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Protect PSA global initialized flag with mutex.

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Unfortunately this requires holding the mutex for the entire
psa_crypto_init() function, as calling psa_crypto_free() from another
thread should block until init has ended, then run.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
This commit is contained in:
Paul Elliott 2024-02-23 17:26:58 +00:00
parent b8e38e0e27
commit 600472b443
1 changed files with 51 additions and 4 deletions
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55
library/psa_crypto.c
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@ -71,6 +71,7 @@
#include "mbedtls/sha256.h" #include "mbedtls/sha256.h"
#include "mbedtls/sha512.h" #include "mbedtls/sha512.h"
#include "mbedtls/psa_util.h" #include "mbedtls/psa_util.h"
#include "mbedtls/threading.h"
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) || \ #if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF) || \
defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) || \ defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT) || \
@ -101,8 +102,25 @@ typedef struct {
static psa_global_data_t global_data; static psa_global_data_t global_data;
static uint8_t psa_get_initialized(void)
{
uint8_t initialized;
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_lock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
initialized = global_data.initialized;
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_unlock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
return initialized;
}
#define GUARD_MODULE_INITIALIZED \ #define GUARD_MODULE_INITIALIZED \
if (global_data.initialized == 0) \ if (psa_get_initialized() == 0) \
return PSA_ERROR_BAD_STATE; return PSA_ERROR_BAD_STATE;
int psa_can_do_hash(psa_algorithm_t hash_alg) int psa_can_do_hash(psa_algorithm_t hash_alg)
@ -7189,7 +7207,7 @@ psa_status_t psa_generate_random(uint8_t *output,
psa_status_t mbedtls_psa_inject_entropy(const uint8_t *seed, psa_status_t mbedtls_psa_inject_entropy(const uint8_t *seed,
size_t seed_size) size_t seed_size)
{ {
if (global_data.initialized) { if (psa_get_initialized()) {
return PSA_ERROR_NOT_PERMITTED; return PSA_ERROR_NOT_PERMITTED;
} }
@ -7442,15 +7460,27 @@ psa_status_t mbedtls_psa_crypto_configure_entropy_sources(
void mbedtls_psa_crypto_free(void) void mbedtls_psa_crypto_free(void)
{ {
/* Need to hold the mutex here to prevent this going ahead before
* psa_crypto_init() has completed, and to ensure integrity of
* global_data. */
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_lock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
psa_wipe_all_key_slots(); psa_wipe_all_key_slots();
if (global_data.rng_state != RNG_NOT_INITIALIZED) { if (global_data.rng_state != RNG_NOT_INITIALIZED) {
mbedtls_psa_random_free(&global_data.rng); mbedtls_psa_random_free(&global_data.rng);
} }
/* Wipe all remaining data, including configuration. /* Wipe all remaining data, including configuration.
* In particular, this sets all state indicator to the value * In particular, this sets all state indicator to the value
* indicating "uninitialized". */ * indicating "uninitialized". */
mbedtls_platform_zeroize(&global_data, sizeof(global_data)); mbedtls_platform_zeroize(&global_data, sizeof(global_data));
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_unlock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
/* Terminate drivers */ /* Terminate drivers */
psa_driver_wrapper_free(); psa_driver_wrapper_free();
} }
@ -7484,8 +7514,20 @@ psa_status_t psa_crypto_init(void)
{ {
psa_status_t status; psa_status_t status;
/* Double initialization is explicitly allowed. */ /* Need to hold the mutex for the entire function to prevent incomplete
if (global_data.initialized != 0) { * initialisation before someone calls psa_crypto_free() or calls this
* function again before we set global_data.initialised to 1. */
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_lock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
/* We cannot use psa_get_initialized() here as we already hold the mutex. */
if (global_data.initialized == 1) {
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_unlock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
/* Double initialization is explicitly allowed. */
return PSA_SUCCESS; return PSA_SUCCESS;
} }
@ -7528,6 +7570,11 @@ psa_status_t psa_crypto_init(void)
global_data.initialized = 1; global_data.initialized = 1;
exit: exit:
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_unlock(&mbedtls_threading_psa_globaldata_mutex);
#endif /* defined(MBEDTLS_THREADING_C) */
if (status != PSA_SUCCESS) { if (status != PSA_SUCCESS) {
mbedtls_psa_crypto_free(); mbedtls_psa_crypto_free();
} }