1 files changed, 247 insertions, 0 deletions
diff --git a/src/contrib/string.c b/src/contrib/string.c
new file mode 100644
index 0000000..272116e
--- /dev/null
+++ b/src/contrib/string.c
@@ -0,0 +1,247 @@
+/*  Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#if defined(HAVE_EXPLICIT_BZERO)
+  #if defined(HAVE_BSD_STRING_H)
+    #include <bsd/string.h>
+  #endif
+  /* #include <string.h> is needed. */
+#elif defined(HAVE_EXPLICIT_MEMSET)
+  /* #include <string.h> is needed. */
+#elif defined(HAVE_GNUTLS_MEMSET)
+  #include <gnutls/gnutls.h>
+#else
+  #define USE_CUSTOM_MEMSET
+#endif
+
+#include "contrib/string.h"
+#include "contrib/ctype.h"
+#include "contrib/tolower.h"
+
+uint8_t *memdup(const uint8_t *data, size_t data_size)
+{
+	uint8_t *result = (uint8_t *)malloc(data_size);
+	if (!result) {
+		return NULL;
+	}
+
+	return memcpy(result, data, data_size);
+}
+
+int strmemcmp(const char *str, const uint8_t *mem, size_t mem_size)
+{
+	if (mem_size == 0) {
+		return 1;
+	}
+	size_t cmp_len = strnlen(str, mem_size - 1) + 1;
+	return memcmp(str, mem, cmp_len);
+}
+
+char *sprintf_alloc(const char *fmt, ...)
+{
+	char *strp = NULL;
+	va_list ap;
+
+	va_start(ap, fmt);
+	int ret = vasprintf(&strp, fmt, ap);
+	va_end(ap);
+
+	if (ret < 0) {
+		return NULL;
+	}
+	return strp;
+}
+
+char *strcdup(const char *s1, const char *s2)
+{
+	if (!s1 || !s2) {
+		return NULL;
+	}
+
+	size_t s1len = strlen(s1);
+	size_t s2len = strlen(s2);
+	size_t nlen = s1len + s2len + 1;
+
+	char* dst = malloc(nlen);
+	if (dst == NULL) {
+		return NULL;
+	}
+
+	memcpy(dst, s1, s1len);
+	memcpy(dst + s1len, s2, s2len + 1);
+	return dst;
+}
+
+char *strstrip(const char *str)
+{
+	// leading white-spaces
+	const char *scan = str;
+	while (is_space(scan[0])) {
+		scan += 1;
+	}
+
+	// trailing white-spaces
+	size_t len = strlen(scan);
+	while (len > 0 && is_space(scan[len - 1])) {
+		len -= 1;
+	}
+
+	char *trimmed = malloc(len + 1);
+	if (!trimmed) {
+		return NULL;
+	}
+
+	memcpy(trimmed, scan, len);
+	trimmed[len] = '\0';
+
+	return trimmed;
+}
+
+void strtolower(char *str)
+{
+	if (str == NULL) {
+		return;
+	}
+
+	for (char *it = str; *it != '\0'; ++it) {
+		*it = knot_tolower(*it);
+	}
+}
+
+int const_time_memcmp(const void *s1, const void *s2, size_t n)
+{
+	volatile uint8_t equal = 0;
+
+	for (size_t i = 0; i < n; i++) {
+		equal |= ((uint8_t *)s1)[i] ^ ((uint8_t *)s2)[i];
+	}
+
+	return equal;
+}
+
+#if defined(USE_CUSTOM_MEMSET)
+typedef void *(*memset_t)(void *, int, size_t);
+static volatile memset_t volatile_memset = memset;
+#endif
+
+void *memzero(void *s, size_t n)
+{
+#if defined(HAVE_EXPLICIT_BZERO)	/* In OpenBSD since 5.5. */
+					/* In FreeBSD since 11.0. */
+					/* In glibc since 2.25. */
+					/* In DragonFly BSD since 5.5. */
+#  if defined(__has_feature)
+#    if __has_feature(memory_sanitizer)
+	#warning "Memory sanitizer detected. Using bzero() instead of explicit_bzero()."
+	bzero(s, n);
+#    else
+	explicit_bzero(s, n);
+#    endif
+#  else
+	explicit_bzero(s, n);
+#  endif
+	return s;
+#elif defined(HAVE_EXPLICIT_MEMSET)	/* In NetBSD since 7.0. */
+	return explicit_memset(s, 0, n);
+#elif defined(HAVE_GNUTLS_MEMSET)	/* In GnuTLS since 3.4.0. */
+	gnutls_memset(s, 0, n);
+	return s;
+#else					/* Knot custom solution as a fallback. */
+	/* Warning: the use of the return value is *probably* needed
+	 * so as to avoid the volatile_memset() to be optimized out.
+	 */
+	return volatile_memset(s, 0, n);
+#endif
+}
+
+static const char BIN_TO_HEX[] = {
+	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
+	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+char *bin_to_hex(const uint8_t *bin, size_t bin_len, bool upper_case)
+{
+	if (bin == NULL) {
+		return NULL;
+	}
+
+	size_t hex_size = bin_len * 2;
+	char *hex = malloc(hex_size + 1);
+	if (hex == NULL) {
+		return NULL;
+	}
+
+	unsigned offset = upper_case ? 16 : 0;
+	for (size_t i = 0; i < bin_len; i++) {
+		hex[2 * i]     = BIN_TO_HEX[offset + (bin[i] >> 4)];
+		hex[2 * i + 1] = BIN_TO_HEX[offset + (bin[i] & 0x0f)];
+	}
+	hex[hex_size] = '\0';
+
+	return hex;
+}
+
+/*!
+ * Convert HEX character to numeric value (assumes valid input).
+ */
+static uint8_t hex_to_number(const char hex)
+{
+	if (hex >= '0' && hex <= '9') {
+		return hex - '0';
+	} else if (hex >= 'a' && hex <= 'f') {
+		return hex - 'a' + 10;
+	} else {
+		assert(hex >= 'A' && hex <= 'F');
+		return hex - 'A' + 10;
+	}
+}
+
+uint8_t *hex_to_bin(const char *hex, size_t *out_len)
+{
+	if (hex == NULL || out_len == NULL) {
+		return NULL;
+	}
+
+	size_t hex_len = strlen(hex);
+	if (hex_len % 2 != 0) {
+		return NULL;
+	}
+
+	size_t bin_len = hex_len / 2;
+	uint8_t *bin = malloc(bin_len + 1);
+	if (bin == NULL) {
+		return NULL;
+	}
+
+	for (size_t i = 0; i < bin_len; i++) {
+		if (!is_xdigit(hex[2 * i]) || !is_xdigit(hex[2 * i + 1])) {
+			free(bin);
+			return NULL;
+		}
+		uint8_t high = hex_to_number(hex[2 * i]);
+		uint8_t low  = hex_to_number(hex[2 * i + 1]);
+		bin[i] = high << 4 | low;
+	}
+
+	*out_len = bin_len;
+
+	return bin;
+}