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fix(crypto): Copy HMAC bytes into a new std::vector, to avoid a use-after-free #342

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Merged
andreiltd merged 2 commits into from
Oct 22, 2026
+7 −8
Merged

fix(crypto): Copy HMAC bytes into a new std::vector, to avoid a use-after-free #342

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20e090f
Copy HMAC bytes into a new std::vector, to avoid a use-after-free.
VirtualTim Oct 22, 2026
73dcd52
Merge branch 'main' into hmac-key-ownership
VirtualTim Oct 22, 2026
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11 changes: 5 additions & 6 deletions builtins/web/crypto/crypto-algorithm.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1358,14 +1358,16 @@ JSObject *CryptoAlgorithmHMAC_Import::importKey(JSContext *cx, CryptoKeyFormat f
return nullptr;
}

std::unique_ptr<std::span<uint8_t>> data;
std::unique_ptr<std::vector<uint8_t>> data;
// 3. Let hash be a new KeyAlgorithm.
// 4.
switch (format) {
// 5. If format is "raw":
case CryptoKeyFormat::Raw: {
// 5.1 Let data be the octet string contained in keyData.
data = std::make_unique<std::span<uint8_t>>(std::get<std::span<uint8_t>>(key_data));
// keyData is a view of the caller's buffer, which can change after import, so copy it.
auto key_bytes = std::get<std::span<uint8_t>>(key_data);
data = std::make_unique<std::vector<uint8_t>>(key_bytes.begin(), key_bytes.end());
if (!data) {
DOMException::raise(cx, "Supplied keyData must be either an ArrayBuffer, TypedArray, or DataView.", "DataError");
return nullptr;
Expand Down Expand Up @@ -1400,10 +1402,7 @@ JSObject *CryptoAlgorithmHMAC_Import::importKey(JSContext *cx, CryptoKeyFormat f
return nullptr;
}
auto data_string = dataResult.unwrap();
auto ddd = std::vector<uint8_t>(data_string.begin(), data_string.end());
data = std::make_unique<std::span<uint8_t>>(
ddd
);
data = std::make_unique<std::vector<uint8_t>>(data_string.begin(), data_string.end());
// 6.7 Set the hash to equal the hash member of normalizedAlgorithm.
CryptoAlgorithmIdentifier hash = this->hashIdentifier;
switch(hash) {
Expand Down
2 changes: 1 addition & 1 deletion builtins/web/crypto/crypto-key.cpp
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Expand Up @@ -594,7 +594,7 @@ EvpPkeyPtr create_rsa_key_from_parts(
} // namespace

JSObject *CryptoKey::createHMAC(JSContext *cx, CryptoAlgorithmHMAC_Import *algorithm,
std::unique_ptr<std::span<uint8_t>> data, unsigned long length,
std::unique_ptr<std::vector<uint8_t>> data, unsigned long length,
bool extractable, CryptoKeyUsages usages) {
MOZ_ASSERT(cx);
MOZ_ASSERT(algorithm);
Expand Down
2 changes: 1 addition & 1 deletion builtins/web/crypto/crypto-key.h
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Expand Up @@ -126,7 +126,7 @@ class CryptoKey : public BuiltinNoConstructor<CryptoKey> {
static bool init_class(JSContext *cx, JS::HandleObject global);

static JSObject *createHMAC(JSContext *cx, CryptoAlgorithmHMAC_Import *algorithm,
std::unique_ptr<std::span<uint8_t>> data, unsigned long length,
std::unique_ptr<std::vector<uint8_t>> data, unsigned long length,
bool extractable, CryptoKeyUsages usages);
static JSObject *createRSA(JSContext *cx, CryptoAlgorithmRSASSA_PKCS1_v1_5_Import *algorithm,
std::unique_ptr<CryptoKeyRSAComponents> keyData, bool extractable,
Expand Down
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