CAS Policy for Sharepoint Application Page

sharepoint

I have an application page that I am creating in SharePoint to host in the LAYOUTS directory. The web project reference an external Assembly that access the file system to get files from a external file share.

My problem is that I want to deploy the assembly to the application BIN directory (not GAC) and use a CAS permission policy to allow it to execute within SharePoint. However, at this point, whenever I deploy the page I get this exception:

Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

I know that the issue is CAS-related, as it works fine when I deploy to the GAC.

My current CAS permissions look like this:

<SecurityClasses>
    <SecurityClass Name="AllMembershipCondition" Description="System.Security.Policy.AllMembershipCondition, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="AspNetHostingPermission" Description="System.Web.AspNetHostingPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="FirstMatchCodeGroup" Description="System.Security.Policy.FirstMatchCodeGroup, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="NamedPermissionSet" Description="System.Security.NamedPermissionSet"/>
    <SecurityClass Name="SecurityPermission" Description="System.Security.Permissions.SecurityPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="StrongNameMembershipCondition" Description="System.Security.Policy.StrongNameMembershipCondition, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="UnionCodeGroup" Description="System.Security.Policy.UnionCodeGroup, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="UrlMembershipCondition" Description="System.Security.Policy.UrlMembershipCondition, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="WebPartPermission" Description="Microsoft.SharePoint.Security.WebPartPermission, Microsoft.SharePoint.Security, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c"/>
    <SecurityClass Name="ZoneMembershipCondition" Description="System.Security.Policy.ZoneMembershipCondition, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="SharePointPermission" Description="Microsoft.SharePoint.Security.SharePointPermission, Microsoft.SharePoint.Security, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
    <SecurityClass Name="FileIOPermission" Description="System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
    <SecurityClass Name="EnvironmentPermission" Description="System.Security.Permissions.EnvironmentPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
</SecurityClasses>
<NamedPermissionSets>
    <PermissionSet
            class="NamedPermissionSet"
            version="1"
            Unrestricted="true"
            Name="FullTrust"
            Description="Allows full access to all resources"
    />
    <PermissionSet
            class="NamedPermissionSet"
            version="1"
            Name="Nothing"
            Description="Denies all resources, including the right to execute"
    />
    <PermissionSet
            class="NamedPermissionSet"
            version="1"
            Name="SPRestricted">
        <IPermission 
                class="AspNetHostingPermission"
                version="1"
                Level="Minimal"
        />
        <IPermission 
                class="SecurityPermission"
                version="1"
                Flags="Execution"
        />
        <IPermission class="WebPartPermission"
                version="1"
                Connections="True"
        />
    </PermissionSet>
    <PermissionSet
            class="NamedPermissionSet"
            version="1"
            Name="CustomTrust">
        <IPermission 
                class="AspNetHostingPermission"
                version="1"
                Level="Medium"
        />                        
        <IPermission class="WebPartPermission"
                version="1"
                Connections="True"
        />
        <IPermission class="SharePointPermission" 
                version="1" 
                ObjectModel="True" />
        <IPermission
                class="FileIOPermission"
                version="1"
                Unrestricted="true"                             
                Read="$AppDir$"
                Write="$AppDir$"
                Append="$AppDir$"
                PathDiscovery="$AppDir$"                                
        />                      
        <IPermission 
                class="SecurityPermission"
                version="1"
                Flags="Assertion, Execution, ControlThread, ControlPrincipal, RemotingConfiguration, ControlEvidence, UnmanagedCode"
                Unrestricted="true"
        />
        <IPermission
                class="EnvironmentPermission"
                version="1"
                Unrestricted="true"
        />
    </PermissionSet>
</NamedPermissionSets>
<CodeGroup 
        class="FirstMatchCodeGroup"
        version="1"
        PermissionSetName="Nothing">
    <IMembershipCondition 
            class="AllMembershipCondition"
            version="1"
    />
<CodeGroup class="UnionCodeGroup" 
    version="1" 
    PermissionSetName="CustomTrust">
    <IMembershipCondition class="StrongNameMembershipCondition" 
        version="1" 
        PublicKeyBlob="0x00240000048000009400000006020000002400005253413100040000010001002B54E7863E7D5443ACBF8DD7F18B9D2399FF73AE7C791BDEFA2BF7544DFB5B8DBB5C8DD705374386CD6A729C755ED4478CD9FA0FF912385FA1AE684345E82E793262A2DCEE1DEC1178BE488C18D338CFE62BCC1C06E4B235BBB6A886884889FC854F8CFA149DFCD18CC479229F0956E19A1DC9FDECAE844F850C2A34121546B8" 
        Name="ConteoPolicy" /> 
    </CodeGroup>
<CodeGroup 
            class="UnionCodeGroup"
            version="1"
            PermissionSetName="FullTrust">
        <IMembershipCondition 
                class="UrlMembershipCondition"
                version="1"
                Url="$AppDirUrl$/_app_bin/*"
        />
    </CodeGroup>
    <CodeGroup 
            class="UnionCodeGroup"
            version="1"
            PermissionSetName="SPRestricted">
        <IMembershipCondition 
                class="UrlMembershipCondition"
                version="1"
                Url="$AppDirUrl$/*"
        />
    </CodeGroup>
    <CodeGroup 
            class="UnionCodeGroup"
            version="1"
            PermissionSetName="FullTrust">
        <IMembershipCondition 
                class="UrlMembershipCondition"
                version="1"
                Url="$CodeGen$/*"
        />
    </CodeGroup>
    <CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="Nothing">
        <IMembershipCondition 
            class="ZoneMembershipCondition"
            version="1"
            Zone="MyComputer" />
        <CodeGroup
                class="UnionCodeGroup"
                version="1"
                PermissionSetName="FullTrust"
                Name="Microsoft_Strong_Name"
                Description="This code group grants code signed with the Microsoft strong name full trust. ">
            <IMembershipCondition
                    class="StrongNameMembershipCondition"
                    version="1"
                    PublicKeyBlob="002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293"
            />
        </CodeGroup>
        <CodeGroup
                class="UnionCodeGroup"
                version="1"
                PermissionSetName="FullTrust"
                Name="Ecma_Strong_Name"
                Description="This code group grants code signed with the ECMA strong name full trust. ">
            <IMembershipCondition
                    class="StrongNameMembershipCondition"
                    version="1"
                    PublicKeyBlob="00000000000000000400000000000000"
            />
        </CodeGroup>
    </CodeGroup>
</CodeGroup>

I used the permcalc tool available from Microsoft on my assembly and added the permissions that it discovered, but the issue was not resolved.

Has anyone ever have this problem deploying application pages in Bin folder?

Best Answer

I prefer to deploy to the bin folder but have had issues specifiying the required permissions.

This approach works well and grants your assembly full trust while still located in the bin folder.

http://blog.tylerholmes.com/2008/11/creating-custom-cas-policy-file-for.html

Unfortunalty it's a manual process.

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