.c
index 114f28606b9d..d42b11a4a735 100644
--- a/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_at.c
+++ b/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_at.c
@@ -69,3 +69,8 @@ int nrf_provisioning_at_cmd(void *resp, size_t resp_sz, const char *cmd)
 {
 	return nrf_modem_at_cmd(resp, resp_sz, "%s", cmd);
 }
+
+int nrf_provisioning_at_del_credential(int tag, int type)
+{
+	return nrf_modem_at_printf("AT%%CMNG=3,%d,%d", tag, type);
+}
diff --git a/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_codec.c b/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_codec.c
index 87fc0eaaa0ac..4e15ad25aa10 100644
--- a/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_codec.c
+++ b/subsys/net/lib/nrf_provisioning/src/nrf_provisioning_codec.c
@@ -5,6 +5,7 @@
  */
 
 #include <string.h>
+#include <stdio.h>
 
 #include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
@@ -287,10 +288,19 @@ static int exec_at_cmd(struct command *cmd_req, struct cdc_out_fmt_data *out)
 		ret = nrf_provisioning_at_cmd(resp, resp_sz, out->at_buff);
 
 		if (ret == -E2BIG) {
+			int tag = 0;
+			int type = 0;
+
 			LOG_DBG("Buffer too small for AT response, retrying");
 			k_free(resp);
 			resp = NULL;
-
+			if (sscanf(out->at_buff, "AT%%KEYGEN=%d,%d,%*s", &tag, &type) == 2) {
+				LOG_DBG("Clear sec_tag %d, type %d", tag, type);
+				ret = nrf_provisioning_at_del_credential(tag, type);
+				if (ret < 0) {
+					LOG_ERR("AT cmd failed, error: %d", ret);
+				}
+			}
 			resp_sz *= 2; /* Previous size wasn't sufficient */
 			if (resp_sz > AT_RESP_MAX_SIZE) {
 				LOG_ERR("Key or CSR too big");