diff options
Diffstat (limited to 'source3/passdb/lookup_sid.c')
-rw-r--r-- | source3/passdb/lookup_sid.c | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/source3/passdb/lookup_sid.c b/source3/passdb/lookup_sid.c index 14494cbeec..d523055b9d 100644 --- a/source3/passdb/lookup_sid.c +++ b/source3/passdb/lookup_sid.c @@ -1514,3 +1514,127 @@ bool sid_to_gid(const struct dom_sid *psid, gid_t *pgid) store_gid_sid_cache(psid, *pgid); return true; } + +/** + * @brief This function gets the primary group SID mapping the primary + * GID of the user as obtained by an actual getpwnam() call. + * This is necessary to avoid issues with arbitrary group SIDs + * stored in passdb. We try as hard as we can to get the SID + * corresponding to the GID, including trying group mapping. + * If nothing else works, we will force "Domain Users" as the + * primary group. + * This is needed because we must always be able to lookup the + * primary group SID, so we cannot settle for an arbitrary SID. + * + * This call can be expensive. Use with moderation. + * If you have a "samu" struct around use pdb_get_group_sid() + * instead as it does properly cache results. + * + * @param mem_ctx[in] The memory context iused to allocate the result. + * @param username[in] The user's name + * @param _pwd[in|out] If available, pass in user's passwd struct. + * It will contain a tallocated passwd if NULL was + * passed in. + * @param _group_sid[out] The user's Primary Group SID + * + * @return NTSTATUS error code. + */ +NTSTATUS get_primary_group_sid(TALLOC_CTX *mem_ctx, + const char *username, + struct passwd **_pwd, + struct dom_sid **_group_sid) +{ + TALLOC_CTX *tmp_ctx; + bool need_lookup_sid = false; + struct dom_sid *group_sid; + struct passwd *pwd = *_pwd; + + tmp_ctx = talloc_new(mem_ctx); + if (!tmp_ctx) { + return NT_STATUS_NO_MEMORY; + } + + if (!pwd) { + pwd = Get_Pwnam_alloc(mem_ctx, username); + if (!pwd) { + DEBUG(0, ("Failed to find a Unix account for %s", + username)); + TALLOC_FREE(tmp_ctx); + return NT_STATUS_NO_SUCH_USER; + } + } + + group_sid = talloc_zero(mem_ctx, struct dom_sid); + if (!group_sid) { + TALLOC_FREE(tmp_ctx); + return NT_STATUS_NO_MEMORY; + } + + gid_to_sid(group_sid, pwd->pw_gid); + if (!is_null_sid(group_sid)) { + struct dom_sid domain_sid; + uint32_t rid; + + /* We need a sid within our domain */ + sid_copy(&domain_sid, group_sid); + sid_split_rid(&domain_sid, &rid); + if (sid_equal(&domain_sid, get_global_sam_sid())) { + /* + * As shortcut for the expensive lookup_sid call + * compare the domain sid part + */ + switch (rid) { + case DOMAIN_RID_ADMINS: + case DOMAIN_RID_USERS: + goto done; + default: + need_lookup_sid = true; + break; + } + } else { + /* Try group mapping */ + ZERO_STRUCTP(group_sid); + if (pdb_gid_to_sid(pwd->pw_gid, group_sid)) { + need_lookup_sid = true; + } + } + } + + /* We must verify that this is a valid SID that resolves to a + * group of the correct type */ + if (need_lookup_sid) { + enum lsa_SidType type = SID_NAME_UNKNOWN; + bool lookup_ret; + + DEBUG(10, ("do lookup_sid(%s) for group of user %s\n", + sid_string_dbg(group_sid), username)); + + /* Now check that it's actually a domain group and + * not something else */ + lookup_ret = lookup_sid(tmp_ctx, group_sid, + NULL, NULL, &type); + + if (lookup_ret && (type == SID_NAME_DOM_GRP)) { + goto done; + } + + DEBUG(3, ("Primary group %s for user %s is" + " a %s and not a domain group\n", + sid_string_dbg(group_sid), username, + sid_type_lookup(type))); + } + + /* Everything else, failed. + * Just set it to the 'Domain Users' RID of 513 which will + always resolve to a name */ + DEBUG(3, ("Forcing Primary Group to 'Domain Users' for %s\n", + username)); + + sid_compose(group_sid, get_global_sam_sid(), DOMAIN_RID_USERS); + +done: + *_pwd = talloc_move(mem_ctx, &pwd); + *_group_sid = talloc_move(mem_ctx, &group_sid); + TALLOC_FREE(tmp_ctx); + return NT_STATUS_OK; +} |