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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:47:29 +0000
commit4f5791ebd03eaec1c7da0865a383175b05102712 (patch)
tree8ce7b00f7a76baa386372422adebbe64510812d4 /librpc/ndr/ndr_dns_utils.c
parentInitial commit. (diff)
downloadsamba-4f5791ebd03eaec1c7da0865a383175b05102712.tar.xz
samba-4f5791ebd03eaec1c7da0865a383175b05102712.zip
Adding upstream version 2:4.17.12+dfsg.upstream/2%4.17.12+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'librpc/ndr/ndr_dns_utils.c')
-rw-r--r--librpc/ndr/ndr_dns_utils.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/librpc/ndr/ndr_dns_utils.c b/librpc/ndr/ndr_dns_utils.c
new file mode 100644
index 0000000..325d9c6
--- /dev/null
+++ b/librpc/ndr/ndr_dns_utils.c
@@ -0,0 +1,134 @@
+#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);
+}