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#include "includes.h"
#include "../librpc/ndr/libndr.h"
#include "ndr_dns_utils.h"
/**
push a dns/nbt string list to the wire
*/
enum ndr_err_code ndr_push_dns_string_list(struct ndr_push *ndr,
struct ndr_token_list *string_list,
int ndr_flags,
const char *s,
bool is_nbt)
{
const char *start = s;
bool use_compression;
size_t max_length;
if (is_nbt) {
use_compression = true;
/*
* Max length is longer in NBT/Wins, because Windows counts
* the semi-decompressed size of the netbios name (16 bytes)
* rather than the wire size of 32, which is what you'd expect
* if it followed RFC1002 (it uses the short form in
* [MS-WINSRA]). In other words the maximum size of the
* "scope" is 237, not 221.
*
* We make the size limit slightly larger than 255 + 16,
* because the 237 scope limit is already enforced in the
* winsserver code with a specific return value; bailing out
* here would muck with that.
*/
max_length = 274;
} else {
use_compression = !(ndr->flags & LIBNDR_FLAG_NO_COMPRESSION);
max_length = 255;
}
if (!(ndr_flags & NDR_SCALARS)) {
return NDR_ERR_SUCCESS;
}
while (s && *s) {
enum ndr_err_code ndr_err;
char *compname;
size_t complen;
uint32_t offset;
if (use_compression) {
/* see if we have pushed the remaining string already,
* if so we use a label pointer to this string
*/
ndr_err = ndr_token_retrieve_cmp_fn(string_list, s,
&offset,
(comparison_fn_t)strcmp,
false);
if (NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
uint8_t b[2];
if (offset > 0x3FFF) {
return ndr_push_error(ndr, NDR_ERR_STRING,
"offset for dns string " \
"label pointer " \
"%u[%08X] > 0x00003FFF",
offset, offset);
}
b[0] = 0xC0 | (offset>>8);
b[1] = (offset & 0xFF);
return ndr_push_bytes(ndr, b, 2);
}
}
complen = strcspn(s, ".");
/* the length must fit into 6 bits (i.e. <= 63) */
if (complen > 0x3F) {
return ndr_push_error(ndr, NDR_ERR_STRING,
"component length %u[%08X] > " \
"0x0000003F",
(unsigned)complen,
(unsigned)complen);
}
if (complen == 0 && s[complen] == '.') {
return ndr_push_error(ndr, NDR_ERR_STRING,
"component length is 0 "
"(consecutive dots)");
}
if (is_nbt && s[complen] == '.' && s[complen + 1] == '\0') {
/* nbt names are sometimes usernames, and we need to
* keep a trailing dot to ensure it is byte-identical,
* (not just semantically identical given DNS
* semantics). */
complen++;
}
compname = talloc_asprintf(ndr, "%c%*.*s",
(unsigned char)complen,
(unsigned char)complen,
(unsigned char)complen, s);
NDR_ERR_HAVE_NO_MEMORY(compname);
/* remember the current component + the rest of the string
* so it can be reused later
*/
if (use_compression) {
NDR_CHECK(ndr_token_store(ndr, string_list, s,
ndr->offset));
}
/* push just this component into the blob */
NDR_CHECK(ndr_push_bytes(ndr, (const uint8_t *)compname,
complen+1));
talloc_free(compname);
s += complen;
if (*s == '.') {
s++;
}
if (s - start > max_length) {
return ndr_push_error(ndr, NDR_ERR_STRING,
"name > %zu character long",
max_length);
}
}
/* if we reach the end of the string and have pushed the last component
* without using a label pointer, we need to terminate the string
*/
return ndr_push_bytes(ndr, (const uint8_t *)"", 1);
}
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