diff options
Diffstat (limited to 'src/basic/util.c')
| -rw-r--r-- | src/basic/util.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/basic/util.c b/src/basic/util.c index 61dd6c4227..bc917ae574 100644 --- a/src/basic/util.c +++ b/src/basic/util.c @@ -954,6 +954,180 @@ int unhexmem(const char *p, size_t l, void **mem, size_t *len) { return 0; } +/* https://tools.ietf.org/html/rfc4648#section-4 */ +char base64char(int x) { + static const char table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "0123456789+/"; + return table[x & 63]; +} + +int unbase64char(char c) { + unsigned offset; + + if (c >= 'A' && c <= 'Z') + return c - 'A'; + + offset = 'Z' - 'A' + 1; + + if (c >= 'a' && c <= 'z') + return c - 'a' + offset; + + offset += 'z' - 'a' + 1; + + if (c >= '0' && c <= '9') + return c - '0' + offset; + + offset += '9' - '0' + 1; + + if (c == '+') + return offset; + + offset ++; + + if (c == '/') + return offset; + + return -EINVAL; +} + +char *base64mem(const void *p, size_t l) { + char *r, *z; + const uint8_t *x; + + /* three input bytes makes four output bytes, padding is added so we must round up */ + z = r = malloc(4 * (l + 2) / 3 + 1); + if (!r) + return NULL; + + for (x = p; x < (const uint8_t*) p + (l / 3) * 3; x += 3) { + /* x[0] == XXXXXXXX; x[1] == YYYYYYYY; x[2] == ZZZZZZZZ */ + *(z++) = base64char(x[0] >> 2); /* 00XXXXXX */ + *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4); /* 00XXYYYY */ + *(z++) = base64char((x[1] & 15) << 2 | x[2] >> 6); /* 00YYYYZZ */ + *(z++) = base64char(x[2] & 63); /* 00ZZZZZZ */ + } + + switch (l % 3) { + case 2: + *(z++) = base64char(x[0] >> 2); /* 00XXXXXX */ + *(z++) = base64char((x[0] & 3) << 4 | x[1] >> 4); /* 00XXYYYY */ + *(z++) = base64char((x[1] & 15) << 2); /* 00YYYY00 */ + *(z++) = '='; + + break; + case 1: + *(z++) = base64char(x[0] >> 2); /* 00XXXXXX */ + *(z++) = base64char((x[0] & 3) << 4); /* 00XX0000 */ + *(z++) = '='; + *(z++) = '='; + + break; + } + + *z = 0; + return r; +} + +int unbase64mem(const char *p, size_t l, void **mem, size_t *_len) { + _cleanup_free_ uint8_t *t = NULL; + int a, b, c, d; + uint8_t *r, *z; + const char *x; + size_t len; + + assert(p); + + /* padding ensures any base63 input has input divisible by 4 */ + if (l % 4 != 0) + return -EINVAL; + + /* strip the padding */ + if (l > 0 && p[l - 1] == '=') + l --; + if (l > 0 && p[l - 1] == '=') + l --; + + /* a group of four input bytes needs three output bytes, in case of + padding we need to add two or three extra bytes */ + len = (l / 4) * 3 + (l % 4 ? (l % 4) - 1 : 0); + + z = r = malloc(len + 1); + if (!r) + return -ENOMEM; + + for (x = p; x < p + (l / 4) * 4; x += 4) { + /* a == 00XXXXXX; b == 00YYYYYY; c == 00ZZZZZZ; d == 00WWWWWW */ + a = unbase64char(x[0]); + if (a < 0) + return -EINVAL; + + b = unbase64char(x[1]); + if (b < 0) + return -EINVAL; + + c = unbase64char(x[2]); + if (c < 0) + return -EINVAL; + + d = unbase64char(x[3]); + if (d < 0) + return -EINVAL; + + *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */ + *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */ + *(z++) = (uint8_t) c << 6 | (uint8_t) d; /* ZZWWWWWW */ + } + + switch (l % 4) { + case 3: + a = unbase64char(x[0]); + if (a < 0) + return -EINVAL; + + b = unbase64char(x[1]); + if (b < 0) + return -EINVAL; + + c = unbase64char(x[2]); + if (c < 0) + return -EINVAL; + + /* c == 00ZZZZ00 */ + if (c & 3) + return -EINVAL; + + *(z++) = (uint8_t) a << 2 | (uint8_t) b >> 4; /* XXXXXXYY */ + *(z++) = (uint8_t) b << 4 | (uint8_t) c >> 2; /* YYYYZZZZ */ + + break; + case 2: + a = unbase64char(x[0]); + if (a < 0) + return -EINVAL; + + b = unbase64char(x[1]); + if (b < 0) + return -EINVAL; + + /* b == 00YY0000 */ + if (b & 15) + return -EINVAL; + + *(z++) = (uint8_t) a << 2 | (uint8_t) (b >> 4); /* XXXXXXYY */ + + break; + } + + *z = 0; + + *mem = r; + r = NULL; + *_len = len; + + return 0; +} + char octchar(int x) { return '0' + (x & 7); } |