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|
//! 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 = "rand_core")]
impl From<rand_core::Error> for Error {
#[cfg(not(feature = "std"))]
fn from(_source: rand_core::Error) -> Error {
Error::new()
}
#[cfg(feature = "std")]
fn from(source: rand_core::Error) -> Error {
Error::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))
}
}
|
