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parse_sec.c

/* 
 *  Unix SMB/Netbios implementation.
 *  Version 1.9.
 *  RPC Pipe client / server routines
 *  Copyright (C) Andrew Tridgell              1992-1998,
 *  Copyright (C) Jeremy R. Allison            1995-1998
 *  Copyright (C) Luke Kenneth Casson Leighton 1996-1998,
 *  Copyright (C) Paul Ashton                  1997-1998.
 *  
 *  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 2 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, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "includes.h"

#define SD_HEADER_SIZE 0x14

/*******************************************************************
 Sets up a SEC_ACCESS structure.
********************************************************************/

void init_sec_access(SEC_ACCESS *t, uint32 mask)
{
      t->mask = mask;
}

/*******************************************************************
 Reads or writes a SEC_ACCESS structure.
********************************************************************/

BOOL sec_io_access(const char *desc, SEC_ACCESS *t, prs_struct *ps, int depth)
{
      if (t == NULL)
            return False;

      prs_debug(ps, depth, desc, "sec_io_access");
      depth++;
      
      if(!prs_uint32("mask", ps, depth, &(t->mask)))
            return False;

      return True;
}


/*******************************************************************
 Sets up a SEC_ACE structure.
********************************************************************/

void init_sec_ace(SEC_ACE *t, DOM_SID *sid, uint8 type, SEC_ACCESS mask, uint8 flag)
{
      t->type = type;
      t->flags = flag;
      t->size = sid_size(sid) + 8;
      t->info = mask;

      ZERO_STRUCTP(&t->trustee);
      sid_copy(&t->trustee, sid);
}

/*******************************************************************
 Reads or writes a SEC_ACE structure.
********************************************************************/

BOOL sec_io_ace(const char *desc, SEC_ACE *psa, prs_struct *ps, int depth)
{
      uint32 old_offset;
      uint32 offset_ace_size;

      if (psa == NULL)
            return False;

      prs_debug(ps, depth, desc, "sec_io_ace");
      depth++;
      
      old_offset = prs_offset(ps);

      if(!prs_uint8("type ", ps, depth, &psa->type))
            return False;

      if(!prs_uint8("flags", ps, depth, &psa->flags))
            return False;

      if(!prs_uint16_pre("size ", ps, depth, &psa->size, &offset_ace_size))
            return False;

      if(!sec_io_access("info ", &psa->info, ps, depth))
            return False;

      if(!smb_io_dom_sid("sid  ", &psa->trustee , ps, depth))
            return False;

      if(!prs_uint16_post("size ", ps, depth, &psa->size, offset_ace_size, old_offset))
            return False;

      return True;
}

/*******************************************************************
 Create a SEC_ACL structure.  
********************************************************************/

SEC_ACL *make_sec_acl(TALLOC_CTX *ctx, uint16 revision, int num_aces, SEC_ACE *ace_list)
{
      SEC_ACL *dst;
      int i;

      if((dst = (SEC_ACL *)talloc_zero(ctx,sizeof(SEC_ACL))) == NULL)
            return NULL;

      dst->revision = revision;
      dst->num_aces = num_aces;
      dst->size = 8;

      /* Now we need to return a non-NULL address for the ace list even
         if the number of aces required is zero.  This is because there
         is a distinct difference between a NULL ace and an ace with zero
         entries in it.  This is achieved by checking that num_aces is a
         positive number. */

      if ((num_aces) && 
            ((dst->ace = (SEC_ACE *)talloc(ctx, sizeof(SEC_ACE) * num_aces)) 
             == NULL)) {
            return NULL;
      }
        
      for (i = 0; i < num_aces; i++) {
            dst->ace[i] = ace_list[i]; /* Structure copy. */
            dst->size += ace_list[i].size;
      }

      return dst;
}

/*******************************************************************
 Duplicate a SEC_ACL structure.  
********************************************************************/

SEC_ACL *dup_sec_acl(TALLOC_CTX *ctx, SEC_ACL *src)
{
      if(src == NULL)
            return NULL;

      return make_sec_acl(ctx, src->revision, src->num_aces, src->ace);
}

/*******************************************************************
 Reads or writes a SEC_ACL structure.  

 First of the xx_io_xx functions that allocates its data structures
 for you as it reads them.
********************************************************************/

BOOL sec_io_acl(const char *desc, SEC_ACL **ppsa, prs_struct *ps, int depth)
{
      int i;
      uint32 old_offset;
      uint32 offset_acl_size;
      SEC_ACL *psa;

      /*
       * Note that the size is always a multiple of 4 bytes due to the
       * nature of the data structure.  Therefore the prs_align() calls
       * have been removed as they through us off when doing two-layer
       * marshalling such as in the printing code (NEW_BUFFER).  --jerry
       */

      if (ppsa == NULL)
            return False;

      psa = *ppsa;

      if(UNMARSHALLING(ps) && psa == NULL) {
            /*
             * This is a read and we must allocate the stuct to read into.
             */
            if((psa = (SEC_ACL *)prs_alloc_mem(ps, sizeof(SEC_ACL))) == NULL)
                  return False;
            *ppsa = psa;
      }

      prs_debug(ps, depth, desc, "sec_io_acl");
      depth++;
      
      old_offset = prs_offset(ps);

      if(!prs_uint16("revision", ps, depth, &psa->revision))
            return False;

      if(!prs_uint16_pre("size     ", ps, depth, &psa->size, &offset_acl_size))
            return False;

      if(!prs_uint32("num_aces ", ps, depth, &psa->num_aces))
            return False;

      if (UNMARSHALLING(ps)) {
            /*
             * Even if the num_aces is zero, allocate memory as there's a difference
             * between a non-present DACL (allow all access) and a DACL with no ACE's
             * (allow no access).
             */
            if((psa->ace = (SEC_ACE *)prs_alloc_mem(ps,sizeof(psa->ace[0]) * (psa->num_aces+1))) == NULL)
                  return False;
      }

      for (i = 0; i < psa->num_aces; i++) {
            fstring tmp;
            slprintf(tmp, sizeof(tmp)-1, "ace_list[%02d]: ", i);
            if(!sec_io_ace(tmp, &psa->ace[i], ps, depth))
                  return False;
      }

      if(!prs_uint16_post("size     ", ps, depth, &psa->size, offset_acl_size, old_offset))
            return False;

      return True;
}

/*******************************************************************
 Works out the linearization size of a SEC_DESC.
********************************************************************/

size_t sec_desc_size(SEC_DESC *psd)
{
      size_t offset;

      if (!psd) return 0;

      offset = SD_HEADER_SIZE;

      /* don't align */

      if (psd->owner_sid != NULL)
            offset += sid_size(psd->owner_sid);

      if (psd->grp_sid != NULL)
            offset += sid_size(psd->grp_sid);

      if (psd->sacl != NULL)
            offset += psd->sacl->size;

      if (psd->dacl != NULL)
            offset += psd->dacl->size;

      return offset;
}

/*******************************************************************
 Compares two SEC_ACE structures
********************************************************************/

BOOL sec_ace_equal(SEC_ACE *s1, SEC_ACE *s2)
{
      /* Trivial case */

      if (!s1 && !s2) return True;

      /* Check top level stuff */

      if (s1->type != s2->type || s1->flags != s2->flags ||
          s1->info.mask != s2->info.mask) {
            return False;
      }

      /* Check SID */

      if (!sid_equal(&s1->trustee, &s2->trustee)) {
            return False;
      }

      return True;
}

/*******************************************************************
 Compares two SEC_ACL structures
********************************************************************/

BOOL sec_acl_equal(SEC_ACL *s1, SEC_ACL *s2)
{
      int i, j;

      /* Trivial cases */

      if (!s1 && !s2) return True;
      if (!s1 || !s2) return False;

      /* Check top level stuff */

      if (s1->revision != s2->revision) {
            DEBUG(10, ("sec_acl_equal(): revision differs (%d != %d)\n",
                     s1->revision, s2->revision));
            return False;
      }

      if (s1->num_aces != s2->num_aces) {
            DEBUG(10, ("sec_acl_equal(): num_aces differs (%d != %d)\n",
                     s1->revision, s2->revision));
            return False;
      }

      /* The ACEs could be in any order so check each ACE in s1 against 
         each ACE in s2. */

      for (i = 0; i < s1->num_aces; i++) {
            BOOL found = False;

            for (j = 0; j < s2->num_aces; j++) {
                  if (sec_ace_equal(&s1->ace[i], &s2->ace[j])) {
                        found = True;
                        break;
                  }
            }

            if (!found) return False;
      }

      return True;
}

/*******************************************************************
 Compares two SEC_DESC structures
********************************************************************/

BOOL sec_desc_equal(SEC_DESC *s1, SEC_DESC *s2)
{
      /* Trivial case */

      if (!s1 && !s2) {
            goto done;
      }

      /* Check top level stuff */

      if (s1->revision != s2->revision) {
            DEBUG(10, ("sec_desc_equal(): revision differs (%d != %d)\n",
                     s1->revision, s2->revision));
            return False;
      }

      if (s1->type!= s2->type) {
            DEBUG(10, ("sec_desc_equal(): type differs (%d != %d)\n",
                     s1->type, s2->type));
            return False;
      }

      /* Check owner and group */

      if (!sid_equal(s1->owner_sid, s2->owner_sid)) {
            fstring str1, str2;

            sid_to_string(str1, s1->owner_sid);
            sid_to_string(str2, s2->owner_sid);

            DEBUG(10, ("sec_desc_equal(): owner differs (%s != %s)\n",
                     str1, str2));
            return False;
      }

      if (!sid_equal(s1->grp_sid, s2->grp_sid)) {
            fstring str1, str2;

            sid_to_string(str1, s1->grp_sid);
            sid_to_string(str2, s2->grp_sid);

            DEBUG(10, ("sec_desc_equal(): group differs (%s != %s)\n",
                     str1, str2));
            return False;
      }

      /* Check ACLs present in one but not the other */

      if ((s1->dacl && !s2->dacl) || (!s1->dacl && s2->dacl) ||
          (s1->sacl && !s2->sacl) || (!s1->sacl && s2->sacl)) {
            DEBUG(10, ("sec_desc_equal(): dacl or sacl not present\n"));
            return False;
      }

      /* Sigh - we have to do it the hard way by iterating over all
         the ACEs in the ACLs */

      if (!sec_acl_equal(s1->dacl, s2->dacl) ||
          !sec_acl_equal(s1->sacl, s2->sacl)) {
            DEBUG(10, ("sec_desc_equal(): dacl/sacl list not equal\n"));
            return False;
      }

 done:
      DEBUG(10, ("sec_desc_equal(): secdescs are identical\n"));
      return True;
}

/*******************************************************************
 Merge part of security descriptor old_sec in to the empty sections of 
 security descriptor new_sec.
********************************************************************/

SEC_DESC_BUF *sec_desc_merge(TALLOC_CTX *ctx, SEC_DESC_BUF *new_sdb, SEC_DESC_BUF *old_sdb)
{
      DOM_SID *owner_sid, *group_sid;
      SEC_DESC_BUF *return_sdb;
      SEC_ACL *dacl, *sacl;
      SEC_DESC *psd = NULL;
      uint16 secdesc_type;
      size_t secdesc_size;

      /* Copy over owner and group sids.  There seems to be no flag for
         this so just check the pointer values. */

      owner_sid = new_sdb->sec->owner_sid ? new_sdb->sec->owner_sid :
            old_sdb->sec->owner_sid;

      group_sid = new_sdb->sec->grp_sid ? new_sdb->sec->grp_sid :
            old_sdb->sec->grp_sid;
      
      secdesc_type = new_sdb->sec->type;

      /* Ignore changes to the system ACL.  This has the effect of making
         changes through the security tab audit button not sticking. 
         Perhaps in future Samba could implement these settings somehow. */

      sacl = NULL;
      secdesc_type &= ~SEC_DESC_SACL_PRESENT;

      /* Copy across discretionary ACL */

      if (secdesc_type & SEC_DESC_DACL_PRESENT) {
            dacl = new_sdb->sec->dacl;
      } else {
            dacl = old_sdb->sec->dacl;
      }

      /* Create new security descriptor from bits */

      psd = make_sec_desc(ctx, new_sdb->sec->revision, 
                      owner_sid, group_sid, sacl, dacl, &secdesc_size);

      return_sdb = make_sec_desc_buf(ctx, secdesc_size, psd);

      return(return_sdb);
}

/*******************************************************************
 Tallocs a duplicate SID. 
********************************************************************/ 

static DOM_SID *sid_dup_talloc(TALLOC_CTX *ctx, DOM_SID *src)
{
  DOM_SID *dst;

  if(!src)
    return NULL;

  if((dst = talloc_zero(ctx, sizeof(DOM_SID))) != NULL) {
    sid_copy( dst, src);
  }

  return dst;
}

/*******************************************************************
 Creates a SEC_DESC structure
********************************************************************/

SEC_DESC *make_sec_desc(TALLOC_CTX *ctx, uint16 revision, 
                  DOM_SID *owner_sid, DOM_SID *grp_sid,
                  SEC_ACL *sacl, SEC_ACL *dacl, size_t *sd_size)
{
      SEC_DESC *dst;
      uint32 offset;

      *sd_size = 0;

      if(( dst = (SEC_DESC *)talloc_zero(ctx, sizeof(SEC_DESC))) == NULL)
            return NULL;

      dst->revision = revision;
      dst->type     = SEC_DESC_SELF_RELATIVE;

      if (sacl) dst->type |= SEC_DESC_SACL_PRESENT;
      if (dacl) dst->type |= SEC_DESC_DACL_PRESENT;

      dst->off_owner_sid = 0;
      dst->off_grp_sid   = 0;
      dst->off_sacl      = 0;
      dst->off_dacl      = 0;

      if(owner_sid && ((dst->owner_sid = sid_dup_talloc(ctx,owner_sid)) == NULL))
            goto error_exit;

      if(grp_sid && ((dst->grp_sid = sid_dup_talloc(ctx,grp_sid)) == NULL))
            goto error_exit;

      if(sacl && ((dst->sacl = dup_sec_acl(ctx, sacl)) == NULL))
            goto error_exit;

      if(dacl && ((dst->dacl = dup_sec_acl(ctx, dacl)) == NULL))
            goto error_exit;
            
      offset = 0;

      /*
       * Work out the linearization sizes.
       */

      if (dst->owner_sid != NULL) {

            if (offset == 0)
                  offset = SD_HEADER_SIZE;

            dst->off_owner_sid = offset;
            offset += sid_size(dst->owner_sid);
      }

      if (dst->grp_sid != NULL) {

            if (offset == 0)
                  offset = SD_HEADER_SIZE;

            dst->off_grp_sid = offset;
            offset += sid_size(dst->grp_sid);
      }

      if (dst->sacl != NULL) {

            if (offset == 0)
                  offset = SD_HEADER_SIZE;

            dst->off_sacl = offset;
            offset += dst->sacl->size;
      }

      if (dst->dacl != NULL) {

            if (offset == 0)
                  offset = SD_HEADER_SIZE;

            dst->off_dacl = offset;
            offset += dst->dacl->size;
      }

      *sd_size = (size_t)((offset == 0) ? SD_HEADER_SIZE : offset);
      return dst;

error_exit:

      *sd_size = 0;
      return NULL;
}

/*******************************************************************
 Duplicate a SEC_DESC structure.  
********************************************************************/

SEC_DESC *dup_sec_desc( TALLOC_CTX *ctx, SEC_DESC *src)
{
      size_t dummy;

      if(src == NULL)
            return NULL;

      return make_sec_desc( ctx, src->revision, 
                        src->owner_sid, src->grp_sid, src->sacl,
                        src->dacl, &dummy);
}

/*******************************************************************
 Creates a SEC_DESC structure with typical defaults.
********************************************************************/

SEC_DESC *make_standard_sec_desc(TALLOC_CTX *ctx, DOM_SID *owner_sid, DOM_SID *grp_sid,
                         SEC_ACL *dacl, size_t *sd_size)
{
      return make_sec_desc(ctx, SEC_DESC_REVISION,
                       owner_sid, grp_sid, NULL, dacl, sd_size);
}

/*******************************************************************
 Reads or writes a SEC_DESC structure.
 If reading and the *ppsd = NULL, allocates the structure.
********************************************************************/

BOOL sec_io_desc(const char *desc, SEC_DESC **ppsd, prs_struct *ps, int depth)
{
      uint32 old_offset;
      uint32 max_offset = 0; /* after we're done, move offset to end */
      uint32 tmp_offset = 0;
      SEC_DESC *psd;

      if (ppsd == NULL)
            return False;

      psd = *ppsd;

      if (psd == NULL) {
            if(UNMARSHALLING(ps)) {
                  if((psd = (SEC_DESC *)prs_alloc_mem(ps,sizeof(SEC_DESC))) == NULL)
                        return False;
                  *ppsd = psd;
            } else {
                  /* Marshalling - just ignore. */
                  return True;
            }
      }

      prs_debug(ps, depth, desc, "sec_io_desc");
      depth++;
      
#if 0 
      /*
       * if alignment is needed, should be done by the the 
       * caller.  Not here.  This caused me problems when marshalling
       * printer info into a buffer.   --jerry
       */
      if(!prs_align(ps))
            return False;
#endif
      
      /* start of security descriptor stored for back-calc offset purposes */
      old_offset = prs_offset(ps);

      if(!prs_uint16("revision ", ps, depth, &psd->revision))
            return False;

      if(!prs_uint16("type     ", ps, depth, &psd->type))
            return False;

      if(!prs_uint32("off_owner_sid", ps, depth, &psd->off_owner_sid))
            return False;

      if(!prs_uint32("off_grp_sid  ", ps, depth, &psd->off_grp_sid))
            return False;

      if(!prs_uint32("off_sacl     ", ps, depth, &psd->off_sacl))
            return False;

      if(!prs_uint32("off_dacl     ", ps, depth, &psd->off_dacl))
            return False;

      max_offset = MAX(max_offset, prs_offset(ps));

      if (psd->off_owner_sid != 0) {

            tmp_offset = ps->data_offset;
            if(!prs_set_offset(ps, old_offset + psd->off_owner_sid))
                  return False;

            if (UNMARSHALLING(ps)) {
                  /* reading */
                  if((psd->owner_sid = (DOM_SID *)prs_alloc_mem(ps,sizeof(*psd->owner_sid))) == NULL)
                        return False;
            }

            if(!smb_io_dom_sid("owner_sid ", psd->owner_sid , ps, depth))
                  return False;

            max_offset = MAX(max_offset, prs_offset(ps));

            if (!prs_set_offset(ps,tmp_offset))
                  return False;
      }

      if (psd->off_grp_sid != 0) {

            tmp_offset = ps->data_offset;
            if(!prs_set_offset(ps, old_offset + psd->off_grp_sid))
                  return False;

            if (UNMARSHALLING(ps)) {
                  /* reading */
                  if((psd->grp_sid = (DOM_SID *)prs_alloc_mem(ps,sizeof(*psd->grp_sid))) == NULL)
                        return False;
            }

            if(!smb_io_dom_sid("grp_sid", psd->grp_sid, ps, depth))
                  return False;

            max_offset = MAX(max_offset, prs_offset(ps));
 
            if (!prs_set_offset(ps,tmp_offset))
                  return False;
      }

      if ((psd->type & SEC_DESC_SACL_PRESENT) && psd->off_sacl) {
            tmp_offset = ps->data_offset;
            if(!prs_set_offset(ps, old_offset + psd->off_sacl))
                  return False;
            if(!sec_io_acl("sacl", &psd->sacl, ps, depth))
                  return False;
            max_offset = MAX(max_offset, prs_offset(ps));
            if (!prs_set_offset(ps,tmp_offset))
                  return False;
      }

      if ((psd->type & SEC_DESC_DACL_PRESENT) && psd->off_dacl != 0) {
            tmp_offset = ps->data_offset;
            if(!prs_set_offset(ps, old_offset + psd->off_dacl))
                  return False;
            if(!sec_io_acl("dacl", &psd->dacl, ps, depth))
                  return False;
            max_offset = MAX(max_offset, prs_offset(ps));
            if (!prs_set_offset(ps,tmp_offset))
                  return False;
      }

      if(!prs_set_offset(ps, max_offset))
            return False;
      return True;
}

/*******************************************************************
 Creates a SEC_DESC_BUF structure.
********************************************************************/

SEC_DESC_BUF *make_sec_desc_buf(TALLOC_CTX *ctx, size_t len, SEC_DESC *sec_desc)
{
      SEC_DESC_BUF *dst;

      if((dst = (SEC_DESC_BUF *)talloc_zero(ctx, sizeof(SEC_DESC_BUF))) == NULL)
            return NULL;

      /* max buffer size (allocated size) */
      dst->max_len = (uint32)len;
      dst->len = (uint32)len;
      
      if(sec_desc && ((dst->sec = dup_sec_desc(ctx, sec_desc)) == NULL)) {
            return NULL;
      }

      dst->ptr = 0x1;

      return dst;
}

/*******************************************************************
 Duplicates a SEC_DESC_BUF structure.
********************************************************************/

SEC_DESC_BUF *dup_sec_desc_buf(TALLOC_CTX *ctx, SEC_DESC_BUF *src)
{
      if(src == NULL)
            return NULL;

      return make_sec_desc_buf( ctx, src->len, src->sec);
}

/*******************************************************************
 Reads or writes a SEC_DESC_BUF structure.
********************************************************************/

BOOL sec_io_desc_buf(const char *desc, SEC_DESC_BUF **ppsdb, prs_struct *ps, int depth)
{
      uint32 off_len;
      uint32 off_max_len;
      uint32 old_offset;
      uint32 size;
      SEC_DESC_BUF *psdb;

      if (ppsdb == NULL)
            return False;

      psdb = *ppsdb;

      if (UNMARSHALLING(ps) && psdb == NULL) {
            if((psdb = (SEC_DESC_BUF *)prs_alloc_mem(ps,sizeof(SEC_DESC_BUF))) == NULL)
                  return False;
            *ppsdb = psdb;
      }

      prs_debug(ps, depth, desc, "sec_io_desc_buf");
      depth++;

      if(!prs_align(ps))
            return False;
      
      if(!prs_uint32_pre("max_len", ps, depth, &psdb->max_len, &off_max_len))
            return False;

      if(!prs_uint32    ("ptr  ", ps, depth, &psdb->ptr))
            return False;

      if(!prs_uint32_pre("len    ", ps, depth, &psdb->len, &off_len))
            return False;

      old_offset = prs_offset(ps);

      /* reading, length is non-zero; writing, descriptor is non-NULL */
      if ((UNMARSHALLING(ps) && psdb->len != 0) || (MARSHALLING(ps) && psdb->sec != NULL)) {
            if(!sec_io_desc("sec   ", &psdb->sec, ps, depth))
                  return False;
      }

      if(!prs_align(ps))
            return False;
      
      size = prs_offset(ps) - old_offset;
      if(!prs_uint32_post("max_len", ps, depth, &psdb->max_len, off_max_len, size == 0 ? psdb->max_len : size))
            return False;

      if(!prs_uint32_post("len    ", ps, depth, &psdb->len, off_len, size))
            return False;

      return True;
}

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