XrdSciTokensAccess.cc

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#include "XrdAcc/XrdAccAuthorize.hh"
#include "XrdOuc/XrdOucEnv.hh"
#include "XrdOuc/XrdOucGatherConf.hh"
#include "XrdOuc/XrdOucPrivateUtils.hh"
#include "XrdSec/XrdSecEntity.hh"
#include "XrdSec/XrdSecEntityAttr.hh"
#include "XrdSys/XrdSysLogger.hh"
#include "XrdTls/XrdTlsContext.hh"
#include "XrdVersion.hh"
 
#include <map>
#include <memory>
#include <mutex>
#include <string>
#include <vector>
#include <sstream>
#include <fstream>
#include <unordered_map>
#include <tuple>
 
#include "fcntl.h"
 
#include "INIReader.h"
#include "picojson.h"
 
#include "scitokens/scitokens.h"
#include "XrdSciTokens/XrdSciTokensAccess.hh"
#include "XrdSciTokens/XrdSciTokensHelper.hh"
#include "XrdSciTokens/XrdSciTokensMon.hh"
 
// The status-quo to retrieve the default object is to copy/paste the
// linker definition and invoke directly.
XrdVERSIONINFO(XrdAccAuthorizeObject, XrdAccSciTokens);
XrdVERSIONINFO(XrdAccAuthorizeObjAdd, XrdAccSciTokens);
 
XrdSciTokensHelper *SciTokensHelper = nullptr;
 
namespace {
 
enum LogMask {
    Debug = 0x01,
    Info = 0x02,
    Warning = 0x04,
    Error = 0x08,
    All = 0xff
};
 
std::string LogMaskToString(int mask) {
    if (mask == LogMask::All) {return "all";}
 
    bool has_entry = false;
    std::stringstream ss;
    if (mask & LogMask::Debug) {
        ss << "debug";
        has_entry = true;
    }
    if (mask & LogMask::Info) {
        ss << (has_entry ? ", " : "") << "info";
        has_entry = true;
    }
    if (mask & LogMask::Warning) {
        ss << (has_entry ? ", " : "") << "warning";
        has_entry = true;
    }
    if (mask & LogMask::Error) {
        ss << (has_entry ? ", " : "") << "error";
        has_entry = true;
    }
    return ss.str();
}
 
inline uint64_t monotonic_time() {
  struct timespec tp;
#ifdef CLOCK_MONOTONIC_COARSE
  clock_gettime(CLOCK_MONOTONIC_COARSE, &tp);
#else
  clock_gettime(CLOCK_MONOTONIC, &tp);
#endif
  return tp.tv_sec + (tp.tv_nsec >= 500000000);
}
 
XrdAccPrivs AddPriv(Access_Operation op, XrdAccPrivs privs)
{
    int new_privs = privs;
    switch (op) {
        case AOP_Any:
            break;
        case AOP_Chmod:
            new_privs |= static_cast<int>(XrdAccPriv_Chmod);
            break;
        case AOP_Chown:
            new_privs |= static_cast<int>(XrdAccPriv_Chown);
            break;
        case AOP_Excl_Create: // fallthrough
        case AOP_Create:
            new_privs |= static_cast<int>(XrdAccPriv_Create);
            break;
        case AOP_Delete:
            new_privs |= static_cast<int>(XrdAccPriv_Delete);
            break;
        case AOP_Excl_Insert: // fallthrough
        case AOP_Insert:
            new_privs |= static_cast<int>(XrdAccPriv_Insert);
            break;
        case AOP_Lock:
            new_privs |= static_cast<int>(XrdAccPriv_Lock);
            break;
        case AOP_Mkdir:
            new_privs |= static_cast<int>(XrdAccPriv_Mkdir);
            break;
        case AOP_Read:
            new_privs |= static_cast<int>(XrdAccPriv_Read);
            break;
        case AOP_Readdir:
            new_privs |= static_cast<int>(XrdAccPriv_Readdir);
            break;
        case AOP_Rename:
            new_privs |= static_cast<int>(XrdAccPriv_Rename);
            break;
        case AOP_Stat:
            new_privs |= static_cast<int>(XrdAccPriv_Lookup);
            break;
        case AOP_Update:
            new_privs |= static_cast<int>(XrdAccPriv_Update);
            break;
    };
    return static_cast<XrdAccPrivs>(new_privs);
}
 
const std::string OpToName(Access_Operation op) {
    switch (op) {
        case AOP_Any: return "any";
        case AOP_Chmod: return "chmod";
        case AOP_Chown: return "chown";
        case AOP_Create: return "create";
        case AOP_Excl_Create: return "excl_create";
        case AOP_Delete: return "del";
        case AOP_Excl_Insert: return "excl_insert";
        case AOP_Insert: return "insert";
        case AOP_Lock: return "lock";
        case AOP_Mkdir: return "mkdir";
        case AOP_Read: return "read";
        case AOP_Readdir: return "dir";
        case AOP_Rename: return "mv";
        case AOP_Stat: return "stat";
        case AOP_Update: return "update";
    };
    return "unknown";
}
 
std::string AccessRuleStr(const AccessRulesRaw &rules) {
    std::unordered_map<std::string, std::unique_ptr<std::stringstream>> rule_map;
    for (const auto &rule : rules) {
        auto iter = rule_map.find(rule.second);
        if (iter == rule_map.end()) {
            auto result = rule_map.insert(std::make_pair(rule.second, std::make_unique<std::stringstream>()));
            iter = result.first;
            *(iter->second) << OpToName(rule.first);
        } else {
            *(iter->second) << "," << OpToName(rule.first);
        }
    }
    std::stringstream ss;
    bool first = true;
    for (const auto &val : rule_map) {
       ss << (first ? "" : ";") << val.first << ":" << val.second->str();
       first = false;
    }
    return ss.str();
}
 
bool MakeCanonical(const std::string &path, std::string &result)
{
    if (path.empty() || path[0] != '/') {return false;}
 
    size_t pos = 0;
    std::vector<std::string> components;
    do {
        while (path.size() > pos && path[pos] == '/') {pos++;}
        auto next_pos = path.find_first_of("/", pos);
        auto next_component = path.substr(pos, next_pos - pos);
        pos = next_pos;
        if (next_component.empty() || next_component == ".") {continue;}
        else if (next_component == "..") {
            if (!components.empty()) {
                components.pop_back();
            }
        } else {
            components.emplace_back(next_component);
        }
    } while (pos != std::string::npos);
    if (components.empty()) {
        result = "/";
        return true;
    }
    std::stringstream ss;
    for (const auto &comp : components) {
        ss << "/" << comp;
    }
    result = ss.str();
    return true;
}
 
void ParseCanonicalPaths(const std::string &path, std::vector<std::string> &results)
{
    size_t pos = 0;
    do {
        while (path.size() > pos && (path[pos] == ',' || path[pos] == ' ')) {pos++;}
        auto next_pos = path.find_first_of(", ", pos);
        auto next_path = path.substr(pos, next_pos - pos);
        pos = next_pos;
        if (!next_path.empty()) {
            std::string canonical_path;
            if (MakeCanonical(next_path, canonical_path)) {
                results.emplace_back(std::move(canonical_path));
            }
        }
    } while (pos != std::string::npos);
}
 
struct IssuerConfig
{
    IssuerConfig(const std::string &issuer_name,
                 const std::string &issuer_url,
                 const std::vector<std::string> &base_paths,
                 const std::vector<std::string> &restricted_paths,
                 bool map_subject,
                 uint32_t authz_strategy,
                 const std::string &default_user,
                 const std::string &username_claim,
                 const std::string &groups_claim,
                 const std::vector<MapRule> rules,
                 AuthzSetting acceptable_authz,
                 AuthzSetting required_authz)
        : m_map_subject(map_subject || !username_claim.empty()),
          m_acceptable_authz(acceptable_authz),
          m_required_authz(required_authz),
          m_authz_strategy(authz_strategy),
          m_name(issuer_name),
          m_url(issuer_url),
          m_default_user(default_user),
          m_username_claim(username_claim),
          m_groups_claim(groups_claim),
          m_base_paths(base_paths),
          m_restricted_paths(restricted_paths),
          m_map_rules(rules)
    {}
 
    const bool m_map_subject;
    const AuthzSetting m_acceptable_authz;
    const AuthzSetting m_required_authz;
    const uint32_t m_authz_strategy;
    const std::string m_name;
    const std::string m_url;
    const std::string m_default_user;
    const std::string m_username_claim;
    const std::string m_groups_claim;
    const std::vector<std::string> m_base_paths;
    const std::vector<std::string> m_restricted_paths;
    const std::vector<MapRule> m_map_rules;
};
 
class OverrideINIReader: public INIReader {
public:
    OverrideINIReader() {};
    inline OverrideINIReader(std::string filename) {
        _error = ini_parse(filename.c_str(), ValueHandler, this);
    }
    inline OverrideINIReader(FILE *file) {
        _error = ini_parse_file(file, ValueHandler, this);
    }
protected:
    inline static int ValueHandler(void* user, const char* section, const char* name,
                            const char* value) {
        OverrideINIReader* reader = (OverrideINIReader*)user;
        std::string key = MakeKey(section, name);
 
        // Overwrite existing values, if they exist
        reader->_values[key] = value;
        reader->_sections.insert(section);
        return 1;
    }
 
};
 
 
void
ParseTokenString(const std::string &param, XrdOucEnv *env, std::vector<std::string_view> &authz_list)
{
    if (!env) {return;}
    const char *authz = env->Get(param.c_str());
    if (!authz) {return;}
    std::string_view authz_view(authz);
    size_t pos;
    do {
        // Note: this is more permissive than the plugin was previously.
        // The prefix 'Bearer%20' used to be required as that's what HTTP
        // required.  However, to make this more pleasant for XRootD protocol
        // users, we now simply "handle" the prefix insterad of requiring it.
        if (authz_view.substr(0, 9) == "Bearer%20") {
            authz_view = authz_view.substr(9);
        }
        pos = authz_view.find(",");
        authz_list.push_back(authz_view.substr(0, pos));
        authz_view = authz_view.substr(pos + 1);
    } while (pos != std::string_view::npos);
}
 
} // namespace
 
std::string
SubpathMatch::str() const {
    return AccessRuleStr(m_rules); // Returns a human-friendly representation of the access rules
}
 
// Convert a list of authorizations into a human-readable string.
const std::string
XrdAccRules::str() const
{
    std::stringstream ss;
    ss << "mapped_username=" << m_username << ", subject=" << m_token_subject
        << ", issuer=" << m_issuer;
    if (!m_groups.empty()) {
        ss << ", groups=";
        bool first=true;
        for (const auto &group : m_groups) {
            ss << (first ? "" : ",") << group;
            first = false;
        }
    }
    if (!m_matcher.empty()) {
        ss << ", authorizations=" << m_matcher.str();
    }
    return ss.str();
}
 
bool XrdAccRules::expired() const
{
    return monotonic_time() > m_expiry_time;
}
 
// Determine whether a list of authorizations contains at least one entry
// from each of the applicable required issuers.
//
// - `oper`: The operation type (read, write) to test for authorization.
// - `path`: The requested path for the operation.
// - `required_issuers`: A map from a list of paths to an issuer.
// - `access_rules_list`: A list of access rules derived from the token
//
// If the requested path/operation matches one of the required issuers, then one
// of the provided authorizations (e.g., the token's scopes) must come from that
// issuer.
//
// The return value indicates whether the required authorization was missing, found,
// or there was no required issuer for the path.
bool AuthorizesRequiredIssuers(Access_Operation client_oper, const std::string_view &path,
    const std::vector<std::pair<std::unique_ptr<SubpathMatch>, std::string>> &required_issuers,
    const std::vector<std::shared_ptr<XrdAccRules>> &access_rules_list)
{
 
    // Translate the client-attempted operation to one of the simpler operations we've defined.
    Access_Operation oper;
    switch (client_oper) {
        case AOP_Any:
            return false; // Invalid request
            break;
        case AOP_Chmod: [[fallthrough]];
        case AOP_Chown: [[fallthrough]];
        case AOP_Create: [[fallthrough]];
        case AOP_Excl_Create: [[fallthrough]];
        case AOP_Delete: [[fallthrough]];
        case AOP_Excl_Insert: [[fallthrough]];
        case AOP_Insert: [[fallthrough]];
        case AOP_Lock:
            oper = AOP_Create;
            break;
        case AOP_Mkdir:
            oper = AOP_Mkdir;
            break;
        case AOP_Read:
            oper = AOP_Read;
            break;
        case AOP_Readdir:
            oper = AOP_Readdir;
            break;
        case AOP_Rename:
            oper = AOP_Create;
            break;
        case AOP_Stat:
            oper = AOP_Stat;
            break;
        case AOP_Update:
            oper = AOP_Update;
            break;
        default:
            return false; // Invalid request
    };
 
    // Iterate through all the required issuers
    for (const auto &info : required_issuers) {
        // See if this issuer is required for this path/operation.
        if (info.first->apply(oper, path)) {
            bool has_authz = false;
            // If so, see if one of the tokens (a) is from this issuer and (b) authorizes the request.
            for (const auto &rules : access_rules_list) {
                if (rules->get_issuer() == info.second && rules->apply(oper, path)) {
                    has_authz = true;
                    break;
                }
            }
            if (!has_authz) {
                return false;
            }
        }
    }
    return true;
}
 
class XrdAccSciTokens;
 
XrdAccSciTokens *accSciTokens = nullptr;
 
class XrdAccSciTokens : public XrdAccAuthorize, public XrdSciTokensHelper,
                        public XrdSciTokensMon
{
 
    enum class AuthzBehavior {
        PASSTHROUGH,
        ALLOW,
        DENY
    };
 
public:
    XrdAccSciTokens(XrdSysLogger *lp, const char *parms, XrdAccAuthorize* chain, XrdOucEnv *envP) :
        m_chain(chain),
        m_parms(parms ? parms : ""),
        m_next_clean(monotonic_time() + m_expiry_secs),
        m_log(lp, "scitokens_")
    {
        pthread_rwlock_init(&m_config_lock, nullptr);
        m_config_lock_initialized = true;
        m_log.Say("++++++ XrdAccSciTokens: Initialized SciTokens-based authorization.");
        if (!Config(envP)) {
            throw std::runtime_error("Failed to configure SciTokens authorization.");
        }
    }
 
    virtual ~XrdAccSciTokens() {
        if (m_config_lock_initialized) {
            pthread_rwlock_destroy(&m_config_lock);
        }
    }
 
    virtual XrdAccPrivs Access(const XrdSecEntity *Entity,
                                  const char         *path,
                                  const Access_Operation oper,
                                        XrdOucEnv       *env) override
    {
        std::vector<std::string_view> authz_list;
        authz_list.reserve(1);
 
        // Parse the authz environment entry as a comma-separated list of tokens.
        // Traditionally, `authz` has been used as the parameter for XRootD; however,
        // RFC 6750 Section 2.3 ("URI Query Parameter") specifies that access_token
        // is correct.  We support both.
        ParseTokenString("authz", env, authz_list);
        ParseTokenString("access_token", env, authz_list);
 
        if (Entity && !strcmp("ztn", Entity->prot) && Entity->creds &&
            Entity->credslen && Entity->creds[Entity->credslen] == '\0')
        {
            authz_list.push_back(Entity->creds);
        }
 
        if (authz_list.empty()) {
            return OnMissing(Entity, path, oper, env);
        }
 
        // A potential DoS would be providing a large number of tokens to consider for ACLs.
        // Have a hardcoded assumption of <10 tokens per request.
        if (authz_list.size() > 10) {
            m_log.Log(LogMask::Warning, "Access", "Request had more than 10 tokens attached; ignoring");
            return OnMissing(Entity, path, oper, env);
        }
 
        m_log.Log(LogMask::Debug, "Access", "Trying token-based access control");
        std::vector<std::shared_ptr<XrdAccRules>> access_rules_list;
        uint64_t now = monotonic_time();
        Check(now);
        for (const auto &authz : authz_list) {
            std::shared_ptr<XrdAccRules> access_rules;
            {
                std::lock_guard<std::mutex> guard(m_mutex);
                const auto iter = m_map.find(authz);
                if (iter != m_map.end() && !iter->second->expired()) {
                    access_rules = iter->second;
                }
            }
            if (!access_rules) {
                m_log.Log(LogMask::Debug, "Access", "Token not found in recent cache; parsing.");
                try {
                    uint64_t cache_expiry;
                    AccessRulesRaw rules;
                    std::string username;
                    std::string token_subject;
                    std::string issuer;
                    std::vector<MapRule> map_rules;
                    std::vector<std::string> groups;
                    uint32_t authz_strategy;
                    AuthzSetting acceptable_authz;
                    if (GenerateAcls(authz, cache_expiry, rules, username, token_subject, issuer, map_rules, groups, authz_strategy, acceptable_authz)) {
                        access_rules.reset(new XrdAccRules(now + cache_expiry, username, token_subject, issuer, map_rules, groups, authz_strategy, acceptable_authz));
                        access_rules->parse(rules);
                    } else {
                        m_log.Log(LogMask::Warning, "Access", "Failed to generate ACLs for token");
                        continue;
                    }
                    if (m_log.getMsgMask() & LogMask::Debug) {
                        m_log.Log(LogMask::Debug, "Access", "New valid token", access_rules->str().c_str());
                    }
                } catch (std::exception &exc) {
                    m_log.Log(LogMask::Warning, "Access", "Error generating ACLs for authorization", exc.what());
                    continue;
                }
                std::lock_guard<std::mutex> guard(m_mutex);
                m_map[std::string(authz)] = access_rules;
            } else if (m_log.getMsgMask() & LogMask::Debug) {
                m_log.Log(LogMask::Debug, "Access", "Cached token", access_rules->str().c_str());
            }
            access_rules_list.push_back(access_rules);
        }
        if (access_rules_list.empty()) {
            return OnMissing(Entity, path, oper, env);
        }
        std::string_view path_view(path, strlen(path));
 
        // Apply the logic for the required issuers.
        if (!AuthorizesRequiredIssuers(oper, path_view, m_required_issuers, access_rules_list)) {
            return OnMissing(Entity, path, oper, env);
        }
 
        // Strategy: assuming the corresponding strategy is enabled, we populate the name in
        // the XrdSecEntity if:
        //    1. There are scopes present in the token that authorize the request,
        //    2. The token is mapped by some rule in the mapfile (group or subject-based mapping).
        // The default username for the issuer is only used in (1).
        // If the scope-based mapping is successful, authorize immediately.  Otherwise, if the
        // mapping is successful, we potentially chain to another plugin.
        //
        // We always populate the issuer and the groups, if present.
 
        // Access may be authorized; populate XrdSecEntity
        for (const auto &access_rules : access_rules_list) {
            // Make sure this issuer is acceptable for the given operation.
            if (!access_rules->acceptable_authz(oper)) {
                m_log.Log(LogMask::Debug, "Access", "Issuer is not acceptable for given operation:", access_rules->get_issuer().c_str());
                continue;
            }
 
            XrdSecEntity new_secentity;
            new_secentity.vorg = nullptr;
            new_secentity.grps = nullptr;
            new_secentity.role = nullptr;
            new_secentity.secMon = Entity->secMon;
            new_secentity.addrInfo = Entity->addrInfo;
            const auto &issuer = access_rules->get_issuer();
            if (!issuer.empty()) {
                new_secentity.vorg = strdup(issuer.c_str());
            }
            bool group_success = false;
            if ((access_rules->get_authz_strategy() & IssuerAuthz::Group) && access_rules->groups().size()) {
                std::stringstream ss;
                for (const auto &grp : access_rules->groups()) {
                    ss << grp << " ";
                }
                const auto &groups_str = ss.str();
                new_secentity.grps = static_cast<char*>(malloc(groups_str.size() + 1));
                if (new_secentity.grps) {
                    memcpy(new_secentity.grps, groups_str.c_str(), groups_str.size());
                    new_secentity.grps[groups_str.size()] = '\0';
                }
                group_success = true;
            }
 
            std::string username;
            bool mapping_success = false;
            bool scope_success = false;
            username = access_rules->get_username(path_view);
 
            mapping_success = (access_rules->get_authz_strategy() & IssuerAuthz::Mapping) && !username.empty();
            scope_success = (access_rules->get_authz_strategy() & IssuerAuthz::Capability) && access_rules->apply(oper, path_view);
            if (scope_success && (m_log.getMsgMask() & LogMask::Debug)) {
                std::stringstream ss;
                ss << "Grant authorization based on scopes for operation=" << OpToName(oper) << ", path=" << path;
                m_log.Log(LogMask::Debug, "Access", ss.str().c_str());
            }
 
            if (!scope_success && !mapping_success && !group_success) {
                auto returned_accs = OnMissing(&new_secentity, path, oper, env);
                // Clean up the new_secentity
                if (new_secentity.vorg != nullptr) free(new_secentity.vorg);
                if (new_secentity.grps != nullptr) free(new_secentity.grps);
                if (new_secentity.role != nullptr) free(new_secentity.role);
 
                return returned_accs;
            }
 
            // Default user only applies to scope-based mappings.
            if (scope_success && username.empty()) {
                username = access_rules->get_default_username();
            }
 
            // Setting the request.name will pass the username to the next plugin.
            // Ensure we do that only if map-based or scope-based authorization worked.
            if (scope_success || mapping_success) {
                // Set scitokens.name in the extra attribute
                Entity->eaAPI->Add("request.name", username, true);
                new_secentity.eaAPI->Add("request.name", username, true);
                m_log.Log(LogMask::Debug, "Access", "Request username", username.c_str());
            }
 
                // Make the token subject available.  Even though it's a reasonably bad idea
                // to use for *authorization* for file access, there may be other use cases.
                // For example, the combination of (vorg, token.subject) is a reasonable
                // approximation of a unique 'entity' (either person or a robot) and is
                // more reasonable to use for resource fairshare in XrdThrottle.
            const auto &token_subject = access_rules->get_token_subject();
            if (!token_subject.empty()) {
                Entity->eaAPI->Add("token.subject", token_subject, true);
            }
 
            // When the scope authorized this access, allow immediately.  Otherwise, chain
            XrdAccPrivs returned_op = scope_success ? AddPriv(oper, XrdAccPriv_None) : OnMissing(&new_secentity, path, oper, env);
 
            // Since we are doing an early return, insert token info into the
            // monitoring stream if monitoring is in effect and access granted
            //
            if (Entity->secMon && scope_success && returned_op && Mon_isIO(oper))
            Mon_Report(new_secentity, token_subject, username);
 
            // Cleanup the new_secentry
            if (new_secentity.vorg != nullptr) free(new_secentity.vorg);
            if (new_secentity.grps != nullptr) free(new_secentity.grps);
            if (new_secentity.role != nullptr) free(new_secentity.role);
            return returned_op;
        }
 
        // We iterated through all available credentials and none provided authorization; fall back
        return OnMissing(Entity, path, oper, env);
    }
 
    virtual  Issuers IssuerList() override
    {
        /*
        Convert the m_issuers into the data structure:
        struct   ValidIssuer
        {std::string issuer_name;
         std::string issuer_url;
        };
        typedef std::vector<ValidIssuer> Issuers;
        */
        Issuers issuers;
        for (auto it: m_issuers) {
            ValidIssuer issuer_info;
            issuer_info.issuer_name = it.first;
            issuer_info.issuer_url = it.second.m_url;
            issuers.push_back(issuer_info);
        }
        return issuers;
 
    }
 
    virtual bool Validate(const char *token, std::string &emsg, long long *expT,
                          XrdSecEntity *Entity) override
    {
        // Just check if the token is valid, no scope checking
 
        // Deserialize the token
        SciToken scitoken;
        char *err_msg;
        if (!strncmp(token, "Bearer%20", 9)) token += 9;
        pthread_rwlock_rdlock(&m_config_lock);
        auto retval = scitoken_deserialize(token, &scitoken, &m_valid_issuers_array[0], &err_msg);
        pthread_rwlock_unlock(&m_config_lock);
        if (retval) {
            // This originally looked like a JWT so log the failure.
            m_log.Log(LogMask::Warning, "Validate", "Failed to deserialize SciToken:", err_msg);
            emsg = err_msg;
            free(err_msg);
            return false;
        }
 
        // If an entity was passed then we will fill it in with the subject
        // name, should it exist. Note that we are gauranteed that all the
        // settable entity fields are null so no need to worry setting them.
        //
        if (Entity)
           {char *value = nullptr;
            if (!scitoken_get_claim_string(scitoken, "sub", &value, &err_msg))
               Entity->name = strdup(value);
           }
 
        // Return the expiration time of this token if so wanted.
        //
        if (expT && scitoken_get_expiration(scitoken, expT, &err_msg)) {
            emsg = err_msg;
            free(err_msg);
            return false;
        }
 
 
        // Delete the scitokens
        scitoken_destroy(scitoken);
 
        // Deserialize checks the key, so we're good now.
        return true;
    }
 
    virtual int Audit(const int              accok,
                      const XrdSecEntity    *Entity,
                      const char            *path,
                      const Access_Operation oper,
                            XrdOucEnv       *Env=0) override
    {
        return 0;
    }
 
    virtual int         Test(const XrdAccPrivs priv,
                             const Access_Operation oper) override
    {
        return (m_chain ? m_chain->Test(priv, oper) : 0);
    }
 
    std::string GetConfigFile() {
        return m_cfg_file;
    }
 
private:
    XrdAccPrivs OnMissing(const XrdSecEntity *Entity, const char *path,
                          const Access_Operation oper, XrdOucEnv *env)
    {
        switch (m_authz_behavior) {
            case AuthzBehavior::PASSTHROUGH:
                return m_chain ? m_chain->Access(Entity, path, oper, env) : XrdAccPriv_None;
            case AuthzBehavior::ALLOW:
                return AddPriv(oper, XrdAccPriv_None);
            case AuthzBehavior::DENY:
                return XrdAccPriv_None;
        }
        // Code should be unreachable.
        return XrdAccPriv_None;
    }
 
    bool GenerateAcls(const std::string_view &authz, uint64_t &cache_expiry, AccessRulesRaw &rules, std::string &username, std::string &token_subject, std::string &issuer, std::vector<MapRule> &map_rules, std::vector<std::string> &groups, uint32_t &authz_strategy, AuthzSetting &acceptable_authz) {
        // Does this look like a JWT?  If not, bail out early and
        // do not pollute the log.
        bool looks_good = true;
        int separator_count = 0;
        for (auto cur_char = authz.data(); *cur_char; cur_char++) {
            if (*cur_char == '.') {
                separator_count++;
                if (separator_count > 2) {
                    break;
                }
            } else
            if (!(*cur_char >= 65 && *cur_char <= 90) && // uppercase letters
                !(*cur_char >= 97 && *cur_char <= 122) && // lowercase letters
                !(*cur_char >= 48 && *cur_char <= 57) && // numbers
                (*cur_char != 43) && (*cur_char != 47) && // + and /
                (*cur_char != 45) && (*cur_char != 95)) // - and _
            {
                looks_good = false;
                break;
            }
        }
        if ((separator_count != 2) || (!looks_good)) {
            m_log.Log(LogMask::Debug, "Parse", "Token does not appear to be a valid JWT; skipping.");
            return false;
        }
 
        char *err_msg;
        SciToken token = nullptr;
        pthread_rwlock_rdlock(&m_config_lock);
        auto retval = scitoken_deserialize(authz.data(), &token, &m_valid_issuers_array[0], &err_msg);
        pthread_rwlock_unlock(&m_config_lock);
        if (retval) {
            // This originally looked like a JWT so log the failure.
            m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to deserialize SciToken:", err_msg);
            free(err_msg);
            return false;
        }
 
        long long expiry;
        if (scitoken_get_expiration(token, &expiry, &err_msg)) {
            m_log.Log(LogMask::Warning, "GenerateAcls", "Unable to determine token expiration:", err_msg);
            free(err_msg);
            scitoken_destroy(token);
            return false;
        }
        if (expiry > 0) {
            expiry = std::max(static_cast<int64_t>(monotonic_time() - expiry),
                static_cast<int64_t>(60));
        } else {
            expiry = 60;
        }
 
        char *value = nullptr;
        if (scitoken_get_claim_string(token, "iss", &value, &err_msg)) {
            m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to get issuer:", err_msg);
            scitoken_destroy(token);
            free(err_msg);
            return false;
        }
        std::string token_issuer(value);
        free(value);
 
        pthread_rwlock_rdlock(&m_config_lock);
        auto enf = enforcer_create(token_issuer.c_str(), &m_audiences_array[0], &err_msg);
        pthread_rwlock_unlock(&m_config_lock);
        if (!enf) {
            m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to create an enforcer:", err_msg);
            scitoken_destroy(token);
            free(err_msg);
            return false;
        }
 
        Acl *acls = nullptr;
        if (enforcer_generate_acls(enf, token, &acls, &err_msg)) {
            scitoken_destroy(token);
            enforcer_destroy(enf);
            m_log.Log(LogMask::Warning, "GenerateAcls", "ACL generation from SciToken failed:", err_msg);
            free(err_msg);
            return false;
        }
        enforcer_destroy(enf);
 
        pthread_rwlock_rdlock(&m_config_lock);
        auto iter = m_issuers.find(token_issuer);
        if (iter == m_issuers.end()) {
            pthread_rwlock_unlock(&m_config_lock);
            m_log.Log(LogMask::Warning, "GenerateAcls", "Authorized issuer without a config.");
            scitoken_destroy(token);
            return false;
        }
        const auto config = iter->second;
        pthread_rwlock_unlock(&m_config_lock);
        value = nullptr;
 
        char **group_list;
        std::vector<std::string> groups_parsed;
        if (scitoken_get_claim_string_list(token, config.m_groups_claim.c_str(), &group_list, &err_msg) == 0) {
            for (int idx=0; group_list[idx]; idx++) {
                groups_parsed.emplace_back(group_list[idx]);
            }
            scitoken_free_string_list(group_list);
        } else {
            // Failing to parse groups is not fatal, but we should still warn about what's wrong
            m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to get token groups:", err_msg);
            free(err_msg);
        }
 
        if (scitoken_get_claim_string(token, "sub", &value, &err_msg)) {
            m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to get token subject:", err_msg);
            free(err_msg);
            scitoken_destroy(token);
            return false;
        }
        token_subject = std::string(value);
        free(value);
 
        auto tmp_username = token_subject;
        if (!config.m_username_claim.empty()) {
            if (scitoken_get_claim_string(token, config.m_username_claim.c_str(), &value, &err_msg)) {
                m_log.Log(LogMask::Warning, "GenerateAcls", "Failed to get token username:", err_msg);
                free(err_msg);
                scitoken_destroy(token);
                return false;
            }
            tmp_username = std::string(value);
            free(value);
        } else if (!config.m_map_subject) {
            tmp_username = config.m_default_user;
        }
 
        for (auto rule : config.m_map_rules) {
            for (auto path : config.m_base_paths) {
                auto path_rule = rule;
                path_rule.m_path_prefix = path + rule.m_path_prefix;
                auto pos = path_rule.m_path_prefix.find("//");
                if (pos != std::string::npos) {
                    path_rule.m_path_prefix.erase(pos + 1, 1);
                }
                map_rules.emplace_back(path_rule);
            }
        }
 
        AccessRulesRaw xrd_rules;
        int idx = 0;
        std::set<std::string> paths_write_seen;
        std::set<std::string> paths_create_or_modify_seen;
        std::vector<std::string> acl_paths;
        acl_paths.reserve(config.m_restricted_paths.size() + 1);
        while (acls[idx].resource && acls[idx++].authz) {
            acl_paths.clear();
            const auto &acl_path = acls[idx-1].resource;
            const auto &acl_authz = acls[idx-1].authz;
            if (config.m_restricted_paths.empty()) {
                acl_paths.push_back(acl_path);
            } else {
                auto acl_path_size = strlen(acl_path);
                for (const auto &restricted_path : config.m_restricted_paths) {
                    // See if the acl_path is more specific than the restricted path; if so, accept it
                    // and move on to applying paths.
                    if (!strncmp(acl_path, restricted_path.c_str(), restricted_path.size())) {
                        // Only do prefix checking on full path components.  If acl_path=/foobar and
                        // restricted_path=/foo, then we shouldn't authorize access to /foobar.
                        if (acl_path_size > restricted_path.size() && acl_path[restricted_path.size()] != '/') {
                            continue;
                        }
                        acl_paths.push_back(acl_path);
                        break;
                    }
                    // See if the restricted_path is more specific than the acl_path; if so, accept the
                    // restricted path as the ACL.  Keep looping to see if other restricted paths add
                    // more possible authorizations.
                    if (!strncmp(acl_path, restricted_path.c_str(), acl_path_size)) {
                        // Only do prefix checking on full path components.  If acl_path=/foo and
                        // restricted_path=/foobar, then we shouldn't authorize access to /foobar. Note:
                        // - The scitokens-cpp library guaranteees that acl_path is normalized and not
                        //   of the form `/foo/`.
                        // - Hence, the only time that the acl_path can end in a '/' is when it is
                        //   set to `/`.
                        if ((restricted_path.size() > acl_path_size && restricted_path[acl_path_size] != '/') && (acl_path_size != 1)) {
                            continue;
                        }
                        acl_paths.push_back(restricted_path);
                    }
                }
            }
            for (const auto &acl_path : acl_paths) {
              for (const auto &base_path : config.m_base_paths) {
                if (!acl_path[0] || acl_path[0] != '/') {continue;}
                std::string path;
                MakeCanonical(base_path + acl_path, path);
                if (!strcmp(acl_authz, "read")) {
                    xrd_rules.emplace_back(AOP_Read, path);
                    xrd_rules.emplace_back(AOP_Readdir, path);
                    xrd_rules.emplace_back(AOP_Stat, path);
                } else if (!strcmp(acl_authz, "create")) {
                    paths_create_or_modify_seen.insert(path);
                    xrd_rules.emplace_back(AOP_Excl_Create, path);
                    xrd_rules.emplace_back(AOP_Mkdir, path);
                    xrd_rules.emplace_back(AOP_Rename, path);
                    xrd_rules.emplace_back(AOP_Excl_Insert, path);
                    xrd_rules.emplace_back(AOP_Stat, path);
                } else if (!strcmp(acl_authz, "modify")) {
                    paths_create_or_modify_seen.insert(path);
                    xrd_rules.emplace_back(AOP_Create, path);
                    xrd_rules.emplace_back(AOP_Mkdir, path);
                    xrd_rules.emplace_back(AOP_Rename, path);
                    xrd_rules.emplace_back(AOP_Insert, path);
                    xrd_rules.emplace_back(AOP_Update, path);
                    xrd_rules.emplace_back(AOP_Chmod, path);
                    xrd_rules.emplace_back(AOP_Stat, path);
                    xrd_rules.emplace_back(AOP_Delete, path);
                } else if (!strcmp(acl_authz, "write")) {
                    paths_write_seen.insert(path);
                }
              }
            }
        }
        for (const auto &write_path : paths_write_seen) {
            if (paths_create_or_modify_seen.find(write_path) == paths_create_or_modify_seen.end()) {
                // This is a SciToken, add write ACLs.
                xrd_rules.emplace_back(AOP_Create, write_path);
                xrd_rules.emplace_back(AOP_Mkdir, write_path);
                xrd_rules.emplace_back(AOP_Rename, write_path);
                xrd_rules.emplace_back(AOP_Insert, write_path);
                xrd_rules.emplace_back(AOP_Update, write_path);
                xrd_rules.emplace_back(AOP_Stat, write_path);
                xrd_rules.emplace_back(AOP_Chmod, write_path);
                xrd_rules.emplace_back(AOP_Delete, write_path);
            }
        }
        authz_strategy = config.m_authz_strategy;
 
        cache_expiry = expiry;
        rules = std::move(xrd_rules);
        username = std::move(tmp_username);
        issuer = std::move(token_issuer);
        groups = std::move(groups_parsed);
        acceptable_authz = config.m_acceptable_authz;
 
        return true;
    }
 
 
    bool Config(XrdOucEnv *envP) {
        // Set default mask for logging.
        m_log.setMsgMask(LogMask::Error | LogMask::Warning);
 
        char *config_filename = nullptr;
        if (!XrdOucEnv::Import("XRDCONFIGFN", config_filename)) {
            return false;
        }
        XrdOucGatherConf scitokens_conf("scitokens.trace", &m_log);
        int result;
        if ((result = scitokens_conf.Gather(config_filename, XrdOucGatherConf::trim_lines)) < 0) {
            m_log.Emsg("Config", -result, "parsing config file", config_filename);
            return false;
        }
 
        char *val;
        std::string map_filename;
        while (scitokens_conf.GetLine()) {
            m_log.setMsgMask(0);
            scitokens_conf.GetToken(); // Ignore the output; we asked for a single config value, trace
            if (!(val = scitokens_conf.GetToken())) {
                m_log.Emsg("Config", "scitokens.trace requires an argument.  Usage: scitokens.trace [all|error|warning|info|debug|none]");
                return false;
            }
            do {
                if (!strcmp(val, "all")) {m_log.setMsgMask(m_log.getMsgMask() | LogMask::All);}
                else if (!strcmp(val, "error")) {m_log.setMsgMask(m_log.getMsgMask() | LogMask::Error);}
                else if (!strcmp(val, "warning")) {m_log.setMsgMask(m_log.getMsgMask() | LogMask::Warning);}
                else if (!strcmp(val, "info")) {m_log.setMsgMask(m_log.getMsgMask() | LogMask::Info);}
                else if (!strcmp(val, "debug")) {m_log.setMsgMask(m_log.getMsgMask() | LogMask::Debug);}
                else if (!strcmp(val, "none")) {m_log.setMsgMask(0);}
                else {m_log.Emsg("Config", "scitokens.trace encountered an unknown directive:", val); return false;}
            } while ((val = scitokens_conf.GetToken()));
        }
        m_log.Emsg("Config", "Logging levels enabled -", LogMaskToString(m_log.getMsgMask()).c_str());
 
        auto xrdEnv = static_cast<XrdOucEnv*>(envP ? envP->GetPtr("xrdEnv*") : nullptr);
        auto tlsCtx = static_cast<XrdTlsContext*>(xrdEnv ? xrdEnv->GetPtr("XrdTlsContext*") : nullptr);
        if (tlsCtx) {
            auto params = tlsCtx->GetParams();
            if (params && !params->cafile.empty()) {
#ifdef HAVE_SCITOKEN_CONFIG_SET_STR
                scitoken_config_set_str("tls.ca_file", params->cafile.c_str(), nullptr);
#else
                m_log.Log(LogMask::Warning, "Config", "tls.ca_file is set but the platform's libscitokens.so does not support setting config parameters");
#endif
            }
        }
 
        return Reconfig();
    }
 
    bool ParseMapfile(const std::string &filename, std::vector<MapRule> &rules)
    {
        std::stringstream ss;
        std::ifstream mapfile(filename);
        if (!mapfile.is_open())
        {
            ss << "Error opening mapfile (" << filename << "): " << strerror(errno);
            m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
            return false;
        }
        picojson::value val;
        auto err = picojson::parse(val, mapfile);
        if (!err.empty()) {
            ss << "Unable to parse mapfile (" << filename << ") as json: " << err;
            m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
            return false;
        }
        if (!val.is<picojson::array>()) {
            ss << "Top-level element of the mapfile " << filename << " must be a list";
            m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
            return false;
        }
        const auto& rule_list = val.get<picojson::array>();
        for (const auto &rule : rule_list)
        {
            if (!rule.is<picojson::object>()) {
                ss << "Mapfile " << filename << " must be a list of JSON objects; found non-object";
                m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
                return false;
            }
            std::string path;
            std::string group;
            std::string sub;
            std::string username;
            std::string result;
            bool ignore = false;
            for (const auto &entry : rule.get<picojson::object>()) {
                if (!entry.second.is<std::string>()) {
                    if (entry.first != "result" && entry.first != "group" && entry.first != "sub" && entry.first != "path") {continue;}
                    ss << "In mapfile " << filename << ", rule entry for " << entry.first << " has non-string value";
                    m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
                    return false;
                }
                if (entry.first == "result") {
                    result = entry.second.get<std::string>();
                }
                else if (entry.first == "group") {
                    group = entry.second.get<std::string>();
                }
                else if (entry.first == "sub") {
                    sub = entry.second.get<std::string>();
                } else if (entry.first == "username") {
                    username = entry.second.get<std::string>();
                } else if (entry.first == "path") {
                    std::string norm_path;
                    if (!MakeCanonical(entry.second.get<std::string>(), norm_path)) {
                        ss << "In mapfile " << filename << " encountered a path " << entry.second.get<std::string>()
                           << " that cannot be normalized";
                        m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
                        return false;
                    }
                    path = norm_path;
                } else if (entry.first == "ignore") {
                    ignore = true;
                    break;
                }
            }
            if (ignore) continue;
            if (result.empty())
            {
                ss << "In mapfile " << filename << " encountered a rule without a 'result' attribute";
                m_log.Log(LogMask::Error, "ParseMapfile", ss.str().c_str());
                return false;
            }
            rules.emplace_back(sub, username, path, group, result);
        }
 
        return true;
    }
 
    // A helper function for parsing one of the authorization setting variables (required_authz, acceptable_authz).
    // The result object is only changed if the variable is set to a non-empty string in the configuration.
    //
    // Returns false on failure.
    bool ParseAuthzSetting(OverrideINIReader &reader, const std::string &section, const std::string &variable, AuthzSetting &result) {
        auto authz_setting_str = reader.Get(section, variable, "");
        AuthzSetting authz_setting(AuthzSetting::None);
        if (authz_setting_str == "") {
            return true;
        } else if (authz_setting_str == "none") {
            authz_setting = AuthzSetting::None;
        } else if (authz_setting_str == "all") {
            authz_setting = AuthzSetting::All;
        } else if (authz_setting_str == "read") {
            authz_setting = AuthzSetting::Read;
        } else if (authz_setting_str == "write") {
            authz_setting = AuthzSetting::Write;
        } else {
            std::stringstream ss;
            ss << "Failed to parse " << variable << " in section " << section << ": unknown authorization setting " << authz_setting_str;
            m_log.Log(LogMask::Error, "Reconfig", ss.str().c_str());
            return false;
        }
        result = authz_setting;
        return true;
    }
 
    bool Reconfig()
    {
        errno = 0;
        m_cfg_file = "/etc/xrootd/scitokens.cfg";
        if (!m_parms.empty()) {
            size_t pos = 0;
            std::vector<std::string> arg_list;
            do {
                while ((m_parms.size() > pos) && (m_parms[pos] == ' ')) {pos++;}
                auto next_pos = m_parms.find_first_of(", ", pos);
                auto next_arg = m_parms.substr(pos, next_pos - pos);
                pos = next_pos;
                if (!next_arg.empty()) {
                    arg_list.emplace_back(std::move(next_arg));
                }
            } while (pos != std::string::npos);
 
            for (const auto &arg : arg_list) {
                if (strncmp(arg.c_str(), "config=", 7)) {
                    m_log.Log(LogMask::Error, "Reconfig", "Ignoring unknown configuration argument:", arg.c_str());
                    continue;
                }
                m_cfg_file = std::string(arg.c_str() + 7);
            }
        }
        m_log.Log(LogMask::Info, "Reconfig", "Parsing configuration file:", m_cfg_file.c_str());
 
        OverrideINIReader reader(m_cfg_file);
        if (reader.ParseError() < 0) {
            std::stringstream ss;
            ss << "Error opening config file (" << m_cfg_file << "): " << strerror(errno);
            m_log.Log(LogMask::Error, "Reconfig", ss.str().c_str());
            return false;
        } else if (reader.ParseError()) {
            std::stringstream ss;
            ss << "Parse error on line " << reader.ParseError() << " of file " << m_cfg_file;
            m_log.Log(LogMask::Error, "Reconfig", ss.str().c_str());
            return false;
        }
        std::vector<std::string> audiences;
        std::unordered_map<std::string, IssuerConfig> issuers;
        for (const auto &section : reader.Sections()) {
            std::string section_lower;
            std::transform(section.begin(), section.end(), std::back_inserter(section_lower),
                [](unsigned char c){ return std::tolower(c); });
 
            if (section_lower.substr(0, 6) == "global") {
                auto audience = reader.Get(section, "audience", "");
                if (!audience.empty()) {
                    size_t pos = 0;
                    do {
                        while (audience.size() > pos && (audience[pos] == ',' || audience[pos] == ' ')) {pos++;}
                        auto next_pos = audience.find_first_of(", ", pos);
                        auto next_aud = audience.substr(pos, next_pos - pos);
                        pos = next_pos;
                        if (!next_aud.empty()) {
                            audiences.push_back(next_aud);
                        }
                    } while (pos != std::string::npos);
                }
                audience = reader.Get(section, "audience_json", "");
                if (!audience.empty()) {
                    picojson::value json_obj;
                    auto err = picojson::parse(json_obj, audience);
                    if (!err.empty()) {
                        m_log.Log(LogMask::Error, "Reconfig", "Unable to parse audience_json:", err.c_str());
                        return false;
                    }
                    if (!json_obj.is<picojson::value::array>()) {
                        m_log.Log(LogMask::Error, "Reconfig", "audience_json must be a list of strings; not a list.");
                        return false;
                    }
                    for (const auto &val : json_obj.get<picojson::value::array>()) {
                        if (!val.is<std::string>()) {
                            m_log.Log(LogMask::Error, "Reconfig", "audience must be a list of strings; value is not a string.");
                            return false;
                        }
                        audiences.push_back(val.get<std::string>());
                    }
                }
                auto onmissing = reader.Get(section, "onmissing", "");
                if (onmissing == "passthrough") {
                    m_authz_behavior = AuthzBehavior::PASSTHROUGH;
                } else if (onmissing == "allow") {
                    m_authz_behavior = AuthzBehavior::ALLOW;
                } else if (onmissing == "deny") {
                    m_authz_behavior = AuthzBehavior::DENY;
                } else if (!onmissing.empty()) {
                    m_log.Log(LogMask::Error, "Reconfig", "Unknown value for onmissing key:", onmissing.c_str());
                    return false;
                }
            }
 
            if (section_lower.substr(0, 7) != "issuer ") {continue;}
 
            auto issuer = reader.Get(section, "issuer", "");
            if (issuer.empty()) {
                m_log.Log(LogMask::Error, "Reconfig", "Ignoring section because 'issuer' attribute is not set:",
                     section.c_str());
                continue;
            }
            m_log.Log(LogMask::Debug, "Reconfig", "Configuring issuer", issuer.c_str());
 
            std::vector<MapRule> rules;
            auto name_mapfile = reader.Get(section, "name_mapfile", "");
            if (!name_mapfile.empty()) {
                if (!ParseMapfile(name_mapfile, rules)) {
                    m_log.Log(LogMask::Error, "Reconfig", "Failed to parse mapfile; failing (re-)configuration", name_mapfile.c_str());
                    return false;
                } else {
                    m_log.Log(LogMask::Info, "Reconfig", "Successfully parsed SciTokens mapfile:", name_mapfile.c_str());
                }
            }
 
            auto base_path = reader.Get(section, "base_path", "");
            if (base_path.empty()) {
                m_log.Log(LogMask::Error, "Reconfig", "Ignoring section because 'base_path' attribute is not set:",
                     section.c_str());
                continue;
            }
 
            size_t pos = 7;
            while (section.size() > pos && std::isspace(section[pos])) {pos++;}
 
            auto name = section.substr(pos);
            if (name.empty()) {
                m_log.Log(LogMask::Error, "Reconfig", "Invalid section name:", section.c_str());
                continue;
            }
 
            std::vector<std::string> base_paths;
            ParseCanonicalPaths(base_path, base_paths);
 
            auto restricted_path = reader.Get(section, "restricted_path", "");
            std::vector<std::string> restricted_paths;
            if (!restricted_path.empty()) {
                ParseCanonicalPaths(restricted_path, restricted_paths);
            }
 
            auto default_user = reader.Get(section, "default_user", "");
            auto map_subject = reader.GetBoolean(section, "map_subject", false);
            auto username_claim = reader.Get(section, "username_claim", "");
            auto groups_claim = reader.Get(section, "groups_claim", "wlcg.groups");
 
            AuthzSetting required_authz(AuthzSetting::None), acceptable_authz(AuthzSetting::All);
            if (!ParseAuthzSetting(reader, section, "required_authorization", required_authz)) {
                m_log.Log(LogMask::Error, "Reconfig", "Ignoring required_authorization and using default of 'none'");
            }
            if (!ParseAuthzSetting(reader, section, "acceptable_authorization", acceptable_authz)) {
                m_log.Log(LogMask::Error, "Reconfig", "Ignoring acceptable_authorization and using default of 'all'");
            }
 
            auto authz_strategy_str = reader.Get(section, "authorization_strategy", "");
            uint32_t authz_strategy = 0;
            if (authz_strategy_str.empty()) {
                authz_strategy = IssuerAuthz::Default;
            } else {
                std::istringstream authz_strategy_stream(authz_strategy_str);
                std::string authz_str;
                while (std::getline(authz_strategy_stream, authz_str, ' ')) {
                    if (!strcasecmp(authz_str.c_str(), "capability")) {
                        authz_strategy |= IssuerAuthz::Capability;
                    } else if (!strcasecmp(authz_str.c_str(), "group")) {
                        authz_strategy |= IssuerAuthz::Group;
                    } else if (!strcasecmp(authz_str.c_str(), "mapping")) {
                        authz_strategy |= IssuerAuthz::Mapping;
                    } else {
                        m_log.Log(LogMask::Error, "Reconfig", "Unknown authorization strategy (ignoring):", authz_str.c_str());
                    }
                }
            }
 
            issuers.emplace(std::piecewise_construct,
                            std::forward_as_tuple(issuer),
                            std::forward_as_tuple(name, issuer, base_paths, restricted_paths,
                                                  map_subject, authz_strategy, default_user, username_claim, groups_claim, rules,
                                                  acceptable_authz, required_authz));
 
            // If this is an issuer that is required for authorization, calculate the paths that it is
            // responsible for.
            if (required_authz != AuthzSetting::None) {
                AccessRulesRaw rules;
                for (const auto &base_path : base_paths) {
                    if (restricted_paths.empty()) {
                        restricted_paths.emplace_back("/");
                    }
                    for (const auto &restricted_path : restricted_paths) {
                        auto full_path = base_path + "/" + restricted_path;
                        std::string cleaned_path;
                        MakeCanonical(full_path, cleaned_path);
                        if (required_authz == AuthzSetting::Read || required_authz == AuthzSetting::All) {
                            rules.emplace_back(AOP_Read, cleaned_path);
                            rules.emplace_back(AOP_Stat, cleaned_path);
                        } else if (required_authz == AuthzSetting::Write || required_authz == AuthzSetting::All) {
                            rules.emplace_back(AOP_Create, cleaned_path);
                            rules.emplace_back(AOP_Mkdir, cleaned_path);
                            rules.emplace_back(AOP_Stat, cleaned_path);
                        }
                    }
                }
                m_required_issuers.emplace_back(std::make_unique<SubpathMatch>(rules), issuer);
            }
        }
 
        if (issuers.empty()) {
            m_log.Log(LogMask::Warning, "Reconfig", "No issuers configured.");
        }
 
        pthread_rwlock_wrlock(&m_config_lock);
        try {
            m_audiences = std::move(audiences);
            size_t idx = 0;
            m_audiences_array.resize(m_audiences.size() + 1);
            for (const auto &audience : m_audiences) {
                m_audiences_array[idx++] = audience.c_str();
            }
            m_audiences_array[idx] = nullptr;
 
            m_issuers = std::move(issuers);
            m_valid_issuers_array.resize(m_issuers.size() + 1);
            idx = 0;
            for (const auto &issuer : m_issuers) {
                m_valid_issuers_array[idx++] = issuer.first.c_str();
            }
            m_valid_issuers_array[idx] = nullptr;
        } catch (...) {
            pthread_rwlock_unlock(&m_config_lock);
            return false;
        }
        pthread_rwlock_unlock(&m_config_lock);
        return true;
    }
 
    void Check(uint64_t now)
    {
        if (now <= m_next_clean) {return;}
        std::lock_guard<std::mutex> guard(m_mutex);
 
        for (auto iter = m_map.begin(); iter != m_map.end(); ) {
            if (iter->second->expired()) {
                iter = m_map.erase(iter);
            } else {
                ++iter;
            }
        }
        Reconfig();
 
        m_next_clean = monotonic_time() + m_expiry_secs;
    }
 
    bool m_config_lock_initialized{false};
    std::mutex m_mutex;
    pthread_rwlock_t m_config_lock;
    std::vector<std::string> m_audiences;
    std::vector<const char *> m_audiences_array;
    std::map<std::string, std::shared_ptr<XrdAccRules>, std::less<>> m_map; // Note: std::less<> is used as the comparator to enable transparent casting from std::string_view for key lookup
    XrdAccAuthorize* m_chain;
    const std::string m_parms;
    std::vector<const char*> m_valid_issuers_array;
    // Authorization from these issuers are required for any matching path.  The map tracks the
    // base prefix to the issuer URL.
    std::vector<std::pair<std::unique_ptr<SubpathMatch>, std::string>> m_required_issuers;
    std::unordered_map<std::string, IssuerConfig> m_issuers;
    uint64_t m_next_clean{0};
    XrdSysError m_log;
    AuthzBehavior m_authz_behavior{AuthzBehavior::PASSTHROUGH};
    std::string m_cfg_file;
 
    static constexpr uint64_t m_expiry_secs = 60;
};
 
void InitAccSciTokens(XrdSysLogger *lp, const char *cfn, const char *parm,
                      XrdAccAuthorize *accP, XrdOucEnv *envP)
{
    try {
        accSciTokens = new XrdAccSciTokens(lp, parm, accP, envP);
        SciTokensHelper = accSciTokens;
    } catch (std::exception &) {
    }
}
 
extern "C" {
 
XrdAccAuthorize *XrdAccAuthorizeObjAdd(XrdSysLogger *lp,
                                          const char   *cfn,
                                          const char   *parm,
                                       XrdOucEnv       *envP,
                                       XrdAccAuthorize *accP)
{
    // Record the parent authorization plugin. There is no need to use
    // unique_ptr as all of this happens once in the main and only thread.
    //
 
    // If we have been initialized by a previous load, them return that result.
    // Otherwise, it's the first time through, get a new SciTokens authorizer.
    //
    if (!accSciTokens) InitAccSciTokens(lp, cfn, parm, accP, envP);
    return accSciTokens;
}
 
XrdAccAuthorize *XrdAccAuthorizeObject(XrdSysLogger *lp,
                                       const char   *cfn,
                                       const char   *parm)
{
    InitAccSciTokens(lp, cfn, parm, nullptr, nullptr);
    return accSciTokens;
}
 
XrdAccAuthorize *XrdAccAuthorizeObject2(XrdSysLogger *lp,
                                        const char   *cfn,
                                        const char   *parm,
                                        XrdOucEnv    *envP)
{
    InitAccSciTokens(lp, cfn, parm, nullptr, envP);
    return accSciTokens;
}
 
 
}