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authorMattias Andrée <maandree@kth.se>2022-02-13 00:28:37 +0100
committerMattias Andrée <maandree@kth.se>2022-02-13 00:28:37 +0100
commit2ef79ab9d01090c1b3a2cc445a18d141cbb3c781 (patch)
tree1a455cc6d734f4b63adaf7857e4747dd2ed8ffcb /libar2simplified_decode.c
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First commit
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to 'libar2simplified_decode.c')
-rw-r--r--libar2simplified_decode.c194
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, &params, &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, &params, 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;
+}