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MFC r275852: MFV r275844:

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Fix unbound remote denial of service vulnerability.

Security:	FreeBSD-SA-14:30.unbound
Security:	CVE-2014-8602
Approved by:	so
This commit is contained in:
Xin LI 2014-12-17 06:58:00 +00:00
parent beb415ae78
commit d8b6f1cf3d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/stable/10/; revision=275853
2 changed files with 50 additions and 0 deletions
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44
contrib/unbound/iterator/iterator.c
View File

@ -120,6 +120,7 @@ iter_new(struct module_qstate* qstate, int id)
iq->query_restart_count = 0;
iq->referral_count = 0;
iq->sent_count = 0;
iq->target_count = NULL;
iq->wait_priming_stub = 0;
iq->refetch_glue = 0;
iq->dnssec_expected = 0;
@ -445,6 +446,26 @@ handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
return 1;
}
/** create target count structure for this query */
static void
target_count_create(struct iter_qstate* iq)
{
if(!iq->target_count) {
iq->target_count = (int*)calloc(2, sizeof(int));
/* if calloc fails we simply do not track this number */
if(iq->target_count)
iq->target_count[0] = 1;
}
}
static void
target_count_increase(struct iter_qstate* iq, int num)
{
target_count_create(iq);
if(iq->target_count)
iq->target_count[1] += num;
}
/**
* Generate a subrequest.
* Generate a local request event. Local events are tied to this module, and
@ -516,6 +537,10 @@ generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype,
subiq = (struct iter_qstate*)subq->minfo[id];
memset(subiq, 0, sizeof(*subiq));
subiq->num_target_queries = 0;
target_count_create(iq);
subiq->target_count = iq->target_count;
if(iq->target_count)
iq->target_count[0] ++; /* extra reference */
subiq->num_current_queries = 0;
subiq->depth = iq->depth+1;
outbound_list_init(&subiq->outlist);
@ -1342,6 +1367,12 @@ query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq,
if(iq->depth == ie->max_dependency_depth)
return 0;
if(iq->depth > 0 && iq->target_count &&
iq->target_count[1] > MAX_TARGET_COUNT) {
verbose(VERB_QUERY, "request has exceeded the maximum "
"number of glue fetches %d", iq->target_count[1]);
return 0;
}
iter_mark_cycle_targets(qstate, iq->dp);
missing = (int)delegpt_count_missing_targets(iq->dp);
@ -1524,6 +1555,7 @@ processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
iq->num_target_queries += qs;
target_count_increase(iq, qs);
if(qs != 0) {
qstate->ext_state[id] = module_wait_subquery;
return 0; /* and wait for them */
@ -1533,6 +1565,12 @@ processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
verbose(VERB_QUERY, "maxdepth and need more nameservers, fail");
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
if(iq->depth > 0 && iq->target_count &&
iq->target_count[1] > MAX_TARGET_COUNT) {
verbose(VERB_QUERY, "request has exceeded the maximum "
"number of glue fetches %d", iq->target_count[1]);
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
/* mark cycle targets for parent-side lookups */
iter_mark_pside_cycle_targets(qstate, iq->dp);
/* see if we can issue queries to get nameserver addresses */
@ -1562,6 +1600,7 @@ processLastResort(struct module_qstate* qstate, struct iter_qstate* iq,
if(query_count != 0) { /* suspend to await results */
verbose(VERB_ALGO, "try parent-side glue lookup");
iq->num_target_queries += query_count;
target_count_increase(iq, query_count);
qstate->ext_state[id] = module_wait_subquery;
return 0;
}
@ -1717,6 +1756,7 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
iq->num_target_queries += extra;
target_count_increase(iq, extra);
if(iq->num_target_queries > 0) {
/* wait to get all targets, we want to try em */
verbose(VERB_ALGO, "wait for all targets for fallback");
@ -1757,6 +1797,7 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
/* errors ignored, these targets are not strictly necessary for
* this result, we do not have to reply with SERVFAIL */
iq->num_target_queries += extra;
target_count_increase(iq, extra);
}
/* Add the current set of unused targets to our queue. */
@ -1802,6 +1843,7 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
return 1;
}
iq->num_target_queries += qs;
target_count_increase(iq, qs);
}
/* Since a target query might have been made, we
* need to check again. */
@ -2894,6 +2936,8 @@ iter_clear(struct module_qstate* qstate, int id)
iq = (struct iter_qstate*)qstate->minfo[id];
if(iq) {
outbound_list_clear(&iq->outlist);
if(iq->target_count && --iq->target_count[0] == 0)
free(iq->target_count);
iq->num_current_queries = 0;
}
qstate->minfo[id] = NULL;

6
contrib/unbound/iterator/iterator.h
View File

@ -52,6 +52,8 @@ struct iter_donotq;
struct iter_prep_list;
struct iter_priv;
/** max number of targets spawned for a query and its subqueries */
#define MAX_TARGET_COUNT 32
/** max number of query restarts. Determines max number of CNAME chain. */
#define MAX_RESTART_COUNT 8
/** max number of referrals. Makes sure resolver does not run away */
@ -254,6 +256,10 @@ struct iter_qstate {
/** number of queries fired off */
int sent_count;
/** number of target queries spawned in [1], for this query and its
* subqueries, the malloced-array is shared, [0] refcount. */
int* target_count;
/**
* The query must store NS records from referrals as parentside RRs