1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3  *
4  * LibTomCrypt is a library that provides various cryptographic
5  * algorithms in a highly modular and flexible manner.
6  *
7  * The library is free for all purposes without any express
8  * guarantee it works.
9  */
10 #include "tomcrypt_private.h"
11 
12 /**
13   @file der_encode_octet_string.c
14   ASN.1 DER, encode a OCTET STRING, Tom St Denis
15 */
16 
17 
18 #ifdef LTC_DER
19 
20 /**
21   Store an OCTET STRING
22   @param in       The array of OCTETS to store (one per char)
23   @param inlen    The number of OCTETS to store
24   @param out      [out] The destination for the DER encoded OCTET STRING
25   @param outlen   [in/out] The max size and resulting size of the DER OCTET STRING
26   @return CRYPT_OK if successful
27 */
der_encode_octet_string(const unsigned char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen)28 int der_encode_octet_string(const unsigned char *in, unsigned long inlen,
29                                   unsigned char *out, unsigned long *outlen)
30 {
31    unsigned long x, y, len;
32    int           err;
33 
34    LTC_ARGCHK(in     != NULL);
35    LTC_ARGCHK(out    != NULL);
36    LTC_ARGCHK(outlen != NULL);
37 
38    /* get the size */
39    if ((err = der_length_octet_string(inlen, &len)) != CRYPT_OK) {
40       return err;
41    }
42 
43    /* too big? */
44    if (len > *outlen) {
45       *outlen = len;
46       return CRYPT_BUFFER_OVERFLOW;
47    }
48 
49    /* encode the header+len */
50    x = 0;
51    out[x++] = 0x04;
52    len = *outlen - x;
53    if ((err = der_encode_asn1_length(inlen, out + x, &len)) != CRYPT_OK) {
54       return err;
55    }
56    x += len;
57 
58    /* store octets */
59    for (y = 0; y < inlen; y++) {
60        out[x++] = in[y];
61    }
62 
63    /* retun length */
64    *outlen = x;
65 
66    return CRYPT_OK;
67 }
68 
69 #endif
70 
71 /* ref:         $Format:%D$ */
72 /* git commit:  $Format:%H$ */
73 /* commit time: $Format:%ai$ */
74