avb2.0: add Android Verified Boot 2.0 library

Add libavb lib (3rd party library from AOSP), that implements support of
AVB 2.0. This library is used for integrity checking of Android partitions
on eMMC.

libavb was added as it is and minimal changes were introduced to reduce
maintenance cost, because it will be deviated from AOSP upstream in the future.

Changes:
- license headers changed to conform SPDX-style
- avb_crc32.c dropped
- updates in avb_sysdeps_posix.c/avb_sysdeps.h

For additional details check [1] AVB 2.0 README.

[1] https://android.googlesource.com/platform/external/avb/+/master/README.md

Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>

1 files changed, 156 insertions, 0 deletions

diff --git a/lib/libavb/avb_crypto.h b/lib/libavb/avb_crypto.h
new file mode 100644
index 0000000000..cede08f1bc
--- /dev/null
+++ b/lib/libavb/avb_crypto.h
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * SPDX-License-Identifier:	MIT
+ */
+
+#if !defined(AVB_INSIDE_LIBAVB_H) && !defined(AVB_COMPILATION)
+#error "Never include this file directly, include libavb.h instead."
+#endif
+
+#ifndef AVB_CRYPTO_H_
+#define AVB_CRYPTO_H_
+
+#include "avb_sysdeps.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Size of a RSA-2048 signature. */
+#define AVB_RSA2048_NUM_BYTES 256
+
+/* Size of a RSA-4096 signature. */
+#define AVB_RSA4096_NUM_BYTES 512
+
+/* Size of a RSA-8192 signature. */
+#define AVB_RSA8192_NUM_BYTES 1024
+
+/* Size in bytes of a SHA-1 digest. */
+#define AVB_SHA1_DIGEST_SIZE 20
+
+/* Size in bytes of a SHA-256 digest. */
+#define AVB_SHA256_DIGEST_SIZE 32
+
+/* Size in bytes of a SHA-512 digest. */
+#define AVB_SHA512_DIGEST_SIZE 64
+
+/* Possible digest types supported by libavb routines. */
+typedef enum {
+  AVB_DIGEST_TYPE_SHA256,
+  AVB_DIGEST_TYPE_SHA512,
+} AvbDigestType;
+
+/* Algorithms that can be used in the vbmeta image for
+ * verification. An algorithm consists of a hash type and a signature
+ * type.
+ *
+ * The data used to calculate the hash is the three blocks mentioned
+ * in the documentation for |AvbVBMetaImageHeader| except for the data
+ * in the "Authentication data" block.
+ *
+ * For signatures with RSA keys, PKCS v1.5 padding is used. The public
+ * key data is stored in the auxiliary data block, see
+ * |AvbRSAPublicKeyHeader| for the serialization format.
+ *
+ * Each algorithm type is described below:
+ *
+ * AVB_ALGORITHM_TYPE_NONE: There is no hash, no signature of the
+ * data, and no public key. The data cannot be verified. The fields
+ * |hash_size|, |signature_size|, and |public_key_size| must be zero.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA2048: The hash function used is
+ * SHA-256, resulting in 32 bytes of hash digest data. This hash is
+ * signed with a 2048-bit RSA key. The field |hash_size| must be 32,
+ * |signature_size| must be 256, and the public key data must have
+ * |key_num_bits| set to 2048.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA4096: Like above, but only with
+ * a 4096-bit RSA key and |signature_size| set to 512.
+ *
+ * AVB_ALGORITHM_TYPE_SHA256_RSA8192: Like above, but only with
+ * a 8192-bit RSA key and |signature_size| set to 1024.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA2048: The hash function used is
+ * SHA-512, resulting in 64 bytes of hash digest data. This hash is
+ * signed with a 2048-bit RSA key. The field |hash_size| must be 64,
+ * |signature_size| must be 256, and the public key data must have
+ * |key_num_bits| set to 2048.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA4096: Like above, but only with
+ * a 4096-bit RSA key and |signature_size| set to 512.
+ *
+ * AVB_ALGORITHM_TYPE_SHA512_RSA8192: Like above, but only with
+ * a 8192-bit RSA key and |signature_size| set to 1024.
+ */
+typedef enum {
+  AVB_ALGORITHM_TYPE_NONE,
+  AVB_ALGORITHM_TYPE_SHA256_RSA2048,
+  AVB_ALGORITHM_TYPE_SHA256_RSA4096,
+  AVB_ALGORITHM_TYPE_SHA256_RSA8192,
+  AVB_ALGORITHM_TYPE_SHA512_RSA2048,
+  AVB_ALGORITHM_TYPE_SHA512_RSA4096,
+  AVB_ALGORITHM_TYPE_SHA512_RSA8192,
+  _AVB_ALGORITHM_NUM_TYPES
+} AvbAlgorithmType;
+
+/* Holds algorithm-specific data. The |padding| is needed by avb_rsa_verify. */
+typedef struct {
+  const uint8_t* padding;
+  size_t padding_len;
+  size_t hash_len;
+} AvbAlgorithmData;
+
+/* Provides algorithm-specific data for a given |algorithm|. Returns NULL if
+ * |algorithm| is invalid.
+ */
+const AvbAlgorithmData* avb_get_algorithm_data(AvbAlgorithmType algorithm)
+    AVB_ATTR_WARN_UNUSED_RESULT;
+
+/* The header for a serialized RSA public key.
+ *
+ * The size of the key is given by |key_num_bits|, for example 2048
+ * for a RSA-2048 key. By definition, a RSA public key is the pair (n,
+ * e) where |n| is the modulus (which can be represented in
+ * |key_num_bits| bits) and |e| is the public exponent. The exponent
+ * is not stored since it's assumed to always be 65537.
+ *
+ * To optimize verification, the key block includes two precomputed
+ * values, |n0inv| (fits in 32 bits) and |rr| and can always be
+ * represented in |key_num_bits|.
+
+ * The value |n0inv| is the value -1/n[0] (mod 2^32). The value |rr|
+ * is (2^key_num_bits)^2 (mod n).
+ *
+ * Following this header is |key_num_bits| bits of |n|, then
+ * |key_num_bits| bits of |rr|. Both values are stored with most
+ * significant bit first. Each serialized number takes up
+ * |key_num_bits|/8 bytes.
+ *
+ * All fields in this struct are stored in network byte order when
+ * serialized.  To generate a copy with fields swapped to native byte
+ * order, use the function avb_rsa_public_key_header_validate_and_byteswap().
+ *
+ * The avb_rsa_verify() function expects a key in this serialized
+ * format.
+ *
+ * The 'avbtool extract_public_key' command can be used to generate a
+ * serialized RSA public key.
+ */
+typedef struct AvbRSAPublicKeyHeader {
+  uint32_t key_num_bits;
+  uint32_t n0inv;
+} AVB_ATTR_PACKED AvbRSAPublicKeyHeader;
+
+/* Copies |src| to |dest| and validates, byte-swapping fields in the
+ * process if needed. Returns true if valid, false if invalid.
+ */
+bool avb_rsa_public_key_header_validate_and_byteswap(
+    const AvbRSAPublicKeyHeader* src,
+    AvbRSAPublicKeyHeader* dest) AVB_ATTR_WARN_UNUSED_RESULT;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AVB_CRYPTO_H_ */