12f48aa65e
Support verify IPA signatures with openssl as an alternative to gnutls, to offer more flexibility in the selection of dependencies. Use gnutls by default, for no specific reason as both are equally well supported. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Tested-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Eric Curtin <ecurtin@redhat.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
141 lines
3.2 KiB
C++
141 lines
3.2 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2020, Google Inc.
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*
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* pub_key.cpp - Public key signature verification
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*/
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#include "libcamera/internal/pub_key.h"
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#if HAVE_CRYPTO
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#include <openssl/evp.h>
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#include <openssl/rsa.h>
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#include <openssl/sha.h>
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#include <openssl/x509.h>
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#elif HAVE_GNUTLS
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#include <gnutls/abstract.h>
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#endif
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/**
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* \file pub_key.h
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* \brief Public key signature verification
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*/
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namespace libcamera {
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/**
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* \class PubKey
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* \brief Public key wrapper for signature verification
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*
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* The PubKey class wraps a public key and implements signature verification. It
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* only supports RSA keys and the RSA-SHA256 signature algorithm.
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*/
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/**
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* \brief Construct a PubKey from key data
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* \param[in] key Key data encoded in DER format
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*/
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PubKey::PubKey([[maybe_unused]] Span<const uint8_t> key)
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: valid_(false)
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{
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#if HAVE_CRYPTO
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const uint8_t *data = key.data();
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pubkey_ = d2i_PUBKEY(nullptr, &data, key.size());
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if (!pubkey_)
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return;
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valid_ = true;
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#elif HAVE_GNUTLS
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int ret = gnutls_pubkey_init(&pubkey_);
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if (ret < 0)
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return;
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const gnutls_datum_t gnuTlsKey{
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const_cast<unsigned char *>(key.data()),
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static_cast<unsigned int>(key.size())
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};
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ret = gnutls_pubkey_import(pubkey_, &gnuTlsKey, GNUTLS_X509_FMT_DER);
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if (ret < 0)
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return;
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valid_ = true;
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#endif
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}
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PubKey::~PubKey()
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{
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#if HAVE_CRYPTO
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EVP_PKEY_free(pubkey_);
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#elif HAVE_GNUTLS
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gnutls_pubkey_deinit(pubkey_);
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#endif
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}
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/**
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* \fn bool PubKey::isValid() const
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* \brief Check is the public key is valid
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* \return True if the public key is valid, false otherwise
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*/
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/**
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* \brief Verify signature on data
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* \param[in] data The signed data
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* \param[in] sig The signature
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*
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* Verify that the signature \a sig matches the signed \a data for the public
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* key. The signture algorithm is hardcoded to RSA-SHA256.
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*
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* \return True if the signature is valid, false otherwise
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*/
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bool PubKey::verify([[maybe_unused]] Span<const uint8_t> data,
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[[maybe_unused]] Span<const uint8_t> sig) const
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{
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if (!valid_)
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return false;
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#if HAVE_CRYPTO
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/*
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* Create and initialize a public key algorithm context for signature
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* verification.
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*/
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EVP_PKEY_CTX *ctx = EVP_PKEY_CTX_new(pubkey_, nullptr);
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if (!ctx)
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return false;
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if (EVP_PKEY_verify_init(ctx) <= 0 ||
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EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0 ||
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EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0) {
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EVP_PKEY_CTX_free(ctx);
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return false;
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}
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/* Calculate the SHA256 digest of the data. */
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uint8_t digest[SHA256_DIGEST_LENGTH];
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SHA256(data.data(), data.size(), digest);
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/* Decrypt the signature and verify it matches the digest. */
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int ret = EVP_PKEY_verify(ctx, sig.data(), sig.size(), digest,
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SHA256_DIGEST_LENGTH);
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EVP_PKEY_CTX_free(ctx);
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return ret == 1;
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#elif HAVE_GNUTLS
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const gnutls_datum_t gnuTlsData{
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const_cast<unsigned char *>(data.data()),
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static_cast<unsigned int>(data.size())
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};
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const gnutls_datum_t gnuTlsSig{
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const_cast<unsigned char *>(sig.data()),
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static_cast<unsigned int>(sig.size())
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};
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int ret = gnutls_pubkey_verify_data2(pubkey_, GNUTLS_SIGN_RSA_SHA256, 0,
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&gnuTlsData, &gnuTlsSig);
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return ret >= 0;
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#else
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return false;
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#endif
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}
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} /* namespace libcamera */
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