Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

[EFR32] Destroy PSA key_id if exists. #21920

Merged
merged 2 commits into from
Aug 16, 2022
Merged

[EFR32] Destroy PSA key_id if exists. #21920

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f61b60b
[EFR32] Recover from PSA keygen error.
rcasallas-silabs Aug 16, 2022
1f0e738
[EFR32] Destroy existing PSA key_id before re-using it.
rcasallas-silabs Aug 16, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
73 changes: 47 additions & 26 deletions src/platform/EFR32/Efr32PsaOpaqueKeypair.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,7 @@ static EFR32OpaqueKeyId opaque_key_id_from_psa(mbedtls_svc_key_id_t id)

EFR32OpaqueKeypair::EFR32OpaqueKeypair()
{
psa_crypto_init();
// Avoid having a reference to PSA datatypes in the signature of this class
mContext = MemoryCalloc(1, sizeof(mbedtls_svc_key_id_t));
}
Expand All @@ -125,24 +126,25 @@ EFR32OpaqueKeypair::~EFR32OpaqueKeypair()
}
}

CHIP_ERROR EFR32OpaqueKeypair::Load(EFR32OpaqueKeyId key_id)
CHIP_ERROR EFR32OpaqueKeypair::Load(EFR32OpaqueKeyId opaque_id)
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
mbedtls_svc_key_id_t key_id = 0;

VerifyOrExit(key_id != kEFR32OpaqueKeyIdVolatile, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(is_opaque_key_valid(key_id), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(opaque_id != kEFR32OpaqueKeyIdVolatile, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(is_opaque_key_valid(opaque_id), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(mContext, error = CHIP_ERROR_INCORRECT_STATE);

psa_crypto_init();

// If the object contains a volatile key, clean it up before reusing the object storage
if (mHasKey && !mIsPersistent)
{
Delete();
}

status = psa_export_public_key(psa_key_id_from_opaque(key_id), mPubkeyRef, mPubkeySize, &mPubkeyLength);
key_id = psa_key_id_from_opaque(opaque_id);

status = psa_export_public_key(key_id, mPubkeyRef, mPubkeySize, &mPubkeyLength);

if (status == PSA_ERROR_DOES_NOT_EXIST)
{
Expand All @@ -156,7 +158,7 @@ CHIP_ERROR EFR32OpaqueKeypair::Load(EFR32OpaqueKeyId key_id)
});

// Store the key ID and mark the key as valid
*(mbedtls_svc_key_id_t *) mContext = psa_key_id_from_opaque(key_id);
*(mbedtls_svc_key_id_t *) mContext = key_id;
mHasKey = true;
mIsPersistent = true;

Expand All @@ -169,27 +171,40 @@ CHIP_ERROR EFR32OpaqueKeypair::Load(EFR32OpaqueKeyId key_id)
return error;
}

CHIP_ERROR EFR32OpaqueKeypair::Create(EFR32OpaqueKeyId key_id, EFR32OpaqueKeyUsages usage)
CHIP_ERROR EFR32OpaqueKeypair::Create(EFR32OpaqueKeyId opaque_id, EFR32OpaqueKeyUsages usage)
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
mbedtls_svc_key_id_t key_id = 0;

VerifyOrExit(is_opaque_key_valid(key_id), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(is_opaque_key_valid(opaque_id), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(mContext, error = CHIP_ERROR_INCORRECT_STATE);

psa_crypto_init();

if (key_id == kEFR32OpaqueKeyIdVolatile)
if (opaque_id == kEFR32OpaqueKeyIdVolatile)
{
psa_set_key_lifetime(
&attr, PSA_KEY_LIFETIME_FROM_PERSISTENCE_AND_LOCATION(PSA_KEY_LIFETIME_VOLATILE, PSA_CRYPTO_LOCATION_FOR_DEVICE));
}
else
{
psa_key_handle_t key_handle;

key_id = psa_key_id_from_opaque(opaque_id);

// Check if the key already exists
int ret = psa_open_key(key_id, &key_handle);
if (PSA_SUCCESS == ret)
{
// WARNING: Existing key! This is caused by a problem in the key store.
// The key must be destroyed, otherwhise the device won't recover.
ChipLogError(Crypto, "WARNING: PSA key recycled: %d / %ld", opaque_id, key_id);
psa_destroy_key(key_id);
}

psa_set_key_id(&attr, key_id);
psa_set_key_lifetime(
&attr, PSA_KEY_LIFETIME_FROM_PERSISTENCE_AND_LOCATION(PSA_KEY_LIFETIME_PERSISTENT, PSA_CRYPTO_LOCATION_FOR_DEVICE));
psa_set_key_id(&attr, psa_key_id_from_opaque(key_id));
}

switch (usage)
Expand All @@ -209,21 +224,20 @@ CHIP_ERROR EFR32OpaqueKeypair::Create(EFR32OpaqueKeyId key_id, EFR32OpaqueKeyUsa
break;
}

status = psa_generate_key(&attr, (mbedtls_svc_key_id_t *) mContext);
status = psa_generate_key(&attr, &key_id);
VerifyOrExit(status == PSA_SUCCESS, {
_log_PSA_error(status);
error = CHIP_ERROR_INTERNAL;
});

// Export the public key
status = psa_export_public_key(*(mbedtls_svc_key_id_t *) mContext, mPubkeyRef, mPubkeySize, &mPubkeyLength);

if (status != PSA_SUCCESS)
status = psa_export_public_key(key_id, mPubkeyRef, mPubkeySize, &mPubkeyLength);
if (PSA_SUCCESS != status)
{
_log_PSA_error(status);
// Key generation succeeded, but pubkey export did not. To avoid
// memory leaks, delete the generated key before returning the error
psa_destroy_key(*(mbedtls_svc_key_id_t *) mContext);
psa_destroy_key(key_id);
error = CHIP_ERROR_INTERNAL;
goto exit;
}
Expand All @@ -234,10 +248,16 @@ CHIP_ERROR EFR32OpaqueKeypair::Create(EFR32OpaqueKeyId key_id, EFR32OpaqueKeyUsa

exit:
psa_reset_key_attributes(&attr);

if (error != CHIP_NO_ERROR && mContext)
if (mContext)
{
*(mbedtls_svc_key_id_t *) mContext = 0;
if (CHIP_NO_ERROR == error)
{
*(mbedtls_svc_key_id_t *) mContext = key_id;
}
else
{
*(mbedtls_svc_key_id_t *) mContext = 0;
}
}
return error;
}
Expand Down Expand Up @@ -281,6 +301,7 @@ CHIP_ERROR EFR32OpaqueKeypair::Sign(const uint8_t * msg, size_t msg_len, uint8_t
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;

VerifyOrExit(mContext, error = CHIP_ERROR_INCORRECT_STATE);
VerifyOrExit(mHasKey, error = CHIP_ERROR_INCORRECT_STATE);

status = psa_sign_message(*(mbedtls_svc_key_id_t *) mContext, PSA_ALG_ECDSA(PSA_ALG_SHA_256), msg, msg_len, output, output_size,
Expand Down
7 changes: 0 additions & 7 deletions src/platform/EFR32/Efr32PsaOperationalKeystore.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -236,13 +236,6 @@ CHIP_ERROR Efr32PsaOperationalKeystore::NewOpKeypairForFabric(FabricIndex fabric

// Create new key on the old or found key ID
error = mPendingKeypair->Create(id, EFR32OpaqueKeyUsages::ECDSA_P256_SHA256);
if (error != CHIP_NO_ERROR)
{
// Try deleting and recreating this key since keys don't get wiped on factory erase yet
mPendingKeypair->Delete();
error = mPendingKeypair->Create(id, EFR32OpaqueKeyUsages::ECDSA_P256_SHA256);
}

if (error != CHIP_NO_ERROR)
{
ResetPendingKey();
Expand Down