Merge pull request #8693 from Ryan-Everett-arm/implement-key-slot-mutex
Implement the key slot mutex
diff --git a/include/mbedtls/threading.h b/include/mbedtls/threading.h
index b504233..b4e0502 100644
--- a/include/mbedtls/threading.h
+++ b/include/mbedtls/threading.h
@@ -100,6 +100,20 @@
extern mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex;
#endif /* MBEDTLS_HAVE_TIME_DATE && !MBEDTLS_PLATFORM_GMTIME_R_ALT */
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+/*
+ * A mutex used to make the PSA subsystem thread safe.
+ *
+ * key_slot_mutex protects the registered_readers and
+ * state variable for all key slots in &global_data.key_slots.
+ *
+ * This mutex must be held when any read from or write to a state or
+ * registered_readers field is performed, i.e. when calling functions:
+ * psa_key_slot_state_transition(), psa_register_read(), psa_unregister_read(),
+ * psa_key_slot_has_readers() and psa_wipe_key_slot(). */
+extern mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex;
+#endif
+
#endif /* MBEDTLS_THREADING_C */
#ifdef __cplusplus
diff --git a/include/psa/crypto_values.h b/include/psa/crypto_values.h
index 8d30bf0..90d98fd 100644
--- a/include/psa/crypto_values.h
+++ b/include/psa/crypto_values.h
@@ -279,6 +279,11 @@
* to read from a resource. */
#define PSA_ERROR_INSUFFICIENT_DATA ((psa_status_t)-143)
+/** This can be returned if a function can no longer operate correctly.
+ * For example, if an essential initialization operation failed or
+ * a mutex operation failed. */
+#define PSA_ERROR_SERVICE_FAILURE ((psa_status_t)-144)
+
/** The key identifier is not valid. See also :ref:\`key-handles\`.
*/
#define PSA_ERROR_INVALID_HANDLE ((psa_status_t)-136)
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index 1edd63e..7b16724 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -117,6 +117,8 @@
0)
/** Test whether a key slot has any registered readers.
+ * If multi-threading is enabled, the caller must hold the
+ * global key slot mutex.
*
* \param[in] slot The key slot to test.
*
@@ -195,6 +197,8 @@
*
* Persistent storage is not affected.
* Sets the slot's state to PSA_SLOT_EMPTY.
+ * If multi-threading is enabled, the caller must hold the
+ * global key slot mutex.
*
* \param[in,out] slot The key slot to wipe.
*
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index 8d7ff90..47ace35 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -23,6 +23,9 @@
#include <stdlib.h>
#include <string.h>
#include "mbedtls/platform.h"
+#if defined(MBEDTLS_THREADING_C)
+#include "mbedtls/threading.h"
+#endif
typedef struct {
psa_key_slot_t key_slots[MBEDTLS_PSA_KEY_SLOT_COUNT];
diff --git a/library/psa_crypto_slot_management.h b/library/psa_crypto_slot_management.h
index 0b0d7b3..002429b 100644
--- a/library/psa_crypto_slot_management.h
+++ b/library/psa_crypto_slot_management.h
@@ -126,6 +126,9 @@
* new state. If the state of the slot was not expected_state, the state is
* unchanged.
*
+ * If multi-threading is enabled, the caller must hold the
+ * global key slot mutex.
+ *
* \param[in] slot The key slot.
* \param[in] expected_state The current state of the slot.
* \param[in] new_state The new state of the slot.
@@ -149,6 +152,8 @@
/** Register as a reader of a key slot.
*
* This function increments the key slot registered reader counter by one.
+ * If multi-threading is enabled, the caller must hold the
+ * global key slot mutex.
*
* \param[in] slot The key slot.
*
@@ -175,6 +180,8 @@
* If the state of the slot is PSA_SLOT_PENDING_DELETION,
* and there is only one registered reader (the caller),
* this function will call psa_wipe_key_slot().
+ * If multi-threading is enabled, the caller must hold the
+ * global key slot mutex.
*
* \note To ease the handling of errors in retrieving a key slot
* a NULL input pointer is valid, and the function returns
diff --git a/library/threading.c b/library/threading.c
index 873b507..c28290f 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -148,6 +148,9 @@
#if defined(THREADING_USE_GMTIME)
mbedtls_mutex_init(&mbedtls_threading_gmtime_mutex);
#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+ mbedtls_mutex_init(&mbedtls_threading_key_slot_mutex);
+#endif
}
/*
@@ -161,6 +164,9 @@
#if defined(THREADING_USE_GMTIME)
mbedtls_mutex_free(&mbedtls_threading_gmtime_mutex);
#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+ mbedtls_mutex_free(&mbedtls_threading_key_slot_mutex);
+#endif
}
#endif /* MBEDTLS_THREADING_ALT */
@@ -176,5 +182,8 @@
#if defined(THREADING_USE_GMTIME)
mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex MUTEX_INIT;
#endif
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex MUTEX_INIT;
+#endif
#endif /* MBEDTLS_THREADING_C */