diff options
| author | Vadim Sukhomlinov <sukhomlinov@google.com> | 2021-10-05 19:07:14 -0700 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2021-10-06 03:59:44 +0000 |
| commit | cc7679235b5b30083cd74a68890b54c71bb61f7f (patch) | |
| tree | 95ea1e287fc320ad75e839196315cc670559d7e6 | |
| parent | 6a1d61e3e507f8f213b7ca6c5c07e3fc87b72d77 (diff) | |
| download | chrome-ec-cc7679235b5b30083cd74a68890b54c71bb61f7f.tar.gz | |
cr50: switch RSA/big numbers to dynamic buffer allocation for RSA 4K
Several bn_* function still use static buffer allocation. Switch to
dynamic allocation to enable support for RSA 3K/4K.
BUG=none
TEST=make BOARD=cr50 CRYPTO_TEST=1; test/tpm_test/tpmtest.py
../../build/tpm_test/bn_test
TCG tests
Signed-off-by: Vadim Sukhomlinov <sukhomlinov@google.com>
Change-Id: I150fa99bde89cc486f7ad945b5a312fe7d787fb0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3207349
Reviewed-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Reviewed-by: Andrey Pronin <apronin@chromium.org>
Tested-by: Vadim Sukhomlinov <sukhomlinov@chromium.org>
Commit-Queue: Vadim Sukhomlinov <sukhomlinov@chromium.org>
| -rw-r--r-- | board/cr50/dcrypto/bn.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/board/cr50/dcrypto/bn.c b/board/cr50/dcrypto/bn.c index e92f366aeb..a65f496429 100644 --- a/board/cr50/dcrypto/bn.c +++ b/board/cr50/dcrypto/bn.c @@ -342,17 +342,19 @@ static void bn_modexp_internal(struct LITE_BIGNUM *output, { int i; uint32_t nprime; - uint32_t RR_buf[RSA_MAX_WORDS]; - uint32_t acc_buf[RSA_MAX_WORDS]; - uint32_t aR_buf[RSA_MAX_WORDS]; + uint8_t *buf; + size_t n_len; struct LITE_BIGNUM RR; struct LITE_BIGNUM acc; struct LITE_BIGNUM aR; - bn_init(&RR, RR_buf, bn_size(N)); - bn_init(&acc, acc_buf, bn_size(N)); - bn_init(&aR, aR_buf, bn_size(N)); + n_len = bn_size(N); + /* Combined buffer for acc, RR and aR. */ + buf = alloca(n_len * 3); + bn_init(&acc, buf, n_len); + bn_init(&RR, buf + n_len, n_len); + bn_init(&aR, buf + n_len + n_len, n_len); nprime = bn_compute_nprime(BN_DIGIT(N, 0)); bn_compute_RR(&RR, N); @@ -381,8 +383,8 @@ static void bn_modexp_internal(struct LITE_BIGNUM *output, bn_mont_mul(output, NULL, &acc, nprime, N); /* Convert out. */ /* Copy to output buffer if necessary. */ - if (acc.d != (struct access_helper *) acc_buf) { - memcpy(acc.d, acc_buf, bn_size(output)); + if (acc.d != (struct access_helper *)buf) { + memcpy(acc.d, buf, bn_size(output)); *output = acc; } @@ -391,9 +393,7 @@ static void bn_modexp_internal(struct LITE_BIGNUM *output, bn_add(output, N); /* Final reduce. */ output->dmax = N->dmax; - always_memset(RR_buf, 0, sizeof(RR_buf)); - always_memset(acc_buf, 0, sizeof(acc_buf)); - always_memset(aR_buf, 0, sizeof(aR_buf)); + always_memset(buf, 0, n_len * 3); } /* output = input ^ exp % N */ @@ -623,8 +623,8 @@ static int bn_div_ex(struct LITE_BIGNUM *q, { uint32_t vtop; int s, i, j; - uint32_t vn[RSA_MAX_WORDS]; /* Normalized v */ - uint32_t un[RSA_MAX_WORDS + 1]; /* Normalized u */ + uint32_t *vn; /* Normalized v */ + uint32_t *un; /* Normalized u */ if (m < n || n <= 0) return 0; @@ -637,6 +637,10 @@ static int bn_div_ex(struct LITE_BIGNUM *q, if (n == 1) return bn_div_word_ex(q, r, u, m, vtop); + /* Allocate buffer for vn and un. */ + vn = alloca((n + m + 1) * sizeof(v->d[0])); + un = vn + n; /* un size is m words. */ + /* Compute shift factor to make v have high bit set */ s = count_leading_zeros(vtop); vtop <<= s; |