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