added jeremy's new c++-like code for parsing of security descriptors.
[samba.git] / source3 / rpc_parse / parse_sec.c
index 409146901d5e9c48c40a9f64cbda6ad31dc41169..886b3f334af4618f5580937e422b907d4383bbcc 100644 (file)
@@ -2,10 +2,10 @@
  *  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.
+ *  Copyright (C) Andrew Tridgell              1992-1999,
+ *  Copyright (C) Jeremy R. Allison            1995-1999
+ *  Copyright (C) Luke Kenneth Casson Leighton 1996-1999,
+ *  Copyright (C) Paul Ashton                  1997-1999.
  *  
  *  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
@@ -29,19 +29,24 @@ extern int DEBUGLEVEL;
 
 
 /*******************************************************************
-makes a structure.
+ Sets up a SEC_ACCESS structure.
 ********************************************************************/
-void make_sec_access(SEC_ACCESS *t, uint32 mask)
+
+void init_sec_access(SEC_ACCESS *t, uint32 mask)
 {
        t->mask = mask;
 }
 
 /*******************************************************************
-reads or writes a structure.
+ Reads or writes a SEC_ACCESS structure.
 ********************************************************************/
-void sec_io_access(char *desc, SEC_ACCESS *t, prs_struct *ps, int depth)
+
+BOOL sec_io_access(char *desc, SEC_ACCESS *t, prs_struct *ps, int depth)
 {
-       if (t == NULL) return;
+       if (t == NULL)
+       {
+               return False;
+       }
 
        prs_debug(ps, depth, desc, "sec_io_access");
        depth++;
@@ -49,30 +54,39 @@ void sec_io_access(char *desc, SEC_ACCESS *t, prs_struct *ps, int depth)
        prs_align(ps);
        
        prs_uint32("mask", ps, depth, &(t->mask));
+       return True;
 }
 
 
 /*******************************************************************
-makes a structure.
+ Sets up a SEC_ACE structure.
 ********************************************************************/
-void make_sec_ace(SEC_ACE *t, DOM_SID *sid, uint8 type, SEC_ACCESS mask, uint8 flag)
+
+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->sid);
        sid_copy(&t->sid, sid);
 }
 
 /*******************************************************************
-reads or writes a structure.
+ Reads or writes a SEC_ACE structure.
 ********************************************************************/
-void sec_io_ace(char *desc, SEC_ACE *t, prs_struct *ps, int depth)
+
+BOOL sec_io_ace(char *desc, SEC_ACE *psa, prs_struct *ps, int depth)
 {
        uint32 old_offset;
        uint32 offset_ace_size;
-       if (t == NULL) return;
+
+       if (psa == NULL)
+       {
+               return False;
+       }
 
        prs_debug(ps, depth, desc, "sec_io_ace");
        depth++;
@@ -81,58 +95,132 @@ void sec_io_ace(char *desc, SEC_ACE *t, prs_struct *ps, int depth)
        
        old_offset = ps->offset;
 
-       prs_uint8     ("type ", ps, depth, &(t->type));
-       prs_uint8     ("flags", ps, depth, &(t->flags));
-       prs_uint16_pre("size ", ps, depth, &(t->size ), &offset_ace_size);
+       prs_uint8     ("type ", ps, depth, &psa->type);
+       prs_uint8     ("flags", ps, depth, &psa->flags);
+       prs_uint16_pre("size ", ps, depth, &psa->size, &offset_ace_size);
+
+       if (!sec_io_access("info ", &psa->info, ps, depth))
+       {
+               return False;
+       }
 
-       sec_io_access   ("info ", &t->info, ps, depth);
        prs_align(ps);
-       smb_io_dom_sid("sid  ", &t->sid , ps, depth);
+       if (!smb_io_dom_sid("sid  ", &psa->sid , ps, depth))
+       {
+               return False;
+       }
 
-       prs_uint16_post("size ", ps, depth, &t->size, offset_ace_size, old_offset);
+
+       prs_uint16_post("size ", ps, depth, &psa->size, offset_ace_size, old_offset);
+       return True;
 }
 
 /*******************************************************************
-makes a structure.  
+ Create a SEC_ACL structure.  
 ********************************************************************/
-void make_sec_acl(SEC_ACL *t, uint16 revision, int num_aces, SEC_ACE *ace)
+
+SEC_ACL *make_sec_acl(uint16 revision, int num_aces, SEC_ACE *ace_list)
 {
+       SEC_ACL *dst;
        int i;
-       t->revision = revision;
-       t->num_aces = num_aces;
-       t->size = 4;
-       t->ace = ace;
+
+       dst = (SEC_ACL *)malloc(sizeof(SEC_ACL));
+       if (dst == NULL)
+       {
+               return NULL;
+       }
+
+       ZERO_STRUCTP(dst);
+
+       dst->revision = revision;
+       dst->num_aces = num_aces;
+       dst->size = 4;
+
+       if ((dst->ace_list = (SEC_ACE *)malloc( sizeof(SEC_ACE) * num_aces )) == NULL) {
+               free_sec_acl(&dst);
+               return NULL;
+       }
 
        for (i = 0; i < num_aces; i++)
        {
-               t->size += ace[i].size;
+               dst->ace_list[i] = ace_list[i]; /* Structure copy. */
+               dst->size += ace_list[i].size;
        }
+
+       return dst;
 }
 
 /*******************************************************************
-frees a structure.  
+ Duplicate a SEC_ACL structure.  
 ********************************************************************/
-void free_sec_acl(SEC_ACL *t)
+
+SEC_ACL *dup_sec_acl( SEC_ACL *src)
 {
-       if (t->ace != NULL)
+       if (src == NULL)
        {
-               free(t->ace);
+               return NULL;
        }
+
+       return make_sec_acl( src->revision, src->num_aces, src->ace_list);
 }
 
 /*******************************************************************
-reads or writes a structure.  
+ Delete a SEC_ACL structure.  
+********************************************************************/
 
-first of the xx_io_xx functions that allocates its data structures
-for you as it reads them.
+void free_sec_acl(SEC_ACL **ppsa)
+{
+       SEC_ACL *psa;
+
+       if (ppsa == NULL || *ppsa == NULL)
+       {
+               return;
+       }
+
+       psa = *ppsa;
+       if (psa->ace_list != NULL)
+       {
+               free(psa->ace_list);
+       }
+
+       free(psa);
+       *ppsa = NULL;
+}
+
+/*******************************************************************
+ 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.
 ********************************************************************/
-void sec_io_acl(char *desc, SEC_ACL *t, prs_struct *ps, int depth)
+
+BOOL sec_io_acl(char *desc, SEC_ACL **ppsa, prs_struct *ps, int depth)
 {
        int i;
        uint32 old_offset;
        uint32 offset_acl_size;
+       SEC_ACL *psa;
 
-       if (t == NULL) return;
+       if (ppsa == NULL)
+       {
+               return False;
+       }
+
+       psa = *ppsa;
+
+       if (ps->io && psa == NULL)
+       {
+               /*
+                * This is a read and we must allocate the stuct to read into.
+                */
+               psa = (SEC_ACL *)malloc(sizeof(SEC_ACL));
+               if (psa == NULL)
+               {
+                       return False;
+               }
+               ZERO_STRUCTP(psa);
+               *ppsa = psa;
+       }
 
        prs_debug(ps, depth, desc, "sec_io_acl");
        depth++;
@@ -141,147 +229,216 @@ void sec_io_acl(char *desc, SEC_ACL *t, prs_struct *ps, int depth)
        
        old_offset = ps->offset;
 
-       prs_uint16("revision", ps, depth, &(t->revision));
-       prs_uint16_pre("size     ", ps, depth, &(t->size     ), &offset_acl_size);
-       prs_uint32("num_aces ", ps, depth, &(t->num_aces ));
+       prs_uint16("revision", ps, depth, &psa->revision);
+       prs_uint16_pre("size     ", ps, depth, &psa->size, &offset_acl_size);
+       prs_uint32("num_aces ", ps, depth, &psa->num_aces);
 
-       if (ps->io && t->num_aces != 0)
+       if (ps->io && psa->num_aces != 0)
        {
                /* reading */
-               t->ace = malloc(sizeof(t->ace[0]) * t->num_aces);
-               ZERO_STRUCTP(t->ace);
-       }
-
-       if (t->ace == NULL && t->num_aces != 0)
-       {
-               DEBUG(0,("INVALID ACL\n"));
-               ps->offset = 0xfffffffe;
-               return;
+               psa->ace_list = malloc(sizeof(psa->ace_list[0]) * psa->num_aces);
+               if (psa->ace_list == NULL)
+               {
+                       return False;
+               }
+               ZERO_STRUCTP(psa->ace_list);
        }
 
-       for (i = 0; i < MIN(t->num_aces, MAX_SEC_ACES); i++)
+       for (i = 0; i < MIN(psa->num_aces, MAX_SEC_ACES); i++)
        {
                fstring tmp;
-               slprintf(tmp, sizeof(tmp)-1, "ace[%02d]: ", i);
-               sec_io_ace(tmp, &t->ace[i], ps, depth);
+               slprintf(tmp, sizeof(tmp)-1, "ace_list[%02d]: ", i);
+               if (!sec_io_ace(tmp, &psa->ace_list[i], ps, depth))
+               {
+                       return False;
+               }
        }
 
        prs_align(ps);
 
-       prs_uint16_post("size     ", ps, depth, &t->size    , offset_acl_size, old_offset);
+       prs_uint16_post("size     ", ps, depth, &psa->size, offset_acl_size, old_offset);
+
+       return True;
 }
 
 
 /*******************************************************************
-makes a structure
+ Creates a SEC_DESC structure
 ********************************************************************/
-int make_sec_desc(SEC_DESC *t, uint16 revision, uint16 type,
-                               DOM_SID *owner_sid, DOM_SID *grp_sid,
-                               SEC_ACL *sacl, SEC_ACL *dacl)
+
+SEC_DESC *make_sec_desc(uint16 revision, uint16 type,
+                       DOM_SID *owner_sid, DOM_SID *grp_sid,
+                       SEC_ACL *sacl, SEC_ACL *dacl, size_t *sec_desc_size)
 {
+       SEC_DESC *dst;
        uint32 offset;
 
-       t->revision = revision;
-       t->type     = type;
+       *sec_desc_size = 0;
+
+       dst = (SEC_DESC *)malloc(sizeof(SEC_DESC));
+
+       if (dst == NULL)
+       {
+               return NULL;
+       }
 
-       t->off_owner_sid = 0;
-       t->off_grp_sid   = 0;
-       t->off_sacl      = 0;
-       t->off_dacl      = 0;
+       ZERO_STRUCTP(dst);
 
-       t->dacl      = dacl;
-       t->sacl      = sacl;
-       t->owner_sid = owner_sid;
-       t->grp_sid   = grp_sid;
+       dst->revision = revision;
+       dst->type     = type;
+
+       dst->off_owner_sid = 0;
+       dst->off_grp_sid   = 0;
+       dst->off_sacl      = 0;
+       dst->off_dacl      = 0;
+
+       /* duplicate sids and acls as necessary */
+
+       if (dacl      != NULL) dst->dacl      = dup_sec_acl(dacl);
+       if (sacl      != NULL) dst->sacl      = dup_sec_acl(sacl);
+       if (owner_sid != NULL) dst->owner_sid = sid_dup(owner_sid);
+       if (grp_sid   != NULL) dst->grp_sid   = sid_dup(grp_sid);
+
+       /* having duplicated sids and acls as necessary, check success */
+
+       if ((dacl      != NULL && dst->dacl      == NULL) ||
+           (sacl      != NULL && dst->sacl      == NULL) ||
+           (owner_sid != NULL && dst->owner_sid == NULL) ||
+           (grp_sid   != NULL && dst->grp_sid   == NULL))
+       {
+               *sec_desc_size = 0;
+               free_sec_desc(&dst);
+
+               return NULL;
+       }
 
        offset = 0x0;
 
-       if (dacl != NULL)
+       /*
+        * Work out the linearization sizes.
+        */
+
+       if (dst->dacl != NULL)
        {
                if (offset == 0)
                {
                        offset = 0x14;
                }
-               t->off_dacl = offset;
+               dst->off_dacl = offset;
                offset += dacl->size;
        }
 
-       if (sacl != NULL)
+       if (dst->sacl != NULL)
        {
                if (offset == 0)
                {
                        offset = 0x14;
                }
-               t->off_dacl = offset;
-               offset += dacl->size;
+               dst->off_sacl = offset;
+               offset += sacl->size;
        }
 
-       if (owner_sid != NULL)
+       if (dst->owner_sid != NULL)
        {
                if (offset == 0)
                {
                        offset = 0x14;
                }
-               t->off_owner_sid = offset;
-               offset += sid_size(owner_sid);
+               dst->off_owner_sid = offset;
+               offset += sid_size(dst->owner_sid);
        }
 
-       if (grp_sid != NULL)
+       if (dst->grp_sid != NULL)
        {
                if (offset == 0)
                {
                        offset = 0x14;
                }
-               t->off_grp_sid = offset;
-               offset += sid_size(grp_sid);
+               dst->off_grp_sid = offset;
+               offset += sid_size(dst->grp_sid);
        }
 
-       return (offset == 0) ? 0x14 : offset;
+       *sec_desc_size = (size_t)((offset == 0) ? 0x14 : offset);
+       return dst;
 }
 
+/*******************************************************************
+ Duplicate a SEC_DESC structure.  
+********************************************************************/
+
+SEC_DESC *dup_sec_desc( SEC_DESC *src)
+{
+       size_t dummy;
+
+       if (src == NULL)
+               return NULL;
+
+       return make_sec_desc( src->revision, src->type, 
+                               src->owner_sid, src->grp_sid, src->sacl,
+                               src->dacl, &dummy);
+}
 
 /*******************************************************************
-frees a structure
+ Deletes a SEC_DESC structure
 ********************************************************************/
-void free_sec_desc(SEC_DESC *t)
+
+void free_sec_desc(SEC_DESC **ppsd)
 {
-       if (t->dacl != NULL)
-       {
-               free_sec_acl(t->dacl);
-       }
+       SEC_DESC *psd;
 
-       if (t->sacl != NULL)
+       if (ppsd == NULL || *ppsd == NULL)
        {
-               free_sec_acl(t->dacl);
+               return;
        }
 
-       if (t->owner_sid != NULL)
-       {
-               free(t->owner_sid);
-       }
+       psd = *ppsd;
 
-       if (t->grp_sid != NULL)
-       {
-               free(t->grp_sid);
-       }
+       free_sec_acl(&psd->dacl);
+       free_sec_acl(&psd->dacl);
+       free(psd->owner_sid);
+       free(psd->grp_sid);
+       free(psd);
+       *ppsd = NULL;
+}
+
+/*******************************************************************
+ Creates a SEC_DESC structure with typical defaults.
+********************************************************************/
+
+SEC_DESC *make_standard_sec_desc(DOM_SID *owner_sid, DOM_SID *grp_sid,
+                                SEC_ACL *dacl, size_t *sec_desc_size)
+{
+       return make_sec_desc(1, SEC_DESC_SELF_RELATIVE|SEC_DESC_DACL_PRESENT,
+                            owner_sid, grp_sid, NULL, dacl, sec_desc_size);
 }
 
 
 /*******************************************************************
-reads or writes a structure.
+ Reads or writes a SEC_DESC structure.
+ If reading and the *ppsd = NULL, allocates the structure.
 ********************************************************************/
-static void sec_io_desc(char *desc, SEC_DESC *t, prs_struct *ps, int depth)
+
+BOOL sec_io_desc(char *desc, SEC_DESC **ppsd, prs_struct *ps, int depth)
 {
-#if 0
-       uint32 off_owner_sid;
-       uint32 off_grp_sid  ;
-       uint32 off_sacl     ;
-       uint32 off_dacl     ;
-#endif
        uint32 old_offset;
        uint32 max_offset = 0; /* after we're done, move offset to end */
+       SEC_DESC *psd;
+
+       if (ppsd == NULL)
+               return False;
+
+       psd = *ppsd;
 
-       if (t == NULL) return;
+       if (ps->io && psd == NULL)
+       {
+               psd = (SEC_DESC *)malloc(sizeof(SEC_DESC));
+               if (psd == NULL)
+               {
+                       return False;
+               }
+               ZERO_STRUCTP(psd);
+               *ppsd = psd;
+       }
 
        prs_debug(ps, depth, desc, "sec_io_desc");
        depth++;
@@ -291,218 +448,207 @@ static void sec_io_desc(char *desc, SEC_DESC *t, prs_struct *ps, int depth)
        /* start of security descriptor stored for back-calc offset purposes */
        old_offset = ps->offset;
 
-       prs_uint16("revision ", ps, depth, &(t->revision ));
-       prs_uint16("type     ", ps, depth, &(t->type     ));
-
-       prs_uint32("off_owner_sid", ps, depth, &(t->off_owner_sid));
-       prs_uint32("off_grp_sid  ", ps, depth, &(t->off_grp_sid  ));
-       prs_uint32("off_sacl     ", ps, depth, &(t->off_sacl     ));
-       prs_uint32("off_dacl     ", ps, depth, &(t->off_dacl     ));
-#if 0
-       prs_uint32_pre("off_owner_sid", ps, depth, &(t->off_owner_sid), &off_owner_sid);
-       prs_uint32_pre("off_grp_sid  ", ps, depth, &(t->off_grp_sid  ), &off_grp_sid  );
-       prs_uint32_pre("off_sacl     ", ps, depth, &(t->off_sacl     ), &off_sacl     );
-       prs_uint32_pre("off_dacl     ", ps, depth, &(t->off_dacl     ), &off_dacl     );
-#endif
+       prs_uint16("revision ", ps, depth, &psd->revision);
+       prs_uint16("type     ", ps, depth, &psd->type);
+
+       prs_uint32("off_owner_sid", ps, depth, &psd->off_owner_sid);
+       prs_uint32("off_grp_sid  ", ps, depth, &psd->off_grp_sid);
+       prs_uint32("off_sacl     ", ps, depth, &psd->off_sacl);
+       prs_uint32("off_dacl     ", ps, depth, &psd->off_dacl);
+
        max_offset = MAX(max_offset, ps->offset);
 
-       if (IS_BITS_SET_ALL(t->type, SEC_DESC_DACL_PRESENT))
+       if (IS_BITS_SET_ALL(psd->type, SEC_DESC_DACL_PRESENT) && psd->dacl)
        {
-#if 0
-               prs_uint32_post("off_dacl    ", ps, depth, &(t->off_dacl     ), off_dacl     , ps->offset - old_offset);
-#endif
-               ps->offset = old_offset + t->off_dacl;
-               if (ps->io)
+               ps->offset = old_offset + psd->off_dacl;
+               if (!sec_io_acl("dacl", &psd->dacl, ps, depth))
                {
-                       /* reading */
-                       t->dacl = malloc(sizeof(*t->dacl));
-                       ZERO_STRUCTP(t->dacl);
-               }
-
-               if (t->dacl == NULL)
-               {
-                       DEBUG(0,("INVALID DACL\n"));
-                       ps->offset = 0xfffffffe;
-                       return;
+                       return False;
                }
-
-               sec_io_acl     ("dacl"        , t->dacl       , ps, depth);
                prs_align(ps);
        }
-#if 0
-       else
-       {
-               prs_uint32_post("off_dacl    ", ps, depth, &(t->off_dacl     ), off_dacl     , 0);
-       }
-#endif
 
        max_offset = MAX(max_offset, ps->offset);
 
-       if (IS_BITS_SET_ALL(t->type, SEC_DESC_SACL_PRESENT))
+       if (IS_BITS_SET_ALL(psd->type, SEC_DESC_SACL_PRESENT) && psd->sacl)
        {
-#if 0
-               prs_uint32_post("off_sacl  ", ps, depth, &(t->off_sacl  ), off_sacl  , ps->offset - old_offset);
-#endif
-               ps->offset = old_offset + t->off_sacl;
-               if (ps->io)
+               ps->offset = old_offset + psd->off_sacl;
+               if (!sec_io_acl("sacl", &psd->sacl, ps, depth))
                {
-                       /* reading */
-                       t->sacl = malloc(sizeof(*t->sacl));
-                       ZERO_STRUCTP(t->sacl);
+                       return False;
                }
-
-               if (t->sacl == NULL)
-               {
-                       DEBUG(0,("INVALID SACL\n"));
-                       ps->offset = 0xfffffffe;
-                       return;
-               }
-
-               sec_io_acl     ("sacl"      , t->sacl       , ps, depth);
                prs_align(ps);
        }
-#if 0
-       else
-       {
-               prs_uint32_post("off_sacl  ", ps, depth, &(t->off_sacl  ), off_sacl  , 0);
-       }
-#endif
 
        max_offset = MAX(max_offset, ps->offset);
 
-#if 0
-       prs_uint32_post("off_owner_sid", ps, depth, &(t->off_owner_sid), off_owner_sid, ps->offset - old_offset);
-#endif
-       if (t->off_owner_sid != 0)
+       if (psd->off_owner_sid != 0)
        {
                if (ps->io)
                {
-                       ps->offset = old_offset + t->off_owner_sid;
-               }
-               if (ps->io)
-               {
+                       ps->offset = old_offset + psd->off_owner_sid;
                        /* reading */
-                       t->owner_sid = malloc(sizeof(*t->owner_sid));
-                       ZERO_STRUCTP(t->owner_sid);
+                       psd->owner_sid = malloc(sizeof(*psd->owner_sid));
+                       if (psd->owner_sid == NULL)
+                       {
+                               return False;
+                       }
+                       ZERO_STRUCTP(psd->owner_sid);
                }
 
-               if (t->owner_sid == NULL)
+               if (!smb_io_dom_sid("owner_sid ", psd->owner_sid , ps, depth))
                {
-                       DEBUG(0,("INVALID OWNER SID\n"));
-                       ps->offset = 0xfffffffe;
-                       return;
+                       return False;
                }
-
-               smb_io_dom_sid("owner_sid ", t->owner_sid , ps, depth);
                prs_align(ps);
        }
 
        max_offset = MAX(max_offset, ps->offset);
 
-#if 0
-       prs_uint32_post("off_grp_sid  ", ps, depth, &(t->off_grp_sid  ), off_grp_sid  , ps->offset - old_offset);
-#endif
-       if (t->off_grp_sid != 0)
+       if (psd->off_grp_sid != 0)
        {
-               if (ps->io)
-               {
-                       ps->offset = old_offset + t->off_grp_sid;
-               }
                if (ps->io)
                {
                        /* reading */
-                       t->grp_sid = malloc(sizeof(*t->grp_sid));
-                       ZERO_STRUCTP(t->grp_sid);
+                       ps->offset = old_offset + psd->off_grp_sid;
+                       psd->grp_sid = malloc(sizeof(*psd->grp_sid));
+                       if (psd->grp_sid == NULL)
+                       {
+                               return False;
+                       }
+                       ZERO_STRUCTP(psd->grp_sid);
                }
 
-               if (t->grp_sid == NULL)
+               if (!smb_io_dom_sid("grp_sid", psd->grp_sid, ps, depth))
                {
-                       DEBUG(0,("INVALID GROUP SID\n"));
-                       ps->offset = 0xfffffffe;
-                       return;
+                       return False;
                }
-
-               smb_io_dom_sid("grp_sid", t->grp_sid, ps, depth);
                prs_align(ps);
        }
 
        max_offset = MAX(max_offset, ps->offset);
 
        ps->offset = max_offset;
+       return True;
 }
 
 /*******************************************************************
-creates a SEC_DESC_BUF structure.
+ Creates a SEC_DESC_BUF structure.
 ********************************************************************/
-void make_sec_desc_buf(SEC_DESC_BUF *buf, int len, SEC_DESC *data)
+
+SEC_DESC_BUF *make_sec_desc_buf(int len, SEC_DESC *sec_desc)
 {
-       ZERO_STRUCTP(buf);
+       SEC_DESC_BUF *dst;
+
+       dst = (SEC_DESC_BUF *)malloc(sizeof(SEC_DESC_BUF));
+       if (dst == NULL)
+       {
+               return NULL;
+       }
+
+       ZERO_STRUCTP(dst);
 
        /* max buffer size (allocated size) */
-       buf->max_len = len;
-       buf->undoc       = 0;
-       buf->len = data != NULL ? len : 0;
-       buf->sec = data;
+       dst->max_len = len;
+       dst->len = len;
+
+       if (sec_desc && ((dst->sec = dup_sec_desc(sec_desc)) == NULL))
+       {
+               free_sec_desc_buf(&dst);
+               return NULL;
+       }
+
+       return dst;
 }
 
 /*******************************************************************
-frees a SEC_DESC_BUF structure.
+ Duplicates a SEC_DESC_BUF structure.
 ********************************************************************/
-void free_sec_desc_buf(SEC_DESC_BUF *buf)
+
+SEC_DESC_BUF *dup_sec_desc_buf(SEC_DESC_BUF *src)
 {
-       if (buf->sec != NULL)
+       if (src == NULL)
        {
-               free_sec_desc(buf->sec);
-               free(buf->sec);
+               return NULL;
        }
+
+       return make_sec_desc_buf( src->len, src->sec);
+}
+
+/*******************************************************************
+ Deletes a SEC_DESC_BUF structure.
+********************************************************************/
+
+void free_sec_desc_buf(SEC_DESC_BUF **ppsdb)
+{
+       SEC_DESC_BUF *psdb;
+
+       if (ppsdb == NULL || *ppsdb == NULL)
+       {
+               return;
+       }
+
+       psdb = *ppsdb;
+       free_sec_desc(&psdb->sec);
+       free(psdb);
+       *ppsdb = NULL;
 }
 
 
 /*******************************************************************
-reads or writes a SEC_DESC_BUF structure.
+ Reads or writes a SEC_DESC_BUF structure.
 ********************************************************************/
-void sec_io_desc_buf(char *desc, SEC_DESC_BUF *sec, prs_struct *ps, int depth)
+
+BOOL sec_io_desc_buf(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 (sec == NULL) return;
+       if (ps->io && psdb == NULL)
+       {
+               psdb = (SEC_DESC_BUF *)malloc(sizeof(SEC_DESC_BUF));
+               if (psdb == NULL)
+               {
+                       return False;
+               }
+               ZERO_STRUCTP(psdb);
+               *ppsdb = psdb;
+       }
 
        prs_debug(ps, depth, desc, "sec_io_desc_buf");
        depth++;
 
        prs_align(ps);
        
-       prs_uint32_pre("max_len", ps, depth, &(sec->max_len), &off_max_len);
-       prs_uint32    ("undoc  ", ps, depth, &(sec->undoc  ));
-       prs_uint32_pre("len    ", ps, depth, &(sec->len    ), &off_len);
+       prs_uint32_pre("max_len", ps, depth, &psdb->max_len, &off_max_len);
+       prs_uint32    ("undoc  ", ps, depth, &psdb->undoc);
+       prs_uint32_pre("len    ", ps, depth, &psdb->len, &off_len);
 
        old_offset = ps->offset;
 
-       if (sec->len != 0 && ps->io)
+       /* reading, length is non-zero; writing, descriptor is non-NULL */
+       if ((psdb->len != 0 || (!ps->io)) && psdb->sec != NULL)
        {
-               /* reading */
-               sec->sec = malloc(sizeof(*sec->sec));
-               ZERO_STRUCTP(sec->sec);
-
-               if (sec->sec == NULL)
+               if (!sec_io_desc("sec   ", &psdb->sec, ps, depth))
                {
-                       DEBUG(0,("INVALID SEC_DESC\n"));
-                       ps->offset = 0xfffffffe;
-                       return;
+                       return False;
                }
        }
 
-       /* reading, length is non-zero; writing, descriptor is non-NULL */
-       if ((sec->len != 0 || (!ps->io)) && sec->sec != NULL)
-       {
-               sec_io_desc("sec   ", sec->sec, ps, depth);
-       }
-
        size = ps->offset - old_offset;
-       prs_uint32_post("max_len", ps, depth, &(sec->max_len), off_max_len, size == 0 ? sec->max_len : size);
-       prs_uint32_post("len    ", ps, depth, &(sec->len    ), off_len    , size);
+       prs_uint32_post("max_len", ps, depth, &psdb->max_len, off_max_len, size == 0 ? psdb->max_len : size);
+       prs_uint32_post("len    ", ps, depth, &psdb->len, off_len, size);
+
+       return True;
 }