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git.ipfire.org Git - thirdparty/u-boot.git/blob - lib/fdt-libcrypto.c
1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2020, Alexandru Gagniuc <mr.nuke.me@gmail.com>
4 * Copyright (c) 2013, Google Inc.
8 #include <u-boot/fdt-libcrypto.h>
10 int fdt_add_bignum(void *blob
, int noffset
, const char *prop_name
,
11 BIGNUM
*num
, int num_bits
)
13 int nwords
= num_bits
/ 32;
16 BIGNUM
*tmp
, *big2
, *big32
, *big2_32
;
26 * Note: This code assumes that all of the above succeed, or all fail.
27 * In practice memory allocations generally do not fail (unless the
28 * process is killed), so it does not seem worth handling each of these
29 * as a separate case. Technicaly this could leak memory on failure,
30 * but a) it won't happen in practice, and b) it doesn't matter as we
31 * will immediately exit with a failure code.
33 if (!tmp
|| !big2
|| !big32
|| !big2_32
) {
34 fprintf(stderr
, "Out of memory (bignum)\n");
39 fprintf(stderr
, "Out of memory (bignum context)\n");
42 BN_set_word(big2
, 2L);
43 BN_set_word(big32
, 32L);
44 BN_exp(big2_32
, big2
, big32
, ctx
); /* B = 2^32 */
46 size
= nwords
* sizeof(uint32_t);
49 fprintf(stderr
, "Out of memory (%d bytes)\n", size
);
53 /* Write out modulus as big endian array of integers */
54 for (ptr
= buf
+ nwords
- 1; ptr
>= buf
; ptr
--) {
55 BN_mod(tmp
, num
, big2_32
, ctx
); /* n = N mod B */
56 *ptr
= cpu_to_fdt32(BN_get_word(tmp
));
57 BN_rshift(num
, num
, 32); /* N = N/B */
61 * We try signing with successively increasing size values, so this
62 * might fail several times
64 ret
= fdt_setprop(blob
, noffset
, prop_name
, buf
, size
);
71 return ret
? -FDT_ERR_NOSPACE
: 0;