/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see .
***/
#ifdef HAVE_LIBIDN
#include
#include
#endif
#include "dns-domain.h"
int dns_label_unescape(const char **name, char *dest, size_t sz) {
const char *n;
char *d;
int r = 0;
assert(name);
assert(*name);
assert(dest);
n = *name;
d = dest;
for (;;) {
if (*n == '.') {
n++;
break;
}
if (*n == 0)
break;
if (sz <= 0)
return -ENOSPC;
if (r >= DNS_LABEL_MAX)
return -EINVAL;
if (*n == '\\') {
/* Escaped character */
n++;
if (*n == 0)
/* Ending NUL */
return -EINVAL;
else if (*n == '\\' || *n == '.') {
/* Escaped backslash or dot */
*(d++) = *(n++);
sz--;
r++;
} else if (n[0] >= '0' && n[0] <= '9') {
unsigned k;
/* Escaped literal ASCII character */
if (!(n[1] >= '0' && n[1] <= '9') ||
!(n[2] >= '0' && n[2] <= '9'))
return -EINVAL;
k = ((unsigned) (n[0] - '0') * 100) +
((unsigned) (n[1] - '0') * 10) +
((unsigned) (n[2] - '0'));
/* Don't allow CC characters or anything that doesn't fit in 8bit */
if (k < ' ' || k > 255 || k == 127)
return -EINVAL;
*(d++) = (char) k;
sz--;
r++;
n += 3;
} else
return -EINVAL;
} else if ((uint8_t) *n >= (uint8_t) ' ' && *n != 127) {
/* Normal character */
*(d++) = *(n++);
sz--;
r++;
} else
return -EINVAL;
}
/* Empty label that is not at the end? */
if (r == 0 && *n)
return -EINVAL;
if (sz >= 1)
*d = 0;
*name = n;
return r;
}
/* @label_terminal: terminal character of a label, updated to point to the terminal character of
* the previous label (always skipping one dot) or to NULL if there are no more
* labels. */
int dns_label_unescape_suffix(const char *name, const char **label_terminal, char *dest, size_t sz) {
const char *terminal;
int r;
assert(name);
assert(label_terminal);
assert(dest);
/* no more labels */
if (!*label_terminal) {
if (sz >= 1)
*dest = 0;
return 0;
}
assert(**label_terminal == '.' || **label_terminal == 0);
/* skip current terminal character */
terminal = *label_terminal - 1;
/* point name to the last label, and terminal to the preceding terminal symbol (or make it a NULL pointer) */
for (;;) {
if (terminal < name) {
/* reached the first label, so indicate that there are no more */
terminal = NULL;
break;
}
/* find the start of the last label */
if (*terminal == '.') {
const char *y;
unsigned slashes = 0;
for (y = terminal - 1; y >= name && *y == '\\'; y--)
slashes ++;
if (slashes % 2 == 0) {
/* the '.' was not escaped */
name = terminal + 1;
break;
} else {
terminal = y;
continue;
}
}
terminal --;
}
r = dns_label_unescape(&name, dest, sz);
if (r < 0)
return r;
*label_terminal = terminal;
return r;
}
int dns_label_escape(const char *p, size_t l, char **ret) {
_cleanup_free_ char *s = NULL;
char *q;
int r;
assert(p);
assert(ret);
if (l > DNS_LABEL_MAX)
return -EINVAL;
s = malloc(l * 4 + 1);
if (!s)
return -ENOMEM;
q = s;
while (l > 0) {
if (*p == '.' || *p == '\\') {
/* Dot or backslash */
*(q++) = '\\';
*(q++) = *p;
} else if (*p == '_' ||
*p == '-' ||
(*p >= '0' && *p <= '9') ||
(*p >= 'a' && *p <= 'z') ||
(*p >= 'A' && *p <= 'Z')) {
/* Proper character */
*(q++) = *p;
} else if ((uint8_t) *p >= (uint8_t) ' ' && *p != 127) {
/* Everything else */
*(q++) = '\\';
*(q++) = '0' + (char) ((uint8_t) *p / 100);
*(q++) = '0' + (char) (((uint8_t) *p / 10) % 10);
*(q++) = '0' + (char) ((uint8_t) *p % 10);
} else
return -EINVAL;
p++;
l--;
}
*q = 0;
*ret = s;
r = q - s;
s = NULL;
return r;
}
int dns_label_apply_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
#ifdef HAVE_LIBIDN
_cleanup_free_ uint32_t *input = NULL;
size_t input_size;
const char *p;
bool contains_8bit = false;
assert(encoded);
assert(decoded);
assert(decoded_max >= DNS_LABEL_MAX);
if (encoded_size <= 0)
return 0;
for (p = encoded; p < encoded + encoded_size; p++)
if ((uint8_t) *p > 127)
contains_8bit = true;
if (!contains_8bit)
return 0;
input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
if (!input)
return -ENOMEM;
if (idna_to_ascii_4i(input, input_size, decoded, 0) != 0)
return -EINVAL;
return strlen(decoded);
#else
return 0;
#endif
}
int dns_label_undo_idna(const char *encoded, size_t encoded_size, char *decoded, size_t decoded_max) {
#ifdef HAVE_LIBIDN
size_t input_size, output_size;
_cleanup_free_ uint32_t *input = NULL;
_cleanup_free_ char *result = NULL;
uint32_t *output = NULL;
size_t w;
/* To be invoked after unescaping */
assert(encoded);
assert(decoded);
if (encoded_size < sizeof(IDNA_ACE_PREFIX)-1)
return 0;
if (memcmp(encoded, IDNA_ACE_PREFIX, sizeof(IDNA_ACE_PREFIX) -1) != 0)
return 0;
input = stringprep_utf8_to_ucs4(encoded, encoded_size, &input_size);
if (!input)
return -ENOMEM;
output_size = input_size;
output = newa(uint32_t, output_size);
idna_to_unicode_44i(input, input_size, output, &output_size, 0);
result = stringprep_ucs4_to_utf8(output, output_size, NULL, &w);
if (!result)
return -ENOMEM;
if (w <= 0)
return 0;
if (w+1 > decoded_max)
return -EINVAL;
memcpy(decoded, result, w+1);
return w;
#else
return 0;
#endif
}
int dns_name_normalize(const char *s, char **_ret) {
_cleanup_free_ char *ret = NULL;
size_t n = 0, allocated = 0;
const char *p = s;
bool first = true;
int r;
assert(s);
for (;;) {
_cleanup_free_ char *t = NULL;
char label[DNS_LABEL_MAX];
int k;
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
return r;
if (r == 0) {
if (*p != 0)
return -EINVAL;
break;
}
k = dns_label_undo_idna(label, r, label, sizeof(label));
if (k < 0)
return k;
if (k > 0)
r = k;
r = dns_label_escape(label, r, &t);
if (r < 0)
return r;
if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1))
return -ENOMEM;
if (!first)
ret[n++] = '.';
else
first = false;
memcpy(ret + n, t, r);
n += r;
}
if (n > DNS_NAME_MAX)
return -EINVAL;
if (!GREEDY_REALLOC(ret, allocated, n + 1))
return -ENOMEM;
ret[n] = 0;
if (_ret) {
*_ret = ret;
ret = NULL;
}
return 0;
}
unsigned long dns_name_hash_func(const void *s, const uint8_t hash_key[HASH_KEY_SIZE]) {
const char *p = s;
unsigned long ul = hash_key[0];
int r;
assert(p);
while (*p) {
char label[DNS_LABEL_MAX+1];
int k;
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
break;
k = dns_label_undo_idna(label, r, label, sizeof(label));
if (k < 0)
break;
if (k > 0)
r = k;
label[r] = 0;
ascii_strlower(label);
ul = ul * hash_key[1] + ul + string_hash_func(label, hash_key);
}
return ul;
}
int dns_name_compare_func(const void *a, const void *b) {
const char *x, *y;
int r, q, k, w;
assert(a);
assert(b);
x = (const char *) a + strlen(a);
y = (const char *) b + strlen(b);
for (;;) {
char la[DNS_LABEL_MAX+1], lb[DNS_LABEL_MAX+1];
if (x == NULL && y == NULL)
return 0;
r = dns_label_unescape_suffix(a, &x, la, sizeof(la));
q = dns_label_unescape_suffix(b, &y, lb, sizeof(lb));
if (r < 0 || q < 0)
return r - q;
k = dns_label_undo_idna(la, r, la, sizeof(la));
w = dns_label_undo_idna(lb, q, lb, sizeof(lb));
if (k < 0 || w < 0)
return k - w;
if (k > 0)
r = k;
if (w > 0)
r = w;
la[r] = lb[q] = 0;
r = strcasecmp(la, lb);
if (r != 0)
return r;
}
}
const struct hash_ops dns_name_hash_ops = {
.hash = dns_name_hash_func,
.compare = dns_name_compare_func
};
int dns_name_equal(const char *x, const char *y) {
int r, q, k, w;
assert(x);
assert(y);
for (;;) {
char la[DNS_LABEL_MAX+1], lb[DNS_LABEL_MAX+1];
if (*x == 0 && *y == 0)
return true;
r = dns_label_unescape(&x, la, sizeof(la));
if (r < 0)
return r;
k = dns_label_undo_idna(la, r, la, sizeof(la));
if (k < 0)
return k;
if (k > 0)
r = k;
q = dns_label_unescape(&y, lb, sizeof(lb));
if (q < 0)
return q;
w = dns_label_undo_idna(lb, q, lb, sizeof(lb));
if (w < 0)
return w;
if (w > 0)
q = w;
la[r] = lb[q] = 0;
if (strcasecmp(la, lb))
return false;
}
}
int dns_name_endswith(const char *name, const char *suffix) {
const char *n, *s, *saved_n = NULL;
int r, q, k, w;
assert(name);
assert(suffix);
n = name;
s = suffix;
for (;;) {
char ln[DNS_LABEL_MAX+1], ls[DNS_LABEL_MAX+1];
r = dns_label_unescape(&n, ln, sizeof(ln));
if (r < 0)
return r;
k = dns_label_undo_idna(ln, r, ln, sizeof(ln));
if (k < 0)
return k;
if (k > 0)
r = k;
if (!saved_n)
saved_n = n;
q = dns_label_unescape(&s, ls, sizeof(ls));
if (q < 0)
return q;
w = dns_label_undo_idna(ls, q, ls, sizeof(ls));
if (w < 0)
return w;
if (w > 0)
q = w;
if (r == 0 && q == 0)
return true;
if (r == 0 && saved_n == n)
return false;
ln[r] = ls[q] = 0;
if (r != q || strcasecmp(ln, ls)) {
/* Not the same, let's jump back, and try with the next label again */
s = suffix;
n = saved_n;
saved_n = NULL;
}
}
}
int dns_name_between(const char *a, const char *b, const char *c) {
int n;
/* Determine if b is strictly greater than a and strictly smaller than c.
We consider the order of names to be circular, so that if a is
strictly greater than c, we consider b to be between them if it is
either greater than a or smaller than c. This is how the canonical
DNS name order used in NSEC records work. */
n = dns_name_compare_func(a, c);
if (n == 0)
return -EINVAL;
else if (n < 0)
/* a<---b--->c */
return dns_name_compare_func(a, b) < 0 &&
dns_name_compare_func(b, c) < 0;
else
/* <--b--c a--b--> */
return dns_name_compare_func(b, c) < 0 ||
dns_name_compare_func(a, b) < 0;
}
int dns_name_reverse(int family, const union in_addr_union *a, char **ret) {
const uint8_t *p;
int r;
assert(a);
assert(ret);
p = (const uint8_t*) a;
if (family == AF_INET)
r = asprintf(ret, "%u.%u.%u.%u.in-addr.arpa", p[3], p[2], p[1], p[0]);
else if (family == AF_INET6)
r = asprintf(ret, "%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.%c.ip6.arpa",
hexchar(p[15] & 0xF), hexchar(p[15] >> 4), hexchar(p[14] & 0xF), hexchar(p[14] >> 4),
hexchar(p[13] & 0xF), hexchar(p[13] >> 4), hexchar(p[12] & 0xF), hexchar(p[12] >> 4),
hexchar(p[11] & 0xF), hexchar(p[11] >> 4), hexchar(p[10] & 0xF), hexchar(p[10] >> 4),
hexchar(p[ 9] & 0xF), hexchar(p[ 9] >> 4), hexchar(p[ 8] & 0xF), hexchar(p[ 8] >> 4),
hexchar(p[ 7] & 0xF), hexchar(p[ 7] >> 4), hexchar(p[ 6] & 0xF), hexchar(p[ 6] >> 4),
hexchar(p[ 5] & 0xF), hexchar(p[ 5] >> 4), hexchar(p[ 4] & 0xF), hexchar(p[ 4] >> 4),
hexchar(p[ 3] & 0xF), hexchar(p[ 3] >> 4), hexchar(p[ 2] & 0xF), hexchar(p[ 2] >> 4),
hexchar(p[ 1] & 0xF), hexchar(p[ 1] >> 4), hexchar(p[ 0] & 0xF), hexchar(p[ 0] >> 4));
else
return -EAFNOSUPPORT;
if (r < 0)
return -ENOMEM;
return 0;
}
int dns_name_address(const char *p, int *family, union in_addr_union *address) {
int r;
assert(p);
assert(family);
assert(address);
r = dns_name_endswith(p, "in-addr.arpa");
if (r < 0)
return r;
if (r > 0) {
uint8_t a[4];
unsigned i;
for (i = 0; i < ELEMENTSOF(a); i++) {
char label[DNS_LABEL_MAX+1];
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
return r;
if (r == 0)
return -EINVAL;
if (r > 3)
return -EINVAL;
r = safe_atou8(label, &a[i]);
if (r < 0)
return r;
}
r = dns_name_equal(p, "in-addr.arpa");
if (r <= 0)
return r;
*family = AF_INET;
address->in.s_addr = htobe32(((uint32_t) a[3] << 24) |
((uint32_t) a[2] << 16) |
((uint32_t) a[1] << 8) |
(uint32_t) a[0]);
return 1;
}
r = dns_name_endswith(p, "ip6.arpa");
if (r < 0)
return r;
if (r > 0) {
struct in6_addr a;
unsigned i;
for (i = 0; i < ELEMENTSOF(a.s6_addr); i++) {
char label[DNS_LABEL_MAX+1];
int x, y;
r = dns_label_unescape(&p, label, sizeof(label));
if (r <= 0)
return r;
if (r != 1)
return -EINVAL;
x = unhexchar(label[0]);
if (x < 0)
return -EINVAL;
r = dns_label_unescape(&p, label, sizeof(label));
if (r <= 0)
return r;
if (r != 1)
return -EINVAL;
y = unhexchar(label[0]);
if (y < 0)
return -EINVAL;
a.s6_addr[ELEMENTSOF(a.s6_addr) - i - 1] = (uint8_t) y << 4 | (uint8_t) x;
}
r = dns_name_equal(p, "ip6.arpa");
if (r <= 0)
return r;
*family = AF_INET6;
address->in6 = a;
return 1;
}
return 0;
}
int dns_name_root(const char *name) {
char label[DNS_LABEL_MAX+1];
int r;
assert(name);
r = dns_label_unescape(&name, label, sizeof(label));
if (r < 0)
return r;
return r == 0 && *name == 0;
}
int dns_name_single_label(const char *name) {
char label[DNS_LABEL_MAX+1];
int r;
assert(name);
r = dns_label_unescape(&name, label, sizeof(label));
if (r < 0)
return r;
if (r == 0)
return 0;
r = dns_label_unescape(&name, label, sizeof(label));
if (r < 0)
return r;
return r == 0 && *name == 0;
}