Add common verified boot tools and library.
This code is originally from the Brillo project but has been adapted for
use in all of Android. It consists of a tool - avbtool - for working
with images (e.g. boot.img, system.img). See the README file for how
it's integrated into the Android build system and how to enable it.
The main job of avbtool is to create vbmeta.img which is the
top-level object for verified boot. This image is designed to go into
the vbmeta partition (or, if using A/B, the slot in question
e.g. vbmeta_a or vbmeta_b) and be of minimal size (for out-of-band
updates). The vbmeta image is cryptographically signed and contains
verification data (e.g. cryptographic digests) for verifying boot.img,
system.img, and other partitions/images.
The vbmeta image can also contain references to other partitions where
verification data is stored as well as a public key indicating who
should sign the verification data. This indirection provides
delegation, that is, it allows a 3rd party to control content on a given
partition by including the public key said 3rd party is using to sign
the data with, in vbmeta.img. By design, this authority can be easily
revoked by simply updating vbmeta.img with new descriptors for the
partition in question.
Storing signed verification data on other images - for example
boot.img and system.img - is also done with avbtool.
In addition to avbtool, a library - libavb - is provided. This library
performs all verification on the device side e.g. it starts by loading
the vbmeta partition, checks the signature, and then goes on to load
the boot partition for verification.
The libavb library is intended to be used in both boot loaders and
inside Android. It has a simple abstraction for system dependencies
(see libavb/avb_sysdeps.h) as well as operations that the boot loader
or OS is expected to implement (see libavb/avb_ops.h).
In addition to handling verified boot, libavb will in the future be
extended to handle A/B selection in a way that can be used in the
device's fastboot implementation, its boot loader, and its
boot_control HAL implementation. This will be implemented in a future
CL.
BUG=29414516
TEST=Unit tests for avbtool and libavb + unit tests pass.
Change-Id: I69ee86878e21fa718faccfc56eb0b1f40707d847
diff --git a/libavb/avb_sha256.c b/libavb/avb_sha256.c
new file mode 100644
index 0000000..b1748eb
--- /dev/null
+++ b/libavb/avb_sha256.c
@@ -0,0 +1,384 @@
+/* SHA-256 and SHA-512 implementation based on code by Oliver Gay
+ * <olivier.gay@a3.epfl.ch> under a BSD-style license. See below.
+ */
+
+/*
+ * FIPS 180-2 SHA-224/256/384/512 implementation
+ * Last update: 02/02/2007
+ * Issue date: 04/30/2005
+ *
+ * Copyright (C) 2005, 2007 Olivier Gay <olivier.gay@a3.epfl.ch>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "avb_sha.h"
+
+#define SHFR(x, n) (x >> n)
+#define ROTR(x, n) ((x >> n) | (x << ((sizeof(x) << 3) - n)))
+#define ROTL(x, n) ((x << n) | (x >> ((sizeof(x) << 3) - n)))
+#define CH(x, y, z) ((x & y) ^ (~x & z))
+#define MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
+
+#define SHA256_F1(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
+#define SHA256_F2(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
+#define SHA256_F3(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHFR(x, 3))
+#define SHA256_F4(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHFR(x, 10))
+
+#define UNPACK32(x, str) \
+ { \
+ *((str) + 3) = (uint8_t)((x)); \
+ *((str) + 2) = (uint8_t)((x) >> 8); \
+ *((str) + 1) = (uint8_t)((x) >> 16); \
+ *((str) + 0) = (uint8_t)((x) >> 24); \
+ }
+
+#define PACK32(str, x) \
+ { \
+ *(x) = ((uint32_t) * ((str) + 3)) | ((uint32_t) * ((str) + 2) << 8) | \
+ ((uint32_t) * ((str) + 1) << 16) | \
+ ((uint32_t) * ((str) + 0) << 24); \
+ }
+
+/* Macros used for loops unrolling */
+
+#define SHA256_SCR(i) \
+ { w[i] = SHA256_F4(w[i - 2]) + w[i - 7] + SHA256_F3(w[i - 15]) + w[i - 16]; }
+
+#define SHA256_EXP(a, b, c, d, e, f, g, h, j) \
+ { \
+ t1 = wv[h] + SHA256_F2(wv[e]) + CH(wv[e], wv[f], wv[g]) + sha256_k[j] + \
+ w[j]; \
+ t2 = SHA256_F1(wv[a]) + MAJ(wv[a], wv[b], wv[c]); \
+ wv[d] += t1; \
+ wv[h] = t1 + t2; \
+ }
+
+static const uint32_t sha256_h0[8] = {0x6a09e667, 0xbb67ae85, 0x3c6ef372,
+ 0xa54ff53a, 0x510e527f, 0x9b05688c,
+ 0x1f83d9ab, 0x5be0cd19};
+
+static const uint32_t sha256_k[64] = {
+ 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+ 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+ 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+ 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+ 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+ 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+ 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+ 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+ 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+ 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+ 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+
+/* SHA-256 implementation */
+void avb_sha256_init(AvbSHA256Ctx* ctx) {
+#ifndef UNROLL_LOOPS
+ int i;
+ for (i = 0; i < 8; i++) {
+ ctx->h[i] = sha256_h0[i];
+ }
+#else
+ ctx->h[0] = sha256_h0[0];
+ ctx->h[1] = sha256_h0[1];
+ ctx->h[2] = sha256_h0[2];
+ ctx->h[3] = sha256_h0[3];
+ ctx->h[4] = sha256_h0[4];
+ ctx->h[5] = sha256_h0[5];
+ ctx->h[6] = sha256_h0[6];
+ ctx->h[7] = sha256_h0[7];
+#endif /* !UNROLL_LOOPS */
+
+ ctx->len = 0;
+ ctx->tot_len = 0;
+}
+
+static void SHA256_transform(AvbSHA256Ctx* ctx, const uint8_t* message,
+ unsigned int block_nb) {
+ uint32_t w[64];
+ uint32_t wv[8];
+ uint32_t t1, t2;
+ const unsigned char* sub_block;
+ int i;
+
+#ifndef UNROLL_LOOPS
+ int j;
+#endif
+
+ for (i = 0; i < (int)block_nb; i++) {
+ sub_block = message + (i << 6);
+
+#ifndef UNROLL_LOOPS
+ for (j = 0; j < 16; j++) {
+ PACK32(&sub_block[j << 2], &w[j]);
+ }
+
+ for (j = 16; j < 64; j++) {
+ SHA256_SCR(j);
+ }
+
+ for (j = 0; j < 8; j++) {
+ wv[j] = ctx->h[j];
+ }
+
+ for (j = 0; j < 64; j++) {
+ t1 = wv[7] + SHA256_F2(wv[4]) + CH(wv[4], wv[5], wv[6]) + sha256_k[j] +
+ w[j];
+ t2 = SHA256_F1(wv[0]) + MAJ(wv[0], wv[1], wv[2]);
+ wv[7] = wv[6];
+ wv[6] = wv[5];
+ wv[5] = wv[4];
+ wv[4] = wv[3] + t1;
+ wv[3] = wv[2];
+ wv[2] = wv[1];
+ wv[1] = wv[0];
+ wv[0] = t1 + t2;
+ }
+
+ for (j = 0; j < 8; j++) {
+ ctx->h[j] += wv[j];
+ }
+#else
+ PACK32(&sub_block[0], &w[0]);
+ PACK32(&sub_block[4], &w[1]);
+ PACK32(&sub_block[8], &w[2]);
+ PACK32(&sub_block[12], &w[3]);
+ PACK32(&sub_block[16], &w[4]);
+ PACK32(&sub_block[20], &w[5]);
+ PACK32(&sub_block[24], &w[6]);
+ PACK32(&sub_block[28], &w[7]);
+ PACK32(&sub_block[32], &w[8]);
+ PACK32(&sub_block[36], &w[9]);
+ PACK32(&sub_block[40], &w[10]);
+ PACK32(&sub_block[44], &w[11]);
+ PACK32(&sub_block[48], &w[12]);
+ PACK32(&sub_block[52], &w[13]);
+ PACK32(&sub_block[56], &w[14]);
+ PACK32(&sub_block[60], &w[15]);
+
+ SHA256_SCR(16);
+ SHA256_SCR(17);
+ SHA256_SCR(18);
+ SHA256_SCR(19);
+ SHA256_SCR(20);
+ SHA256_SCR(21);
+ SHA256_SCR(22);
+ SHA256_SCR(23);
+ SHA256_SCR(24);
+ SHA256_SCR(25);
+ SHA256_SCR(26);
+ SHA256_SCR(27);
+ SHA256_SCR(28);
+ SHA256_SCR(29);
+ SHA256_SCR(30);
+ SHA256_SCR(31);
+ SHA256_SCR(32);
+ SHA256_SCR(33);
+ SHA256_SCR(34);
+ SHA256_SCR(35);
+ SHA256_SCR(36);
+ SHA256_SCR(37);
+ SHA256_SCR(38);
+ SHA256_SCR(39);
+ SHA256_SCR(40);
+ SHA256_SCR(41);
+ SHA256_SCR(42);
+ SHA256_SCR(43);
+ SHA256_SCR(44);
+ SHA256_SCR(45);
+ SHA256_SCR(46);
+ SHA256_SCR(47);
+ SHA256_SCR(48);
+ SHA256_SCR(49);
+ SHA256_SCR(50);
+ SHA256_SCR(51);
+ SHA256_SCR(52);
+ SHA256_SCR(53);
+ SHA256_SCR(54);
+ SHA256_SCR(55);
+ SHA256_SCR(56);
+ SHA256_SCR(57);
+ SHA256_SCR(58);
+ SHA256_SCR(59);
+ SHA256_SCR(60);
+ SHA256_SCR(61);
+ SHA256_SCR(62);
+ SHA256_SCR(63);
+
+ wv[0] = ctx->h[0];
+ wv[1] = ctx->h[1];
+ wv[2] = ctx->h[2];
+ wv[3] = ctx->h[3];
+ wv[4] = ctx->h[4];
+ wv[5] = ctx->h[5];
+ wv[6] = ctx->h[6];
+ wv[7] = ctx->h[7];
+
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 0);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 1);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 2);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 3);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 4);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 5);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 6);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 7);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 8);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 9);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 10);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 11);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 12);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 13);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 14);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 15);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 16);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 17);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 18);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 19);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 20);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 21);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 22);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 23);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 24);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 25);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 26);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 27);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 28);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 29);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 30);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 31);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 32);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 33);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 34);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 35);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 36);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 37);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 38);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 39);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 40);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 41);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 42);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 43);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 44);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 45);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 46);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 47);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 48);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 49);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 50);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 51);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 52);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 53);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 54);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 55);
+ SHA256_EXP(0, 1, 2, 3, 4, 5, 6, 7, 56);
+ SHA256_EXP(7, 0, 1, 2, 3, 4, 5, 6, 57);
+ SHA256_EXP(6, 7, 0, 1, 2, 3, 4, 5, 58);
+ SHA256_EXP(5, 6, 7, 0, 1, 2, 3, 4, 59);
+ SHA256_EXP(4, 5, 6, 7, 0, 1, 2, 3, 60);
+ SHA256_EXP(3, 4, 5, 6, 7, 0, 1, 2, 61);
+ SHA256_EXP(2, 3, 4, 5, 6, 7, 0, 1, 62);
+ SHA256_EXP(1, 2, 3, 4, 5, 6, 7, 0, 63);
+
+ ctx->h[0] += wv[0];
+ ctx->h[1] += wv[1];
+ ctx->h[2] += wv[2];
+ ctx->h[3] += wv[3];
+ ctx->h[4] += wv[4];
+ ctx->h[5] += wv[5];
+ ctx->h[6] += wv[6];
+ ctx->h[7] += wv[7];
+#endif /* !UNROLL_LOOPS */
+ }
+}
+
+void avb_sha256_update(AvbSHA256Ctx* ctx, const uint8_t* data, uint32_t len) {
+ unsigned int block_nb;
+ unsigned int new_len, rem_len, tmp_len;
+ const uint8_t* shifted_data;
+
+ tmp_len = AVB_SHA256_BLOCK_SIZE - ctx->len;
+ rem_len = len < tmp_len ? len : tmp_len;
+
+ avb_memcpy(&ctx->block[ctx->len], data, rem_len);
+
+ if (ctx->len + len < AVB_SHA256_BLOCK_SIZE) {
+ ctx->len += len;
+ return;
+ }
+
+ new_len = len - rem_len;
+ block_nb = new_len / AVB_SHA256_BLOCK_SIZE;
+
+ shifted_data = data + rem_len;
+
+ SHA256_transform(ctx, ctx->block, 1);
+ SHA256_transform(ctx, shifted_data, block_nb);
+
+ rem_len = new_len % AVB_SHA256_BLOCK_SIZE;
+
+ avb_memcpy(ctx->block, &shifted_data[block_nb << 6], rem_len);
+
+ ctx->len = rem_len;
+ ctx->tot_len += (block_nb + 1) << 6;
+}
+
+uint8_t* avb_sha256_final(AvbSHA256Ctx* ctx) {
+ unsigned int block_nb;
+ unsigned int pm_len;
+ unsigned int len_b;
+#ifndef UNROLL_LOOPS
+ int i;
+#endif
+
+ block_nb =
+ (1 + ((AVB_SHA256_BLOCK_SIZE - 9) < (ctx->len % AVB_SHA256_BLOCK_SIZE)));
+
+ len_b = (ctx->tot_len + ctx->len) << 3;
+ pm_len = block_nb << 6;
+
+ avb_memset(ctx->block + ctx->len, 0, pm_len - ctx->len);
+ ctx->block[ctx->len] = 0x80;
+ UNPACK32(len_b, ctx->block + pm_len - 4);
+
+ SHA256_transform(ctx, ctx->block, block_nb);
+
+#ifndef UNROLL_LOOPS
+ for (i = 0; i < 8; i++) {
+ UNPACK32(ctx->h[i], &ctx->buf[i << 2]);
+ }
+#else
+ UNPACK32(ctx->h[0], &ctx->buf[0]);
+ UNPACK32(ctx->h[1], &ctx->buf[4]);
+ UNPACK32(ctx->h[2], &ctx->buf[8]);
+ UNPACK32(ctx->h[3], &ctx->buf[12]);
+ UNPACK32(ctx->h[4], &ctx->buf[16]);
+ UNPACK32(ctx->h[5], &ctx->buf[20]);
+ UNPACK32(ctx->h[6], &ctx->buf[24]);
+ UNPACK32(ctx->h[7], &ctx->buf[28]);
+#endif /* !UNROLL_LOOPS */
+
+ return ctx->buf;
+}