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ee8d777bbf
From RFC 1035: 3.3.14. TXT RDATA format +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ / TXT-DATA / +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ where: TXT-DATA One or more <character-string>s. TXT RRs are used to hold descriptive text. The semantics of the text depends on the domain where it is found. Each record contains an array of strings instead of just one string. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11128 BUG: https://bugzilla.samba.org/show_bug.cgi?id=11686 Signed-off-by: Stefan Metzmacher <metze@samba.org> Reviewed-by: Garming Sam <garming@catalyst.net.nz> Reviewed-by: Andrew Bartlett <abartlet@samba.org>
370 lines
10 KiB
C
370 lines
10 KiB
C
/*
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Unix SMB/CIFS implementation.
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manipulate dns name structures
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Copyright (C) 2010 Kai Blin <kai@samba.org>
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Heavily based on nbtname.c which is:
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Copyright (C) Andrew Tridgell 2005
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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see rfc1002 for the detailed format of compressed names
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*/
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#include "includes.h"
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#include "librpc/gen_ndr/ndr_dns.h"
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#include "librpc/gen_ndr/ndr_misc.h"
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#include "librpc/gen_ndr/ndr_dnsp.h"
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#include "system/locale.h"
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#include "lib/util/util_net.h"
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/* don't allow an unlimited number of name components */
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#define MAX_COMPONENTS 128
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/**
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print a dns string
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*/
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_PUBLIC_ void ndr_print_dns_string(struct ndr_print *ndr,
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const char *name,
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const char *s)
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{
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ndr_print_string(ndr, name, s);
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}
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/*
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pull one component of a dns_string
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*/
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static enum ndr_err_code ndr_pull_component(struct ndr_pull *ndr,
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uint8_t **component,
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uint32_t *offset,
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uint32_t *max_offset)
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{
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uint8_t len;
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unsigned int loops = 0;
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while (loops < 5) {
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if (*offset >= ndr->data_size) {
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME component, bad offset");
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}
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len = ndr->data[*offset];
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if (len == 0) {
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*offset += 1;
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*max_offset = MAX(*max_offset, *offset);
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*component = NULL;
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return NDR_ERR_SUCCESS;
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}
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if ((len & 0xC0) == 0xC0) {
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/* its a label pointer */
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if (1 + *offset >= ndr->data_size) {
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME component, " \
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"bad label offset");
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}
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*max_offset = MAX(*max_offset, *offset + 2);
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*offset = ((len&0x3F)<<8) | ndr->data[1 + *offset];
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*max_offset = MAX(*max_offset, *offset);
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loops++;
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continue;
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}
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if ((len & 0xC0) != 0) {
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/* its a reserved length field */
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME component, " \
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"reserved length field: 0x%02x",
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(len &0xC));
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}
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if (*offset + len + 1 > ndr->data_size) {
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME component, "\
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"length too long");
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}
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*component = (uint8_t*)talloc_strndup(ndr,
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(const char *)&ndr->data[1 + *offset], len);
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NDR_ERR_HAVE_NO_MEMORY(*component);
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*offset += len + 1;
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*max_offset = MAX(*max_offset, *offset);
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return NDR_ERR_SUCCESS;
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}
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/* too many pointers */
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME component, too many pointers");
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}
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/**
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pull a dns_string from the wire
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*/
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_PUBLIC_ enum ndr_err_code ndr_pull_dns_string(struct ndr_pull *ndr,
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int ndr_flags,
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const char **s)
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{
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uint32_t offset = ndr->offset;
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uint32_t max_offset = offset;
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unsigned num_components;
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char *name;
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if (!(ndr_flags & NDR_SCALARS)) {
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return NDR_ERR_SUCCESS;
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}
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name = talloc_strdup(ndr->current_mem_ctx, "");
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/* break up name into a list of components */
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for (num_components=0; num_components<MAX_COMPONENTS;
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num_components++) {
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uint8_t *component = NULL;
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NDR_CHECK(ndr_pull_component(ndr, &component, &offset,
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&max_offset));
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if (component == NULL) break;
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if (num_components > 0) {
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name = talloc_asprintf_append_buffer(name, ".%s",
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component);
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} else {
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name = talloc_asprintf_append_buffer(name, "%s",
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component);
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}
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NDR_ERR_HAVE_NO_MEMORY(name);
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}
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if (num_components == MAX_COMPONENTS) {
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return ndr_pull_error(ndr, NDR_ERR_STRING,
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"BAD DNS NAME too many components");
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}
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(*s) = name;
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ndr->offset = max_offset;
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return NDR_ERR_SUCCESS;
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}
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/**
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push a dns string to the wire
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*/
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_PUBLIC_ enum ndr_err_code ndr_push_dns_string(struct ndr_push *ndr,
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int ndr_flags,
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const char *s)
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{
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if (!(ndr_flags & NDR_SCALARS)) {
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return NDR_ERR_SUCCESS;
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}
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while (s && *s) {
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enum ndr_err_code ndr_err;
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char *compname;
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size_t complen;
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uint32_t offset;
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/* see if we have pushed the remaining string already,
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* if so we use a label pointer to this string
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*/
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ndr_err = ndr_token_retrieve_cmp_fn(&ndr->dns_string_list, s,
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&offset,
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(comparison_fn_t)strcmp,
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false);
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if (NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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uint8_t b[2];
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if (offset > 0x3FFF) {
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return ndr_push_error(ndr, NDR_ERR_STRING,
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"offset for dns string " \
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"label pointer " \
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"%u[%08X] > 0x00003FFF",
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offset, offset);
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}
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b[0] = 0xC0 | (offset>>8);
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b[1] = (offset & 0xFF);
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return ndr_push_bytes(ndr, b, 2);
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}
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complen = strcspn(s, ".");
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/* we need to make sure the length fits into 6 bytes */
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if (complen > 0x3F) {
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return ndr_push_error(ndr, NDR_ERR_STRING,
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"component length %u[%08X] > " \
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"0x0000003F",
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(unsigned)complen,
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(unsigned)complen);
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}
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compname = talloc_asprintf(ndr, "%c%*.*s",
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(unsigned char)complen,
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(unsigned char)complen,
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(unsigned char)complen, s);
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NDR_ERR_HAVE_NO_MEMORY(compname);
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/* remember the current componemt + the rest of the string
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* so it can be reused later
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*/
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NDR_CHECK(ndr_token_store(ndr, &ndr->dns_string_list, s,
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ndr->offset));
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/* push just this component into the blob */
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NDR_CHECK(ndr_push_bytes(ndr, (const uint8_t *)compname,
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complen+1));
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talloc_free(compname);
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s += complen;
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if (*s == '.') s++;
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}
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/* if we reach the end of the string and have pushed the last component
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* without using a label pointer, we need to terminate the string
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*/
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return ndr_push_bytes(ndr, (const uint8_t *)"", 1);
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}
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_PUBLIC_ enum ndr_err_code ndr_pull_dns_txt_record(struct ndr_pull *ndr, int ndr_flags, struct dns_txt_record *r)
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{
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NDR_PULL_CHECK_FLAGS(ndr, ndr_flags);
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if (ndr_flags & NDR_SCALARS) {
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enum ndr_err_code ndr_err;
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uint32_t data_size = ndr->data_size;
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uint32_t record_size = 0;
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ndr_err = ndr_token_retrieve(&ndr->array_size_list, r,
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&record_size);
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if (NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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NDR_PULL_NEED_BYTES(ndr, record_size);
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ndr->data_size = ndr->offset + record_size;
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}
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NDR_CHECK(ndr_pull_align(ndr, 1));
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NDR_CHECK(ndr_pull_dnsp_string_list(ndr, NDR_SCALARS, &r->txt));
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NDR_CHECK(ndr_pull_trailer_align(ndr, 1));
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ndr->data_size = data_size;
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}
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if (ndr_flags & NDR_BUFFERS) {
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}
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return NDR_ERR_SUCCESS;
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}
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_PUBLIC_ enum ndr_err_code ndr_push_dns_res_rec(struct ndr_push *ndr,
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int ndr_flags,
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const struct dns_res_rec *r)
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{
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uint32_t _flags_save_STRUCT = ndr->flags;
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uint32_t _saved_offset1, _saved_offset2;
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uint16_t length;
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ndr_set_flags(&ndr->flags, LIBNDR_PRINT_ARRAY_HEX |
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LIBNDR_FLAG_NOALIGN);
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if (ndr_flags & NDR_SCALARS) {
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NDR_CHECK(ndr_push_align(ndr, 4));
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NDR_CHECK(ndr_push_dns_string(ndr, NDR_SCALARS, r->name));
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NDR_CHECK(ndr_push_dns_qtype(ndr, NDR_SCALARS, r->rr_type));
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NDR_CHECK(ndr_push_dns_qclass(ndr, NDR_SCALARS, r->rr_class));
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NDR_CHECK(ndr_push_uint32(ndr, NDR_SCALARS, r->ttl));
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_saved_offset1 = ndr->offset;
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NDR_CHECK(ndr_push_uint16(ndr, NDR_SCALARS, 0));
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if (r->length > 0) {
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NDR_CHECK(ndr_push_set_switch_value(ndr, &r->rdata,
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r->rr_type));
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NDR_CHECK(ndr_push_dns_rdata(ndr, NDR_SCALARS,
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&r->rdata));
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if (r->unexpected.length > 0) {
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return ndr_push_error(ndr,
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NDR_ERR_LENGTH,
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"Invalid...Unexpected " \
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"blob length is too " \
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"large");
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}
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}
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if (r->unexpected.length > UINT16_MAX) {
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return ndr_push_error(ndr, NDR_ERR_LENGTH,
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"Unexpected blob length "\
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"is too large");
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}
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NDR_CHECK(ndr_push_bytes(ndr, r->unexpected.data,
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r->unexpected.length));
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NDR_CHECK(ndr_push_trailer_align(ndr, 4));
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length = ndr->offset - (_saved_offset1 + 2);
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_saved_offset2 = ndr->offset;
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ndr->offset = _saved_offset1;
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NDR_CHECK(ndr_push_uint16(ndr, NDR_SCALARS, length));
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ndr->offset = _saved_offset2;
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}
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if (ndr_flags & NDR_BUFFERS) {
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NDR_CHECK(ndr_push_dns_rdata(ndr, NDR_BUFFERS,
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&r->rdata));
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}
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ndr->flags = _flags_save_STRUCT;
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return NDR_ERR_SUCCESS;
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}
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_PUBLIC_ enum ndr_err_code ndr_pull_dns_res_rec(struct ndr_pull *ndr,
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int ndr_flags,
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struct dns_res_rec *r)
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{
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uint32_t _flags_save_STRUCT = ndr->flags;
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uint32_t _saved_offset1;
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uint32_t pad, length;
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ndr_set_flags(&ndr->flags, LIBNDR_PRINT_ARRAY_HEX |
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LIBNDR_FLAG_NOALIGN);
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if (ndr_flags & NDR_SCALARS) {
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NDR_CHECK(ndr_pull_align(ndr, 4));
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NDR_CHECK(ndr_pull_dns_string(ndr, NDR_SCALARS, &r->name));
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NDR_CHECK(ndr_pull_dns_qtype(ndr, NDR_SCALARS, &r->rr_type));
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NDR_CHECK(ndr_pull_dns_qclass(ndr, NDR_SCALARS, &r->rr_class));
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NDR_CHECK(ndr_pull_uint32(ndr, NDR_SCALARS, &r->ttl));
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NDR_CHECK(ndr_pull_uint16(ndr, NDR_SCALARS, &r->length));
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_saved_offset1 = ndr->offset;
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if (r->length > 0) {
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NDR_CHECK(ndr_token_store(ndr, &ndr->array_size_list,
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&r->rdata,
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r->length));
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NDR_CHECK(ndr_pull_set_switch_value(ndr, &r->rdata,
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r->rr_type));
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NDR_CHECK(ndr_pull_dns_rdata(ndr, NDR_SCALARS,
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&r->rdata));
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} else {
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ZERO_STRUCT(r->rdata);
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}
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length = ndr->offset - _saved_offset1;
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if (length > r->length) {
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return ndr_pull_error(ndr, NDR_ERR_LENGTH, "TODO");
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}
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r->unexpected = data_blob_null;
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pad = r->length - length;
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if (pad > 0) {
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NDR_PULL_NEED_BYTES(ndr, pad);
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r->unexpected = data_blob_talloc(ndr->current_mem_ctx,
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ndr->data +
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ndr->offset,
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pad);
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if (r->unexpected.data == NULL) {
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return ndr_pull_error(ndr,
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NDR_ERR_ALLOC,
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"Failed to allocate a " \
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"data blob");
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}
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ndr->offset += pad;
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}
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NDR_CHECK(ndr_pull_trailer_align(ndr, 4));
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}
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if (ndr_flags & NDR_BUFFERS) {
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NDR_CHECK(ndr_pull_dns_rdata(ndr, NDR_BUFFERS, &r->rdata));
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}
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ndr->flags = _flags_save_STRUCT;
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return NDR_ERR_SUCCESS;
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}
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