| <!DOCTYPE html> |
| <html> |
| <head> |
| <script src="../../resources/js-test.js"></script> |
| <script src="../resources/common.js"></script> |
| </head> |
| <body> |
| <p id="description"></p> |
| <div id="console"></div> |
| |
| <script> |
| description("Test importing a PKCS8 ECDSA key with invalid length byte causing buffer overread"); |
| |
| // This test verifies that importing a malformed PKCS8 key where the final |
| // length byte has a large value (0xFF) is rejected gracefully. |
| // Without proper bounds checking, subvector(index) would access memory |
| // far beyond the buffer. |
| // |
| // Key structure (71 bytes): |
| // - Offset 0: 0x30 (SequenceMark - outer) |
| // - Offset 1: 0x00 (length byte) |
| // - Offset 2-4: 02 01 00 (Version) |
| // - Offset 5: 0x30 (SequenceMark - AlgorithmIdentifier) |
| // - Offset 6: 0x00 (length byte) |
| // - Offset 7-15: IdEcPublicKey OID (06 07 2a 86 48 ce 3d 02 01) |
| // - Offset 16-25: Secp256r1 OID (06 08 2a 86 48 ce 3d 03 01 07) |
| // - Offset 26: 0x04 (OCTET STRING) |
| // - Offset 27: 0x00 (length byte) |
| // - Offset 28: 0x30 (SEQUENCE - ECPrivateKey) |
| // - Offset 29: 0x00 (length byte) |
| // - Offset 30-32: 02 01 01 (PrivateKeyVersion) |
| // - Offset 33: 0x04 (OCTET STRING) |
| // - Offset 34: 0x00 (length byte) |
| // - Offset 35-66: 32 zero bytes (private key data) |
| // - Offset 67: 0xa1 (TaggedType1) |
| // - Offset 68: 0x00 (length byte) |
| // - Offset 69: 0x03 (BIT STRING) |
| // - Offset 70: 0xFF (length byte, bytesUsedToEncodedLength returns 128) |
| // |
| // At offset 70: bytesUsedToEncodedLength(0xFF) = 128 |
| // index = 70 + 128 + 1 = 199 |
| // keyData.subvector(199) on 71-byte buffer -> OOB access without bounds check |
| |
| var extractable = true; |
| |
| // 71 bytes: valid PKCS8 EC structure with IdEcPublicKey + Secp256r1 OIDs, then 0xFF length byte |
| var invalidLengthPkcs8Key = hexStringToUint8Array("3000020100300006072a8648ce3d020106082a8648ce3d0301070400300002010104000000000000000000000000000000000000000000000000000000000000000000a10003ff"); |
| |
| // Should reject with DataError, not crash or read beyond buffer |
| shouldReject('crypto.subtle.importKey("pkcs8", invalidLengthPkcs8Key, {name: "ECDSA", namedCurve: "P-256"}, extractable, ["sign"])'); |
| |
| </script> |
| |
| </body> |
| </html> |
