diff options
Diffstat (limited to '')
| -rw-r--r-- | libar2simplified_decode.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/libar2simplified_decode.c b/libar2simplified_decode.c new file mode 100644 index 0000000..ab4db5a --- /dev/null +++ b/libar2simplified_decode.c @@ -0,0 +1,194 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" +#ifdef __linux__ +#include <sys/random.h> +#endif +#include <time.h> + + +static size_t +decode_u32(const char *s, uint_least32_t *outp) +{ + uint_least32_t digit; + size_t i; + + if ((s[0] == '0' && s[1] == '0') || !isdigit(s[0])) { + errno = EINVAL; + return 0; + } + + *outp = 0; + for (i = 0; isdigit(s[i]); i++) { + digit = (uint_least32_t)(s[i] & 15); + if (*outp > ((uint_least32_t)0xFFFFffffUL - digit) / 10) { + errno = ERANGE; + return 0; + } + *outp = *outp * 10 + digit; + } + + return i; +} + + +static int +random_salt(char *out, size_t n, int (*random_byte_generator)(char *out, size_t n)) +{ +#define ALPHABET "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" + static int srand_called = 0; + + double x; + size_t i; + int xi; +#ifdef __linux__ + ssize_t r; +#endif + + if (random_byte_generator) { + if (random_byte_generator(out, n)) + return -1; + } else { + i = 0; +#ifdef __linux__ + for(; i < n; i += (size_t)r) { + r = getrandom(&out[i], n - i, GRND_NONBLOCK); + if(r < 0) + break; + } +#endif + if (!srand_called) { + srand((unsigned int)time(NULL)); + srand_called = 1; + } + for(; i < n; i++) { + xi = rand(); + x = (double)xi; + x /= (double)RAND_MAX; + x *= 63; + out[i] = (char)x; + } + } + + for (i = 0; i < n; i++) + out[i] = ALPHABET[out[i] % 64]; + return 0; +} + + +static void * +allocate(size_t num, size_t size, size_t alignment, struct libar2_context *ctx) +{ + (void) ctx; + (void) alignment; + return malloc(num * size); +} + + +static void +deallocate(void *ptr, struct libar2_context *ctx) +{ + (void) ctx; + free(ptr); +} + + +struct libar2_argon2_parameters * +libar2simplified_decode(const char *str, char **tagp, char **endp, int (*random_byte_generator)(char *out, size_t n)) +{ + struct libar2_argon2_parameters params, *ret; + const char *p = str; + const char *end; + char *str_free = NULL; + char *buf = NULL; + size_t n, saltsize, offset; + uint_least32_t saltlen, hashlen; + struct libar2_context ctx; + + if (*p != '$') + goto einval; + p = strchr(&p[1], '$'); + if (!p) + goto einval; + if (p[1] == 'v' && p[2] == '=') { + p = strchr(&p[1], '$'); + if (!p) + goto einval; + } + p = strchr(&p[1], '$'); + if (!p) + goto einval; + p++; + end = strchr(p, '$'); + if (!end) + goto einval; + + if (*p == '*') { + n = decode_u32(&p[1], &saltlen); + if (!n++) + goto fail; + if (&p[n] != end) + goto einval; + params.saltlen = (size_t)saltlen; + saltsize = libar2_encode_base64(NULL, NULL, saltlen) - 1; + offset = (size_t)(p - str); + str_free = malloc(offset + saltsize + strlen(&p[n]) + 1); + if (!str_free) + goto enomem; + memcpy(str_free, str, offset); + if (random_salt(&str_free[offset], saltsize, random_byte_generator)) + goto fail; + offset += saltsize; + stpcpy(&str_free[offset], &p[n]); + str = str_free; + } + end++; + + ctx.allocate = allocate; + ctx.deallocate = deallocate; + + if (!libar2_decode_params(str, ¶ms, &buf, &ctx)) + goto fail; + + if (*end == '*') { + n = decode_u32(&end[1], &hashlen); + if (!n++) + goto fail; + end = &end[n]; + params.hashlen = (size_t)hashlen; + if (tagp) + *tagp = NULL; + } else { + if (tagp) + *tagp = *(void **)(void *)&end; + end = &end[libar2_encode_base64(NULL, NULL, params.hashlen) - 1]; + } + + ret = malloc(sizeof(params) + params.saltlen); + if (!ret) + goto enomem; + memcpy(ret, ¶ms, sizeof(params)); + if (buf) { + memcpy(&((char *)ret)[sizeof(params)], buf, params.saltlen); + ret->salt = &((unsigned char *)ret)[sizeof(params)]; + deallocate(buf, &ctx); + } + + if (endp) + *endp = *(void **)(void *)&end; + + free(str_free); + return ret; + +einval: + errno = EINVAL; + return NULL; + +fail: + free(str_free); + return NULL; + +enomem: + free(str_free); + errno = ENOMEM; + return NULL; +} |