diff options
Diffstat (limited to 'firmware/2lib/2common.c')
| -rw-r--r-- | firmware/2lib/2common.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/firmware/2lib/2common.c b/firmware/2lib/2common.c index 6da2fc3e..b05e7245 100644 --- a/firmware/2lib/2common.c +++ b/firmware/2lib/2common.c @@ -148,3 +148,218 @@ vb2_error_t vb2_verify_member_inside(const void *parent, size_t parent_size, return VB2_SUCCESS; } + +vb2_error_t vb2_verify_digest(const struct vb2_public_key *key, + struct vb2_signature *sig, const uint8_t *digest, + const struct vb2_workbuf *wb) +{ + /* A signature is destroyed in the process of being verified. */ + uint8_t *sig_data = vb2_signature_data_mutable(sig); + + if (sig->sig_size != vb2_rsa_sig_size(key->sig_alg)) { + VB2_DEBUG("Wrong data signature size for algorithm, " + "sig_size=%d, expected %d for algorithm %d.\n", + sig->sig_size, vb2_rsa_sig_size(key->sig_alg), + key->sig_alg); + return VB2_ERROR_VDATA_SIG_SIZE; + } + + return vb2_rsa_verify_digest(key, sig_data, digest, wb); +} + +vb2_error_t vb2_verify_data(const uint8_t *data, uint32_t size, + struct vb2_signature *sig, + const struct vb2_public_key *key, + const struct vb2_workbuf *wb) +{ + struct vb2_workbuf wblocal = *wb; + struct vb2_digest_context *dc; + uint8_t *digest; + uint32_t digest_size; + vb2_error_t rv; + + if (sig->data_size > size) { + VB2_DEBUG("Data buffer smaller than length of signed data.\n"); + return VB2_ERROR_VDATA_NOT_ENOUGH_DATA; + } + + /* Digest goes at start of work buffer */ + digest_size = vb2_digest_size(key->hash_alg); + if (!digest_size) + return VB2_ERROR_VDATA_DIGEST_SIZE; + + digest = vb2_workbuf_alloc(&wblocal, digest_size); + if (!digest) + return VB2_ERROR_VDATA_WORKBUF_DIGEST; + + /* Hashing requires temp space for the context */ + dc = vb2_workbuf_alloc(&wblocal, sizeof(*dc)); + if (!dc) + return VB2_ERROR_VDATA_WORKBUF_HASHING; + + rv = vb2_digest_init(dc, key->hash_alg); + if (rv) + return rv; + + rv = vb2_digest_extend(dc, data, sig->data_size); + if (rv) + return rv; + + rv = vb2_digest_finalize(dc, digest, digest_size); + if (rv) + return rv; + + vb2_workbuf_free(&wblocal, sizeof(*dc)); + + return vb2_verify_digest(key, sig, digest, &wblocal); +} + +vb2_error_t vb2_check_keyblock(const struct vb2_keyblock *block, uint32_t size, + const struct vb2_signature *sig) +{ + if(size < sizeof(*block)) { + VB2_DEBUG("Not enough space for keyblock header.\n"); + return VB2_ERROR_KEYBLOCK_TOO_SMALL_FOR_HEADER; + } + + if (memcmp(block->magic, VB2_KEYBLOCK_MAGIC, VB2_KEYBLOCK_MAGIC_SIZE)) { + VB2_DEBUG("Not a valid verified boot keyblock.\n"); + return VB2_ERROR_KEYBLOCK_MAGIC; + } + + if (block->header_version_major != VB2_KEYBLOCK_VERSION_MAJOR) { + VB2_DEBUG("Incompatible keyblock header version.\n"); + return VB2_ERROR_KEYBLOCK_HEADER_VERSION; + } + + if (size < block->keyblock_size) { + VB2_DEBUG("Not enough data for keyblock.\n"); + return VB2_ERROR_KEYBLOCK_SIZE; + } + + if (vb2_verify_signature_inside(block, block->keyblock_size, sig)) { + VB2_DEBUG("Keyblock signature off end of block\n"); + return VB2_ERROR_KEYBLOCK_SIG_OUTSIDE; + } + + /* Make sure advertised signature data sizes are sane. */ + if (block->keyblock_size < sig->data_size) { + VB2_DEBUG("Signature calculated past end of block\n"); + return VB2_ERROR_KEYBLOCK_SIGNED_TOO_MUCH; + } + + /* Verify we signed enough data */ + if (sig->data_size < sizeof(struct vb2_keyblock)) { + VB2_DEBUG("Didn't sign enough data\n"); + return VB2_ERROR_KEYBLOCK_SIGNED_TOO_LITTLE; + } + + /* Verify data key is inside the block and inside signed data */ + if (vb2_verify_packed_key_inside(block, block->keyblock_size, + &block->data_key)) { + VB2_DEBUG("Data key off end of keyblock\n"); + return VB2_ERROR_KEYBLOCK_DATA_KEY_OUTSIDE; + } + if (vb2_verify_packed_key_inside(block, sig->data_size, + &block->data_key)) { + VB2_DEBUG("Data key off end of signed data\n"); + return VB2_ERROR_KEYBLOCK_DATA_KEY_UNSIGNED; + } + + return VB2_SUCCESS; +} + +vb2_error_t vb2_verify_keyblock(struct vb2_keyblock *block, uint32_t size, + const struct vb2_public_key *key, + const struct vb2_workbuf *wb) +{ + struct vb2_signature *sig = &block->keyblock_signature; + vb2_error_t rv; + + /* Sanity check keyblock before attempting signature check of data */ + rv = vb2_check_keyblock(block, size, sig); + if (rv) + return rv; + + VB2_DEBUG("Checking keyblock signature...\n"); + rv = vb2_verify_data((const uint8_t *)block, size, sig, key, wb); + if (rv) { + VB2_DEBUG("Invalid keyblock signature.\n"); + return VB2_ERROR_KEYBLOCK_SIG_INVALID; + } + + /* Success */ + return VB2_SUCCESS; +} + +vb2_error_t vb2_verify_fw_preamble(struct vb2_fw_preamble *preamble, + uint32_t size, + const struct vb2_public_key *key, + const struct vb2_workbuf *wb) +{ + struct vb2_signature *sig = &preamble->preamble_signature; + + VB2_DEBUG("Verifying preamble.\n"); + + /* Sanity checks before attempting signature of data */ + if(size < sizeof(*preamble)) { + VB2_DEBUG("Not enough data for preamble header\n"); + return VB2_ERROR_PREAMBLE_TOO_SMALL_FOR_HEADER; + } + if (preamble->header_version_major != + VB2_FIRMWARE_PREAMBLE_HEADER_VERSION_MAJOR) { + VB2_DEBUG("Incompatible firmware preamble header version.\n"); + return VB2_ERROR_PREAMBLE_HEADER_VERSION; + } + + if (preamble->header_version_minor < 1) { + VB2_DEBUG("Only preamble header 2.1+ supported\n"); + return VB2_ERROR_PREAMBLE_HEADER_OLD; + } + + if (size < preamble->preamble_size) { + VB2_DEBUG("Not enough data for preamble.\n"); + return VB2_ERROR_PREAMBLE_SIZE; + } + + /* Check signature */ + if (vb2_verify_signature_inside(preamble, preamble->preamble_size, + sig)) { + VB2_DEBUG("Preamble signature off end of preamble\n"); + return VB2_ERROR_PREAMBLE_SIG_OUTSIDE; + } + + /* Make sure advertised signature data sizes are sane. */ + if (preamble->preamble_size < sig->data_size) { + VB2_DEBUG("Signature calculated past end of the block\n"); + return VB2_ERROR_PREAMBLE_SIGNED_TOO_MUCH; + } + + if (vb2_verify_data((const uint8_t *)preamble, size, sig, key, wb)) { + VB2_DEBUG("Preamble signature validation failed\n"); + return VB2_ERROR_PREAMBLE_SIG_INVALID; + } + + /* Verify we signed enough data */ + if (sig->data_size < sizeof(struct vb2_fw_preamble)) { + VB2_DEBUG("Didn't sign enough data\n"); + return VB2_ERROR_PREAMBLE_SIGNED_TOO_LITTLE; + } + + /* Verify body signature is inside the signed data */ + if (vb2_verify_signature_inside(preamble, sig->data_size, + &preamble->body_signature)) { + VB2_DEBUG("Firmware body signature off end of preamble\n"); + return VB2_ERROR_PREAMBLE_BODY_SIG_OUTSIDE; + } + + /* Verify kernel subkey is inside the signed data */ + if (vb2_verify_packed_key_inside(preamble, sig->data_size, + &preamble->kernel_subkey)) { + VB2_DEBUG("Kernel subkey off end of preamble\n"); + return VB2_ERROR_PREAMBLE_KERNEL_SUBKEY_OUTSIDE; + } + + /* Success */ + return VB2_SUCCESS; +} |