PermissionListSet.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / PermissionListSet.cs / 3 / PermissionListSet.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*==============================================================================
** 
** Class: PermissionListSet.cs 
**
** Purpose: Holds state about A/G/R permissionsets in a callstack or appdomain 
**          (Replacement for PermissionListSet)
**
=============================================================================*/
 
namespace System.Security
{ 
    using System.Globalization; 
    using System.Reflection;
    using System.Runtime.InteropServices; 
    using System.Security;
    using System.Security.Permissions;
    using System.Threading;
    using System.Collections; 

    [Serializable()] 
    sealed internal class PermissionListSet 
    {
        // Only internal (public) methods are creation methods and demand evaluation methods. 
        // Scroll down to the end to see them.
        private PermissionSetTriple m_firstPermSetTriple;
        private ArrayList m_permSetTriples;
        private ArrayList m_zoneList; 
        private ArrayList m_originList;
 
        internal PermissionListSet() {} 

        private void EnsureTriplesListCreated() 
        {
            if (m_permSetTriples == null)
            {
                m_permSetTriples = new ArrayList(); 
                if (m_firstPermSetTriple != null)
                { 
                    m_permSetTriples.Add(m_firstPermSetTriple); 
                    m_firstPermSetTriple = null;
                } 
            }
        }

        internal void UpdateDomainPLS (PermissionListSet adPLS) { 
            if (adPLS != null && adPLS.m_firstPermSetTriple != null)
                UpdateDomainPLS(adPLS.m_firstPermSetTriple.GrantSet, adPLS.m_firstPermSetTriple.RefusedSet); 
        } 

        internal void UpdateDomainPLS (PermissionSet grantSet, PermissionSet deniedSet) { 
            BCLDebug.Assert(m_permSetTriples == null, "m_permSetTriples != null");
            if (m_firstPermSetTriple == null)
                m_firstPermSetTriple = new PermissionSetTriple();
 
            // update the grant and denied sets
            m_firstPermSetTriple.UpdateGrant(grantSet); 
            m_firstPermSetTriple.UpdateRefused(deniedSet); 
        }
 
        private void Terminate(PermissionSetTriple currentTriple)
        {
            UpdateTripleListAndCreateNewTriple(currentTriple, null);
        } 

        private void Terminate(PermissionSetTriple currentTriple, PermissionListSet pls) 
        { 
            this.UpdateZoneAndOrigin(pls);
            this.UpdatePermissions(currentTriple, pls); 
            this.UpdateTripleListAndCreateNewTriple(currentTriple, null);
        }

        private bool Update(PermissionSetTriple currentTriple, PermissionListSet pls) 
        {
            this.UpdateZoneAndOrigin(pls); 
            return this.UpdatePermissions(currentTriple, pls); 
        }
 
        private bool Update(PermissionSetTriple currentTriple, FrameSecurityDescriptor fsd)
        {
           // check imperative
           bool fHalt = Update2(currentTriple, fsd, false); 
           if (!fHalt)
           { 
                // then declarative 
                fHalt = Update2(currentTriple, fsd, true);
           } 
           return fHalt;
        }

        private bool Update2(PermissionSetTriple currentTriple, FrameSecurityDescriptor fsd, bool fDeclarative) 
        {
            // Deny 
            PermissionSet deniedPset = fsd.GetDenials(fDeclarative); 
            if (deniedPset != null)
            { 
                currentTriple.UpdateRefused(deniedPset);
            }

            // permit only 
            PermissionSet permitOnlyPset = fsd.GetPermitOnly(fDeclarative);
            if (permitOnlyPset != null) 
            { 
                currentTriple.UpdateGrant(permitOnlyPset);
            } 

            // Assert all possible
            if (fsd.GetAssertAllPossible())
            { 
                // If we've got no grant set, it means that the only assembly we've seen on the stack so
                // far is mscorlib. Since mscorlib will always be fully trusted, the grant set of the 
                // compressed stack is also FullTrust. 
                if (currentTriple.GrantSet == null)
                    currentTriple.GrantSet = PermissionSet.s_fullTrust; 

                return true; // halt the construction
            }
 
            // Assert
            PermissionSet assertPset = fsd.GetAssertions(fDeclarative); 
            if (assertPset != null) 
            {
                if (assertPset.IsUnrestricted()) 
                {
                    // If we've got no grant set, it means that the only assembly we've seen on the stack so
                    // far is mscorlib. Since mscorlib will always be fully trusted, the grant set of the
                    // compressed stack is also FullTrust. 
                    if (currentTriple.GrantSet == null)
                        currentTriple.GrantSet = PermissionSet.s_fullTrust; 
 
                    return true; // halt the construction
                } 

                PermissionSetTriple retTriple = currentTriple.UpdateAssert(assertPset);
                if (retTriple != null)
                { 
                    EnsureTriplesListCreated();
                    m_permSetTriples.Add(retTriple); 
                } 
            }
 
            return false;
        }
        private void Update(PermissionSetTriple currentTriple, PermissionSet in_g, PermissionSet in_r)
        { 
            ZoneIdentityPermission z;
            UrlIdentityPermission u; 
            currentTriple.UpdateGrant(in_g, out z, out u); 
            currentTriple.UpdateRefused(in_r);
            AppendZoneOrigin(z, u); 
        }

        // Called from the VM for HG CS construction
        private void Update(PermissionSet in_g) 
        {
            if (m_firstPermSetTriple == null) 
                m_firstPermSetTriple = new PermissionSetTriple(); 
            Update(m_firstPermSetTriple, in_g, null);
        } 

        private void UpdateZoneAndOrigin(PermissionListSet pls)
        {
            if (pls != null) 
            {
                if (this.m_zoneList == null && pls.m_zoneList != null && pls.m_zoneList.Count > 0) 
                    this.m_zoneList = new ArrayList(); 
                UpdateArrayList(this.m_zoneList, pls.m_zoneList);
                if (this.m_originList == null && pls.m_originList != null && pls.m_originList.Count > 0) 
                    this.m_originList = new ArrayList();
                UpdateArrayList(this.m_originList, pls.m_originList);
            }
        } 

        private bool UpdatePermissions(PermissionSetTriple currentTriple, PermissionListSet pls) 
        { 
            if (pls != null)
            { 
                if (pls.m_permSetTriples != null)
                {
                    // DCS has an AGR List. So we need to add the AGR List
                    UpdateTripleListAndCreateNewTriple(currentTriple,pls.m_permSetTriples); 
                }
                else 
                { 
                    // Common case: One AGR set
 
                    PermissionSetTriple tmp_psTriple = pls.m_firstPermSetTriple;
                    PermissionSetTriple retTriple;
                    // First try and update currentTriple. Return value indicates if we can stop construction
                    if (currentTriple.Update(tmp_psTriple, out retTriple)) 
                        return true;
                    // If we got a non-null retTriple, what it means is that compression failed, 
                    // and we now have 2 triples to deal with: retTriple and currentTriple. 
                    // retTriple has to be appended first. then currentTriple.
                    if (retTriple != null) 
                    {
                        EnsureTriplesListCreated();
                        // we just created a new triple...add the previous one (returned) to the list
                        m_permSetTriples.Add(retTriple); 
                    }
                } 
            } 
            else
            { 
                // pls can be null only outside the loop in CreateCompressedState
                UpdateTripleListAndCreateNewTriple(currentTriple, null);
            }
 

            return false; 
 
        }
 

        private void UpdateTripleListAndCreateNewTriple(PermissionSetTriple currentTriple, ArrayList tripleList)
        {
            if (!currentTriple.IsEmpty()) 
            {
                if (m_firstPermSetTriple == null && m_permSetTriples == null) 
                { 
                    m_firstPermSetTriple = new PermissionSetTriple(currentTriple);
                } 
                else
                {
                    EnsureTriplesListCreated();
                    m_permSetTriples.Add(new PermissionSetTriple(currentTriple)); 
                }
                currentTriple.Reset(); 
            } 
            if (tripleList != null)
            { 
                EnsureTriplesListCreated();
                m_permSetTriples.AddRange(tripleList);
            }
        } 

        private static void UpdateArrayList(ArrayList current, ArrayList newList) 
        { 
            if (newList == null)
                return; 

            for(int i=0;i < newList.Count; i++)
            {
                if (!current.Contains(newList[i])) 
                    current.Add(newList[i]);
            } 
 
        }
 
        private void AppendZoneOrigin(ZoneIdentityPermission z, UrlIdentityPermission u)
        {

            if (z != null) 
            {
                if (m_zoneList == null) 
                    m_zoneList = new ArrayList(); 
                m_zoneList.Add( z.SecurityZone );
            } 

            if (u != null)
            {
                if (m_originList == null) 
                    m_originList = new ArrayList();
                m_originList.Add( u.Url ); 
            } 
        }
 
[System.Runtime.InteropServices.ComVisible(true)]
        // public(internal) interface begins...
        // Creation functions
        static internal PermissionListSet CreateCompressedState(CompressedStack cs, CompressedStack innerCS) 
        {
            // function that completes the construction of the compressed stack if not done so already (bottom half for demand evaluation) 
 
            bool bHaltConstruction = false;
            if (cs.CompressedStackHandle == null) 
                return null; //  FT case or Security off

            PermissionListSet pls = new PermissionListSet();
            PermissionSetTriple currentTriple = new PermissionSetTriple(); 
            int numDomains = CompressedStack.GetDCSCount(cs.CompressedStackHandle);
            for (int i=numDomains-1; (i >= 0 && !bHaltConstruction) ; i--) 
            { 
                DomainCompressedStack dcs = CompressedStack.GetDomainCompressedStack(cs.CompressedStackHandle, i);
                if (dcs == null) 
                    continue; // we hit a FT Domain
                if (dcs.PLS == null)
                {
                    // We failed on some DCS 
                    throw new SecurityException(String.Format(CultureInfo.InvariantCulture, Environment.GetResourceString("Security_Generic")));
                } 
                pls.UpdateZoneAndOrigin(dcs.PLS); 
                pls.Update(currentTriple, dcs.PLS);
                bHaltConstruction = dcs.ConstructionHalted; 
            }
            if (!bHaltConstruction)
            {
                PermissionListSet tmp_pls = null; 
                // Construction did not halt.
                if (innerCS != null) 
                { 
                    innerCS.CompleteConstruction(null);
                    tmp_pls = innerCS.PLS; 
                }
                pls.Terminate(currentTriple, tmp_pls);
            }
            else 
            {
                pls.Terminate(currentTriple); 
            } 

            return pls; 
        }

        static internal PermissionListSet CreateCompressedState(IntPtr unmanagedDCS, out bool bHaltConstruction)
        { 
            PermissionListSet pls = new PermissionListSet();
            PermissionSetTriple currentTriple = new PermissionSetTriple(); 
 
            PermissionSet tmp_g, tmp_r;
            // Construct the descriptor list 
            int descCount = DomainCompressedStack.GetDescCount(unmanagedDCS);
            bHaltConstruction = false;
            for(int i=0; (i < descCount && !bHaltConstruction); i++)
            { 
                FrameSecurityDescriptor fsd;
                Assembly assembly; 
                if (DomainCompressedStack.GetDescriptorInfo(unmanagedDCS, i, out tmp_g, out tmp_r, out assembly, out fsd)) 
                {
                    // Got an FSD 
                    bHaltConstruction = pls.Update(currentTriple, fsd);
                }
                else
                { 
                    pls.Update(currentTriple, tmp_g, tmp_r);
                } 
 
            }
            if (!bHaltConstruction) 
            {
                // domain
                if (!DomainCompressedStack.IgnoreDomain(unmanagedDCS))
                { 
                    DomainCompressedStack.GetDomainPermissionSets(unmanagedDCS, out tmp_g, out tmp_r);
                    pls.Update(currentTriple, tmp_g, tmp_r); 
                } 
            }
            pls.Terminate(currentTriple); 


            // return the created object
            return pls; 

        } 
        static internal PermissionListSet CreateCompressedState_HG() 
        {
            PermissionListSet pls = new PermissionListSet(); 
            CompressedStack.GetHomogeneousPLS(pls);
            return pls;
        }
 
        // Private Demand evaluation functions - only called from the VM
        internal bool CheckDemandNoThrow(CodeAccessPermission demand) 
        { 
            // AppDomain permissions - no asserts. So there should only be one triple to work with
            BCLDebug.Assert(m_permSetTriples == null && m_firstPermSetTriple != null, "More than one PermissionSetTriple encountered in AD PermissionListSet"); 



            PermissionToken permToken = null; 
            if (demand != null)
                permToken = PermissionToken.GetToken(demand); 
 
            return m_firstPermSetTriple.CheckDemandNoThrow(demand, permToken);
 

        }
        internal bool CheckSetDemandNoThrow(PermissionSet pSet)
        { 
            // AppDomain permissions - no asserts. So there should only be one triple to work with
            BCLDebug.Assert(m_permSetTriples == null && m_firstPermSetTriple != null, "More than one PermissionSetTriple encountered in AD PermissionListSet"); 
 

            return m_firstPermSetTriple.CheckSetDemandNoThrow(pSet); 
        }

        // Demand evauation functions
        internal bool CheckDemand(CodeAccessPermission demand, PermissionToken permToken, RuntimeMethodHandle rmh) 
        {
            bool bRet = SecurityRuntime.StackContinue; 
            if (m_permSetTriples != null) 
            {
                for (int i=0; (i < m_permSetTriples.Count && bRet != SecurityRuntime.StackHalt) ; i++) 
                {

                    PermissionSetTriple psTriple = (PermissionSetTriple)m_permSetTriples[i];
                    bRet = psTriple.CheckDemand(demand, permToken, rmh); 
                }
            } 
            else if (m_firstPermSetTriple != null) 
            {
                bRet = m_firstPermSetTriple.CheckDemand(demand, permToken, rmh); 
            }

            return SecurityRuntime.StackHalt; //  CS demand check always terminates the stackwalk
        } 

        internal bool CheckSetDemand(PermissionSet pset , RuntimeMethodHandle rmh) 
        { 
            bool bRet = SecurityRuntime.StackContinue;
            PermissionSet demandSet = pset; 
            PermissionSet alteredDemandSet;
            if (m_permSetTriples != null)
            {
                for (int i=0; (i < m_permSetTriples.Count && bRet != SecurityRuntime.StackHalt) ; i++) 
                {
 
                    PermissionSetTriple psTriple = (PermissionSetTriple)m_permSetTriples[i]; 
                    bRet = psTriple.CheckSetDemand(demandSet, out alteredDemandSet, rmh);
                    if (alteredDemandSet != null) 
                        demandSet = alteredDemandSet;
                }
            }
            else if (m_firstPermSetTriple != null) 
            {
                bRet = m_firstPermSetTriple.CheckSetDemand(demandSet, out alteredDemandSet, rmh); 
            } 

            return SecurityRuntime.StackHalt; //  CS demand check always terminates the stackwalk 
        }

        /// 
        ///     Check to see if the PLS satisfies a demand for the special permissions encoded in flags 
        /// 
        /// set of flags to check (See PermissionType) 
        private bool CheckFlags(int flags) 
        {
            BCLDebug.Assert(flags != 0, "Invalid permission flag demand"); 

            bool check = true;

            if (m_permSetTriples != null) 
            {
                for (int i = 0; i < m_permSetTriples.Count && check && flags != 0; i++) 
                { 
                    check &= ((PermissionSetTriple)m_permSetTriples[i]).CheckFlags(ref flags);
                } 
            }
            else if (m_firstPermSetTriple != null)
            {
                check = m_firstPermSetTriple.CheckFlags(ref flags); 
            }
 
            return check; 
        }
 
        /// 
        ///     Demand which succeeds if either a set of special permissions or a permission set is granted
        ///     to the call stack
        ///  
        /// set of flags to check (See PermissionType)
        /// alternate permission set to check 
        internal void DemandFlagsOrGrantSet(int flags, PermissionSet grantSet) 
        {
            if (CheckFlags(flags)) 
                return;

            CheckSetDemand(grantSet, new RuntimeMethodHandle());
        } 

        internal void GetZoneAndOrigin(ArrayList zoneList, ArrayList originList, PermissionToken zoneToken, PermissionToken originToken) 
        { 
            if (m_zoneList != null)
                zoneList.AddRange(m_zoneList); 
            if (m_originList != null)
                originList.AddRange(m_originList);
        }
    } 
}

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