s3: RPC: Don't crash on trying to talloc_free(-1) if smb_iconv_open_ex() fails.

[Samba.git] / source3 / rpc_server / rpc_handles.c

/* 
 *  Unix SMB/CIFS implementation.
 *  RPC Pipe client / server routines
 *  Copyright (C) Andrew Tridgell              1992-1997,
 *  Copyright (C) Luke Kenneth Casson Leighton 1996-1997,
 *  Copyright (C) Jeremy Allison                           2001.
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *  
 *  This program 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 General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"
#include "system/passwd.h" /* uid_wrapper */
#include "../librpc/gen_ndr/ndr_lsa.h"
#include "../librpc/gen_ndr/ndr_samr.h"
#include "auth.h"
#include "rpc_server/rpc_pipes.h"
#include "../libcli/security/security.h"
#include "lib/tsocket/tsocket.h"
#include "librpc/ndr/ndr_table.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_RPC_SRV

static struct pipes_struct *InternalPipes;

/* TODO
 * the following prototypes are declared here to avoid
 * code being moved about too much for a patch to be
 * disrupted / less obvious.
 *
 * these functions, and associated functions that they
 * call, should be moved behind a .so module-loading
 * system _anyway_.  so that's the next step...
 */

int make_base_pipes_struct(TALLOC_CTX *mem_ctx,
                           struct messaging_context *msg_ctx,
                           const char *pipe_name,
                           enum dcerpc_transport_t transport,
                           bool endian,
                           const struct tsocket_address *remote_address,
                           const struct tsocket_address *local_address,
                           struct pipes_struct **_p)
{
        struct pipes_struct *p;

        p = talloc_zero(mem_ctx, struct pipes_struct);
        if (!p) {
                return ENOMEM;
        }

        p->mem_ctx = talloc_named(p, 0, "pipe %s %p", pipe_name, p);
        if (!p->mem_ctx) {
                talloc_free(p);
                return ENOMEM;
        }

        p->msg_ctx = msg_ctx;
        p->transport = transport;
        p->endian = endian;
        p->allow_bind = true;

        p->remote_address = tsocket_address_copy(remote_address, p);
        if (p->remote_address == NULL) {
                talloc_free(p);
                return ENOMEM;
        }

        if (local_address) {
                p->local_address = tsocket_address_copy(local_address, p);
                if (p->local_address == NULL) {
                        talloc_free(p);
                        return ENOMEM;
                }
        }

        DLIST_ADD(InternalPipes, p);
        talloc_set_destructor(p, close_internal_rpc_pipe_hnd);

        *_p = p;
        return 0;
}


bool check_open_pipes(void)
{
        struct pipes_struct *p;

        for (p = InternalPipes; p != NULL; p = p->next) {
                if (num_pipe_handles(p) != 0) {
                        return true;
                }
        }
        return false;
}

/****************************************************************************
 Close an rpc pipe.
****************************************************************************/

int close_internal_rpc_pipe_hnd(struct pipes_struct *p)
{
        if (!p) {
                DEBUG(0,("Invalid pipe in close_internal_rpc_pipe_hnd\n"));
                return False;
        }

        /* Free the handles database. */
        close_policy_by_pipe(p);

        DLIST_REMOVE(InternalPipes, p);

        return 0;
}

/*
 * Handle database - stored per pipe.
 */

struct dcesrv_handle_old {
        struct dcesrv_handle_old *prev, *next;
        struct policy_handle wire_handle;
        uint32_t access_granted;
        void *data;
};

struct handle_list {
        struct dcesrv_handle_old *handles;      /* List of pipe handles. */
        size_t count;                   /* Current number of handles. */
        size_t pipe_ref_count;          /* Number of pipe handles referring
                                         * to this tree. */
};

/* This is the max handles across all instances of a pipe name. */
#ifndef MAX_OPEN_POLS
#define MAX_OPEN_POLS 2048
#endif

/****************************************************************************
 Hack as handles need to be persistent over lsa pipe closes so long as a samr
 pipe is open. JRA.
****************************************************************************/

static bool is_samr_lsa_pipe(const struct ndr_syntax_id *syntax)
{
        return (ndr_syntax_id_equal(syntax, &ndr_table_samr.syntax_id)
                || ndr_syntax_id_equal(syntax, &ndr_table_lsarpc.syntax_id));
}

size_t num_pipe_handles(struct pipes_struct *p)
{
        if (p->pipe_handles == NULL) {
                return 0;
        }
        return p->pipe_handles->count;
}

/****************************************************************************
 Initialise a policy handle list on a pipe. Handle list is shared between all
 pipes of the same name.
****************************************************************************/

bool init_pipe_handles(struct pipes_struct *p, const struct ndr_syntax_id *syntax)
{
        struct pipes_struct *plist;
        struct handle_list *hl;

        for (plist = InternalPipes; plist; plist = plist->next) {
                struct pipe_rpc_fns *p_ctx;
                bool stop = false;

                for (p_ctx = plist->contexts;
                     p_ctx != NULL;
                     p_ctx = p_ctx->next) {
                        if (ndr_syntax_id_equal(syntax, &p_ctx->syntax)) {
                                stop = true;
                                break;
                        }
                        if (is_samr_lsa_pipe(&p_ctx->syntax)
                            && is_samr_lsa_pipe(syntax)) {
                                /*
                                 * samr and lsa share a handle space (same process
                                 * under Windows?)
                                 */
                                stop = true;
                                break;
                        }
                }

                if (stop) {
                        break;
                }
        }

        if (plist != NULL) {
                hl = plist->pipe_handles;
                if (hl == NULL) {
                        return false;
                }
        } else {
                /*
                 * First open, we have to create the handle list
                 */
                hl = talloc_zero(NULL, struct handle_list);
                if (hl == NULL) {
                        return false;
                }

                DEBUG(10,("init_pipe_handle_list: created handle list for "
                          "pipe %s\n",
                          ndr_interface_name(&syntax->uuid,
                                             syntax->if_version)));
        }

        /*
         * One more pipe is using this list.
         */

        hl->pipe_ref_count++;

        /*
         * Point this pipe at this list.
         */

        p->pipe_handles = hl;

        DEBUG(10,("init_pipe_handle_list: pipe_handles ref count = %lu for "
                  "pipe %s\n", (unsigned long)p->pipe_handles->pipe_ref_count,
                  ndr_interface_name(&syntax->uuid, syntax->if_version)));

        return True;
}

/****************************************************************************
  find first available policy slot.  creates a policy handle for you.

  If "data_ptr" is given, this must be a talloc'ed object, create_policy_hnd
  talloc_moves this into the handle. If the policy_hnd is closed,
  data_ptr is TALLOC_FREE()'ed
****************************************************************************/

static struct dcesrv_handle_old *create_rpc_handle_internal(
                                struct pipes_struct *p,
                                struct policy_handle *hnd,
                                uint8_t handle_type,
                                void *data_ptr)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;
        static uint32_t pol_hnd_low  = 0;
        static uint32_t pol_hnd_high = 0;
        time_t t = time(NULL);

        if (p->pipe_handles->count > MAX_OPEN_POLS) {
                DEBUG(0,("create_policy_hnd: ERROR: too many handles (%d) on this pipe.\n",
                                (int)p->pipe_handles->count));
                return NULL;
        }

        rpc_hnd = talloc_zero(p->pipe_handles, struct dcesrv_handle_old);
        if (!rpc_hnd) {
                DEBUG(0,("create_policy_hnd: ERROR: out of memory!\n"));
                return NULL;
        }

        if (data_ptr != NULL) {
                rpc_hnd->data = talloc_move(rpc_hnd, &data_ptr);
        }

        pol_hnd_low++;
        if (pol_hnd_low == 0) {
                pol_hnd_high++;
        }

        rpc_hnd->wire_handle.handle_type = handle_type;

        /* second bit is incrementing */
        SIVAL(&rpc_hnd->wire_handle.uuid.time_low, 0 , pol_hnd_low);
        SSVAL(&rpc_hnd->wire_handle.uuid.time_mid, 0 , pol_hnd_high);
        SSVAL(&rpc_hnd->wire_handle.uuid.time_hi_and_version, 0, (pol_hnd_high >> 16));

        /* split the current time into two 16 bit values */

        /* something random */
        SSVAL(rpc_hnd->wire_handle.uuid.clock_seq, 0, (t >> 16));
        /* something random */
        SSVAL(rpc_hnd->wire_handle.uuid.node, 0, t);
        /* something more random */
        SIVAL(rpc_hnd->wire_handle.uuid.node, 2, getpid());

        DLIST_ADD(p->pipe_handles->handles, rpc_hnd);
        p->pipe_handles->count++;

        *hnd = rpc_hnd->wire_handle;

        DEBUG(6, ("Opened policy hnd[%d] ", (int)p->pipe_handles->count));
        dump_data(6, (uint8_t *)hnd, sizeof(*hnd));

        return rpc_hnd;
}

bool create_policy_hnd(struct pipes_struct *p,
                        struct policy_handle *hnd,
                        uint8_t handle_type,
                        void *data_ptr)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;

        rpc_hnd = create_rpc_handle_internal(p, hnd, handle_type, data_ptr);
        if (rpc_hnd == NULL) {
                return false;
        }
        return true;
}

/****************************************************************************
  find policy by handle - internal version.
****************************************************************************/

static struct dcesrv_handle_old *find_policy_by_hnd_internal(struct pipes_struct *p,
                                const struct policy_handle *hnd, void **data_p)
{
        struct dcesrv_handle_old *h = NULL;
        unsigned int count;

        if (data_p) {
                *data_p = NULL;
        }

        count = 0;
        for (h = p->pipe_handles->handles; h != NULL; h = h->next) {
                if (memcmp(&h->wire_handle, hnd, sizeof(*hnd)) == 0) {
                        DEBUG(6,("Found policy hnd[%u] ", count));
                        dump_data(6, (const uint8_t *)hnd, sizeof(*hnd));
                        if (data_p) {
                                *data_p = h->data;
                        }
                        return h;
                }
                count++;
        }

        DEBUG(4,("Policy not found: "));
        dump_data(4, (const uint8_t *)hnd, sizeof(*hnd));

        p->fault_state = DCERPC_FAULT_CONTEXT_MISMATCH;

        return NULL;
}

/****************************************************************************
  find policy by handle
****************************************************************************/

bool find_policy_by_hnd(struct pipes_struct *p, const struct policy_handle *hnd,
                        void **data_p)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;

        rpc_hnd = find_policy_by_hnd_internal(p, hnd, data_p);
        if (rpc_hnd == NULL) {
                return false;
        }
        return true;
}

/****************************************************************************
  Close a policy.
****************************************************************************/

bool close_policy_hnd(struct pipes_struct *p, struct policy_handle *hnd)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;

        rpc_hnd = find_policy_by_hnd_internal(p, hnd, NULL);

        if (rpc_hnd == NULL) {
                DEBUG(3, ("Error closing policy (policy not found)\n"));
                return false;
        }

        DEBUG(6,("Closed policy\n"));

        p->pipe_handles->count--;

        DLIST_REMOVE(p->pipe_handles->handles, rpc_hnd);
        TALLOC_FREE(rpc_hnd);

        return true;
}

/****************************************************************************
 Close a pipe - free the handle set if it was the last pipe reference.
****************************************************************************/

void close_policy_by_pipe(struct pipes_struct *p)
{
        if (p->pipe_handles == NULL) {
                return;
        }

        p->pipe_handles->pipe_ref_count--;

        if (p->pipe_handles->pipe_ref_count == 0) {
                /*
                 * Last pipe open on this list - free the list.
                 */
                TALLOC_FREE(p->pipe_handles);

                DBG_DEBUG("Deleted handle list for RPC connection %s\n",
                                p->contexts ?
                                ndr_interface_name(&p->contexts->syntax.uuid,
                                        p->contexts->syntax.if_version) :
                                "Unknown");
        }
}

/*******************************************************************
Shall we allow access to this rpc?  Currently this function
implements the 'restrict anonymous' setting by denying access to
anonymous users if the restrict anonymous level is > 0.  Further work
will be checking a security descriptor to determine whether a user
token has enough access to access the pipe.
********************************************************************/

bool pipe_access_check(struct pipes_struct *p)
{
        /* Don't let anonymous users access this RPC if restrict
           anonymous > 0 */

        if (lp_restrict_anonymous() > 0) {

                /* schannel, so we must be ok */
                if (p->pipe_bound &&
                    (p->auth.auth_type == DCERPC_AUTH_TYPE_SCHANNEL)) {
                        return True;
                }

                if (security_session_user_level(p->session_info, NULL) < SECURITY_USER) {
                        return False;
                }
        }

        return True;
}

void *_policy_handle_create(struct pipes_struct *p,
                        struct policy_handle *hnd,
                        uint8_t handle_type,
                        uint32_t access_granted,
                        size_t data_size,
                        const char *type,
                        NTSTATUS *pstatus)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;
        void *data;

        if (p->pipe_handles->count > MAX_OPEN_POLS) {
                DEBUG(0, ("ERROR: Too many handles (%d) for RPC connection %s\n",
                          (int) p->pipe_handles->count,
                          ndr_interface_name(&p->contexts->syntax.uuid,
                                             p->contexts->syntax.if_version)));

                *pstatus = NT_STATUS_INSUFFICIENT_RESOURCES;
                return NULL;
        }

        data = talloc_size(talloc_tos(), data_size);
        if (data == NULL) {
                *pstatus = NT_STATUS_NO_MEMORY;
                return NULL;
        }
        talloc_set_name_const(data, type);

        rpc_hnd = create_rpc_handle_internal(p, hnd, handle_type, data);
        if (rpc_hnd == NULL) {
                TALLOC_FREE(data);
                *pstatus = NT_STATUS_NO_MEMORY;
                return NULL;
        }
        rpc_hnd->access_granted = access_granted;
        *pstatus = NT_STATUS_OK;
        return data;
}

void *_policy_handle_find(struct pipes_struct *p,
                          const struct policy_handle *hnd,
                          uint32_t access_required,
                          uint32_t *paccess_granted,
                          const char *name, const char *location,
                          NTSTATUS *pstatus)
{
        struct dcesrv_handle_old *rpc_hnd = NULL;
        void *data;

        rpc_hnd = find_policy_by_hnd_internal(p, hnd, &data);
        if (rpc_hnd == NULL) {
                *pstatus = NT_STATUS_INVALID_HANDLE;
                return NULL;
        }
        if (strcmp(name, talloc_get_name(data)) != 0) {
                DEBUG(10, ("expected %s, got %s\n", name,
                           talloc_get_name(data)));
                *pstatus = NT_STATUS_INVALID_HANDLE;
                return NULL;
        }
        if ((access_required & rpc_hnd->access_granted) != access_required) {
                if (root_mode()) {
                        DEBUG(4, ("%s: ACCESS should be DENIED (granted: "
                                  "%#010x; required: %#010x)\n", location,
                                  rpc_hnd->access_granted, access_required));
                        DEBUGADD(4,("but overwritten by euid == 0\n"));
                        goto okay;
                }
                DEBUG(2,("%s: ACCESS DENIED (granted: %#010x; required: "
                         "%#010x)\n", location, rpc_hnd->access_granted,
                         access_required));
                *pstatus = NT_STATUS_ACCESS_DENIED;
                return NULL;
        }

 okay:
        DEBUG(10, ("found handle of type %s\n", talloc_get_name(data)));
        if (paccess_granted != NULL) {
                *paccess_granted = rpc_hnd->access_granted;
        }
        *pstatus = NT_STATUS_OK;
        return data;
}