From d15ffe1ba204480a99ba021bb68bd2dbde9206fa Mon Sep 17 00:00:00 2001 From: Andrew Bartlett Date: Fri, 1 Oct 2021 11:55:11 +1300 Subject: [PATCH] CVE-2020-25718 s4-rpc_server: Put msDS-KrbTgtLinkBL and UF_INTERDOMAIN_TRUST_ACCOUNT RODC checks in common While these checks were not in the NETLOGON case, there is no sense where an RODC should be resetting a bad password count on either a UF_INTERDOMAIN_TRUST_ACCOUNT nor a RODC krbtgt account. BUG: https://bugzilla.samba.org/show_bug.cgi?id=14558 Signed-off-by: Andrew Bartlett Reviewed-by: Joseph Sutton --- source4/rpc_server/common/sid_helper.c | 29 ++++++++++++++++--- source4/rpc_server/drsuapi/getncchanges.c | 13 +-------- source4/rpc_server/netlogon/dcerpc_netlogon.c | 1 + 3 files changed, 27 insertions(+), 16 deletions(-) diff --git a/source4/rpc_server/common/sid_helper.c b/source4/rpc_server/common/sid_helper.c index eaeab236fc0..ab2b4373b47 100644 --- a/source4/rpc_server/common/sid_helper.c +++ b/source4/rpc_server/common/sid_helper.c @@ -133,16 +133,37 @@ WERROR samdb_result_sid_array_dn(struct ldb_context *sam_ctx, WERROR samdb_confirm_rodc_allowed_to_repl_to_sid_list(struct ldb_context *sam_ctx, struct ldb_message *rodc_msg, + struct ldb_message *obj_msg, uint32_t num_token_sids, struct dom_sid *token_sids) { uint32_t num_never_reveal_sids, num_reveal_sids; struct dom_sid *never_reveal_sids, *reveal_sids; TALLOC_CTX *frame = talloc_stackframe(); - WERROR werr = samdb_result_sid_array_dn(sam_ctx, rodc_msg, - frame, "msDS-NeverRevealGroup", - &num_never_reveal_sids, - &never_reveal_sids); + WERROR werr; + + /* + * We are not allowed to get anyone elses krbtgt secrets (and + * in callers that don't shortcut before this, the RODC should + * not deal with any krbtgt) + */ + if (samdb_result_dn(sam_ctx, frame, + obj_msg, "msDS-KrbTgtLinkBL", NULL)) { + TALLOC_FREE(frame); + return WERR_DS_DRA_SECRETS_DENIED; + } + + if (ldb_msg_find_attr_as_uint(obj_msg, + "userAccountControl", 0) & + UF_INTERDOMAIN_TRUST_ACCOUNT) { + TALLOC_FREE(frame); + return WERR_DS_DRA_SECRETS_DENIED; + } + + werr = samdb_result_sid_array_dn(sam_ctx, rodc_msg, + frame, "msDS-NeverRevealGroup", + &num_never_reveal_sids, + &never_reveal_sids); if (!W_ERROR_IS_OK(werr)) { TALLOC_FREE(frame); return WERR_DS_DRA_SECRETS_DENIED; diff --git a/source4/rpc_server/drsuapi/getncchanges.c b/source4/rpc_server/drsuapi/getncchanges.c index 3b1d674573f..a9d305fc9a0 100644 --- a/source4/rpc_server/drsuapi/getncchanges.c +++ b/source4/rpc_server/drsuapi/getncchanges.c @@ -1296,20 +1296,9 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state, goto denied; } - /* but it isn't allowed to get anyone elses krbtgt secrets */ - if (samdb_result_dn(b_state->sam_ctx_system, mem_ctx, - obj_res->msgs[0], "msDS-KrbTgtLinkBL", NULL)) { - goto denied; - } - - if (ldb_msg_find_attr_as_uint(obj_res->msgs[0], - "userAccountControl", 0) & - UF_INTERDOMAIN_TRUST_ACCOUNT) { - goto denied; - } - werr = samdb_confirm_rodc_allowed_to_repl_to_sid_list(b_state->sam_ctx_system, rodc_res->msgs[0], + obj_res->msgs[0], num_token_sids, token_sids); diff --git a/source4/rpc_server/netlogon/dcerpc_netlogon.c b/source4/rpc_server/netlogon/dcerpc_netlogon.c index 1aecd65bb61..92dd693ddcc 100644 --- a/source4/rpc_server/netlogon/dcerpc_netlogon.c +++ b/source4/rpc_server/netlogon/dcerpc_netlogon.c @@ -2888,6 +2888,7 @@ static bool sam_rodc_access_check(struct ldb_context *sam_ctx, werr = samdb_confirm_rodc_allowed_to_repl_to_sid_list(sam_ctx, rodc_res->msgs[0], + obj_res->msgs[0], num_token_sids, token_sids); -- 2.47.2