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/isccc/cc.c b/lib/isccc/cc.c
index b548a7a7bf34dcb0d9284fec63da443e4bfba068..5a716bdcf2c5c24b6b381a5691b11b42ac644d17 100644 (file)
--- a/lib/isccc/cc.c
+++ b/lib/isccc/cc.c
@@ -54,6 +54,10 @@
 
 #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;
 
@@ -486,19 +490,25 @@ 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);
        }
@@ -519,9 +529,9 @@ 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;
        }
@@ -531,7 +541,7 @@ 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;
@@ -541,6 +551,10 @@ 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();
@@ -557,7 +571,7 @@ 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;
                }
@@ -595,14 +609,19 @@ 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);
@@ -634,7 +653,7 @@ 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

diff --git a/lib/isccc/include/isccc/result.h b/lib/isccc/include/isccc/result.h
index 0f0b0f6534b873d353c3d810699393c0e590e499..56f9c386e0f86e896ffeca0db872f791a1ea2c3e 100644 (file)
--- a/lib/isccc/include/isccc/result.h
+++ b/lib/isccc/include/isccc/result.h
@@ -35,8 +35,10 @@
 #define ISCCC_R_CLOCKSKEW (ISC_RESULTCLASS_ISCCC + 4)
 /*% Duplicate */
 #define ISCCC_R_DUPLICATE (ISC_RESULTCLASS_ISCCC + 5)
+/*% Maximum recursion depth */
+#define ISCCC_R_MAXDEPTH (ISC_RESULTCLASS_ISCCC + 6)
 
-#define ISCCC_R_NRESULTS 6 /*%< Number of results */
+#define ISCCC_R_NRESULTS 7 /*%< Number of results */
 
 ISC_LANG_BEGINDECLS
 

diff --git a/lib/isccc/result.c b/lib/isccc/result.c
index 1498c2a859d9aba9f137d639befee670a48612ed..127dd77e3b929745d889bc8b5bfe334765de11aa 100644 (file)
--- a/lib/isccc/result.c
+++ b/lib/isccc/result.c
@@ -25,12 +25,14 @@ static const char *text[ISCCC_R_NRESULTS] = {
        "bad auth",        /* 3 */
        "expired",         /* 4 */
        "clock skew",      /* 5 */
-       "duplicate"        /* 6 */
+       "duplicate",       /* 6 */
+       "max depth"        /* 7 */
 };
 
 static const char *ids[ISCCC_R_NRESULTS] = {
        "ISCCC_R_UNKNOWNVERSION", "ISCCC_R_SYNTAX",    "ISCCC_R_BADAUTH",
        "ISCCC_R_EXPIRED",        "ISCCC_R_CLOCKSKEW", "ISCCC_R_DUPLICATE",
+       "ISCCC_R_MAXDEPTH"
 };
 
 #define ISCCC_RESULT_RESULTSET 2