| //! Signature error types |
| |
| use core::fmt::{self, Debug, Display}; |
| |
| #[cfg(feature = "std")] |
| use std::boxed::Box; |
| |
| /// Result type. |
| /// |
| /// A result with the `signature` crate's [`Error`] type. |
| pub type Result<T> = core::result::Result<T, Error>; |
| |
| /// Signature errors. |
| /// |
| /// This type is deliberately opaque as to avoid sidechannel leakage which |
| /// could potentially be used recover signing private keys or forge signatures |
| /// (e.g. [BB'06]). |
| /// |
| /// When the `std` feature is enabled, it impls [`std::error::Error`] and |
| /// supports an optional [`std::error::Error::source`], which can be used by |
| /// things like remote signers (e.g. HSM, KMS) to report I/O or auth errors. |
| /// |
| /// [BB'06]: https://en.wikipedia.org/wiki/Daniel_Bleichenbacher |
| #[derive(Default)] |
| #[non_exhaustive] |
| pub struct Error { |
| /// Source of the error (if applicable). |
| #[cfg(feature = "std")] |
| source: Option<Box<dyn std::error::Error + Send + Sync + 'static>>, |
| } |
| |
| impl Error { |
| /// Create a new error with no associated source |
| pub fn new() -> Self { |
| Self::default() |
| } |
| |
| /// Create a new error with an associated source. |
| /// |
| /// **NOTE:** The "source" should **NOT** be used to propagate cryptographic |
| /// errors e.g. signature parsing or verification errors. The intended use |
| /// cases are for propagating errors related to external signers, e.g. |
| /// communication/authentication errors with HSMs, KMS, etc. |
| #[cfg(feature = "std")] |
| pub fn from_source( |
| source: impl Into<Box<dyn std::error::Error + Send + Sync + 'static>>, |
| ) -> Self { |
| Self { |
| source: Some(source.into()), |
| } |
| } |
| } |
| |
| impl Debug for Error { |
| #[cfg(not(feature = "std"))] |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.write_str("signature::Error {}") |
| } |
| |
| #[cfg(feature = "std")] |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.write_str("signature::Error { source: ")?; |
| |
| if let Some(source) = &self.source { |
| write!(f, "Some({})", source)?; |
| } else { |
| f.write_str("None")?; |
| } |
| |
| f.write_str(" }") |
| } |
| } |
| |
| impl Display for Error { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.write_str("signature error")?; |
| |
| #[cfg(feature = "std")] |
| { |
| if let Some(source) = &self.source { |
| write!(f, ": {}", source)?; |
| } |
| } |
| |
| Ok(()) |
| } |
| } |
| |
| #[cfg(feature = "std")] |
| impl From<Box<dyn std::error::Error + Send + Sync + 'static>> for Error { |
| fn from(source: Box<dyn std::error::Error + Send + Sync + 'static>) -> Error { |
| Self::from_source(source) |
| } |
| } |
| |
| #[cfg(feature = "std")] |
| impl std::error::Error for Error { |
| fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { |
| self.source |
| .as_ref() |
| .map(|source| source.as_ref() as &(dyn std::error::Error + 'static)) |
| } |
| } |