From c4fac5ca98efd02fbaef43601627c7a3a09f5a71 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. Taken from BIND 9.16.44 change. Upstream-Status: Backport [https://gitlab.isc.org/isc-projects/bind9/-/commit/c4fac5ca98efd02fbaef43601627c7a3a09f5a71] CVE: CVE-2023-3341 Signed-off-by: Vijay Anusuri --- lib/isccc/cc.c | 38 +++++++++++++++++++++++--------- lib/isccc/include/isccc/result.h | 4 +++- lib/isccc/result.c | 4 +++- 3 files changed, 34 insertions(+), 12 deletions(-) diff --git a/lib/isccc/cc.c b/lib/isccc/cc.c index e012685..8eac3d6 100644 --- a/lib/isccc/cc.c +++ b/lib/isccc/cc.c @@ -53,6 +53,10 @@ #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; @@ -561,19 +565,25 @@ 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); GET8(msgtype, source->rstart); @@ -591,9 +601,9 @@ value_fromwire(isccc_region_t *source, isccc_sexpr_t **valuep) { } 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 @@ 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; @@ -613,6 +623,10 @@ 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(); @@ -628,7 +642,7 @@ 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; if (isccc_alist_define(alist, key, value) == NULL) { @@ -661,14 +675,18 @@ table_fromwire(isccc_region_t *source, isccc_region_t *secret, } 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 +717,7 @@ isccc_cc_fromwire(isccc_region_t *source, isccc_sexpr_t **alistp, 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 diff --git a/lib/isccc/include/isccc/result.h b/lib/isccc/include/isccc/result.h index 6c79dd7..a85861c 100644 --- a/lib/isccc/include/isccc/result.h +++ b/lib/isccc/include/isccc/result.h @@ -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 diff --git a/lib/isccc/result.c b/lib/isccc/result.c index 8419bbb..325200b 100644 --- a/lib/isccc/result.c +++ b/lib/isccc/result.c @@ -40,7 +40,8 @@ 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] = { @@ -50,6 +51,7 @@ static const char *ids[ISCCC_R_NRESULTS] = { "ISCCC_R_EXPIRED", "ISCCC_R_CLOCKSKEW", "ISCCC_R_DUPLICATE", + "ISCCC_R_MAXDEPTH", }; #define ISCCC_RESULT_RESULTSET 2 -- 2.25.1