Limit isccc_cc_fromwire recursion depth

Named and rndc do not need a lot of recursion so the depth is
set to 10.
This commit is contained in:
Mark Andrews 2023-06-20 15:21:36 +10:00 committed by Michal Nowak
parent 6bda72d26f
commit 820b0cceef
No known key found for this signature in database
3 changed files with 32 additions and 10 deletions

View file

@ -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,

View file

@ -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),

View file

@ -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