1 // Copyright 2023, The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 //! Errors and relating functions thrown in this library.
16
17 use open_dice_cbor_bindgen::DiceResult;
18 use std::{fmt, result};
19
20 #[cfg(feature = "std")]
21 use std::error::Error;
22
23 /// Error type used by DICE.
24 #[derive(Debug)]
25 pub enum DiceError {
26 /// Provided input was invalid.
27 InvalidInput,
28 /// Provided buffer was too small.
29 BufferTooSmall(usize),
30 /// Platform error.
31 PlatformError,
32 /// Unsupported key algorithm.
33 UnsupportedKeyAlgorithm(coset::iana::Algorithm),
34 }
35
36 /// This makes `DiceError` accepted by anyhow.
37 #[cfg(feature = "std")]
38 impl Error for DiceError {}
39
40 impl fmt::Display for DiceError {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result41 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
42 match self {
43 Self::InvalidInput => write!(f, "Invalid input"),
44 Self::BufferTooSmall(buffer_required_size) => {
45 write!(f, "Buffer too small; need {buffer_required_size} bytes")
46 }
47 Self::PlatformError => write!(f, "Platform error"),
48 Self::UnsupportedKeyAlgorithm(algorithm) => {
49 write!(f, "Unsupported key algorithm: {algorithm:?}")
50 }
51 }
52 }
53 }
54
55 /// DICE result type.
56 pub type Result<T> = result::Result<T, DiceError>;
57
58 /// Checks the given `DiceResult`. Returns an error if it's not OK.
check_result(result: DiceResult, buffer_required_size: usize) -> Result<()>59 pub(crate) fn check_result(result: DiceResult, buffer_required_size: usize) -> Result<()> {
60 match result {
61 DiceResult::kDiceResultOk => Ok(()),
62 DiceResult::kDiceResultInvalidInput => Err(DiceError::InvalidInput),
63 DiceResult::kDiceResultBufferTooSmall => {
64 Err(DiceError::BufferTooSmall(buffer_required_size))
65 }
66 DiceResult::kDiceResultPlatformError => Err(DiceError::PlatformError),
67 }
68 }
69