Backport of: --- From 639e5b671c0422ec52df91236db8a110c034aefa Mon Sep 17 00:00:00 2001 From: Mark Andrews Date: Tue, 20 Jun 2023 15:21:36 +1000 Subject: [PATCH] Limit isccc_cc_fromwire recursion depth Named and rndc do not need a lot of recursion so the depth is set to 10. (cherry picked from commit 820b0cceef0b67b041973da4041ea53d5e276363) --- lib/isccc/cc.c | 60 ++++++++++++++++++++++---------- lib/isccc/include/isccc/result.h | 4 ++- lib/isccc/result.c | 4 ++- 3 files changed, 47 insertions(+), 21 deletions(-) Index: bind9-9.11.5.P4+dfsg/lib/isccc/cc.c =================================================================== --- bind9-9.11.5.P4+dfsg.orig/lib/isccc/cc.c 2024-01-14 14:04:30.405992161 +0100 +++ bind9-9.11.5.P4+dfsg/lib/isccc/cc.c 2024-01-14 14:13:09.633428358 +0100 @@ -51,8 +51,12 @@ #include #include -#define MAX_TAGS 256 -#define DUP_LIFETIME 900 +#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; @@ -561,19 +565,25 @@ 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); GET8(msgtype, source->rstart); @@ -591,9 +601,9 @@ } else 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; @@ -602,7 +612,7 @@ 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; @@ -613,6 +623,10 @@ REQUIRE(alistp != NULL && *alistp == NULL); + if (depth > ISCCC_MAXDEPTH) { + return (ISCCC_R_MAXDEPTH); + } + checksum_rstart = NULL; first_tag = true; alist = isccc_alist_create(); @@ -628,9 +642,10 @@ GET_MEM(key, len, source->rstart); key[len] = '\0'; /* Ensure NUL termination. */ value = NULL; - result = value_fromwire(source, &value); - if (result != ISC_R_SUCCESS) + result = value_fromwire(source, depth + 1, &value); + if (result != ISC_R_SUCCESS) { goto bad; + } if (isccc_alist_define(alist, key, value) == NULL) { result = ISC_R_NOMEMORY; goto bad; @@ -661,14 +676,19 @@ } 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); @@ -699,7 +719,7 @@ if (version != 1) return (ISCCC_R_UNKNOWNVERSION); - return (table_fromwire(source, secret, algorithm, alistp)); + return (table_fromwire(source, secret, algorithm, 0, alistp)); } static isc_result_t Index: bind9-9.11.5.P4+dfsg/lib/isccc/include/isccc/result.h =================================================================== --- bind9-9.11.5.P4+dfsg.orig/lib/isccc/include/isccc/result.h 2024-01-14 14:04:30.405992161 +0100 +++ bind9-9.11.5.P4+dfsg/lib/isccc/include/isccc/result.h 2024-01-14 14:04:30.405992161 +0100 @@ -47,8 +47,10 @@ #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 Index: bind9-9.11.5.P4+dfsg/lib/isccc/result.c =================================================================== --- bind9-9.11.5.P4+dfsg.orig/lib/isccc/result.c 2024-01-14 14:04:30.405992161 +0100 +++ bind9-9.11.5.P4+dfsg/lib/isccc/result.c 2024-01-14 14:04:30.405992161 +0100 @@ -40,7 +40,8 @@ "bad auth", /* 3 */ "expired", /* 4 */ "clock skew", /* 5 */ - "duplicate" /* 6 */ + "duplicate", /* 6 */ + "max depth" /* 7 */ }; static const char *ids[ISCCC_R_NRESULTS] = { @@ -50,6 +51,7 @@ "ISCCC_R_EXPIRED", "ISCCC_R_CLOCKSKEW", "ISCCC_R_DUPLICATE", + "ISCCC_R_MAXDEPTH", }; #define ISCCC_RESULT_RESULTSET 2