| // Copyright 2016 Brian Smith. |
| // |
| // Permission to use, copy, modify, and/or distribute this software for any |
| // purpose with or without fee is hereby granted, provided that the above |
| // copyright notice and this permission notice appear in all copies. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES |
| // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
| // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| |
| //! Error reporting. |
| |
| use core; |
| use untrusted; |
| |
| #[cfg(feature = "use_heap")] |
| use std; |
| |
| /// An error with absolutely no details. |
| /// |
| /// *ring* uses this unit type as the error type in most of its results |
| /// because (a) usually the specific reasons for a failure are obvious or are |
| /// not useful to know, and/or (b) providing more details about a failure might |
| /// provide a dangerous side channel, and/or (c) it greatly simplifies the |
| /// error handling logic. |
| /// |
| /// `Result<T, ring::error::Unspecified>` is mostly equivalent to |
| /// `Result<T, ()>`. However, `ring::error::Unspecified` implements |
| /// [`std::error::Error`] and users of *ring* can implement |
| /// `From<ring::error::Unspecified>` to map this to their own error types, as |
| /// described in [“Error Handling” in the Rust Book]: |
| /// |
| /// ``` |
| /// extern crate ring; |
| /// use ring::rand; |
| /// use ring::rand::SecureRandom; |
| /// |
| /// enum Error { |
| /// CryptoError, |
| /// |
| /// # #[cfg(feature = "use_heap")] |
| /// IOError(std::io::Error), |
| /// // [...] |
| /// } |
| /// |
| /// impl From<ring::error::Unspecified> for Error { |
| /// fn from(_: ring::error::Unspecified) -> Self { Error::CryptoError } |
| /// } |
| /// |
| /// fn eight_random_bytes() -> Result<[u8; 8], Error> { |
| /// let rng = rand::SystemRandom::new(); |
| /// let mut bytes = [0; 8]; |
| /// |
| /// // The `From<ring::error::Unspecified>` implementation above makes this |
| /// // equivalent to |
| /// // `rng.fill(&mut bytes).map_err(|_| Error::CryptoError)?`. |
| /// rng.fill(&mut bytes)?; |
| /// |
| /// Ok(bytes) |
| /// } |
| /// |
| /// # fn main() { |
| /// # assert!(eight_random_bytes().is_ok()); |
| /// # } |
| /// ``` |
| /// |
| /// Experience with using and implementing other crypto libraries like has |
| /// shown that sophisticated error reporting facilities often cause significant |
| /// bugs themselves, both within the crypto library and within users of the |
| /// crypto library. This approach attempts to minimize complexity in the hopes |
| /// of avoiding such problems. In some cases, this approach may be too extreme, |
| /// and it may be important for an operation to provide some details about the |
| /// cause of a failure. Users of *ring* are encouraged to report such cases so |
| /// that they can be addressed individually. |
| /// |
| /// [`std::error::Error`]: https://doc.rust-lang.org/std/error/trait.Error.html |
| /// [“Error Handling” in the Rust Book]: |
| /// https://doc.rust-lang.org/book/first-edition/error-handling.html#the-from-trait |
| #[derive(Clone, Copy, Debug, PartialEq)] |
| pub struct Unspecified; |
| |
| // This is required for the implementation of `std::error::Error`. |
| impl core::fmt::Display for Unspecified { |
| fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { |
| f.write_str("ring::error::Unspecified") |
| } |
| } |
| |
| #[cfg(feature = "use_heap")] |
| impl std::error::Error for Unspecified { |
| #[inline] |
| fn cause(&self) -> Option<&std::error::Error> { None } |
| |
| #[inline] |
| fn description(&self) -> &str { "ring::error::Unspecified" } |
| } |
| |
| impl From<untrusted::EndOfInput> for Unspecified { |
| fn from(_: untrusted::EndOfInput) -> Self { Unspecified } |
| } |