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094a81f5de
For signed EC RW images (CONFIG_RWSIG), there's no point in embedding the public key or signature into the image itself since it will just be replaced by the signer (either as the next step in the build process, or after the fact for MP releases). This takes that out and just points to where the pubkey and signature will be placed. BUG=none BRANCH=none TEST=make buildall I also checked the signatures with futility show -t build/*/ec.bin They still look good, and the one signed image I booted (Cr50) works as before. Change-Id: Ib39b7c508914851f81a1bebb2450e08ef0def76c Signed-off-by: Bill Richardson <wfrichar@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/302630 Reviewed-by: Randall Spangler <rspangler@chromium.org>
75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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/*
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* Implementation of the RW firmware signature verification and jump.
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*/
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#include "console.h"
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#include "ec_commands.h"
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#include "rsa.h"
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#include "sha256.h"
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#include "shared_mem.h"
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#include "system.h"
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#include "usb_pd.h"
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#include "util.h"
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/* Console output macros */
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#define CPRINTF(format, args...) cprintf(CC_SYSTEM, format, ## args)
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#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ## args)
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/* RW firmware reset vector */
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static uint32_t * const rw_rst =
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(uint32_t *)(CONFIG_PROGRAM_MEMORY_BASE + CONFIG_RW_MEM_OFF + 4);
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void check_rw_signature(void)
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{
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struct sha256_ctx ctx;
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int good, res;
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uint8_t *hash;
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uint32_t *rsa_workbuf;
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/* Only the Read-Only firmware needs to do the signature check */
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if (system_get_image_copy() != SYSTEM_IMAGE_RO)
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return;
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/* Check if we have a RW firmware flashed */
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if (*rw_rst == 0xffffffff)
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return;
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CPRINTS("Verifying RW image...");
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/* Large buffer for RSA computation : could be re-use afterwards... */
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res = shared_mem_acquire(3 * RSANUMBYTES, (char **)&rsa_workbuf);
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if (res) {
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CPRINTS("No memory for RW verification");
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return;
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}
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/* SHA-256 Hash of the RW firmware */
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/* TODO(crosbug.com/p/44803): Do we have to hash the whole region? */
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SHA256_init(&ctx);
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SHA256_update(&ctx, (void *)CONFIG_PROGRAM_MEMORY_BASE
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+ CONFIG_RW_MEM_OFF,
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CONFIG_RW_SIZE - CONFIG_RW_SIG_SIZE);
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hash = SHA256_final(&ctx);
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good = rsa_verify((const struct rsa_public_key *)CONFIG_RO_PUBKEY_ADDR,
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(const uint8_t *)CONFIG_RW_SIG_ADDR,
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hash, rsa_workbuf);
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if (good) {
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CPRINTS("RW image verified");
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/* Jump to the RW firmware */
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system_run_image_copy(SYSTEM_IMAGE_RW);
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} else {
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CPRINTS("RSA verify FAILED");
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pd_log_event(PD_EVENT_ACC_RW_FAIL, 0, 0, NULL);
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/* RW firmware is invalid : do not jump there */
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if (system_is_locked())
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system_disable_jump();
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}
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shared_mem_release(rsa_workbuf);
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}
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