tuf/src/error.rs

//! Error types and converters.

use std::io;
use thiserror::Error;

use crate::metadata::{MetadataPath, MetadataVersion, TargetPath};

/// Alias for `Result<T, Error>`.
pub type Result<T> = std::result::Result<T, Error>;

/// Error type for all TUF related errors.
#[non_exhaustive]
#[derive(Error, Debug)]
pub enum Error {
    /// The metadata had a bad signature.
    #[error("metadata {0} has a bad signature")]
    BadSignature(MetadataPath),

    /// There was a problem encoding or decoding.
    #[error("encoding: {0}")]
    Encoding(String),

    /// Metadata was expired.
    #[error("expired {0} metadata")]
    ExpiredMetadata(MetadataPath),

    /// An illegal argument was passed into a function.
    #[error("illegal argument: {0}")]
    IllegalArgument(String),

    /// Generic error for HTTP connections.
    #[error("http error for {uri}")]
    Http {
        /// URI Resource that resulted in the error.
        uri: String,

        /// The error.
        #[source]
        err: http::Error,
    },

    /// Errors that can occur parsing HTTP streams.
    #[cfg(feature = "hyper")]
    #[error("hyper error for {uri}")]
    Hyper {
        /// URI Resource that resulted in the error.
        uri: String,

        /// The error.
        #[source]
        err: hyper::Error,
    },

    /// Unexpected HTTP response status.
    #[error("error getting {uri}: request failed with status code {code}")]
    BadHttpStatus {
        /// URI Resource that resulted in the error.
        uri: String,

        /// HTTP status code.
        code: http::StatusCode,
    },

    /// An IO error occurred.
    #[error(transparent)]
    Io(#[from] io::Error),

    /// An IO error occurred for a path.
    #[error("IO error on path {path}")]
    IoPath {
        /// Path where the error occurred.
        path: std::path::PathBuf,

        /// The IO error.
        #[source]
        err: io::Error,
    },

    /// A json serialization error occurred.
    #[error(transparent)]
    Json(#[from] serde_json::error::Error),

    /// There were no available hash algorithms.
    #[error("no supported hash algorithm")]
    NoSupportedHashAlgorithm,

    /// The metadata was not found.
    #[error("metadata {path} at version {version} not found")]
    MetadataNotFound {
        /// The metadata path.
        path: MetadataPath,

        /// The metadata version.
        version: MetadataVersion,
    },

    /// The target was not found.
    #[error("target {0} not found")]
    TargetNotFound(TargetPath),

    /// Opaque error type, to be interpreted similar to HTTP 500. Something went wrong, and you may
    /// or may not be able to do anything about it.
    #[error("opaque: {0}")]
    Opaque(String),

    /// There is no known or available key type.
    #[error("unknown key type: {0}")]
    UnknownKeyType(String),

    /// There is no known or available signature scheme.
    #[error("unknown signature scheme: {0}")]
    UnknownSignatureScheme(String),

    /// The metadata threshold cannot equal 0.
    #[error("metadata {0} threshold must be greater than zero")]
    MetadataThresholdMustBeGreaterThanZero(MetadataPath),

    /// The metadata's version must be less than `u32::MAX`.
    #[error("metadata {0} version should be less than max u32")]
    MetadataVersionMustBeSmallerThanMaxU32(MetadataPath),

    /// The metadata was not signed with enough valid signatures.
    #[error("metadata {0} signature threshold not met: {number_of_valid_signatures}/{threshold}")]
    MetadataMissingSignatures {
        /// The signed metadata.
        role: MetadataPath,
        /// The number of signatures which are valid.
        number_of_valid_signatures: u32,
        /// The minimum number of valid signatures.
        threshold: u32,
    },

    /// Attempted to update metadata with an older version.
    #[error("attempted to roll back metadata {0} from version {trusted_version} to {new_version}")]
    AttemptedMetadataRollBack {
        /// The metadata.
        role: MetadataPath,
        /// The trusted metadata's version.
        trusted_version: u32,
        /// The new metadata's version.
        new_version: u32,
    },

    /// The parent metadata expected the child metadata to be at one version, but was found to be at
    /// another version.
    #[error("metadata {parent_role} expected metadata {child_role} version {expected_version}, but found {new_version}")]
    WrongMetadataVersion {
        /// The parent metadata that contains the child metadata's version.
        parent_role: MetadataPath,
        /// The child metadata that has an unexpected version.
        child_role: MetadataPath,
        /// The expected version of the child metadata.
        expected_version: u32,
        /// The actual version of the child metadata.
        new_version: u32,
    },

    /// The parent metadata does not contain a description of the child metadata.
    #[error("metadata {parent_role} missing description of {child_role}")]
    MissingMetadataDescription {
        /// The parent metadata that contains the child metadata's description.
        parent_role: MetadataPath,
        /// The child metadata that should have been contained in the parent.
        child_role: MetadataPath,
    },

    /// The parent metadata did not delegate to the child role.
    #[error("{parent_role} delegation to {child_role} is not authorized")]
    UnauthorizedDelegation {
        /// The parent metadata that did not delegate to the child.
        parent_role: MetadataPath,
        /// That child metadata that was not delegated to by the parent.
        child_role: MetadataPath,
    },
}

pub(crate) fn derp_error_to_error(err: derp::Error) -> Error {
    Error::Encoding(format!("DER: {:?}", err))
}