diff options
| -rw-r--r-- | src/network/kernel/qdnslookup_unix.cpp | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/src/network/kernel/qdnslookup_unix.cpp b/src/network/kernel/qdnslookup_unix.cpp index 75f7c6c440..de0113494f 100644 --- a/src/network/kernel/qdnslookup_unix.cpp +++ b/src/network/kernel/qdnslookup_unix.cpp @@ -193,7 +193,6 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN // responseLength in case of error, we still can extract the // exact error code from the response. HEADER *header = (HEADER*)response; - const int answerCount = ntohs(header->ancount); switch (header->rcode) { case NOERROR: break; @@ -226,18 +225,31 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN return; } - // Skip the query host, type (2 bytes) and class (2 bytes). char host[PACKETSZ], answer[PACKETSZ]; unsigned char *p = response + sizeof(HEADER); - int status = local_dn_expand(response, response + responseLength, p, host, sizeof(host)); - if (status < 0) { + int status; + + if (ntohs(header->qdcount) == 1) { + // Skip the query host, type (2 bytes) and class (2 bytes). + status = local_dn_expand(response, response + responseLength, p, host, sizeof(host)); + if (status < 0) { + reply->error = QDnsLookup::InvalidReplyError; + reply->errorString = tr("Could not expand domain name"); + return; + } + if ((p - response) + status + 4 >= responseLength) + header->qdcount = 0xffff; // invalid reply below + else + p += status + 4; + } + if (ntohs(header->qdcount) > 1) { reply->error = QDnsLookup::InvalidReplyError; - reply->errorString = tr("Could not expand domain name"); + reply->errorString = tr("Invalid reply received"); return; } - p += status + 4; // Extract results. + const int answerCount = ntohs(header->ancount); int answerIndex = 0; while ((p < response + responseLength) && (answerIndex < answerCount)) { status = local_dn_expand(response, response + responseLength, p, host, sizeof(host)); @@ -249,6 +261,11 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN const QString name = QUrl::fromAce(host); p += status; + + if ((p - response) + 10 > responseLength) { + // probably just a truncated reply, return what we have + return; + } const quint16 type = (p[0] << 8) | p[1]; p += 2; // RR type p += 2; // RR class @@ -256,6 +273,8 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN p += 4; const quint16 size = (p[0] << 8) | p[1]; p += 2; + if ((p - response) + size > responseLength) + return; // truncated if (type == QDnsLookup::A) { if (size != 4) { |