/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/* DEBUG: section 28    Access Control */

#include "squid.h"
#include "acl/Acl.h"
#include "acl/Checklist.h"
#include "acl/Gadgets.h"
#include "acl/Options.h"
#include "anyp/PortCfg.h"
#include "base/IoManip.h"
#include "cache_cf.h"
#include "ConfigParser.h"
#include "debug/Stream.h"
#include "fatal.h"
#include "globals.h"
#include "mem/PoolingAllocator.h"
#include "sbuf/Algorithms.h"
#include "sbuf/List.h"
#include "sbuf/Stream.h"
#include "SquidConfig.h"

#include <algorithm>
#include <map>
#include <unordered_map>

namespace Acl {

/// parsed "acl aclname ..." directives indexed by aclname
class NamedAcls: public std::unordered_map<SBuf, Acl::Node::Pointer,
    CaseInsensitiveSBufHash, CaseInsensitiveSBufEqual,
    PoolingAllocator< std::pair<const SBuf, Acl::Node::Pointer> > > {
};

/// Acl::Node type name comparison functor
class TypeNameCmp {
public:
    bool operator()(TypeName a, TypeName b) const { return strcmp(a, b) < 0; }
};

/// Acl::Node makers indexed by Node type name
typedef std::map<TypeName, Maker, TypeNameCmp> Makers;

/// registered Acl::Node Makers
static Makers &
TheMakers()
{
    static Makers Registry;
    return Registry;
}

/// creates an Acl::Node object of the named (and already registered) Node child type
static
Acl::Node *
Make(TypeName typeName)
{
    const auto pos = TheMakers().find(typeName);
    if (pos == TheMakers().end())
        throw TextException(ToSBuf("invalid ACL type '", typeName, "'"), Here());

    auto *result = (pos->second)(pos->first);
    debugs(28, 4, typeName << '=' << result);
    assert(result);
    return result;
}

/// CodeContext of the being-parsed acl directive
class ParsingContext: public CodeContext
{
public:
    using Pointer = RefCount<ParsingContext>;

    explicit ParsingContext(const SBuf &name): name_(name) {}

    /* CodeContext API */
    ScopedId codeContextGist() const override;
    std::ostream &detailCodeContext(std::ostream &os) const override;

private:
    SBuf name_; ///< the aclname parameter of the being-parsed acl directive
};

} // namespace Acl

void
Acl::RegisterMaker(TypeName typeName, Maker maker)
{
    assert(typeName);
    assert(*typeName);
    TheMakers().emplace(typeName, maker);
}

void
Acl::SetKey(SBuf &keyStorage, const char *keyParameterName, const char *newKey)
{
    if (!newKey) {
        throw TextException(ToSBuf("An acl declaration is missing a ", keyParameterName), Here());
    }

    if (keyStorage.isEmpty()) {
        keyStorage = newKey;
        return;
    }

    if (keyStorage.caseCmp(newKey) == 0)
        return; // no change

    throw TextException(ToSBuf("Attempt to change the value of the ", keyParameterName, " argument in a subsequent acl declaration:",
                               Debug::Extra, "previously seen value: ", keyStorage,
                               Debug::Extra, "new/conflicting value: ", newKey,
                               Debug::Extra, "advice: Use a dedicated ACL name for each distinct ", keyParameterName,
                               " (and group those ACLs together using an 'any-of' ACL)."),
                        Here());
}

const SBuf &
Acl::Answer::lastCheckDescription() const
{
    static const auto none = new SBuf("[no-ACL]");
    // no value_or() because it would create a new SBuf object here
    return lastCheckedName ? *lastCheckedName : *none;
}

/* Acl::ParsingContext */

ScopedId
Acl::ParsingContext::codeContextGist() const {
    return ScopedId("acl");
}

std::ostream &
Acl::ParsingContext::detailCodeContext(std::ostream &os) const
{
    return os << Debug::Extra << "acl name: " << name_ <<
           Debug::Extra << "configuration context: " << ConfigParser::CurrentLocation();
}

/* Acl::Node */

void *
Acl::Node::operator new (size_t)
{
    fatal ("unusable Acl::Node::new");
    return (void *)1;
}

void Acl::Node::operator delete(void *)
{
    fatal ("unusable Acl::Node::delete");
}

Acl::Node *
Acl::Node::FindByName(const SBuf &name)
{
    if (!Config.namedAcls) {
        debugs(28, 8, "no named ACLs to find " << name);
        return nullptr;
    }

    const auto result = Config.namedAcls->find(name);
    if (result == Config.namedAcls->end()) {
        debugs(28, 8, "no ACL named " << name);
        return nullptr;
    }

    debugs(28, 8, result->second << " is named " << name);
    assert(result->second);
    return result->second.getRaw();
}

Acl::Node::Node()
{
    debugs(28, 8, "constructing, this=" << this);
}

bool
Acl::Node::valid() const
{
    return true;
}

bool
Acl::Node::matches(ACLChecklist *checklist) const
{
    debugs(28, 5, "checking " << name);

    checklist->setLastCheckedName(name);

    int result = 0;
    if (!checklist->hasAle() && requiresAle()) {
        debugs(28, DBG_IMPORTANT, "WARNING: " << name << " ACL is used in " <<
               "context without an ALE state. Assuming mismatch.");
    } else if (!checklist->hasRequest() && requiresRequest()) {
        debugs(28, DBG_IMPORTANT, "WARNING: " << name << " ACL is used in " <<
               "context without an HTTP request. Assuming mismatch.");
    } else if (!checklist->hasReply() && requiresReply()) {
        debugs(28, DBG_IMPORTANT, "WARNING: " << name << " ACL is used in " <<
               "context without an HTTP response. Assuming mismatch.");
    } else {
        // make sure the ALE has as much data as possible
        if (requiresAle())
            checklist->verifyAle();

        // have to cast because old match() API is missing const
        result = const_cast<Node*>(this)->match(checklist);
    }

    const char *extra = checklist->asyncInProgress() ? " async" : "";
    debugs(28, 3, "checked: " << name << " = " << result << extra);
    return result == 1; // true for match; false for everything else
}

void
Acl::Node::context(const SBuf &aName, const char *aCfgLine)
{
    name = aName;
    safe_free(cfgline);
    if (aCfgLine)
        cfgline = xstrdup(aCfgLine);
}

void
Acl::Node::ParseNamedAcl(ConfigParser &parser, NamedAcls *&namedAcls)
{
    /* we're already using strtok() to grok the line */
    char *t = nullptr;

    /* snarf the ACL name */

    if ((t = ConfigParser::NextToken()) == nullptr) {
        debugs(28, DBG_CRITICAL, "ERROR: aclParseAclLine: missing ACL name.");
        parser.destruct();
        return;
    }

    if (!namedAcls)
        namedAcls = new NamedAcls();

    SBuf aclname(t);
    CallParser(ParsingContext::Pointer::Make(aclname), [&] {
        ParseNamed(parser, *namedAcls, aclname);
    });
}

/// parses acl directive parts that follow aclname
void
Acl::Node::ParseNamed(ConfigParser &parser, NamedAcls &namedAcls, const SBuf &aclname)
{
    /* snarf the ACL type */
    const char *theType;

    if ((theType = ConfigParser::NextToken()) == nullptr) {
        debugs(28, DBG_CRITICAL, "ERROR: aclParseAclLine: missing ACL type.");
        parser.destruct();
        return;
    }

    // Is this ACL going to work?
    if (strcmp(theType, "myip") == 0) {
        AnyP::PortCfgPointer p = HttpPortList;
        while (p != nullptr) {
            // Bug 3239: not reliable when there is interception traffic coming
            if (p->flags.natIntercept)
                debugs(28, DBG_CRITICAL, "WARNING: 'myip' ACL is not reliable for interception proxies. Please use 'myportname' instead.");
            p = p->next;
        }
        debugs(28, DBG_IMPORTANT, "WARNING: UPGRADE: ACL 'myip' type has been renamed to 'localip' and matches the IP the client connected to.");
        theType = "localip";
    } else if (strcmp(theType, "myport") == 0) {
        AnyP::PortCfgPointer p = HttpPortList;
        while (p != nullptr) {
            // Bug 3239: not reliable when there is interception traffic coming
            // Bug 3239: myport - not reliable (yet) when there is interception traffic coming
            if (p->flags.natIntercept)
                debugs(28, DBG_CRITICAL, "WARNING: 'myport' ACL is not reliable for interception proxies. Please use 'myportname' instead.");
            p = p->next;
        }
        theType = "localport";
        debugs(28, DBG_IMPORTANT, "WARNING: UPGRADE: ACL 'myport' type has been renamed to 'localport' and matches the port the client connected to.");
    } else if (strcmp(theType, "proto") == 0 && aclname.cmp("manager") == 0) {
        // ACL manager is now a built-in and has a different type.
        debugs(28, DBG_PARSE_NOTE(DBG_IMPORTANT), "WARNING: UPGRADE: ACL 'manager' is now a built-in ACL. Remove it from your config file.");
        return; // ignore the line
    } else if (strcmp(theType, "clientside_mark") == 0) {
        debugs(28, DBG_IMPORTANT, "WARNING: UPGRADE: ACL 'clientside_mark' type has been renamed to 'client_connection_mark'.");
        theType = "client_connection_mark";
    }

    auto A = FindByName(aclname);
    int new_acl = 0;
    if (!A) {
        debugs(28, 3, "aclParseAclLine: Creating ACL '" << aclname << "'");
        A = Acl::Make(theType);
        A->context(aclname, config_input_line);
        new_acl = 1;
    } else {
        if (strcmp (A->typeString(),theType) ) {
            debugs(28, DBG_CRITICAL, "aclParseAclLine: ACL '" << A->name << "' already exists with different type.");
            parser.destruct();
            return;
        }

        debugs(28, 3, "aclParseAclLine: Appending to '" << aclname << "'");
        new_acl = 0;
    }

    A->parseFlags();

    /*split the function here */
    A->parse();

    if (!new_acl)
        return;

    if (A->empty()) {
        debugs(28, DBG_CRITICAL, "WARNING: empty ACL: " << A->cfgline);
    }

    if (!A->valid()) {
        fatalf("ERROR: Invalid ACL: %s\n",
               A->cfgline);
    }

    const auto insertion = namedAcls.emplace(A->name, A);
    Assure(insertion.second); // FindByName() above checked that A is a new ACL
}

void
Acl::DumpNamedAcls(std::ostream &os, const char * const directiveName, NamedAcls * const namedAcls)
{
    if (namedAcls) {
        for (const auto &nameAndAcl: *namedAcls) {
            debugs(3, 3, directiveName << ' ' << nameAndAcl.first);
            nameAndAcl.second->dumpWhole(directiveName, os);
        }
    }
}

void
Acl::FreeNamedAcls(NamedAcls ** const namedAcls)
{
    assert(namedAcls);
    delete *namedAcls;
    *namedAcls = nullptr;
}

bool
Acl::Node::isProxyAuth() const
{
    return false;
}

void
Acl::Node::parseFlags()
{
    Acl::Options allOptions = options();
    for (const auto lineOption: lineOptions()) {
        lineOption->unconfigure(); // forget any previous "acl ..." line effects
        allOptions.push_back(lineOption);
    }
    Acl::ParseFlags(allOptions);
}

void
Acl::Node::dumpWhole(const char * const directiveName, std::ostream &os)
{
    // XXX: No lineOptions() call here because we do not remember ACL "line"
    // boundaries and associated "line" options; we cannot report them.
    os << directiveName << ' ' << name << ' ' << typeString() << options() <<
       asList(dump()).prefixedBy(" ").delimitedBy(" ") <<
       '\n';
}

/* ACL result caching routines */

int
Acl::Node::matchForCache(ACLChecklist *)
{
    /* This is a fatal to ensure that cacheMatchAcl calls are _only_
     * made for supported acl types */
    fatal("aclCacheMatchAcl: unknown or unexpected ACL type");
    return 0;       /* NOTREACHED */
}

/*
 * we lookup an acl's cached results, and if we cannot find the acl being
 * checked we check it and cache the result. This function is a template
 * method to support caching of multiple acl types.
 * Note that caching of time based acl's is not
 * wise in long lived caches (i.e. the auth_user proxy match cache)
 * RBC
 * TODO: does a dlink_list perform well enough? Kinkie
 */
int
Acl::Node::cacheMatchAcl(dlink_list * cache, ACLChecklist *checklist)
{
    acl_proxy_auth_match_cache *auth_match;
    dlink_node *link;
    link = cache->head;

    while (link) {
        auth_match = (acl_proxy_auth_match_cache *)link->data;

        if (auth_match->acl_data == this) {
            debugs(28, 4, "cache hit on acl '" << name << "' (" << this << ")");
            return auth_match->matchrv;
        }

        link = link->next;
    }

    auth_match = new acl_proxy_auth_match_cache(matchForCache(checklist), this);
    dlinkAddTail(auth_match, &auth_match->link, cache);
    debugs(28, 4, "miss for acl '" << name << "'. Adding result " << auth_match->matchrv);
    return auth_match->matchrv;
}

void
aclCacheMatchFlush(dlink_list * cache)
{
    acl_proxy_auth_match_cache *auth_match;
    dlink_node *link, *tmplink;
    link = cache->head;

    debugs(28, 8, "aclCacheMatchFlush called for cache " << cache);

    while (link) {
        auth_match = (acl_proxy_auth_match_cache *)link->data;
        tmplink = link;
        link = link->next;
        dlinkDelete(tmplink, cache);
        delete auth_match;
    }
}

bool
Acl::Node::requiresAle() const
{
    return false;
}

bool
Acl::Node::requiresReply() const
{
    return false;
}

bool
Acl::Node::requiresRequest() const
{
    return false;
}

/*********************/
/* Destroy functions */
/*********************/

Acl::Node::~Node()
{
    debugs(28, 8, "destructing " <<  name << ", this=" << this);
    safe_free(cfgline);
}

void
Acl::Node::Initialize()
{
    debugs(28, 3, (Config.namedAcls ? Config.namedAcls->size() : 0));
    if (Config.namedAcls) {
        for (const auto &nameAndAcl: *Config.namedAcls)
            nameAndAcl.second->prepareForUse();
    }
}


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