Limit isccc_cc_fromwire recursion depth

Named and rndc do not need a lot of recursion so the depth is
set to 10.

diff --git a/lib/isc/include/isc/result.h b/lib/isc/include/isc/result.h
index 734ace772839f5cbbb012e13c555e7d4e385c18e..4d2aedcc7790416b82d8a4e7fa4918fa3dbdb001 100644 (file)
--- a/lib/isc/include/isc/result.h
+++ b/lib/isc/include/isc/result.h
@@ -273,6 +273,7 @@ typedef enum isc_result {
        ISCCC_R_EXPIRED,
        ISCCC_R_CLOCKSKEW,
        ISCCC_R_DUPLICATE,
+       ISCCC_R_MAXDEPTH,
 
        ISC_R_NRESULTS, /*% The number of results. */
        ISC_R_MAKE_ENUM_32BIT = INT32_MAX,

diff --git a/lib/isc/result.c b/lib/isc/result.c
index 99e0be7d389c44e37f634b30eb07db681bd1edbb..765105ab5547ea100fe24e8152104b3cbc6f0bb7 100644 (file)
--- a/lib/isc/result.c
+++ b/lib/isc/result.c
@@ -270,6 +270,7 @@ static const char *description[ISC_R_NRESULTS] = {
        [ISCCC_R_EXPIRED] = "expired",
        [ISCCC_R_CLOCKSKEW] = "clock skew",
        [ISCCC_R_DUPLICATE] = "duplicate",
+       [ISCCC_R_MAXDEPTH] = "max depth",
 };
 
 static const char *identifier[ISC_R_NRESULTS] = {
@@ -521,6 +522,7 @@ static const char *identifier[ISC_R_NRESULTS] = {
        [ISCCC_R_EXPIRED] = "ISCCC_R_EXPIRED",
        [ISCCC_R_CLOCKSKEW] = "ISCCC_R_CLOCKSKEW",
        [ISCCC_R_DUPLICATE] = "ISCCC_R_DUPLICATE",
+       [ISCCC_R_MAXDEPTH] = "ISCCC_R_MAXDEPTH",
 };
 
 STATIC_ASSERT((DNS_R_SERVFAIL - DNS_R_NOERROR == 2),

diff --git a/lib/isccc/cc.c b/lib/isccc/cc.c
index 58fb86e6e2c53ae6bf128f03ca5b538827b84f51..dd8397054a6e7630eecf5dd34c7b2f036d66d500 100644 (file)
--- a/lib/isccc/cc.c
+++ b/lib/isccc/cc.c
@@ -51,6 +51,10 @@
 
 #define MAX_TAGS     256
 #define DUP_LIFETIME 900
+#ifndef ISCCC_MAXDEPTH
+#define ISCCC_MAXDEPTH \
+       10 /* Big enough for rndc which just sends a string each way. */
+#endif
 
 typedef isccc_sexpr_t *sexpr_ptr;
 
@@ -483,19 +487,25 @@ verify(isccc_sexpr_t *alist, unsigned char *data, unsigned int length,
 
 static isc_result_t
 table_fromwire(isccc_region_t *source, isccc_region_t *secret,
-              uint32_t algorithm, isccc_sexpr_t **alistp);
+              uint32_t algorithm, unsigned int depth, isccc_sexpr_t **alistp);
 
 static isc_result_t
-list_fromwire(isccc_region_t *source, isccc_sexpr_t **listp);
+list_fromwire(isccc_region_t *source, unsigned int depth,
+             isccc_sexpr_t **listp);
 
 static isc_result_t
-value_fromwire(isccc_region_t *source, isccc_sexpr_t **valuep) {
+value_fromwire(isccc_region_t *source, unsigned int depth,
+              isccc_sexpr_t **valuep) {
        unsigned int msgtype;
        uint32_t len;
        isccc_sexpr_t *value;
        isccc_region_t active;
        isc_result_t result;
 
+       if (depth > ISCCC_MAXDEPTH) {
+               return (ISCCC_R_MAXDEPTH);
+       }
+
        if (REGION_SIZE(*source) < 1 + 4) {
                return (ISC_R_UNEXPECTEDEND);
        }
@@ -516,9 +526,9 @@ value_fromwire(isccc_region_t *source, isccc_sexpr_t **valuep) {
                        result = ISC_R_NOMEMORY;
                }
        } else if (msgtype == ISCCC_CCMSGTYPE_TABLE) {
-               result = table_fromwire(&active, NULL, 0, valuep);
+               result = table_fromwire(&active, NULL, 0, depth + 1, valuep);
        } else if (msgtype == ISCCC_CCMSGTYPE_LIST) {
-               result = list_fromwire(&active, valuep);
+               result = list_fromwire(&active, depth + 1, valuep);
        } else {
                result = ISCCC_R_SYNTAX;
        }
@@ -528,7 +538,7 @@ value_fromwire(isccc_region_t *source, isccc_sexpr_t **valuep) {
 
 static isc_result_t
 table_fromwire(isccc_region_t *source, isccc_region_t *secret,
-              uint32_t algorithm, isccc_sexpr_t **alistp) {
+              uint32_t algorithm, unsigned int depth, isccc_sexpr_t **alistp) {
        char key[256];
        uint32_t len;
        isc_result_t result;
@@ -538,6 +548,10 @@ table_fromwire(isccc_region_t *source, isccc_region_t *secret,
 
        REQUIRE(alistp != NULL && *alistp == NULL);
 
+       if (depth > ISCCC_MAXDEPTH) {
+               return (ISCCC_R_MAXDEPTH);
+       }
+
        checksum_rstart = NULL;
        first_tag = true;
        alist = isccc_alist_create();
@@ -554,7 +568,7 @@ table_fromwire(isccc_region_t *source, isccc_region_t *secret,
                GET_MEM(key, len, source->rstart);
                key[len] = '\0'; /* Ensure NUL termination. */
                value = NULL;
-               result = value_fromwire(source, &value);
+               result = value_fromwire(source, depth + 1, &value);
                if (result != ISC_R_SUCCESS) {
                        goto bad;
                }
@@ -592,14 +606,19 @@ bad:
 }
 
 static isc_result_t
-list_fromwire(isccc_region_t *source, isccc_sexpr_t **listp) {
+list_fromwire(isccc_region_t *source, unsigned int depth,
+             isccc_sexpr_t **listp) {
        isccc_sexpr_t *list, *value;
        isc_result_t result;
 
+       if (depth > ISCCC_MAXDEPTH) {
+               return (ISCCC_R_MAXDEPTH);
+       }
+
        list = NULL;
        while (!REGION_EMPTY(*source)) {
                value = NULL;
-               result = value_fromwire(source, &value);
+               result = value_fromwire(source, depth + 1, &value);
                if (result != ISC_R_SUCCESS) {
                        isccc_sexpr_free(&list);
                        return (result);
@@ -631,7 +650,7 @@ isccc_cc_fromwire(isccc_region_t *source, isccc_sexpr_t **alistp,
                return (ISCCC_R_UNKNOWNVERSION);
        }
 
-       return (table_fromwire(source, secret, algorithm, alistp));
+       return (table_fromwire(source, secret, algorithm, 0, alistp));
 }
 
 static isc_result_t