ed25519_dalek/
errors.rs

1// -*- mode: rust; -*-
2//
3// This file is part of ed25519-dalek.
4// Copyright (c) 2017-2019 isis lovecruft
5// See LICENSE for licensing information.
6//
7// Authors:
8// - isis agora lovecruft <isis@patternsinthevoid.net>
9
10//! Errors which may occur when parsing keys and/or signatures to or from wire formats.
11
12// rustc seems to think the typenames in match statements (e.g. in
13// Display) should be snake cased, for some reason.
14#![allow(non_snake_case)]
15
16use core::fmt;
17use core::fmt::Display;
18
19#[cfg(feature = "std")]
20use std::error::Error;
21
22/// Internal errors.  Most application-level developers will likely not
23/// need to pay any attention to these.
24#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
25pub(crate) enum InternalError {
26    PointDecompression,
27    ScalarFormat,
28    /// An error in the length of bytes handed to a constructor.
29    ///
30    /// To use this, pass a string specifying the `name` of the type which is
31    /// returning the error, and the `length` in bytes which its constructor
32    /// expects.
33    BytesLength {
34        name: &'static str,
35        length: usize,
36    },
37    /// The verification equation wasn't satisfied
38    Verify,
39    /// Two arrays did not match in size, making the called signature
40    /// verification method impossible.
41    #[cfg(feature = "batch")]
42    ArrayLength {
43        name_a: &'static str,
44        length_a: usize,
45        name_b: &'static str,
46        length_b: usize,
47        name_c: &'static str,
48        length_c: usize,
49    },
50    /// An ed25519ph signature can only take up to 255 octets of context.
51    #[cfg(feature = "digest")]
52    PrehashedContextLength,
53    /// A mismatched (public, secret) key pair.
54    MismatchedKeypair,
55}
56
57impl Display for InternalError {
58    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
59        match *self {
60            InternalError::PointDecompression => write!(f, "Cannot decompress Edwards point"),
61            InternalError::ScalarFormat => write!(f, "Cannot use scalar with high-bit set"),
62            InternalError::BytesLength { name: n, length: l } => {
63                write!(f, "{} must be {} bytes in length", n, l)
64            }
65            InternalError::Verify => write!(f, "Verification equation was not satisfied"),
66            #[cfg(feature = "batch")]
67            InternalError::ArrayLength {
68                name_a: na,
69                length_a: la,
70                name_b: nb,
71                length_b: lb,
72                name_c: nc,
73                length_c: lc,
74            } => write!(
75                f,
76                "Arrays must be the same length: {} has length {},
77                              {} has length {}, {} has length {}.",
78                na, la, nb, lb, nc, lc
79            ),
80            #[cfg(feature = "digest")]
81            InternalError::PrehashedContextLength => write!(
82                f,
83                "An ed25519ph signature can only take up to 255 octets of context"
84            ),
85            InternalError::MismatchedKeypair => write!(f, "Mismatched Keypair detected"),
86        }
87    }
88}
89
90#[cfg(feature = "std")]
91impl Error for InternalError {}
92
93/// Errors which may occur while processing signatures and keypairs.
94///
95/// This error may arise due to:
96///
97/// * Being given bytes with a length different to what was expected.
98///
99/// * A problem decompressing `r`, a curve point, in the `Signature`, or the
100///   curve point for a `PublicKey`.
101///
102/// * A problem with the format of `s`, a scalar, in the `Signature`.  This
103///   is only raised if the high-bit of the scalar was set.  (Scalars must
104///   only be constructed from 255-bit integers.)
105///
106/// * Failure of a signature to satisfy the verification equation.
107pub type SignatureError = ed25519::signature::Error;
108
109impl From<InternalError> for SignatureError {
110    #[cfg(not(feature = "std"))]
111    fn from(_err: InternalError) -> SignatureError {
112        SignatureError::new()
113    }
114
115    #[cfg(feature = "std")]
116    fn from(err: InternalError) -> SignatureError {
117        SignatureError::from_source(err)
118    }
119}
ed25519_dalek/errors.rs

ed25519_dalek/
errors.rs
