New POSIX ACL mapping code. Works with UNIX permissions, now for testing

with real ACLs...
Jeremy.
(This used to be commit 852b9e15ac245a593460cfff3f629d0333372e41)

1 files changed, 684 insertions, 338 deletions

diff --git a/source3/smbd/posix_acls.c b/source3/smbd/posix_acls.c
index e358e0238c..22d1038fcc 100644
--- a/source3/smbd/posix_acls.c
+++ b/source3/smbd/posix_acls.c
@@ -21,6 +21,10 @@
 
 #include "includes.h"
 
+/****************************************************************************
+ Data structures representing the internal ACE format.
+****************************************************************************/
+
 enum ace_owner {UID_ACE, GID_ACE, WORLD_ACE};
 enum ace_attribute {ALLOW_ACE, DENY_ACE}; /* Used for incoming NT ACLS. */
 
@@ -40,9 +44,40 @@ typedef struct canon_ace {
 	posix_id unix_ug; 
 } canon_ace;
 
-static void free_canon_ace_list( canon_ace *list_head );
+#define ALL_ACE_PERMS (S_IRUSR|S_IWUSR|S_IXUSR)
+
+/****************************************************************************
+ Functions to manipulate the internal ACE format.
+****************************************************************************/
+
+/****************************************************************************
+ Count a linked list of canonical ACE entries.
+****************************************************************************/
+
+static size_t count_canon_ace_list( canon_ace *list_head )
+{
+	size_t count = 0;
+	canon_ace *ace;
+
+	for (ace = list_head; ace; ace = ace->next)
+		count++;
+
+	return count;
+}
+
+/****************************************************************************
+ Free a linked list of canonical ACE entries.
+****************************************************************************/
+
+static void free_canon_ace_list( canon_ace *list_head )
+{
+	while (list_head) {
+		canon_ace *old_head = list_head;
+		DLIST_REMOVE(list_head, list_head);
+		free(old_head);
+	}
+}
 
-#if !defined(HAVE_NO_ACLS)
 /****************************************************************************
  Function to duplicate a canon_ace entry.
 ****************************************************************************/
@@ -58,7 +93,6 @@ static canon_ace *dup_canon_ace( canon_ace *src_ace)
 	dst_ace->prev = dst_ace->next = NULL;
 	return dst_ace;
 }
-#endif /* HAVE_NO_ACLS */
 
 /****************************************************************************
  Function to create owner and group SIDs from a SMB_STRUCT_STAT.
@@ -78,7 +112,7 @@ static void print_canon_ace(canon_ace *ace, int num)
 {
 	fstring str;
 
-	dbgtext( "canon_ace index %d. Type = %s", num, ace->attr == ALLOW_ACE ? "allow" : "deny" );
+	dbgtext( "canon_ace index %d. Type = %s ", num, ace->attr == ALLOW_ACE ? "allow" : "deny" );
     dbgtext( "SID = %s ", sid_to_string( str, &ace->sid));
 	if (ace->owner_type == UID_ACE) {
 		struct passwd *pass = sys_getpwuid(ace->unix_ug.uid);
@@ -112,6 +146,118 @@ static void print_canon_ace(canon_ace *ace, int num)
 }
 
 /****************************************************************************
+ Merge aces with a common sid - if both are allow or deny, OR the permissions together and
+ delete the second one. If the first is deny, mask the permissions off and delete the allow
+ if the permissions become zero, delete the deny if the permissions are non zero.
+****************************************************************************/
+
+static void merge_aces( canon_ace **pp_list_head )
+{
+	canon_ace *list_head = *pp_list_head;
+	canon_ace *curr_ace_outer;
+	canon_ace *curr_ace_outer_next;
+
+	/*
+	 * First, merge allow entries with identical SIDs, and deny entries
+	 * with identical SIDs.
+	 */
+
+	for (curr_ace_outer = list_head; curr_ace_outer; curr_ace_outer = curr_ace_outer_next) {
+		canon_ace *curr_ace;
+		canon_ace *curr_ace_next;
+
+		curr_ace_outer_next = curr_ace_outer->next; /* Save the link in case we delete. */
+
+		for (curr_ace = curr_ace_outer->next; curr_ace; curr_ace = curr_ace_next) {
+
+			curr_ace_next = curr_ace->next; /* Save the link in case of delete. */
+
+			if (sid_equal(&curr_ace->sid, &curr_ace_outer->sid) &&
+				(curr_ace->attr == curr_ace_outer->attr)) {
+
+				if( DEBUGLVL( 10 )) {
+					dbgtext("merge_aces: Merging ACE's\n");
+					print_canon_ace( curr_ace_outer, 0);
+					print_canon_ace( curr_ace, 0);
+				}
+
+				/* Merge two allow or two deny ACE's. */
+
+				curr_ace_outer->perms |= curr_ace->perms;
+				DLIST_REMOVE(list_head, curr_ace);
+				free(curr_ace);
+				curr_ace_outer_next = curr_ace_outer->next; /* We may have deleted the link. */
+			}
+		}
+	}
+
+	/*
+	 * Now go through and mask off allow permissions with deny permissions.
+	 * We can delete either the allow or deny here as we know that each SID
+	 * appears only once in the list.
+	 */
+
+	for (curr_ace_outer = list_head; curr_ace_outer; curr_ace_outer = curr_ace_outer_next) {
+		canon_ace *curr_ace;
+		canon_ace *curr_ace_next;
+
+		curr_ace_outer_next = curr_ace_outer->next; /* Save the link in case we delete. */
+
+		for (curr_ace = curr_ace_outer->next; curr_ace; curr_ace = curr_ace_next) {
+
+			curr_ace_next = curr_ace->next; /* Save the link in case of delete. */
+
+			/*
+			 * Subtract ACE's with different entries. Due to the ordering constraints
+			 * we've put on the ACL, we know the deny must be the first one.
+			 */
+
+			if ((curr_ace_outer->attr == DENY_ACE) && (curr_ace->attr == ALLOW_ACE)) {
+
+				if( DEBUGLVL( 10 )) {
+					dbgtext("merge_aces: Masking ACE's\n");
+					print_canon_ace( curr_ace_outer, 0);
+					print_canon_ace( curr_ace, 0);
+				}
+
+				curr_ace->perms &= ~curr_ace_outer->perms;
+
+				if (curr_ace->perms == 0) {
+
+					/*
+					 * The deny overrides the allow. Remove the allow.
+					 */
+
+					DLIST_REMOVE(list_head, curr_ace);
+					free(curr_ace);
+					curr_ace_outer_next = curr_ace_outer->next; /* We may have deleted the link. */
+
+				} else {
+
+					/*
+					 * Even after removing permissions, there
+					 * are still allow permissions - delete the deny.
+					 * It is safe to delete the deny here,
+					 * as we are guarenteed by the deny first
+					 * ordering that all the deny entries for
+					 * this SID have already been merged into one
+					 * before we can get to an allow ace.
+					 */
+
+					DLIST_REMOVE(list_head, curr_ace_outer);
+					free(curr_ace_outer);
+				}
+			}
+
+		} /* end for curr_ace */
+	} /* end for curr_ace_outer */
+
+	/* We may have modified the list. */
+
+	*pp_list_head = list_head;
+}
+
+/****************************************************************************
  Map canon_ace perms to permission bits NT.
  The attr element is not used here - we only process deny entries on set,
  not get. Deny entries are implicit on get with ace->perms = 0.
@@ -124,9 +270,9 @@ static SEC_ACCESS map_canon_ace_perms(int *pacl_type, DOM_SID *powner_sid, canon
 
 	*pacl_type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 
-	if((ace->perms & (S_IRUSR|S_IWUSR|S_IXUSR)) == (S_IRUSR|S_IWUSR|S_IXUSR)) {
+	if ((ace->perms & ALL_ACE_PERMS) == ALL_ACE_PERMS) {
 			nt_mask = UNIX_ACCESS_RWX;
-	} else if((ace->perms & (S_IRUSR|S_IWUSR|S_IXUSR)) == 0) {
+	} else if ((ace->perms & ALL_ACE_PERMS) == (mode_t)0) {
 		/*
 		 * Here we differentiate between the owner and any other user.
 		 */
@@ -249,36 +395,6 @@ static BOOL unpack_nt_owners(SMB_STRUCT_STAT *psbuf, uid_t *puser, gid_t *pgrp,
 	return True;
 }
 
-#if !defined(HAVE_NO_ACLS)
-/****************************************************************************
- Merge aces with a common user.
-****************************************************************************/
-
-static BOOL merge_aces( canon_ace *list_head, canon_ace *p_ace)
-{
-	canon_ace *curr_ace;
-
-	for (curr_ace = list_head; curr_ace; curr_ace = curr_ace->next) {
-		if (curr_ace == p_ace)
-			continue;
-
-		if ((curr_ace->type == p_ace->type) && (curr_ace->attr == p_ace->attr) &&
-						sid_equal(&curr_ace->sid, &p_ace->sid)) {
-			if( DEBUGLVL( 10 )) {
-				dbgtext("Merging ACE's\n");
-				print_canon_ace( p_ace, 0);
-				print_canon_ace( curr_ace, 0);
-			}
-			p_ace->perms |= curr_ace->perms;
-			DLIST_REMOVE(list_head, curr_ace);
-			free(curr_ace);
-			return True;
-		}
-	}
-
-	return False;
-}
-
 /****************************************************************************
  Create a default mode for a directory default ACE.
 ****************************************************************************/
@@ -312,6 +428,7 @@ static mode_t get_default_ace_mode(files_struct *fsp, int type)
 /****************************************************************************
  A well formed POSIX file or default ACL has at least 3 entries, a 
  SMB_ACL_USER_OBJ, SMB_ACL_GROUP_OBJ, SMB_ACL_OTHER_OBJ.
+ In addition, the owner must always have at least read access.
 ****************************************************************************/
 
 static BOOL ensure_canon_entry_valid(canon_ace **pp_ace,
@@ -328,9 +445,12 @@ static BOOL ensure_canon_entry_valid(canon_ace **pp_ace,
 	BOOL got_other = False;
 
 	for (pace = *pp_ace; pace; pace = pace->next) {
-		if (pace->type == SMB_ACL_USER_OBJ)
+		if (pace->type == SMB_ACL_USER_OBJ) {
+			/* Ensure owner has read access. */
+			if (pace->perms == (mode_t)0)
+				pace->perms = S_IRUSR;
 			got_user = True;
-		else if (pace->type == SMB_ACL_GROUP_OBJ)
+		} else if (pace->type == SMB_ACL_GROUP_OBJ)
 			got_grp = True;
 		else if (pace->type == SMB_ACL_OTHER)
 			got_other = True;
@@ -389,62 +509,38 @@ static BOOL ensure_canon_entry_valid(canon_ace **pp_ace,
 
 	return True;
 }
-#endif /* HAVE_NO_ACLS */
 
 /****************************************************************************
- Unpack a SEC_DESC into two canonical ace lists. We don't depend on this
- succeeding.
+ Unpack a SEC_DESC into two canonical ace lists.
 ****************************************************************************/
 
-static BOOL unpack_canon_ace(files_struct *fsp, 
-							SMB_STRUCT_STAT *pst,
+static BOOL create_canon_ace_lists(files_struct *fsp, 
 							DOM_SID *pfile_owner_sid,
 							DOM_SID *pfile_grp_sid,
 							canon_ace **ppfile_ace, canon_ace **ppdir_ace,
-							uint32 security_info_sent, SEC_DESC *psd)
+							SEC_ACL *dacl)
 {
-#if !defined(HAVE_NO_ACLS)
 	extern DOM_SID global_sid_World;
 	BOOL all_aces_are_inherit_only = (fsp->is_directory ? True : False);
 	canon_ace *file_ace = NULL;
 	canon_ace *dir_ace = NULL;
+	canon_ace *tmp_ace = NULL;
 	canon_ace *current_ace = NULL;
-	enum SID_NAME_USE sid_type;
+	BOOL got_dir_allow = False;
+	BOOL got_file_allow = False;
 	int i;
-#endif /* HAVE_NO_ACLS */
-	SEC_ACL *dacl = psd->dacl;
 
 	*ppfile_ace = NULL;
 	*ppdir_ace = NULL;
 
-	if(security_info_sent == 0) {
-		DEBUG(0,("unpack_canon_ace: no security info sent !\n"));
-		return False;
-	}
-
-	/*
-	 * If no DACL then this is a chown only security descriptor.
-	 */
-
-	if(!(security_info_sent & DACL_SECURITY_INFORMATION) || !dacl)
-		return True;
-
-#if defined(HAVE_NO_ACLS)
-
-	/* No point in doing this if we have no ACL support. */
-	return False;
-
-#else /* HAVE_NO_ACLS */
-
-	/*
-	 * Now go through the DACL and create the canon_ace lists.
-	 */
-
 	for(i = 0; i < dacl->num_aces; i++) {
+		enum SID_NAME_USE sid_type;
 		SEC_ACE *psa = &dacl->ace[i];
 
 		if((psa->type != SEC_ACE_TYPE_ACCESS_ALLOWED) && (psa->type != SEC_ACE_TYPE_ACCESS_DENIED)) {
-			DEBUG(3,("unpack_canon_ace: unable to set anything but an ALLOW or DENY ACE.\n"));
+			free_canon_ace_list(file_ace);
+			free_canon_ace_list(dir_ace);
+			DEBUG(3,("create_canon_ace_lists: unable to set anything but an ALLOW or DENY ACE.\n"));
 			return False;
 		}
 
@@ -468,7 +564,7 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 		if ((current_ace = (canon_ace *)malloc(sizeof(canon_ace))) == NULL) {
 			free_canon_ace_list(file_ace);
 			free_canon_ace_list(dir_ace);
-			DEBUG(0,("unpack_canon_ace: malloc fail.\n"));
+			DEBUG(0,("create_canon_ace_lists: malloc fail.\n"));
 			return False;
 		}
 
@@ -494,7 +590,7 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 			free_canon_ace_list(file_ace);
 			free_canon_ace_list(dir_ace);
 			free(current_ace);
-			DEBUG(0,("unpack_canon_ace: unable to map SID %s to uid or gid.\n",
+			DEBUG(0,("create_canon_ace_lists: unable to map SID %s to uid or gid.\n",
 				sid_to_string(str, &current_ace->sid) ));
 			return False;
 		}
@@ -504,13 +600,8 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 		 * S_I(R|W|X)USR bits.
 		 */
 
-		if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) {
-			current_ace->perms |= map_nt_perms( psa->info, S_IRUSR);
-			current_ace->attr = ALLOW_ACE;
-		} else {
-			current_ace->perms = 0;
-			current_ace->attr = DENY_ACE;
-		}
+		current_ace->perms |= map_nt_perms( psa->info, S_IRUSR);
+		current_ace->attr = (psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) ? ALLOW_ACE : DENY_ACE;
 
 		/*
 		 * Now note what kind of a POSIX ACL this should map to.
@@ -534,20 +625,43 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 			current_ace->type = (current_ace->owner_type == UID_ACE) ? SMB_ACL_USER : SMB_ACL_GROUP;
 		}
 
+		/*
+		 * Now add the created ace to either the file list, the directory
+		 * list, or both. We *MUST* preserve the order here (hence we use
+		 * DLIST_ADD_END) as NT ACLs are order dependent.
+		 */
+
 		if (fsp->is_directory) {
 
 			/*
 			 * We can only add to the default POSIX ACE list if the ACE is
 			 * designed to be inherited by both files and directories.
 			 */
+
 			if ((psa->flags & (SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT)) ==
 				(SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT)) {
 
-				DLIST_ADD(dir_ace, current_ace);
+				DLIST_ADD_END(dir_ace, current_ace, tmp_ace);
 
+				/*
+				 * Note if this was an allow ace. We can't process
+				 * any further deny ace's after this.
+				 */
+
+				if (current_ace->attr == ALLOW_ACE)
+					got_dir_allow = True;
+
+				if ((current_ace->attr == DENY_ACE) && got_dir_allow) {
+					DEBUG(0,("create_canon_ace_lists: malformed ACL in inheritable ACL ! \
+Deny entry after Allow entry. Failing to set on file %s.\n", fsp->fsp_name ));
+					free_canon_ace_list(file_ace);
+					free_canon_ace_list(dir_ace);
+					free(current_ace);
+					return False;
+				}	
 
 				if( DEBUGLVL( 10 )) {
-					dbgtext("unpack_canon_ace: adding dir ACL:\n");
+					dbgtext("create_canon_ace_lists: adding dir ACL:\n");
 					print_canon_ace( current_ace, 0);
 				}
 
@@ -560,7 +674,7 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 					canon_ace *dup_ace = dup_canon_ace(current_ace);
 
 					if (!dup_ace) {
-						DEBUG(0,("unpack_canon_ace: malloc fail !\n"));
+						DEBUG(0,("create_canon_ace_lists: malloc fail !\n"));
 						free_canon_ace_list(file_ace);
 						free_canon_ace_list(dir_ace);
 						return False;
@@ -578,13 +692,35 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 		 */
 
 		if (!(psa->flags & SEC_ACE_FLAG_INHERIT_ONLY)) {
-			DLIST_ADD(file_ace, current_ace);
+			DLIST_ADD_END(file_ace, current_ace, tmp_ace);
+
+			/*
+			 * Note if this was an allow ace. We can't process
+			 * any further deny ace's after this.
+			 */
+
+			if (current_ace->attr == ALLOW_ACE)
+				got_file_allow = True;
+
+			if ((current_ace->attr == DENY_ACE) && got_file_allow) {
+				DEBUG(0,("create_canon_ace_lists: malformed ACL in file ACL ! \
+Deny entry after Allow entry. Failing to set on file %s.\n", fsp->fsp_name ));
+				free_canon_ace_list(file_ace);
+				free_canon_ace_list(dir_ace);
+				free(current_ace);
+				return False;
+			}	
+
+			if( DEBUGLVL( 10 )) {
+				dbgtext("create_canon_ace_lists: adding file ACL:\n");
+				print_canon_ace( current_ace, 0);
+			}
 			all_aces_are_inherit_only = False;
 			current_ace = NULL;
 		}
 
 		/*
-		 * Free if ACE was not addedd.
+		 * Free if ACE was not added.
 		 */
 
 		if (current_ace)
@@ -598,28 +734,375 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 		 * there was no DACL sent. JRA.
 		 */
 
-		DEBUG(10,("unpack_canon_ace: Win2k inherit acl traverse. Ignoring DACL.\n"));
+		DEBUG(10,("create_canon_ace_lists: Win2k inherit acl traverse. Ignoring DACL.\n"));
+		free_canon_ace_list(file_ace);
+		free_canon_ace_list(dir_ace);
+		file_ace = NULL;
+		dir_ace = NULL;
 	}
 
+	*ppfile_ace = file_ace;
+	*ppdir_ace = dir_ace;
+
+	return True;
+}
+
+/****************************************************************************
+ Check if a given uid/SID is in a group gid/SID. This is probably very
+ expensive and will need optimisation. A *lot* of optimisation :-). JRA.
+****************************************************************************/
+
+static BOOL uid_entry_in_group( canon_ace *uid_ace, canon_ace *group_ace )
+{
+	extern DOM_SID global_sid_World;
+	struct passwd *pass = NULL;
+	struct group *gptr = NULL;
+
+	/* "Everyone" always matches every uid. */
+
+	if (sid_equal(&group_ace->sid, &global_sid_World))
+		return True;
+
+	if (!(pass = sys_getpwuid(uid_ace->unix_ug.uid)))
+		return False;
+
+	if (!(gptr = getgrgid(uid_ace->unix_ug.gid)))
+		return False;
+
 	/*
-	 * Now go through the canon_ace lists and merge entries
-	 * belonging to identical users.
+	 * Due to the winbind interfaces we need to do this via names,
+	 * not uids/gids.
 	 */
 
-  again_file:
+	return user_in_group_list(pass->pw_name, gptr->gr_name );
+}
+
+/****************************************************************************
+ ASCII art time again... JRA :-).
+
+ We have 3 cases to process when moving from an NT ACL to a POSIX ACL. Firstly,
+ we insist the ACL is in canonical form (ie. all DENY entries preceede ALLOW
+ entries). Secondly, the merge code has ensured that all duplicate SID entries for
+ allow or deny have been merged, so the same SID can only appear once in the deny
+ list or once in the allow list.
+
+ We then process as follows :
+
+ ---------------------------------------------------------------------------
+ First pass - look for a Everyone DENY entry.
+
+ If it is deny all (rwx) trunate the list at this point.
+ Else, walk the list from this point and use the deny permissions of this
+ entry as a mask on all following allow entries. Finally, delete
+ the Everyone DENY entry (we have applied it to everything possible).
+
+ In addition, in this pass we remove any DENY entries that have 
+ no permissions (ie. they are a DENY nothing).
+ ---------------------------------------------------------------------------
+ Second pass - only deal with deny user entries.
+
+ DENY user1 (perms XXX)
+
+ new_perms = 0
+ for all following allow group entries where user1 is in group
+	new_perms |= group_perms;
+
+ user1 entry perms = new_perms & ~ XXX;
+
+ Convert the deny entry to an allow entry with the new perms and
+ push to the end of the list. Note if the user was in no groups
+ this maps to a specific allow nothing entry for this user.
+
+ The common case from the NT ACL choser (userX deny all) is
+ optimised so we don't do the group lookup - we just map to
+ an allow nothing entry.
+
+ What we're doing here is inferring the allow permissions the
+ person setting the ACE on user1 wanted by looking at the allow
+ permissions on the groups the user is currently in. This will
+ be a snapshot, depending on group membership but is the best
+ we can do and has the advantage of failing closed rather than
+ open.
+ ---------------------------------------------------------------------------
+ Third pass - only deal with deny group entries.
+
+ DENY group1 (perms XXX)
+
+ for all following allow user entries where user is in group1
+   user entry perms = user entry perms & ~ XXX;
+
+ If there is a group Everyone allow entry with permissions YYY,
+ convert the group1 entry to an allow entry and modify its
+ permissions to be :
+
+ new_perms = YYY & ~ XXX
+
+ and push to the end of the list.
+
+ If there is no group Everyone allow entry then convert the
+ group1 entry to a allow nothing entry and push to the end of the list.
+
+ Note that the common case from the NT ACL choser (groupX deny all)
+ cannot be optimised here as we need to modify user entries who are
+ in the group to change them to a deny all also.
+
+ What we're doing here is modifying the allow permissions of
+ user entries (which are more specific in POSIX ACLs) to mask
+ out the explicit deny set on the group they are in. This will
+ be a snapshot depending on current group membership but is the
+ best we can do and has the advantage of failing closed rather
+ than open.
+ ---------------------------------------------------------------------------
+
+ Note we *MUST* do the deny user pass first as this will convert deny user
+ entries into allow user entries which can then be processed by the deny
+ group pass.
+
+ The above algorithm took a *lot* of thinking about - hence this
+ explaination :-). JRA.
+****************************************************************************/
+
+/****************************************************************************
+ Process a canon_ace list entries. This is very complex code. We need
+ to go through and remove the "deny" permissions from any allow entry that matches
+ the id of this entry. We have already refused any NT ACL that wasn't in correct
+ order (DENY followed by ALLOW). If any allow entry ends up with zero permissions,
+ we just remove it (to fail safe). We have already removed any duplicate ace
+ entries. Treat an "Everyone" DENY_ACE as a special case - use it to mask all
+ allow entries.
+****************************************************************************/
+
+static void process_deny_list( canon_ace **pp_ace_list )
+{
+	extern DOM_SID global_sid_World;
+	canon_ace *ace_list = *pp_ace_list;
+	canon_ace *curr_ace = NULL;
+	canon_ace *curr_ace_next = NULL;
+
+	/* Pass 1 above - look for an Everyone, deny entry. */
+
+	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
+		canon_ace *allow_ace_p;
+
+		curr_ace_next = curr_ace->next; /* So we can't lose the link. */
+
+		if (curr_ace->attr != DENY_ACE)
+			continue;
 
-	for (current_ace = file_ace; current_ace; current_ace = current_ace->next ) {
-		if (merge_aces( file_ace, current_ace))
-			goto again_file;
+		if (curr_ace->perms == (mode_t)0) {
+
+			/* Deny nothing entry - delete. */
+
+			DLIST_REMOVE(ace_list, curr_ace);
+			continue;
+		}
+
+		if (!sid_equal(&curr_ace->sid, &global_sid_World))
+			continue;
+
+		/* JRATEST - assert. */
+		SMB_ASSERT(curr_ace->owner_type == WORLD_ACE);
+
+		if (curr_ace->perms == ALL_ACE_PERMS) {
+
+			/*
+			 * Optimisation. This is a DENY_ALL to Everyone. Truncate the
+			 * list at this point including this entry.
+			 */
+
+			canon_ace *prev_entry = curr_ace->prev;
+
+			free_canon_ace_list( curr_ace );
+			if (prev_entry)
+				prev_entry->next = NULL;
+			else {
+				/* We deleted the entire list. */
+				ace_list = NULL;
+			}
+			break;
+		}
+
+		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {
+
+			/* 
+			 * Only mask off allow entries.
+			 */
+
+			if (allow_ace_p->attr != ALLOW_ACE)
+				continue;
+
+			allow_ace_p->perms &= ~curr_ace->perms;
+		}
+
+		/*
+		 * Now it's been applied, remove it.
+		 */
+
+		DLIST_REMOVE(ace_list, curr_ace);
+	}
+
+	/* Pass 2 above - deal with deny user entries. */
+
+	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
+		mode_t new_perms = (mode_t)0;
+		canon_ace *allow_ace_p;
+		canon_ace *tmp_ace;
+
+		curr_ace_next = curr_ace->next; /* So we can't lose the link. */
+
+		if (curr_ace->attr != DENY_ACE)
+			continue;
+
+		if (curr_ace->owner_type != UID_ACE)
+			continue;
+
+		if (curr_ace->perms == ALL_ACE_PERMS) {
+
+			/*
+			 * Optimisation - this is a deny everything to this user.
+			 * Convert to an allow nothing and push to the end of the list.
+			 */
+
+			curr_ace->attr = ALLOW_ACE;
+			curr_ace->perms = (mode_t)0;
+			DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);
+			continue;
+		}
+
+		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {
+
+			if (allow_ace_p->attr != ALLOW_ACE)
+				continue;
+
+			/* We process GID_ACE and WORLD_ACE entries only. */
+
+			if (allow_ace_p->owner_type == UID_ACE)
+				continue;
+
+			if (uid_entry_in_group( curr_ace, allow_ace_p))
+				new_perms |= allow_ace_p->perms;
+		}
+
+		/*
+		 * Convert to a allow entry, modify the perms and push to the end
+		 * of the list.
+		 */
+
+		curr_ace->attr = ALLOW_ACE;
+		curr_ace->perms = (new_perms & ~curr_ace->perms);
+		DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);
 	}
 
-  again_dir:
+	/* Pass 3 above - deal with deny group entries. */
+
+	for (curr_ace = ace_list; curr_ace; curr_ace = curr_ace_next) {
+		canon_ace *tmp_ace;
+		canon_ace *allow_ace_p;
+		canon_ace *allow_everyone_p = NULL;
+
+		curr_ace_next = curr_ace->next; /* So we can't lose the link. */
+
+		if (curr_ace->attr != DENY_ACE)
+			continue;
+
+		if (curr_ace->owner_type != GID_ACE)
+			continue;
+
+		for (allow_ace_p = curr_ace->next; allow_ace_p; allow_ace_p = allow_ace_p->next) {
+
+			if (allow_ace_p->attr != ALLOW_ACE)
+				continue;
+
+			/* Store a pointer to the Everyone allow, if it exists. */
+			if (allow_ace_p->owner_type == WORLD_ACE)
+				allow_everyone_p = allow_ace_p;
+
+			/* We process UID_ACE entries only. */
+
+			if (allow_ace_p->owner_type != UID_ACE)
+				continue;
+
+			/* Mask off the deny group perms. */
+
+			if (uid_entry_in_group( allow_ace_p, curr_ace))
+				allow_ace_p->perms &= ~curr_ace->perms;
+		}
+
+		/*
+		 * Convert the deny to an allow with the correct perms and
+		 * push to the end of the list.
+		 */
+
+		curr_ace->attr = ALLOW_ACE;
+		if (allow_everyone_p)
+			curr_ace->perms = allow_everyone_p->perms & ~curr_ace->perms;
+		else
+			curr_ace->perms = (mode_t)0;
+		DLIST_DEMOTE(ace_list, curr_ace, tmp_ace);
 
-	for (current_ace = dir_ace; current_ace; current_ace = current_ace->next ) {
-		if (merge_aces( dir_ace, current_ace))
-			goto again_dir;
 	}
 
+	*pp_ace_list = ace_list;
+}
+
+/****************************************************************************
+ Unpack a SEC_DESC into two canonical ace lists. We don't depend on this
+ succeeding.
+****************************************************************************/
+
+static BOOL unpack_canon_ace(files_struct *fsp, 
+							SMB_STRUCT_STAT *pst,
+							DOM_SID *pfile_owner_sid,
+							DOM_SID *pfile_grp_sid,
+							canon_ace **ppfile_ace, canon_ace **ppdir_ace,
+							uint32 security_info_sent, SEC_DESC *psd)
+{
+	canon_ace *file_ace = NULL;
+	canon_ace *dir_ace = NULL;
+	canon_ace *current_ace = NULL;
+	int i;
+
+	*ppfile_ace = NULL;
+	*ppdir_ace = NULL;
+
+	if(security_info_sent == 0) {
+		DEBUG(0,("unpack_canon_ace: no security info sent !\n"));
+		return False;
+	}
+
+	/*
+	 * If no DACL then this is a chown only security descriptor.
+	 */
+
+	if(!(security_info_sent & DACL_SECURITY_INFORMATION) || !psd->dacl)
+		return True;
+
+	/*
+	 * Now go through the DACL and create the canon_ace lists.
+	 */
+
+	if (!create_canon_ace_lists( fsp, pfile_owner_sid, pfile_grp_sid,
+								&file_ace, &dir_ace, psd->dacl))
+		return False;
+
+	/*
+	 * Go through the canon_ace list and merge entries
+	 * belonging to identical users of identical allow or deny type.
+	 * We can do this as all deny entries come first, followed by
+	 * all allow entries (we have mandated this before accepting this acl).
+	 */
+
+	merge_aces( &file_ace );
+	merge_aces( &dir_ace );
+
+	/*
+	 * NT ACLs are order dependent. Go through the acl lists and
+	 * process DENY entries by masking the allow entries.
+	 */
+
+	process_deny_list( &file_ace);
+	process_deny_list( &dir_ace);
+
 	/*
 	 * A well formed POSIX file or default ACL has at least 3 entries, a 
 	 * SMB_ACL_USER_OBJ, SMB_ACL_GROUP_OBJ, SMB_ACL_OTHER_OBJ
@@ -654,188 +1137,6 @@ static BOOL unpack_canon_ace(files_struct *fsp,
 	*ppdir_ace = dir_ace;
 	return True;
 
-#endif /* HAVE_NO_ACLS */
-}
-
-/****************************************************************************
- Unpack a SEC_DESC into a set of standard POSIX permissions.
-****************************************************************************/
-
-static BOOL unpack_posix_permissions(files_struct *fsp, SMB_STRUCT_STAT *psbuf, mode_t *pmode,
-								uint32 security_info_sent, SEC_DESC *psd, BOOL posix_acls)
-{
-  extern DOM_SID global_sid_World;
-  connection_struct *conn = fsp->conn;
-  DOM_SID file_owner_sid;
-  DOM_SID file_grp_sid;
-  SEC_ACL *dacl = psd->dacl;
-  BOOL all_aces_are_inherit_only = (fsp->is_directory ? True : False);
-  int i;
-
-  *pmode = 0;
-
-  if(security_info_sent == 0) {
-    DEBUG(0,("unpack_posix_permissions: no security info sent !\n"));
-    return False;
-  }
-
-  /*
-   * Windows 2000 sends the owner and group SIDs as the logged in
-   * user, not the connected user. But it still sends the file
-   * owner SIDs on an ACL set. So we need to check for the file
-   * owner and group SIDs as well as the owner SIDs. JRA.
-   */
- 
-  create_file_sids(psbuf, &file_owner_sid, &file_grp_sid);
-
-  /*
-   * If no DACL then this is a chown only security descriptor.
-   */
-
-  if(!(security_info_sent & DACL_SECURITY_INFORMATION) || !dacl) {
-    *pmode = 0;
-    return True;
-  }
-
-  /*
-   * Now go through the DACL and ensure that
-   * any owner/group sids match.
-   */
-
-  for(i = 0; i < dacl->num_aces; i++) {
-    DOM_SID ace_sid;
-    SEC_ACE *psa = &dacl->ace[i];
-
-    if((psa->type != SEC_ACE_TYPE_ACCESS_ALLOWED) &&
-       (psa->type != SEC_ACE_TYPE_ACCESS_DENIED)) {
-      DEBUG(3,("unpack_posix_permissions: unable to set anything but an ALLOW or DENY ACE.\n"));
-      return False;
-    }
-
-    /*
-     * Ignore or remove bits we don't care about on a directory ACE.
-     */
-
-    if(fsp->is_directory) {
-      if(psa->flags & SEC_ACE_FLAG_INHERIT_ONLY) {
-        DEBUG(3,("unpack_posix_permissions: ignoring inherit only ACE.\n"));
-        continue;
-      }
-
-      /*
-       * At least one of the ACE entries wasn't inherit only.
-       * Flag this so we know the returned mode is valid.
-       */
-
-      all_aces_are_inherit_only = False;
-    }
-
-    /*
-     * Windows 2000 sets these flags even on *file* ACE's. This is wrong
-     * but we can ignore them for now. Revisit this when we go to POSIX
-     * ACLs on directories.
-     */
-
-    psa->flags &= ~(SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT|SEC_ACE_FLAG_INHERITED_ACE);
-
-    if(psa->flags != 0) {
-      DEBUG(1,("unpack_posix_permissions: unable to set ACE flags (%x).\n", 
-            (unsigned int)psa->flags));
-      return False;
-    }
-
-    /*
-     * The security mask may be UNIX_ACCESS_NONE which should map into
-     * no permissions (we overload the WRITE_OWNER bit for this) or it
-     * should be one of the ALL/EXECUTE/READ/WRITE bits. Arrange for this
-     * to be so. Any other bits override the UNIX_ACCESS_NONE bit.
-     */
-
-    psa->info.mask &= (GENERIC_ALL_ACCESS|GENERIC_EXECUTE_ACCESS|GENERIC_WRITE_ACCESS|
-                     GENERIC_READ_ACCESS|UNIX_ACCESS_NONE|FILE_ALL_ATTRIBUTES);
-
-    if(psa->info.mask != UNIX_ACCESS_NONE)
-      psa->info.mask &= ~UNIX_ACCESS_NONE;
-
-    sid_copy(&ace_sid, &psa->sid);
-
-    if(sid_equal(&ace_sid, &file_owner_sid)) {
-      /*
-       * Map the desired permissions into owner perms.
-       */
-
-      if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED)
-        *pmode |= map_nt_perms( psa->info, S_IRUSR);
-      else
-        *pmode &= ~(map_nt_perms( psa->info, S_IRUSR));
-
-      
-    } else if( sid_equal(&ace_sid, &file_grp_sid)) {
-      /*
-       * Map the desired permissions into group perms.
-       */
-
-      if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED)
-        *pmode |= map_nt_perms( psa->info, S_IRGRP);
-      else
-        *pmode &= ~(map_nt_perms( psa->info, S_IRGRP));
-
-    } else if( sid_equal(&ace_sid, &global_sid_World)) {
-      /*
-       * Map the desired permissions into other perms.
-       */
-
-      if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED)
-        *pmode |= map_nt_perms( psa->info, S_IROTH);
-      else
-        *pmode &= ~(map_nt_perms( psa->info, S_IROTH));
-
-    } else {
-      /*
-       * Only bother printing the level zero error if we didn't get any
-       * POSIX ACLS.
-       */
-      if (!posix_acls)
-        DEBUG(0,("unpack_posix_permissions: unknown SID used in ACL.\n"));
-      return False;
-    }
-  }
-
-  if (fsp->is_directory && all_aces_are_inherit_only) {
-    /*
-     * Windows 2000 is doing one of these weird 'inherit acl'
-     * traverses to conserve NTFS ACL resources. Just pretend
-     * there was no DACL sent. JRA.
-     */
-
-    DEBUG(10,("unpack_posix_permissions: Win2k inherit acl traverse. Ignoring DACL.\n"));
-  }
-
-  /*
-   * Check to see if we need to change anything.
-   * Enforce limits on modified bits *only*. Don't enforce masks
-   * on bits not changed by the user.
-   */
-
-  if(fsp->is_directory) {
-
-    *pmode &= (lp_dir_security_mask(SNUM(conn)) | psbuf->st_mode);
-    *pmode |= (lp_force_dir_security_mode(SNUM(conn)) & ( *pmode ^ psbuf->st_mode ));
-
-  } else {
-
-    *pmode &= (lp_security_mask(SNUM(conn)) | psbuf->st_mode); 
-    *pmode |= (lp_force_security_mode(SNUM(conn)) & ( *pmode ^ psbuf->st_mode ));
-
-  }
-
-  /*
-   * Preserve special bits.
-   */
-
-  *pmode |= (psbuf->st_mode & ~0777);
-
-  return True;
 }
 
 /****************************************************************************
@@ -895,39 +1196,24 @@ static int map_acl_perms_to_permset(mode_t mode, SMB_ACL_PERMSET_T *p_permset)
 	return 0;
 }
 
-/****************************************************************************
- Count a linked list of canonical ACE entries.
-****************************************************************************/
-
-static size_t count_canon_ace_list( canon_ace *list_head )
-{
-	size_t count = 0;
-	canon_ace *ace;
-
-	for (ace = list_head; ace; ace = ace->next)
-		count++;
-
-	return count;
-}
-
-/****************************************************************************
- Free a linked list of canonical ACE entries.
-****************************************************************************/
-
-static void free_canon_ace_list( canon_ace *list_head )
-{
-	while (list_head) {
-		canon_ace *old_head = list_head;
-		DLIST_REMOVE(list_head, list_head);
-		free(old_head);
-	}
-}
-
 /******************************************************************************
  When returning permissions, try and fit NT display
  semantics if possible. Note the the canon_entries here must have been malloced.
  The list format should be - first entry = owner, followed by group and other user
  entries, last entry = other.
+
+ Note that this doesn't exactly match the NT semantics for an ACL. As POSIX entries
+ are not ordered, and match on the most specific entry rather than walking a list,
+ then a simple POSIX permission of rw-r--r-- should really map to 6 entries,
+
+ Entry 0: owner : deny all except read and write.
+ Entry 1: group : deny all except read.
+ Entry 2: Everyone : deny all except read.
+ Entry 3: owner : allow read and write.
+ Entry 4: group : allow read.
+ Entry 5: Everyone : allow read.
+
+ But NT cannot display this in their ACL editor !
 ********************************************************************************/
 
 static void arrange_posix_perms( char *filename, canon_ace **pp_list_head)
@@ -1221,7 +1507,7 @@ static canon_ace *canonicalise_acl( files_struct *fsp, SMB_ACL_T posix_acl, SMB_
 
 	/*
 	 * Now go through the list, masking the permissions with the
-	 * acl_mask.
+	 * acl_mask. Ensure all DENY Entries are at the start of the list.
 	 */
 
 	DEBUG(10,("canonicalize_acl: ace entries before arrange :\n"));
@@ -1281,14 +1567,15 @@ static BOOL set_canon_ace_list(files_struct *fsp, canon_ace *the_ace, BOOL defau
 	SMB_ACL_TYPE_T the_acl_type = (default_ace ? SMB_ACL_TYPE_DEFAULT : SMB_ACL_TYPE_ACCESS);
 
 	if (the_acl == NULL) {
-#if !defined(HAVE_NO_ACLS)
-		/*
-		 * Only print this error message if we have some kind of ACL
-		 * support that's not working. Otherwise we would always get this.
-		 */
-		DEBUG(0,("set_canon_ace_list: Unable to init %s ACL. (%s)\n",
-			default_ace ? "default" : "file", strerror(errno) ));
-#endif
+
+		if (errno != ENOSYS) {
+			/*
+			 * Only print this error message if we have some kind of ACL
+			 * support that's not working. Otherwise we would always get this.
+			 */
+			DEBUG(0,("set_canon_ace_list: Unable to init %s ACL. (%s)\n",
+				default_ace ? "default" : "file", strerror(errno) ));
+		}
 		*pacl_set_support = False;
 		return False;
 	}
@@ -1441,6 +1728,63 @@ static BOOL set_canon_ace_list(files_struct *fsp, canon_ace *the_ace, BOOL defau
 }
 
 /****************************************************************************
+ Convert a canon_ace to a generic 3 element permission - if possible.
+****************************************************************************/
+
+#define MAP_PERM(p,mask,result) (((p) & (mask)) ? (result) : 0 )
+
+static BOOL convert_canon_ace_to_posix_perms( files_struct *fsp, canon_ace *file_ace_list, mode_t *posix_perms)
+{
+	size_t ace_count = count_canon_ace_list(file_ace_list);
+	canon_ace *ace_p;
+	canon_ace *owner_ace = NULL;
+	canon_ace *group_ace = NULL;
+	canon_ace *other_ace = NULL;
+
+	if (ace_count != 3) {
+		DEBUG(3,("convert_canon_ace_to_posix_perms: Too many ACE entries for file %s to convert to \
+posix perms.\n", fsp->fsp_name ));
+		return False;
+	}
+
+	for (ace_p = file_ace_list; ace_p; ace_p = ace_p->next) {
+		if (ace_p->owner_type == UID_ACE)
+			owner_ace = ace_p;
+		else if (ace_p->owner_type == GID_ACE)
+			group_ace = ace_p;
+		else if (ace_p->owner_type == WORLD_ACE)
+			other_ace = ace_p;
+	}
+
+	if (!owner_ace || !group_ace || !other_ace) {
+		DEBUG(3,("convert_canon_ace_to_posix_perms: Can't get standard entries for file %s.\n",
+				fsp->fsp_name ));
+		return False;
+	}
+
+	*posix_perms = (mode_t)0;
+
+	*posix_perms |= owner_ace->perms;
+	*posix_perms |= MAP_PERM(group_ace->perms, S_IRUSR, S_IRGRP);
+	*posix_perms |= MAP_PERM(group_ace->perms, S_IWUSR, S_IWGRP);
+	*posix_perms |= MAP_PERM(group_ace->perms, S_IXUSR, S_IXGRP);
+	*posix_perms |= MAP_PERM(other_ace->perms, S_IRUSR, S_IROTH);
+	*posix_perms |= MAP_PERM(other_ace->perms, S_IWUSR, S_IWOTH);
+	*posix_perms |= MAP_PERM(other_ace->perms, S_IXUSR, S_IXOTH);
+
+	/* The owner must have at least read access. */
+
+	if (*posix_perms == (mode_t)0)
+		*posix_perms = S_IRUSR;
+
+	DEBUG(10,("convert_canon_ace_to_posix_perms: converted u=%o,g=%o,w=%o to perm=0%o for file %s.\n",
+		(int)owner_ace->perms, (int)group_ace->perms, (int)other_ace->perms, (int)*posix_perms,
+		fsp->fsp_name ));
+
+	return True;
+}
+
+/****************************************************************************
  Reply to query a security descriptor from an fsp. If it succeeds it allocates
  the space for the return elements and returns the size needed to return the
  security descriptor. This should be the only external function needed for
@@ -1596,14 +1940,12 @@ BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd)
 	connection_struct *conn = fsp->conn;
 	uid_t user = (uid_t)-1;
 	gid_t grp = (gid_t)-1;
-	mode_t perms = 0;
 	SMB_STRUCT_STAT sbuf;  
 	DOM_SID file_owner_sid;
 	DOM_SID file_grp_sid;
 	canon_ace *file_ace_list = NULL;
 	canon_ace *dir_ace_list = NULL;
-	BOOL posix_perms;
-	BOOL acl_perms;
+	BOOL acl_perms = False;
 
 	DEBUG(10,("set_nt_acl: called for file %s\n", fsp->fsp_name ));
 
@@ -1668,14 +2010,9 @@ BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd)
 
 	acl_perms = unpack_canon_ace( fsp, &sbuf, &file_owner_sid, &file_grp_sid,
 									&file_ace_list, &dir_ace_list, security_info_sent, psd);
-	posix_perms = unpack_posix_permissions( fsp, &sbuf, &perms, security_info_sent, psd, acl_perms);
-
-	if (!posix_perms && !acl_perms) {
-		/*
-		 * Neither method of setting permissions can work. Fail here.
-		 */
 
-		DEBUG(3,("set_nt_acl: cannot set normal POSIX permissions or POSIX ACL permissions\n"));
+	if (!acl_perms) {
+		DEBUG(3,("set_nt_acl: cannot set permissions\n"));
 		free_canon_ace_list(file_ace_list);
 		free_canon_ace_list(dir_ace_list); 
 		return False;
@@ -1691,7 +2028,7 @@ BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd)
 		BOOL ret = False;
 
 		/*
-		 * Try using the POSIX ACL set first. All back to chmod if
+		 * Try using the POSIX ACL set first. Fall back to chmod if
 		 * we have no ACL support on this filesystem.
 		 */
 
@@ -1718,20 +2055,29 @@ BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd)
 		 * If we cannot set using POSIX ACLs we fall back to checking if we need to chmod.
 		 */
 
-		if(!acl_set_support && posix_perms && (sbuf.st_mode != perms)) {
+		if(!acl_set_support && acl_perms) {
+			mode_t posix_perms;
 
-			free_canon_ace_list(file_ace_list);
-			free_canon_ace_list(dir_ace_list); 
-			file_ace_list = NULL;
-			dir_ace_list = NULL;
+			if (!convert_canon_ace_to_posix_perms( fsp, file_ace_list, &posix_perms)) {
+				free_canon_ace_list(file_ace_list);
+				free_canon_ace_list(dir_ace_list);
+				DEBUG(3,("set_nt_acl: failed to convert file acl to posix permissions for file %s.\n",
+					fsp->fsp_name ));
+				return False;
+			}
 
-			DEBUG(3,("set_nt_acl: chmod %s. perms = 0%o.\n",
-				fsp->fsp_name, (unsigned int)perms ));
+			if (sbuf.st_mode != posix_perms) {
 
-			if(conn->vfs_ops.chmod(conn,dos_to_unix(fsp->fsp_name, False), perms) == -1) {
-				DEBUG(3,("set_nt_acl: chmod %s, 0%o failed. Error = %s.\n",
-						fsp->fsp_name, (unsigned int)perms, strerror(errno) ));
-				return False;
+				DEBUG(3,("set_nt_acl: chmod %s. perms = 0%o.\n",
+					fsp->fsp_name, (unsigned int)posix_perms ));
+
+				if(conn->vfs_ops.chmod(conn,dos_to_unix(fsp->fsp_name, False), posix_perms) == -1) {
+					DEBUG(3,("set_nt_acl: chmod %s, 0%o failed. Error = %s.\n",
+							fsp->fsp_name, (unsigned int)posix_perms, strerror(errno) ));
+					free_canon_ace_list(file_ace_list);
+					free_canon_ace_list(dir_ace_list);
+					return False;
+				}
 			}
 		}
 	}