From f74764136b8b0564aa0e75e5c667b9d11158a2a9 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Tue, 15 Feb 2022 16:21:36 +0100
Subject: Add libar2simplified_decode_r
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 libar2simplified_decode_r.c | 196 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 196 insertions(+)
 create mode 100644 libar2simplified_decode_r.c

(limited to 'libar2simplified_decode_r.c')

diff --git a/libar2simplified_decode_r.c b/libar2simplified_decode_r.c
new file mode 100644
index 0000000..e49907c
--- /dev/null
+++ b/libar2simplified_decode_r.c
@@ -0,0 +1,196 @@
+/* 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, void *user_data), void *user_data)
+{
+#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, user_data))
+			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) ^ (unsigned int)rand());
+			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_r(const char *str, char **tagp, char **endp,
+                          int (*random_byte_generator)(char *out, size_t n, void *user_data),
+                          void *user_data)
+{
+	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, user_data))
+			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;
+}
-- 
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