1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun #include <linux/errno.h>
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun int ceph_armor(char *dst, const char *src, const char *end);
6*4882a593Smuzhiyun int ceph_unarmor(char *dst, const char *src, const char *end);
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun /*
9*4882a593Smuzhiyun * base64 encode/decode.
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun static const char *pem_key =
13*4882a593Smuzhiyun "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
14*4882a593Smuzhiyun
encode_bits(int c)15*4882a593Smuzhiyun static int encode_bits(int c)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun return pem_key[c];
18*4882a593Smuzhiyun }
19*4882a593Smuzhiyun
decode_bits(char c)20*4882a593Smuzhiyun static int decode_bits(char c)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun if (c >= 'A' && c <= 'Z')
23*4882a593Smuzhiyun return c - 'A';
24*4882a593Smuzhiyun if (c >= 'a' && c <= 'z')
25*4882a593Smuzhiyun return c - 'a' + 26;
26*4882a593Smuzhiyun if (c >= '0' && c <= '9')
27*4882a593Smuzhiyun return c - '0' + 52;
28*4882a593Smuzhiyun if (c == '+')
29*4882a593Smuzhiyun return 62;
30*4882a593Smuzhiyun if (c == '/')
31*4882a593Smuzhiyun return 63;
32*4882a593Smuzhiyun if (c == '=')
33*4882a593Smuzhiyun return 0; /* just non-negative, please */
34*4882a593Smuzhiyun return -EINVAL;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun
ceph_armor(char * dst,const char * src,const char * end)37*4882a593Smuzhiyun int ceph_armor(char *dst, const char *src, const char *end)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun int olen = 0;
40*4882a593Smuzhiyun int line = 0;
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun while (src < end) {
43*4882a593Smuzhiyun unsigned char a, b, c;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun a = *src++;
46*4882a593Smuzhiyun *dst++ = encode_bits(a >> 2);
47*4882a593Smuzhiyun if (src < end) {
48*4882a593Smuzhiyun b = *src++;
49*4882a593Smuzhiyun *dst++ = encode_bits(((a & 3) << 4) | (b >> 4));
50*4882a593Smuzhiyun if (src < end) {
51*4882a593Smuzhiyun c = *src++;
52*4882a593Smuzhiyun *dst++ = encode_bits(((b & 15) << 2) |
53*4882a593Smuzhiyun (c >> 6));
54*4882a593Smuzhiyun *dst++ = encode_bits(c & 63);
55*4882a593Smuzhiyun } else {
56*4882a593Smuzhiyun *dst++ = encode_bits((b & 15) << 2);
57*4882a593Smuzhiyun *dst++ = '=';
58*4882a593Smuzhiyun }
59*4882a593Smuzhiyun } else {
60*4882a593Smuzhiyun *dst++ = encode_bits(((a & 3) << 4));
61*4882a593Smuzhiyun *dst++ = '=';
62*4882a593Smuzhiyun *dst++ = '=';
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun olen += 4;
65*4882a593Smuzhiyun line += 4;
66*4882a593Smuzhiyun if (line == 64) {
67*4882a593Smuzhiyun line = 0;
68*4882a593Smuzhiyun *(dst++) = '\n';
69*4882a593Smuzhiyun olen++;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun return olen;
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun
ceph_unarmor(char * dst,const char * src,const char * end)75*4882a593Smuzhiyun int ceph_unarmor(char *dst, const char *src, const char *end)
76*4882a593Smuzhiyun {
77*4882a593Smuzhiyun int olen = 0;
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun while (src < end) {
80*4882a593Smuzhiyun int a, b, c, d;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun if (src[0] == '\n') {
83*4882a593Smuzhiyun src++;
84*4882a593Smuzhiyun continue;
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun if (src + 4 > end)
87*4882a593Smuzhiyun return -EINVAL;
88*4882a593Smuzhiyun a = decode_bits(src[0]);
89*4882a593Smuzhiyun b = decode_bits(src[1]);
90*4882a593Smuzhiyun c = decode_bits(src[2]);
91*4882a593Smuzhiyun d = decode_bits(src[3]);
92*4882a593Smuzhiyun if (a < 0 || b < 0 || c < 0 || d < 0)
93*4882a593Smuzhiyun return -EINVAL;
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun *dst++ = (a << 2) | (b >> 4);
96*4882a593Smuzhiyun if (src[2] == '=')
97*4882a593Smuzhiyun return olen + 1;
98*4882a593Smuzhiyun *dst++ = ((b & 15) << 4) | (c >> 2);
99*4882a593Smuzhiyun if (src[3] == '=')
100*4882a593Smuzhiyun return olen + 2;
101*4882a593Smuzhiyun *dst++ = ((c & 3) << 6) | d;
102*4882a593Smuzhiyun olen += 3;
103*4882a593Smuzhiyun src += 4;
104*4882a593Smuzhiyun }
105*4882a593Smuzhiyun return olen;
106*4882a593Smuzhiyun }
107