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author | Alexandru Gagniuc <mr.nuke.me@gmail.com> | 2021-02-19 21:45:11 +0300 |
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committer | Tom Rini <trini@konsulko.com> | 2021-04-14 22:06:08 +0300 |
commit | 4c17e5f69170bf033df7b4f1a2b87fa72f18aaf5 (patch) | |
tree | a9e87dde0c1072b2b4096edcbdda61fb3da3e448 /lib/fdt-libcrypto.c | |
parent | 0bcb28dfb946b32ed7550fc4c24c5dcea6718554 (diff) | |
download | u-boot-4c17e5f69170bf033df7b4f1a2b87fa72f18aaf5.tar.xz |
lib/rsa: Make fdt_add_bignum() available outside of RSA code
fdt_add_bignum() is useful for algorithms other than just RSA. To
allow its use for ECDSA, move it to a common file under lib/.
The new file is suffixed with '-libcrypto' because it has a direct
dependency on openssl. This is due to the use of the "BIGNUM *" type.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'lib/fdt-libcrypto.c')
-rw-r--r-- | lib/fdt-libcrypto.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/fdt-libcrypto.c b/lib/fdt-libcrypto.c new file mode 100644 index 0000000000..ecb0344c8f --- /dev/null +++ b/lib/fdt-libcrypto.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com> + * Copyright (c) 2013, Google Inc. + */ + +#include <libfdt.h> +#include <u-boot/fdt-libcrypto.h> + +int fdt_add_bignum(void *blob, int noffset, const char *prop_name, + BIGNUM *num, int num_bits) +{ + int nwords = num_bits / 32; + int size; + uint32_t *buf, *ptr; + BIGNUM *tmp, *big2, *big32, *big2_32; + BN_CTX *ctx; + int ret; + + tmp = BN_new(); + big2 = BN_new(); + big32 = BN_new(); + big2_32 = BN_new(); + + /* + * Note: This code assumes that all of the above succeed, or all fail. + * In practice memory allocations generally do not fail (unless the + * process is killed), so it does not seem worth handling each of these + * as a separate case. Technicaly this could leak memory on failure, + * but a) it won't happen in practice, and b) it doesn't matter as we + * will immediately exit with a failure code. + */ + if (!tmp || !big2 || !big32 || !big2_32) { + fprintf(stderr, "Out of memory (bignum)\n"); + return -ENOMEM; + } + ctx = BN_CTX_new(); + if (!ctx) { + fprintf(stderr, "Out of memory (bignum context)\n"); + return -ENOMEM; + } + BN_set_word(big2, 2L); + BN_set_word(big32, 32L); + BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */ + + size = nwords * sizeof(uint32_t); + buf = malloc(size); + if (!buf) { + fprintf(stderr, "Out of memory (%d bytes)\n", size); + return -ENOMEM; + } + + /* Write out modulus as big endian array of integers */ + for (ptr = buf + nwords - 1; ptr >= buf; ptr--) { + BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */ + *ptr = cpu_to_fdt32(BN_get_word(tmp)); + BN_rshift(num, num, 32); /* N = N/B */ + } + + /* + * We try signing with successively increasing size values, so this + * might fail several times + */ + ret = fdt_setprop(blob, noffset, prop_name, buf, size); + free(buf); + BN_free(tmp); + BN_free(big2); + BN_free(big32); + BN_free(big2_32); + + return ret ? -FDT_ERR_NOSPACE : 0; +} |