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from trunk: Match the query in DNS replies to the query in the request; from Vsevolod Stakhov

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svn:r932
This commit is contained in:
Niels Provos 2008-08-30 23:24:25 +00:00
parent 2821152f7f
commit bc465d0a80
2 changed files with 35 additions and 14 deletions
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3
ChangeLog
View File

@ -1,3 +1,6 @@
Changes in 1.4.8-stable:
o Match the query in DNS replies to the query in the request; from Vsevolod Stakhov.
Changes in 1.4.7-stable:
o Fix a bug where headers arriving in multiple packets were not parsed; fix from Jiang Hong; test by me.

46
evdns.c
View File

@ -680,7 +680,10 @@ reply_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply)
static void
reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) {
int error;
static const int error_codes[] = {DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST, DNS_ERR_NOTIMPL, DNS_ERR_REFUSED};
static const int error_codes[] = {
DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST,
DNS_ERR_NOTIMPL, DNS_ERR_REFUSED
};
if (flags & 0x020f || !reply || !reply->have_answer) {
/* there was an error */
@ -709,9 +712,10 @@ reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply)
}
break;
case DNS_ERR_SERVERFAILED:
/* rcode 2 (servfailed) sometimes means "we are broken" and
* sometimes (with some binds) means "that request was very
* confusing." Treat this as a timeout, not a failure.
/* rcode 2 (servfailed) sometimes means "we
* are broken" and sometimes (with some binds)
* means "that request was very confusing."
* Treat this as a timeout, not a failure.
*/
log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver %s; "
"will allow the request to time out.",
@ -723,10 +727,13 @@ reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply)
}
if (req->search_state && req->request_type != TYPE_PTR) {
/* if we have a list of domains to search in, try the next one */
/* if we have a list of domains to search in,
* try the next one */
if (!search_try_next(req)) {
/* a new request was issued so this request is finished and */
/* the user callback will be made when that request (or a */
/* a new request was issued so this
* request is finished and */
/* the user callback will be made when
* that request (or a */
/* child of it) finishes. */
request_finished(req, &req_head);
return;
@ -803,10 +810,10 @@ name_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) {
/* parses a raw request from a nameserver */
static int
reply_parse(u8 *packet, int length) {
int j = 0; /* index into packet */
int j = 0, k = 0; /* index into packet */
u16 _t; /* used by the macros */
u32 _t32; /* used by the macros */
char tmp_name[256]; /* used by the macros */
char tmp_name[256], cmp_name[256]; /* used by the macros */
u16 trans_id, questions, answers, authority, additional, datalength;
u16 flags = 0;
@ -839,10 +846,21 @@ reply_parse(u8 *packet, int length) {
/* This macro skips a name in the DNS reply. */
#define SKIP_NAME \
do { tmp_name[0] = '\0'; \
if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0) \
goto err; \
} while(0);
do { tmp_name[0] = '\0'; \
if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
goto err; \
} while(0)
#define TEST_NAME \
do { tmp_name[0] = '\0'; \
cmp_name[0] = '\0'; \
k = j; \
if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)\
goto err; \
if (name_parse(req->request, req->request_len, &k, cmp_name, sizeof(cmp_name))<0) \
goto err; \
if (memcmp(tmp_name, cmp_name, strlen (tmp_name)) != 0) \
return (-1); /* we ignore mismatching names */ \
} while(0)
reply.type = req->request_type;
@ -851,7 +869,7 @@ reply_parse(u8 *packet, int length) {
/* the question looks like
* <label:name><u16:type><u16:class>
*/
SKIP_NAME;
TEST_NAME;
j += 4;
if (j > length) goto err;
}