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fix parsing unexpected mdns txt response

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This commit is contained in:
John
2025-01-09 20:44:34 +01:00
parent 2b3aa08673
commit 0445e4412e
1 changed files with 17 additions and 7 deletions
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src/lib/utils/tcpsocket.cpp
+16 -6
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@@ -579,23 +579,33 @@ int resolveMdnsOneShot(const char* url, mdns_oneshot_t *result, mdns_oneshot_t *
printf(" %s=%s\n", (atype == DNS_TYPE_TXT) ? "txt" : "ptr", name);
#endif
if (atype == DNS_TYPE_TXT && name[0]) {
// parse id=xxxxxxxxxxxx[.proto=xxx]
char* sep = strchr(name, '=');
char* sep2;
if (sep && strncmp(name, "id", sep-name) == 0) {
sep2 = strchr(name, '.');
if (sep && sep-name == 2 && strncmp(name, "id", 2) == 0) {
sep2 = strchr(sep+1, '.');
if (!sep2) {
sep2 = name + pos;
}
if (sep2-sep-1 == sizeof(mdns_oneshot_t::id)-1) {
memcpy(id, sep+1, sizeof(mdns_oneshot_t::id)-1);
} else {
sep = nullptr;
}
sep = sep ? strchr(sep2+1, '=') : nullptr;
sep = sep && sep2 < name + pos ? strchr(sep2+1, '=') : nullptr;
} else {
sep2 = name - 1;
}
if (sep && strncmp(sep2+1, "proto", sep-sep2-1) == 0 && (
pos == (size_t)(sep-name)+1+sizeof(mdns_oneshot_t::proto)-1
|| strchr(sep+1, '.') == sep+1+sizeof(mdns_oneshot_t::proto)-1)) {
if (sep && sep-sep2-1 == 5 && strncmp(sep2+1, "proto", 5) == 0) {
sep2 = strchr(sep+1, '.');
if (!sep2) {
sep2 = name + pos;
}
if (sep2-sep-1 == sizeof(mdns_oneshot_t::proto)-1) {
memcpy(proto, sep+1, sizeof(mdns_oneshot_t::proto)-1);
}
}
}
} else if (atype == DNS_TYPE_SRV && rdLen >= sizeof(dns_rr_srv_t)) {
dns_rr_srv_t *srv = reinterpret_cast<dns_rr_srv_t*>(record+len);
size_t pos = 0;