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authorJack Rosenthal <jrosenth@chromium.org>2021-11-04 12:11:58 -0600
committerCommit Bot <commit-bot@chromium.org>2021-11-05 04:22:34 +0000
commit252457d4b21f46889eebad61d4c0a65331919cec (patch)
tree01856c4d31d710b20e85a74c8d7b5836e35c3b98 /common/rsa.c
parent08f5a1e6fc2c9467230444ac9b582dcf4d9f0068 (diff)
downloadchrome-ec-stabilize-quickfix-14695.187.B-ish.tar.gz
In the interest of making long-term branch maintenance incur as little technical debt on us as possible, we should not maintain any files on the branch we are not actually using. This has the added effect of making it extremely clear when merging CLs from the main branch when changes have the possibility to affect us. The follow-on CL adds a convenience script to actually pull updates from the main branch and generate a CL for the update. BUG=b:204206272 BRANCH=ish TEST=make BOARD=arcada_ish && make BOARD=drallion_ish Signed-off-by: Jack Rosenthal <jrosenth@chromium.org> Change-Id: I17e4694c38219b5a0823e0a3e55a28d1348f4b18 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3262038 Reviewed-by: Jett Rink <jettrink@chromium.org> Reviewed-by: Tom Hughes <tomhughes@chromium.org>
Diffstat (limited to 'common/rsa.c')
-rw-r--r--common/rsa.c259
1 files changed, 0 insertions, 259 deletions
diff --git a/common/rsa.c b/common/rsa.c
deleted file mode 100644
index 10f0afa4b4..0000000000
--- a/common/rsa.c
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@@ -1,259 +0,0 @@
-/* Copyright 2014 The Chromium OS Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/*
- * Implementation of RSA signature verification which uses a pre-processed key
- * for computation.
- */
-
-#include "rsa.h"
-#include "sha256.h"
-#include "util.h"
-
-/**
- * a[] -= mod
- */
-static void sub_mod(const struct rsa_public_key *key, uint32_t *a)
-{
- int64_t A = 0;
- uint32_t i;
- for (i = 0; i < RSANUMWORDS; ++i) {
- A += (uint64_t)a[i] - key->n[i];
- a[i] = (uint32_t)A;
- A >>= 32;
- }
-}
-
-/**
- * Return a[] >= mod
- */
-static int ge_mod(const struct rsa_public_key *key, const uint32_t *a)
-{
- uint32_t i;
- for (i = RSANUMWORDS; i;) {
- --i;
- if (a[i] < key->n[i])
- return 0;
- if (a[i] > key->n[i])
- return 1;
- }
- return 1; /* equal */
-}
-
-/**
- * Montgomery c[] += a * b[] / R % mod
- */
-static void mont_mul_add(const struct rsa_public_key *key,
- uint32_t *c,
- const uint32_t a,
- const uint32_t *b)
-{
- uint64_t A = mula32(a, b[0], c[0]);
- uint32_t d0 = (uint32_t)A * key->n0inv;
- uint64_t B = mula32(d0, key->n[0], A);
- uint32_t i;
-
- for (i = 1; i < RSANUMWORDS; ++i) {
- A = mulaa32(a, b[i], c[i], A >> 32);
- B = mulaa32(d0, key->n[i], A, B >> 32);
- c[i - 1] = (uint32_t)B;
- }
-
- A = (A >> 32) + (B >> 32);
-
- c[i - 1] = (uint32_t)A;
-
- if (A >> 32)
- sub_mod(key, c);
-}
-
-#ifdef CONFIG_RSA_EXPONENT_3
-/**
- * Montgomery c[] += 0 * b[] / R % mod
- */
-static void mont_mul_add_0(const struct rsa_public_key *key,
- uint32_t *c,
- const uint32_t *b)
-{
- uint32_t d0 = c[0] * key->n0inv;
- uint64_t B = mula32(d0, key->n[0], c[0]);
- uint32_t i;
-
- for (i = 1; i < RSANUMWORDS; ++i) {
- B = mulaa32(d0, key->n[i], c[i], B >> 32);
- c[i - 1] = (uint32_t)B;
- }
-
- c[i - 1] = B >> 32;
-}
-
-/* Montgomery c[] = a[] * 1 / R % key. */
-static void mont_mul_1(const struct rsa_public_key *key,
- uint32_t *c,
- const uint32_t *a)
-{
- int i;
-
- for (i = 0; i < RSANUMWORDS; ++i)
- c[i] = 0;
-
- mont_mul_add(key, c, 1, a);
- for (i = 1; i < RSANUMWORDS; ++i)
- mont_mul_add_0(key, c, a);
-}
-#endif
-
-/**
- * Montgomery c[] = a[] * b[] / R % mod
- */
-static void mont_mul(const struct rsa_public_key *key,
- uint32_t *c,
- const uint32_t *a,
- const uint32_t *b)
-{
- uint32_t i;
- for (i = 0; i < RSANUMWORDS; ++i)
- c[i] = 0;
-
- for (i = 0; i < RSANUMWORDS; ++i)
- mont_mul_add(key, c, a[i], b);
-}
-
-/**
- * In-place public exponentiation.
- * Exponent depends on the configuration (65537 (default), or 3).
- *
- * @param key Key to use in signing
- * @param inout Input and output big-endian byte array
- * @param workbuf32 Work buffer; caller must verify this is
- * 3 x RSANUMWORDS elements long.
- */
-static void mod_pow(const struct rsa_public_key *key, uint8_t *inout,
- uint32_t *workbuf32)
-{
- uint32_t *a = workbuf32;
- uint32_t *a_r = a + RSANUMWORDS;
- uint32_t *aa_r = a_r + RSANUMWORDS;
- uint32_t *aaa = aa_r; /* Re-use location. */
- int i;
-
- /* Convert from big endian byte array to little endian word array. */
- for (i = 0; i < RSANUMWORDS; ++i) {
- uint32_t tmp =
- (inout[((RSANUMWORDS - 1 - i) * 4) + 0] << 24) |
- (inout[((RSANUMWORDS - 1 - i) * 4) + 1] << 16) |
- (inout[((RSANUMWORDS - 1 - i) * 4) + 2] << 8) |
- (inout[((RSANUMWORDS - 1 - i) * 4) + 3] << 0);
- a[i] = tmp;
- }
-
- /* TODO(drinkcat): This operation could be precomputed to save time. */
- mont_mul(key, a_r, a, key->rr); /* a_r = a * RR / R mod M */
-#ifdef CONFIG_RSA_EXPONENT_3
- mont_mul(key, aa_r, a_r, a_r);
- mont_mul(key, a, aa_r, a_r);
- mont_mul_1(key, aaa, a);
-#else
- /* Exponent 65537 */
- for (i = 0; i < 16; i += 2) {
- mont_mul(key, aa_r, a_r, a_r); /* aa_r = a_r * a_r / R mod M */
- mont_mul(key, a_r, aa_r, aa_r);/* a_r = aa_r * aa_r / R mod M */
- }
- mont_mul(key, aaa, a_r, a); /* aaa = a_r * a / R mod M */
-#endif
-
- /* Make sure aaa < mod; aaa is at most 1x mod too large. */
- if (ge_mod(key, aaa))
- sub_mod(key, aaa);
-
- /* Convert to bigendian byte array */
- for (i = RSANUMWORDS - 1; i >= 0; --i) {
- uint32_t tmp = aaa[i];
- *inout++ = (uint8_t)(tmp >> 24);
- *inout++ = (uint8_t)(tmp >> 16);
- *inout++ = (uint8_t)(tmp >> 8);
- *inout++ = (uint8_t)(tmp >> 0);
- }
-}
-
-/*
- * PKCS#1 padding (from the RSA PKCS#1 v2.1 standard)
- *
- * The DER-encoded padding is defined as follows :
- * 0x00 || 0x01 || PS || 0x00 || T
- *
- * T: DER Encoded DigestInfo value which depends on the hash function used,
- * for SHA-256:
- * (0x)30 31 30 0d 06 09 60 86 48 01 65 03 04 02 01 05 00 04 20 || H.
- *
- * Length(T) = 51 octets for SHA-256
- *
- * PS: octet string consisting of {Length(RSA Key) - Length(T) - 3} 0xFF
- */
-static const uint8_t sha256_tail[] = {
- 0x00, 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
- 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
- 0x05, 0x00, 0x04, 0x20
-};
-
-#define PKCS_PAD_SIZE (RSANUMBYTES - SHA256_DIGEST_SIZE)
-
-/**
- * Check PKCS#1 padding bytes
- *
- * @param sig Signature to verify
- * @return 0 if the padding is correct.
- */
-static int check_padding(const uint8_t *sig)
-{
- uint8_t *ptr = (uint8_t *)sig;
- int result = 0;
- int i;
-
- /* First 2 bytes are always 0x00 0x01 */
- result |= *ptr++ ^ 0x00;
- result |= *ptr++ ^ 0x01;
-
- /* Then 0xff bytes until the tail */
- for (i = 0; i < PKCS_PAD_SIZE - sizeof(sha256_tail) - 2; i++)
- result |= *ptr++ ^ 0xff;
-
- /* Check the tail. */
- result |= memcmp(ptr, sha256_tail, sizeof(sha256_tail));
-
- return !!result;
-}
-
-/*
- * Verify a SHA256WithRSA PKCS#1 v1.5 signature against an expected
- * SHA256 hash.
- *
- * @param key RSA public key
- * @param signature RSA signature
- * @param sha SHA-256 digest of the content to verify
- * @param workbuf32 Work buffer; caller must verify this is
- * 3 x RSANUMWORDS elements long.
- * @return 0 on failure, 1 on success.
- */
-int rsa_verify(const struct rsa_public_key *key, const uint8_t *signature,
- const uint8_t *sha, uint32_t *workbuf32)
-{
- uint8_t buf[RSANUMBYTES];
-
- /* Copy input to local workspace. */
- memcpy(buf, signature, RSANUMBYTES);
-
- mod_pow(key, buf, workbuf32); /* In-place exponentiation. */
-
- /* Check the PKCS#1 padding */
- if (check_padding(buf) != 0)
- return 0;
-
- /* Check the digest. */
- if (memcmp(buf + PKCS_PAD_SIZE, sha, SHA256_DIGEST_SIZE) != 0)
- return 0;
-
- return 1; /* All checked out OK. */
-}