1 files changed, 446 insertions, 0 deletions

diff --git a/source3/lib/util_seaccess.c b/source3/lib/util_seaccess.c
new file mode 100644
index 0000000000..8ed266aced
--- /dev/null
+++ b/source3/lib/util_seaccess.c
@@ -0,0 +1,446 @@
+/*
+   Unix SMB/CIFS implementation.
+   Copyright (C) Luke Kenneth Casson Leighton 1996-2000.
+   Copyright (C) Tim Potter 2000.
+   Copyright (C) Re-written by Jeremy Allison 2000.
+
+   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"
+#include "nterr.h"
+#include "sids.h"
+
+/**********************************************************************************
+ Check if this ACE has a SID in common with the token.
+**********************************************************************************/
+
+static BOOL token_sid_in_ace(const NT_USER_TOKEN *token, const SEC_ACE *ace)
+{
+	size_t i;
+
+	for (i = 0; i < token->num_sids; i++) {
+		if (sid_equal(&ace->trustee, &token->user_sids[i]))
+			return True;
+	}
+
+	return False;
+}
+
+/*********************************************************************************
+ Check an ACE against a SID.  We return the remaining needed permission
+ bits not yet granted. Zero means permission allowed (no more needed bits).
+**********************************************************************************/
+
+static uint32 check_ace(SEC_ACE *ace, NT_USER_TOKEN *token, uint32 acc_desired, 
+			NTSTATUS *status)
+{
+	uint32 mask = ace->info.mask;
+
+	/*
+	 * Inherit only is ignored.
+	 */
+
+	if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY) {
+		return acc_desired;
+	}
+
+	/*
+	 * If this ACE has no SID in common with the token,
+	 * ignore it as it cannot be used to make an access
+	 * determination.
+	 */
+
+	if (!token_sid_in_ace( token, ace))
+		return acc_desired;	
+
+	switch (ace->type) {
+		case SEC_ACE_TYPE_ACCESS_ALLOWED:
+			/*
+			 * This is explicitly allowed.
+			 * Remove the bits from the remaining
+			 * access required. Return the remaining
+			 * bits needed.
+			 */
+			acc_desired &= ~mask;
+			break;
+		case SEC_ACE_TYPE_ACCESS_DENIED:
+			/*
+			 * This is explicitly denied.
+			 * If any bits match terminate here,
+			 * we are denied.
+			 */
+			if (acc_desired & mask) {
+				*status = NT_STATUS_ACCESS_DENIED;
+				return 0xFFFFFFFF;
+			}
+			break;
+		case SEC_ACE_TYPE_SYSTEM_ALARM:
+		case SEC_ACE_TYPE_SYSTEM_AUDIT:
+			*status = NT_STATUS_NOT_IMPLEMENTED;
+			return 0xFFFFFFFF;
+		default:
+			*status = NT_STATUS_INVALID_PARAMETER;
+			return 0xFFFFFFFF;
+	}
+
+	return acc_desired;
+}
+
+/*********************************************************************************
+ Maximum access was requested. Calculate the max possible. Fail if it doesn't
+ include other bits requested.
+**********************************************************************************/ 
+
+static BOOL get_max_access( SEC_ACL *the_acl, NT_USER_TOKEN *token, uint32 *granted, 
+			    uint32 desired, 
+			    NTSTATUS *status)
+{
+	uint32 acc_denied = 0;
+	uint32 acc_granted = 0;
+	size_t i;
+	
+	for ( i = 0 ; i < the_acl->num_aces; i++) {
+		SEC_ACE *ace = &the_acl->ace[i];
+		uint32 mask = ace->info.mask;
+
+		if (!token_sid_in_ace( token, ace))
+			continue;
+
+		switch (ace->type) {
+			case SEC_ACE_TYPE_ACCESS_ALLOWED:
+				acc_granted |= (mask & ~acc_denied);
+				break;
+			case SEC_ACE_TYPE_ACCESS_DENIED:
+				acc_denied |= (mask & ~acc_granted);
+				break;
+			case SEC_ACE_TYPE_SYSTEM_ALARM:
+			case SEC_ACE_TYPE_SYSTEM_AUDIT:
+				*status = NT_STATUS_NOT_IMPLEMENTED;
+				*granted = 0;
+				return False;
+			default:
+				*status = NT_STATUS_INVALID_PARAMETER;
+				*granted = 0;
+				return False;
+		}                           
+	}
+
+	/*
+	 * If we were granted no access, or we desired bits that we
+	 * didn't get, then deny.
+	 */
+
+	if ((acc_granted == 0) || ((acc_granted & desired) != desired)) {
+		*status = NT_STATUS_ACCESS_DENIED;
+		*granted = 0;
+		return False;
+	}
+
+	/*
+	 * Return the access we did get.
+	 */
+
+	*granted = acc_granted;
+	*status = NT_STATUS_OK;
+	return True;
+}
+
+/* Map generic access rights to object specific rights.  This technique is
+   used to give meaning to assigning read, write, execute and all access to
+   objects.  Each type of object has its own mapping of generic to object
+   specific access rights. */
+
+void se_map_generic(uint32 *access_mask, struct generic_mapping *mapping)
+{
+	uint32 old_mask = *access_mask;
+
+	if (*access_mask & GENERIC_READ_ACCESS) {
+		*access_mask &= ~GENERIC_READ_ACCESS;
+		*access_mask |= mapping->generic_read;
+	}
+
+	if (*access_mask & GENERIC_WRITE_ACCESS) {
+		*access_mask &= ~GENERIC_WRITE_ACCESS;
+		*access_mask |= mapping->generic_write;
+	}
+
+	if (*access_mask & GENERIC_EXECUTE_ACCESS) {
+		*access_mask &= ~GENERIC_EXECUTE_ACCESS;
+		*access_mask |= mapping->generic_execute;
+	}
+
+	if (*access_mask & GENERIC_ALL_ACCESS) {
+		*access_mask &= ~GENERIC_ALL_ACCESS;
+		*access_mask |= mapping->generic_all;
+	}
+
+	if (old_mask != *access_mask) {
+		DEBUG(10, ("se_map_generic(): mapped mask 0x%08x to 0x%08x\n",
+			   old_mask, *access_mask));
+	}
+}
+
+/* Map standard access rights to object specific rights.  This technique is
+   used to give meaning to assigning read, write, execute and all access to
+   objects.  Each type of object has its own mapping of standard to object
+   specific access rights. */
+
+void se_map_standard(uint32 *access_mask, struct standard_mapping *mapping)
+{
+	uint32 old_mask = *access_mask;
+
+	if (*access_mask & READ_CONTROL_ACCESS) {
+		*access_mask &= ~READ_CONTROL_ACCESS;
+		*access_mask |= mapping->std_read;
+	}
+
+	if (*access_mask & (DELETE_ACCESS|WRITE_DAC_ACCESS|WRITE_OWNER_ACCESS|SYNCHRONIZE_ACCESS)) {
+		*access_mask &= ~(DELETE_ACCESS|WRITE_DAC_ACCESS|WRITE_OWNER_ACCESS|SYNCHRONIZE_ACCESS);
+		*access_mask |= mapping->std_all;
+	}
+
+	if (old_mask != *access_mask) {
+		DEBUG(10, ("se_map_standard(): mapped mask 0x%08x to 0x%08x\n",
+			   old_mask, *access_mask));
+	}
+}
+
+/*****************************************************************************
+ Check access rights of a user against a security descriptor.  Look at
+ each ACE in the security descriptor until an access denied ACE denies
+ any of the desired rights to the user or any of the users groups, or one
+ or more ACEs explicitly grant all requested access rights.  See
+ "Access-Checking" document in MSDN.
+*****************************************************************************/ 
+
+BOOL se_access_check(SEC_DESC *sd, NT_USER_TOKEN *token,
+		     uint32 acc_desired, uint32 *acc_granted, 
+		     NTSTATUS *status)
+{
+	extern NT_USER_TOKEN anonymous_token;
+	size_t i;
+	SEC_ACL *the_acl;
+	fstring sid_str;
+	uint32 tmp_acc_desired = acc_desired;
+
+	if (!status || !acc_granted)
+		return False;
+
+	if (!token)
+		token = &anonymous_token;
+
+	*status = NT_STATUS_OK;
+	*acc_granted = 0;
+
+	DEBUG(10,("se_access_check: requested access 0x%08x, for NT token with %u entries and first sid %s.\n",
+		 (unsigned int)acc_desired, (unsigned int)token->num_sids,
+		sid_to_string(sid_str, &token->user_sids[0])));
+
+	/*
+	 * No security descriptor or security descriptor with no DACL
+	 * present allows all access.
+	 */
+
+	/* ACL must have something in it */
+
+	if (!sd || (sd && (!(sd->type & SEC_DESC_DACL_PRESENT) || sd->dacl == NULL))) {
+		*status = NT_STATUS_OK;
+		*acc_granted = acc_desired;
+		DEBUG(5, ("se_access_check: no sd or blank DACL, access allowed\n"));
+		return True;
+	}
+
+	/* The user sid is the first in the token */
+
+	DEBUG(3, ("se_access_check: user sid is %s\n", sid_to_string(sid_str, &token->user_sids[PRIMARY_USER_SID_INDEX]) ));
+
+	for (i = 1; i < token->num_sids; i++) {
+		DEBUG(3, ("se_access_check: also %s\n",
+			  sid_to_string(sid_str, &token->user_sids[i])));
+	}
+
+	/* Is the token the owner of the SID ? */
+
+	if (sd->owner_sid) {
+		for (i = 0; i < token->num_sids; i++) {
+			if (sid_equal(&token->user_sids[i], sd->owner_sid)) {
+				/*
+				 * The owner always has SEC_RIGHTS_WRITE_DAC & READ_CONTROL.
+				 */
+				if (tmp_acc_desired & WRITE_DAC_ACCESS)
+					tmp_acc_desired &= ~WRITE_DAC_ACCESS;
+				if (tmp_acc_desired & READ_CONTROL_ACCESS)
+					tmp_acc_desired &= ~READ_CONTROL_ACCESS;
+			}
+		}
+	}
+
+	the_acl = sd->dacl;
+
+	if (tmp_acc_desired & MAXIMUM_ALLOWED_ACCESS) {
+		tmp_acc_desired &= ~MAXIMUM_ALLOWED_ACCESS;
+		return get_max_access( the_acl, token, acc_granted, tmp_acc_desired, 
+				       status);
+	}
+
+	for ( i = 0 ; i < the_acl->num_aces && tmp_acc_desired != 0; i++) {
+		SEC_ACE *ace = &the_acl->ace[i];
+
+		DEBUG(10,("se_access_check: ACE %u: type %d, flags = 0x%02x, SID = %s mask = %x, current desired = %x\n",
+			  (unsigned int)i, ace->type, ace->flags,
+			  sid_to_string(sid_str, &ace->trustee),
+			  (unsigned int) ace->info.mask, 
+			  (unsigned int)tmp_acc_desired ));
+
+		tmp_acc_desired = check_ace( ace, token, tmp_acc_desired, status);
+		if (NT_STATUS_V(*status)) {
+			*acc_granted = 0;
+			DEBUG(5,("se_access_check: ACE %u denied with status %s.\n", (unsigned int)i, nt_errstr(*status)));
+			return False;
+		}
+	}
+
+	/*
+	 * If there are no more desired permissions left then
+	 * access was allowed.
+	 */
+
+	if (tmp_acc_desired == 0) {
+		*acc_granted = acc_desired;
+		*status = NT_STATUS_OK;
+		DEBUG(5,("se_access_check: access (%x) granted.\n", (unsigned int)acc_desired ));
+		return True;
+	}
+		
+	*acc_granted = 0;
+	*status = NT_STATUS_ACCESS_DENIED;
+	DEBUG(5,("se_access_check: access (%x) denied.\n", (unsigned int)acc_desired ));
+	return False;
+}
+
+/* Create a child security descriptor using another security descriptor as
+   the parent container.  This child object can either be a container or
+   non-container object. */
+
+SEC_DESC_BUF *se_create_child_secdesc(TALLOC_CTX *ctx, SEC_DESC *parent_ctr, 
+				      BOOL child_container)
+{
+	SEC_DESC_BUF *sdb;
+	SEC_DESC *sd;
+	SEC_ACL *new_dacl, *the_acl;
+	SEC_ACE *new_ace_list = NULL;
+	int new_ace_list_ndx = 0, i;
+	size_t size;
+
+	/* Currently we only process the dacl when creating the child.  The
+	   sacl should also be processed but this is left out as sacls are
+	   not implemented in Samba at the moment.*/
+
+	the_acl = parent_ctr->dacl;
+
+	if (!(new_ace_list = talloc(ctx, sizeof(SEC_ACE) * the_acl->num_aces))) 
+		return NULL;
+
+	for (i = 0; the_acl && i < the_acl->num_aces; i++) {
+		SEC_ACE *ace = &the_acl->ace[i];
+		SEC_ACE *new_ace = &new_ace_list[new_ace_list_ndx];
+		uint8 new_flags = 0;
+		BOOL inherit = False;
+		fstring sid_str;
+
+		/* The OBJECT_INHERIT_ACE flag causes the ACE to be
+		   inherited by non-container children objects.  Container
+		   children objects will inherit it as an INHERIT_ONLY
+		   ACE. */
+
+		if (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT) {
+
+			if (!child_container) {
+				new_flags |= SEC_ACE_FLAG_OBJECT_INHERIT;
+			} else {
+				new_flags |= SEC_ACE_FLAG_INHERIT_ONLY;
+			}
+
+			inherit = True;
+		}
+
+		/* The CONAINER_INHERIT_ACE flag means all child container
+		   objects will inherit and use the ACE. */
+
+		if (ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) {
+			if (!child_container) {
+				inherit = False;
+			} else {
+				new_flags |= SEC_ACE_FLAG_CONTAINER_INHERIT;
+			}
+		}
+
+		/* The INHERIT_ONLY_ACE is not used by the se_access_check()
+		   function for the parent container, but is inherited by
+		   all child objects as a normal ACE. */
+
+		if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY) {
+			/* Move along, nothing to see here */
+		}
+
+		/* The SEC_ACE_FLAG_NO_PROPAGATE_INHERIT flag means the ACE
+		   is inherited by child objects but not grandchildren
+		   objects.  We clear the object inherit and container
+		   inherit flags in the inherited ACE. */
+
+		if (ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT) {
+			new_flags &= ~(SEC_ACE_FLAG_OBJECT_INHERIT |
+				       SEC_ACE_FLAG_CONTAINER_INHERIT);
+		}
+
+		/* Add ACE to ACE list */
+
+		if (!inherit)
+			continue;
+
+		init_sec_access(&new_ace->info, ace->info.mask);
+		init_sec_ace(new_ace, &ace->trustee, ace->type,
+			     new_ace->info, new_flags);
+
+		sid_to_string(sid_str, &ace->trustee);
+
+		DEBUG(5, ("se_create_child_secdesc(): %s:%d/0x%02x/0x%08x "
+			  " inherited as %s:%d/0x%02x/0x%08x\n", sid_str,
+			  ace->type, ace->flags, ace->info.mask,
+			  sid_str, new_ace->type, new_ace->flags,
+			  new_ace->info.mask));
+
+		new_ace_list_ndx++;
+	}
+
+	/* Create child security descriptor to return */
+	
+	new_dacl = make_sec_acl(ctx, ACL_REVISION, new_ace_list_ndx, new_ace_list);
+
+	/* Use the existing user and group sids.  I don't think this is
+	   correct.  Perhaps the user and group should be passed in as
+	   parameters by the caller? */
+
+	sd = make_sec_desc(ctx, SEC_DESC_REVISION,
+			   parent_ctr->owner_sid,
+			   parent_ctr->grp_sid,
+			   parent_ctr->sacl,
+			   new_dacl, &size);
+
+	sdb = make_sec_desc_buf(ctx, size, sd);
+
+	return sdb;
+}