/*
 * Tokens
 *
 * Copyright (C) 1998 Alexandre Julliard
 * Copyright (C) 2003 Mike McCormack
 * Copyright (C) 2005 Robert Shearman
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "config.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>

#include "windef.h"

#include "handle.h"
#include "thread.h"
#include "process.h"
#include "request.h"
#include "security.h"

#define MAX_SUBAUTH_COUNT 1

const LUID SeIncreaseQuotaPrivilege        = {  5, 0 };
const LUID SeSecurityPrivilege             = {  8, 0 };
const LUID SeTakeOwnershipPrivilege        = {  9, 0 };
const LUID SeLoadDriverPrivilege           = { 10, 0 };
const LUID SeSystemProfilePrivilege        = { 11, 0 };
const LUID SeSystemtimePrivilege           = { 12, 0 };
const LUID SeProfileSingleProcessPrivilege = { 13, 0 };
const LUID SeIncreaseBasePriorityPrivilege = { 14, 0 };
const LUID SeCreatePagefilePrivilege       = { 15, 0 };
const LUID SeBackupPrivilege               = { 17, 0 };
const LUID SeRestorePrivilege              = { 18, 0 };
const LUID SeShutdownPrivilege             = { 19, 0 };
const LUID SeDebugPrivilege                = { 20, 0 };
const LUID SeSystemEnvironmentPrivilege    = { 22, 0 };
const LUID SeChangeNotifyPrivilege         = { 23, 0 };
const LUID SeRemoteShutdownPrivilege       = { 24, 0 };
const LUID SeUndockPrivilege               = { 25, 0 };
const LUID SeManageVolumePrivilege         = { 28, 0 };
const LUID SeImpersonatePrivilege          = { 29, 0 };
const LUID SeCreateGlobalPrivilege         = { 30, 0 };

struct token
{
    struct object  obj;             /* object header */
    struct list    privileges;      /* privileges available to the token */
    SID           *user;            /* SID of user this token represents */
};

struct privilege
{
    struct list entry;
    LUID        luid;
    unsigned    enabled  : 1; /* is the privilege currently enabled? */
    unsigned    def      : 1; /* is the privilege enabled by default? */
};

static void token_dump( struct object *obj, int verbose );
static void token_destroy( struct object *obj );

static const struct object_ops token_ops =
{
    sizeof(struct token),      /* size */
    token_dump,                /* dump */
    no_add_queue,              /* add_queue */
    NULL,                      /* remove_queue */
    NULL,                      /* signaled */
    NULL,                      /* satisfied */
    no_signal,                 /* signal */
    no_get_fd,                 /* get_fd */
    token_destroy              /* destroy */
};


static void token_dump( struct object *obj, int verbose )
{
    fprintf( stderr, "Security token\n" );
}

static SID *security_sid_alloc( const SID_IDENTIFIER_AUTHORITY *idauthority, int subauthcount, const unsigned int subauth[] )
{
    int i;
    SID *sid = mem_alloc( FIELD_OFFSET(SID, SubAuthority[subauthcount]) );
    if (!sid) return NULL;
    sid->Revision = MAX_ACL_REVISION;
    sid->SubAuthorityCount = subauthcount;
    sid->IdentifierAuthority = *idauthority;
    for (i = 0; i < subauthcount; i++)
        sid->SubAuthority[i] = subauth[i];
    return sid;
}

static inline int security_equal_sid( const SID *sid1, const SID *sid2 )
{
    return ((sid1->SubAuthorityCount == sid2->SubAuthorityCount) &&
        !memcmp( sid1, sid2, FIELD_OFFSET(SID, SubAuthority[sid1->SubAuthorityCount]) ));
}

static inline int is_equal_luid( const LUID *luid1, const LUID *luid2 )
{
    return (luid1->LowPart == luid2->LowPart && luid1->HighPart == luid2->HighPart);
}

static inline void luid_and_attr_from_privilege( LUID_AND_ATTRIBUTES *out, const struct privilege *in)
{
    out->Luid = in->luid;
    out->Attributes =
        (in->enabled ? SE_PRIVILEGE_ENABLED : 0) |
        (in->def ? SE_PRIVILEGE_ENABLED_BY_DEFAULT : 0);
}

static struct privilege *privilege_add( struct token *token, const LUID *luid, int enabled )
{
    struct privilege *privilege = mem_alloc( sizeof(*privilege) );
    if (privilege)
    {
        privilege->luid = *luid;
        privilege->def = privilege->enabled = (enabled != 0);
        list_add_tail( &token->privileges, &privilege->entry );
    }
    return privilege;
}

static inline void privilege_remove( struct privilege *privilege )
{
    list_remove( &privilege->entry );
    free( privilege );
}

static void token_destroy( struct object *obj )
{
    struct token* token;
    struct list *cursor, *cursor_next;

    assert( obj->ops == &token_ops );
    token = (struct token *)obj;

    free( token->user );

    LIST_FOR_EACH_SAFE( cursor, cursor_next, &token->privileges )
    {
        struct privilege *privilege = LIST_ENTRY( cursor, struct privilege, entry );
        privilege_remove( privilege );
    }
}

static struct token *create_token( const SID *user, const LUID_AND_ATTRIBUTES *privs, unsigned int priv_count )
{
    struct token *token = alloc_object( &token_ops );
    if (token)
    {
        int i;
        list_init( &token->privileges );
        /* copy user */
        token->user = memdup( user, FIELD_OFFSET(SID, SubAuthority[user->SubAuthorityCount]) );
        if (!token->user)
        {
            release_object( token );
            return NULL;
        }
        /* copy privileges */
        for (i = 0; i < priv_count; i++)
        {
            /* note: we don't check uniqueness: the caller must make sure
             * privs doesn't contain any duplicate luids */
            if (!privilege_add( token, &privs[i].Luid,
                                privs[i].Attributes & SE_PRIVILEGE_ENABLED ))
            {
                release_object( token );
                return NULL;
            }
        }
    }
    return token;
}

struct sid_data
{
    SID_IDENTIFIER_AUTHORITY idauth;
    int count;
    unsigned int subauth[MAX_SUBAUTH_COUNT];
};

struct token *token_create_admin( void )
{
    struct token *token;
    const LUID_AND_ATTRIBUTES admin_privs[] =
    {
        { SeChangeNotifyPrivilege        , SE_PRIVILEGE_ENABLED },
        { SeSecurityPrivilege            , 0                    },
        { SeBackupPrivilege              , 0                    },
        { SeRestorePrivilege             , 0                    },
        { SeSystemtimePrivilege          , 0                    },
        { SeShutdownPrivilege            , 0                    },
        { SeRemoteShutdownPrivilege      , 0                    },
        { SeTakeOwnershipPrivilege       , 0                    },
        { SeDebugPrivilege               , 0                    },
        { SeSystemEnvironmentPrivilege   , 0                    },
        { SeSystemProfilePrivilege       , 0                    },
        { SeProfileSingleProcessPrivilege, 0                    },
        { SeIncreaseBasePriorityPrivilege, 0                    },
        { SeLoadDriverPrivilege          , 0                    },
        { SeCreatePagefilePrivilege      , 0                    },
        { SeIncreaseQuotaPrivilege       , 0                    },
        { SeUndockPrivilege              , 0                    },
        { SeManageVolumePrivilege        , 0                    },
        { SeImpersonatePrivilege         , SE_PRIVILEGE_ENABLED },
        { SeCreateGlobalPrivilege        , SE_PRIVILEGE_ENABLED },
    };
    static const struct sid_data well_known_sid_data[] =
    {
        { { SECURITY_NT_AUTHORITY }, 1, { SECURITY_LOCAL_SYSTEM_RID } }, /* LOCAL_SYSTEM */
    };
    SID *local_system_sid = security_sid_alloc(
        &well_known_sid_data[0].idauth,
        well_known_sid_data[0].count,
        well_known_sid_data[0].subauth );
    if (!local_system_sid) return NULL;
    token = create_token( local_system_sid, admin_privs, sizeof(admin_privs)/sizeof(admin_privs[0]) );
    free( local_system_sid );
    return token;
}

static struct privilege *token_find_privilege( struct token *token, const LUID *luid, int enabled_only)
{
    struct privilege *privilege;
    LIST_FOR_EACH_ENTRY( privilege, &token->privileges, struct privilege, entry )
    {
        if (is_equal_luid( luid, &privilege->luid ))
        {
            if (enabled_only && !privilege->enabled)
                return NULL;
            return privilege;
        }
    }
    return NULL;
}

static unsigned int token_adjust_privileges( struct token *token, const LUID_AND_ATTRIBUTES *privs,
                                             unsigned int count, LUID_AND_ATTRIBUTES *mod_privs,
                                             unsigned int mod_privs_count)
{
    int i;
    unsigned int modified_count = 0;

    for (i = 0; i < count; i++)
    {
        struct privilege *privilege =
            token_find_privilege( token, &privs[i].Luid, FALSE );
        if (!privilege)
        {
            set_error( STATUS_NOT_ALL_ASSIGNED );
            continue;
        }

        if (privs[i].Attributes & SE_PRIVILEGE_REMOVE)
            privilege_remove( privilege );
        else
        {
            /* save previous state for caller */
            if (mod_privs_count)
            {
                luid_and_attr_from_privilege(mod_privs, privilege);
                mod_privs++;
                mod_privs_count--;
                modified_count++;
            }

            if (privs[i].Attributes & SE_PRIVILEGE_ENABLED)
                privilege->enabled = TRUE;
            else
                privilege->enabled = FALSE;
        }
    }
    return modified_count;
}

static void token_disable_privileges( struct token *token )
{
    struct privilege *privilege;
    LIST_FOR_EACH_ENTRY( privilege, &token->privileges, struct privilege, entry )
        privilege->enabled = FALSE;
}

int token_check_privileges( struct token *token, int all_required,
                            const LUID_AND_ATTRIBUTES *reqprivs,
                            unsigned int count, LUID_AND_ATTRIBUTES *usedprivs)
{
    int i;
    unsigned int enabled_count = 0;

    for (i = 0; i < count; i++)
    {
        struct privilege *privilege = 
            token_find_privilege( token, &reqprivs[i].Luid, TRUE );

        if (usedprivs)
            usedprivs[i] = reqprivs[i];

        if (privilege && privilege->enabled)
        {
            enabled_count++;
            if (usedprivs)
                usedprivs[i].Attributes |= SE_PRIVILEGE_USED_FOR_ACCESS;
        }
    }

    if (all_required)
        return (enabled_count == count);
    else
        return (enabled_count > 0);
}

/* open a security token */
DECL_HANDLER(open_token)
{
    if( req->flags & OPEN_TOKEN_THREAD )
    {
        struct thread *thread = get_thread_from_handle( req->handle, 0 );
        if (thread)
        {
            if (thread->token)
                reply->token = alloc_handle( current->process, thread->token, TOKEN_ALL_ACCESS, 0);
            else
                set_error(STATUS_NO_TOKEN);
            release_object( thread );
        }
    }
    else
    {
        struct process *process = get_process_from_handle( req->handle, 0 );
        if (process)
        {
            if (process->token)
                reply->token = alloc_handle( current->process, process->token, TOKEN_ALL_ACCESS, 0);
            else
                set_error(STATUS_NO_TOKEN);
            release_object( process );
        }
    }
}

/* adjust the privileges held by a token */
DECL_HANDLER(adjust_token_privileges)
{
    struct token *token;
    unsigned int access = TOKEN_ADJUST_PRIVILEGES;

    if (req->get_modified_state) access |= TOKEN_QUERY;

    if ((token = (struct token *)get_handle_obj( current->process, req->handle,
                                                 access, &token_ops )))
    {
        const LUID_AND_ATTRIBUTES *privs = get_req_data();
        LUID_AND_ATTRIBUTES *modified_privs = NULL;
        unsigned int priv_count = get_req_data_size() / sizeof(LUID_AND_ATTRIBUTES);
        unsigned int modified_priv_count = 0;

        if (req->get_modified_state && !req->disable_all)
        {
            int i;
            /* count modified privs */
            for (i = 0; i < priv_count; i++)
            {
                struct privilege *privilege =
                    token_find_privilege( token, &privs[i].Luid, FALSE );
                if (privilege && req->get_modified_state)
                    modified_priv_count++;
            }
            reply->len = modified_priv_count;
            modified_priv_count = min( modified_priv_count, get_reply_max_size() / sizeof(*modified_privs) );
            if (modified_priv_count)
                modified_privs = set_reply_data_size( modified_priv_count * sizeof(*modified_privs) );
        }
        reply->len = modified_priv_count * sizeof(*modified_privs);

        if (req->disable_all)
            token_disable_privileges( token );
        else
            modified_priv_count = token_adjust_privileges( token, privs,
                priv_count, modified_privs, modified_priv_count );

        release_object( token );
    }
}

/* retrieves the list of privileges that may be held be the token */
DECL_HANDLER(get_token_privileges)
{
    struct token *token;

    if ((token = (struct token *)get_handle_obj( current->process, req->handle,
                                                 TOKEN_QUERY,
                                                 &token_ops )))
    {
        int priv_count = 0;
        LUID_AND_ATTRIBUTES *privs;
        struct privilege *privilege;

        LIST_FOR_EACH_ENTRY( privilege, &token->privileges, struct privilege, entry )
            priv_count++;

        reply->len = priv_count * sizeof(*privs);
        if (reply->len <= get_reply_max_size())
        {
            privs = set_reply_data_size( priv_count * sizeof(*privs) );
            if (privs)
            {
                int i = 0;
                LIST_FOR_EACH_ENTRY( privilege, &token->privileges, struct privilege, entry )
                {
                    luid_and_attr_from_privilege( &privs[i], privilege );
                    i++;
                }
            }
        }
        else
            set_error(STATUS_BUFFER_TOO_SMALL);

        release_object( token );
    }
}

/* creates a duplicate of the token */
DECL_HANDLER(duplicate_token)
{
    struct token *src_token;
    if ((src_token = (struct token *)get_handle_obj( current->process, req->handle,
                                                     TOKEN_DUPLICATE,
                                                     &token_ops )))
    {
        /* FIXME: use req->primary and req->impersonation_level */
        struct token *token = create_token( src_token->user, NULL, 0 );
        if (token)
        {
            struct privilege *privilege;
            unsigned int access;

            LIST_FOR_EACH_ENTRY( privilege, &src_token->privileges, struct privilege, entry )
                privilege_add( token, &privilege->luid, privilege->enabled );

            access = req->access;
            if (access & MAXIMUM_ALLOWED) access = TOKEN_ALL_ACCESS; /* FIXME: needs general solution */
            reply->new_handle = alloc_handle( current->process, token, access, req->inherit);
            release_object( token );
        }
        release_object( src_token );
    }
}

/* checks the specified privileges are held by the token */
DECL_HANDLER(check_token_privileges)
{
    struct token *token;

    if ((token = (struct token *)get_handle_obj( current->process, req->handle,
                                                 TOKEN_QUERY,
                                                 &token_ops )))
    {
        unsigned int count = get_req_data_size() / sizeof(LUID_AND_ATTRIBUTES);
        if (get_reply_max_size() >= count * sizeof(LUID_AND_ATTRIBUTES))
        {
            LUID_AND_ATTRIBUTES *usedprivs = set_reply_data_size( count * sizeof(*usedprivs) );
            reply->has_privileges = token_check_privileges( token, req->all_required, get_req_data(), count, usedprivs );
        }
        else
            set_error( STATUS_BUFFER_OVERFLOW );
        release_object( token );
    }
}