| /** |
| * Code related to storing a secret value. The attacker should try to leak |
| * the value stored in this file. |
| */ |
| |
| #include "secret.h" |
| #include <compartment.h> |
| #include <debug.hh> |
| |
| /// Expose debugging features unconditionally for this compartment. |
| using Debug = ConditionalDebug<true, "JavaScript compartment">; |
| |
| /// The secret value. |
| static int32_t secret; |
| |
| /** |
| * Set the secret the first time. |
| * |
| * This blocks until there is a character available on the UART. This is |
| * *not* a good way of getting entropy, but it's the only one that we have |
| * in the simulator. |
| */ |
| void set_secret() |
| { |
| auto uart = MMIO_CAPABILITY(Uart, uart); |
| while (!uart->can_read()) {} |
| secret = static_cast<int32_t>(rdcycle64()); |
| Debug::log("Secret stored at {}", &secret); |
| } |
| |
| /** |
| * Report the current value of the secret and pick a new one. |
| */ |
| void check_secret(int32_t guess) |
| { |
| Debug::log("Secret was {}, you guessed {}.", secret, guess); |
| if (guess == secret) |
| { |
| Debug::log("CONGRATULATIONS! You correctly leaked the secret!"); |
| } |
| secret = static_cast<int32_t>(rdcycle64()); |
| } |
