ea.c File Reference

#include "ext2fs.h"
#include <linux/ext4_xattr.h>

Include dependency graph for ea.c:

Go to the source code of this file.

Classes
struct	EaIterator

Functions
static int	Ext2IterateAllEa (struct ext4_xattr_ref *xattr_ref, struct ext4_xattr_item *item, BOOL is_last)
NTSTATUS	Ext2QueryEa (IN PEXT2_IRP_CONTEXT IrpContext)
BOOLEAN	Ext2IsEaNameValid (IN OEM_STRING Name)
NTSTATUS	Ext2SetEa (IN PEXT2_IRP_CONTEXT IrpContext)

Function Documentation

Ext2IsEaNameValid()

BOOLEAN Ext2IsEaNameValid

(

IN OEM_STRING

Name

)

Definition at line 389 of file ea.c.

{
    ULONG Index;
    UCHAR Char;

    //
    //  Empty names are not valid
    //

    if (Name.Length == 0)
        return FALSE;

    //
    // Do not allow EA name longer than 255 bytes
    //
    if (Name.Length > 255)
        return FALSE;

    for (Index = 0; Index < (ULONG)Name.Length; Index += 1) {

        Char = Name.Buffer[Index];

        //
        //  Skip over and Dbcs chacters
        //
        if (FsRtlIsLeadDbcsCharacter(Char)) {

            ASSERT(Index != (ULONG)(Name.Length - 1));
            Index += 1;
            continue;
        }

        //
        //  Make sure this character is legal, and if a wild card, that
        //  wild cards are permissible.
        //
        if (!FsRtlIsAnsiCharacterLegalFat(Char, FALSE))
            return FALSE;

    }

    return TRUE;
}

Referenced by Ext2OverwriteEa(), and Ext2SetEa().

Ext2IterateAllEa()

static int Ext2IterateAllEa ( struct ext4_xattr_ref *  xattr_ref, struct ext4_xattr_item *  item, BOOL  is_last  )

static

Definition at line 46 of file ea.c.

{
    struct EaIterator *pEaIterator = xattr_ref->iter_arg;
    ULONG EaEntrySize = 4 + 1 + 1 + 2 + item->name_len + 1 + item->data_size;
    ASSERT(pEaIterator);
    if (!is_last && !pEaIterator->ReturnSingleEntry)
        EaEntrySize = ALIGN_UP(EaEntrySize, ULONG);

    // Start iteration from index specified
    if (pEaIterator->EaIndexCounter < pEaIterator->EaIndex) {
        pEaIterator->EaIndexCounter++;
        return EXT4_XATTR_ITERATE_CONT;
    }
    pEaIterator->EaIndexCounter++;

    if (EaEntrySize > pEaIterator->RemainingUserBufferLength) {
        pEaIterator->OverFlow = TRUE;
        return EXT4_XATTR_ITERATE_STOP;
    }
    pEaIterator->FullEa->NextEntryOffset = 0;
    pEaIterator->FullEa->Flags = 0;
    pEaIterator->FullEa->EaNameLength = (UCHAR)item->name_len;
    pEaIterator->FullEa->EaValueLength = (USHORT)item->data_size;
    RtlCopyMemory(&pEaIterator->FullEa->EaName[0],
        item->name,
        item->name_len);
    RtlCopyMemory(&pEaIterator->FullEa->EaName[0] + item->name_len + 1,
        item->data,
        item->data_size);

    // Link FullEa and LastFullEa together
    if (pEaIterator->LastFullEa) {
        pEaIterator->LastFullEa->NextEntryOffset = (ULONG)
            ((PCHAR)pEaIterator->FullEa - (PCHAR)pEaIterator->LastFullEa);
    }

    pEaIterator->LastFullEa = pEaIterator->FullEa;
    pEaIterator->FullEa = (PFILE_FULL_EA_INFORMATION)
            ((PCHAR)pEaIterator->FullEa + EaEntrySize);
    pEaIterator->RemainingUserBufferLength -= EaEntrySize;

    if (pEaIterator->ReturnSingleEntry)
        return EXT4_XATTR_ITERATE_STOP;

    return EXT4_XATTR_ITERATE_CONT;
}

Referenced by Ext2QueryEa().

Ext2QueryEa()

NTSTATUS Ext2QueryEa

(

IN PEXT2_IRP_CONTEXT

IrpContext

)

Definition at line 94 of file ea.c.

{
    PIRP                Irp = NULL;
    PIO_STACK_LOCATION  IrpSp;

    PDEVICE_OBJECT      DeviceObject;

    PEXT2_VCB           Vcb = NULL;
    PEXT2_FCB           Fcb = NULL;
    PEXT2_CCB           Ccb = NULL;
    PEXT2_MCB           Mcb = NULL;

    PUCHAR  UserEaList;
    ULONG   UserEaListLength;
    ULONG   UserEaIndex;

    BOOLEAN RestartScan;
    BOOLEAN ReturnSingleEntry;
    BOOLEAN IndexSpecified;

    BOOLEAN             MainResourceAcquired = FALSE;
    BOOLEAN             XattrRefAcquired = FALSE;

    NTSTATUS            Status = STATUS_UNSUCCESSFUL;

    struct ext4_xattr_ref xattr_ref;
    PCHAR UserBuffer;

    ULONG UserBufferLength = 0;
    ULONG RemainingUserBufferLength = 0;

    PFILE_FULL_EA_INFORMATION FullEa, LastFullEa = NULL;

    _SEH2_TRY {

        Ccb = IrpContext->Ccb;
        ASSERT(Ccb != NULL);
        ASSERT((Ccb->Identifier.Type == EXT2CCB) &&
            (Ccb->Identifier.Size == sizeof(EXT2_CCB)));
        DeviceObject = IrpContext->DeviceObject;
        Vcb = (PEXT2_VCB)DeviceObject->DeviceExtension;
        Fcb = IrpContext->Fcb;
        Mcb = Fcb->Mcb;
        Irp = IrpContext->Irp;
        IrpSp = IoGetCurrentIrpStackLocation(Irp);

        Irp->IoStatus.Information = 0;

        //
        // Receive input parameter from caller
        //
        UserBuffer = Ext2GetUserBuffer(Irp);
        if (!UserBuffer) {
            Status = STATUS_INSUFFICIENT_RESOURCES;
            _SEH2_LEAVE;
        }
        UserBufferLength = IrpSp->Parameters.QueryEa.Length;
        RemainingUserBufferLength = UserBufferLength;
        UserEaList = IrpSp->Parameters.QueryEa.EaList;
        UserEaListLength = IrpSp->Parameters.QueryEa.EaListLength;
        UserEaIndex = IrpSp->Parameters.QueryEa.EaIndex;
        RestartScan = BooleanFlagOn(IrpSp->Flags, SL_RESTART_SCAN);
        ReturnSingleEntry = BooleanFlagOn(IrpSp->Flags, SL_RETURN_SINGLE_ENTRY);
        IndexSpecified = BooleanFlagOn(IrpSp->Flags, SL_INDEX_SPECIFIED);

        if (!Mcb)
            _SEH2_LEAVE;

        //
        // We do not allow multiple instance gaining EA access to the same file
        //
        if (!ExAcquireResourceExclusiveLite(
            &Fcb->MainResource,
            IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT))) {
            Status = STATUS_PENDING;
            _SEH2_LEAVE;
        }
        MainResourceAcquired = TRUE;

        Status = Ext2WinntError(ext4_fs_get_xattr_ref(IrpContext, Vcb, Fcb->Mcb, &xattr_ref));
        if (!NT_SUCCESS(Status)) {
            DbgPrint("ext4_fs_get_xattr_ref() failed!\n");
            _SEH2_LEAVE;
        }

        FullEa = (PFILE_FULL_EA_INFORMATION)UserBuffer;

        XattrRefAcquired = TRUE;

        if (RemainingUserBufferLength)
            RtlZeroMemory(FullEa, RemainingUserBufferLength);

        if (UserEaList != NULL) {
            int i = 0;
            PFILE_GET_EA_INFORMATION GetEa;
            for (GetEa = (PFILE_GET_EA_INFORMATION)&UserEaList[0];
                    GetEa < (PFILE_GET_EA_INFORMATION)((PUCHAR)UserEaList
                    + UserEaListLength);
                GetEa = (GetEa->NextEntryOffset == 0
                    ? (PFILE_GET_EA_INFORMATION)MAXUINT_PTR
                    : (PFILE_GET_EA_INFORMATION)((PUCHAR)GetEa
                        + GetEa->NextEntryOffset))) {

                size_t ItemSize;
                OEM_STRING Str;
                ULONG EaEntrySize;
                BOOL is_last = !GetEa->NextEntryOffset;

                Str.MaximumLength = Str.Length = GetEa->EaNameLength;
                Str.Buffer = &GetEa->EaName[0];

                //
                // At the moment we only need to know whether the item exists
                // and its size.
                //
                Status = Ext2WinntError(ext4_fs_get_xattr(&xattr_ref,
                    EXT4_XATTR_INDEX_USER,
                    Str.Buffer,
                    Str.Length,
                    NULL,
                    0,
                    &ItemSize));
                if (!NT_SUCCESS(Status))
                    continue;

                //
                //  We were not able to locate the name therefore we must
                //  dummy up a entry for the query.  The needed Ea size is
                //  the size of the name + 4 (next entry offset) + 1 (flags)
                //  + 1 (name length) + 2 (value length) + the name length +
                //  1 (null byte) + Data Size.
                //
                EaEntrySize = 4 + 1 + 1 + 2 + GetEa->EaNameLength + 1 + ItemSize;
                if (!is_last)
                    EaEntrySize = ALIGN_UP(EaEntrySize, ULONG);

                if (EaEntrySize > RemainingUserBufferLength) {

                    Status = i ? STATUS_BUFFER_OVERFLOW : STATUS_BUFFER_TOO_SMALL;
                    _SEH2_LEAVE;
                }
                FullEa->NextEntryOffset = 0;
                FullEa->Flags = 0;
                FullEa->EaNameLength = GetEa->EaNameLength;
                FullEa->EaValueLength = (USHORT)ItemSize;
                RtlCopyMemory(&FullEa->EaName[0],
                    &GetEa->EaName[0],
                    GetEa->EaNameLength);

                //
                // This query must succeed, or is guarenteed to succeed
                // since we are only looking up
                // an EA entry in a in-memory tree structure.
                // Otherwise that means someone might be operating on
                // the xattr_ref without acquiring Inode lock.
                //
                ASSERT(NT_SUCCESS(Ext2WinntError(
                    ext4_fs_get_xattr(&xattr_ref,
                        EXT4_XATTR_INDEX_USER,
                        Str.Buffer,
                        Str.Length,
                        &FullEa->EaName[0] + FullEa->EaNameLength + 1,
                        ItemSize,
                        &ItemSize
                ))));
                FullEa->EaValueLength = (USHORT)ItemSize;

                // Link FullEa and LastFullEa together
                if (LastFullEa)
                    LastFullEa->NextEntryOffset = (ULONG)((PCHAR)FullEa - 
                                                          (PCHAR)LastFullEa);

                LastFullEa = FullEa;
                FullEa = (PFILE_FULL_EA_INFORMATION)
                    ((PCHAR)FullEa + EaEntrySize);
                RemainingUserBufferLength -= EaEntrySize;
                i++;
            }
        } else if (IndexSpecified) {
            struct EaIterator EaIterator;
            //
            //  The user supplied an index into the Ea list.
            //
            if (RemainingUserBufferLength)
                RtlZeroMemory(FullEa, RemainingUserBufferLength);

            EaIterator.OverFlow = FALSE;
            EaIterator.RemainingUserBufferLength = UserBufferLength;
            // In this case, return only an entry.
            EaIterator.ReturnSingleEntry = TRUE;
            EaIterator.FullEa = (PFILE_FULL_EA_INFORMATION)UserBuffer;
            EaIterator.LastFullEa = NULL;
            EaIterator.UserBufferLength = UserBufferLength;
            EaIterator.EaIndex = UserEaIndex;
            EaIterator.EaIndexCounter = 1;

            xattr_ref.iter_arg = &EaIterator;
            ext4_fs_xattr_iterate(&xattr_ref, Ext2IterateAllEa);

            RemainingUserBufferLength = EaIterator.RemainingUserBufferLength;

            Status = STATUS_SUCCESS;

            // It seems that the item isn't found
            if (RemainingUserBufferLength == UserBufferLength)
                Status = STATUS_OBJECTID_NOT_FOUND;

            if (EaIterator.OverFlow) {
                if (RemainingUserBufferLength == UserBufferLength)
                    Status = STATUS_BUFFER_TOO_SMALL;
                else
                    Status = STATUS_BUFFER_OVERFLOW;
            }

        } else {
            struct EaIterator EaIterator;
            //
            //  Else perform a simple scan, taking into account the restart
            //  flag and the position of the next Ea stored in the Ccb.
            //
            if (RestartScan)
                Ccb->EaIndex = 1;

            if (RemainingUserBufferLength)
                RtlZeroMemory(FullEa, RemainingUserBufferLength);

            EaIterator.OverFlow = FALSE;
            EaIterator.RemainingUserBufferLength = UserBufferLength;
            EaIterator.ReturnSingleEntry = ReturnSingleEntry;
            EaIterator.FullEa = (PFILE_FULL_EA_INFORMATION)UserBuffer;
            EaIterator.LastFullEa = NULL;
            EaIterator.UserBufferLength = UserBufferLength;
            EaIterator.EaIndex = Ccb->EaIndex;
            EaIterator.EaIndexCounter = 1;

            xattr_ref.iter_arg = &EaIterator;
            ext4_fs_xattr_iterate(&xattr_ref, Ext2IterateAllEa);

            RemainingUserBufferLength = EaIterator.RemainingUserBufferLength;

            if (Ccb->EaIndex < EaIterator.EaIndexCounter)
                Ccb->EaIndex = EaIterator.EaIndexCounter;

            Status = STATUS_SUCCESS;

            if (EaIterator.OverFlow) {
                if (RemainingUserBufferLength == UserBufferLength)
                    Status = STATUS_BUFFER_TOO_SMALL;
                else
                    Status = STATUS_BUFFER_OVERFLOW;
            }

        }
    }
    _SEH2_FINALLY {

        if (XattrRefAcquired) {
            if (!NT_SUCCESS(Status)) {
                xattr_ref.dirty = FALSE;
                ext4_fs_put_xattr_ref(&xattr_ref);
            }
            else
                Status = Ext2WinntError(ext4_fs_put_xattr_ref(&xattr_ref));
        }

        if (MainResourceAcquired) {
            ExReleaseResourceLite(&Fcb->MainResource);
        }

        if (NT_SUCCESS(Status)) {
            Ext2NotifyReportChange(
                IrpContext,
                Vcb,
                Mcb,
                FILE_NOTIFY_CHANGE_EA,
                FILE_ACTION_MODIFIED);
            Irp->IoStatus.Information = UserBufferLength - RemainingUserBufferLength;
        }

        if (!_SEH2_AbnormalTermination()) {
            if (Status == STATUS_PENDING || Status == STATUS_CANT_WAIT) {
                Status = Ext2QueueRequest(IrpContext);
            }
            else {
                Ext2CompleteIrpContext(IrpContext, Status);
            }
        }
    } _SEH2_END;

    return Status;
}

Referenced by Ext2DispatchRequest().

Ext2SetEa()

NTSTATUS Ext2SetEa

(

IN PEXT2_IRP_CONTEXT

IrpContext

)

Definition at line 436 of file ea.c.

{
    PIRP                Irp = NULL;
    PIO_STACK_LOCATION  IrpSp;

    PDEVICE_OBJECT      DeviceObject;

    PEXT2_VCB           Vcb = NULL;
    PEXT2_FCB           Fcb = NULL;
    PEXT2_CCB           Ccb = NULL;
    PEXT2_MCB           Mcb = NULL;

    BOOLEAN             MainResourceAcquired = FALSE;
    BOOLEAN             FcbLockAcquired = FALSE;
    BOOLEAN             XattrRefAcquired = FALSE;

    NTSTATUS            Status = STATUS_UNSUCCESSFUL;

    struct ext4_xattr_ref xattr_ref;
    PCHAR UserBuffer;
    ULONG UserBufferLength;

    PFILE_FULL_EA_INFORMATION FullEa;

    _SEH2_TRY {

        Ccb = IrpContext->Ccb;
        ASSERT(Ccb != NULL);
        ASSERT((Ccb->Identifier.Type == EXT2CCB) &&
            (Ccb->Identifier.Size == sizeof(EXT2_CCB)));
        DeviceObject = IrpContext->DeviceObject;
        Vcb = (PEXT2_VCB)DeviceObject->DeviceExtension;
        Fcb = IrpContext->Fcb;
        Mcb = Fcb->Mcb;
        Irp = IrpContext->Irp;
        IrpSp = IoGetCurrentIrpStackLocation(Irp);

        Irp->IoStatus.Information = 0;

        //
        // Receive input parameter from caller
        //
        UserBufferLength = IrpSp->Parameters.SetEa.Length;
        UserBuffer = Irp->UserBuffer;

        // Check if the EA buffer provided is valid
        Status = IoCheckEaBufferValidity((PFILE_FULL_EA_INFORMATION)UserBuffer,
            UserBufferLength,
            (PULONG)&Irp->IoStatus.Information);
        if (!NT_SUCCESS(Status))
            _SEH2_LEAVE;

        ExAcquireResourceExclusiveLite(&Vcb->FcbLock, TRUE);
        FcbLockAcquired = TRUE;

        if (!Mcb)
            _SEH2_LEAVE;

        //
        // We do not allow multiple instance gaining EA access to the same file
        //
        if (!ExAcquireResourceExclusiveLite(
            &Fcb->MainResource,
            IsFlagOn(IrpContext->Flags, IRP_CONTEXT_FLAG_WAIT))) {
            Status = STATUS_PENDING;
            _SEH2_LEAVE;
        }
        MainResourceAcquired = TRUE;

        Status = Ext2WinntError(ext4_fs_get_xattr_ref(IrpContext, Vcb, Fcb->Mcb, &xattr_ref));
        if (!NT_SUCCESS(Status)) {
            DbgPrint("ext4_fs_get_xattr_ref() failed!\n");
            _SEH2_LEAVE;
        }

        XattrRefAcquired = TRUE;

        //
        // Remove all existing EA entries.
        //
        ext4_xattr_purge_items(&xattr_ref);
        xattr_ref.dirty = TRUE;
        Status = STATUS_SUCCESS;

        // Iterate the whole EA buffer to do inspection
        for (FullEa = (PFILE_FULL_EA_INFORMATION)UserBuffer;
            FullEa < (PFILE_FULL_EA_INFORMATION)&UserBuffer[UserBufferLength];
            FullEa = (PFILE_FULL_EA_INFORMATION)(FullEa->NextEntryOffset == 0 ?
                &UserBuffer[UserBufferLength] :
                (PCHAR)FullEa + FullEa->NextEntryOffset)) {

            OEM_STRING EaName;

            EaName.MaximumLength = EaName.Length = FullEa->EaNameLength;
            EaName.Buffer = &FullEa->EaName[0];

            // Check if EA's name is valid
            if (!Ext2IsEaNameValid(EaName)) {
                Irp->IoStatus.Information = (PCHAR)FullEa - UserBuffer;
                Status = STATUS_INVALID_EA_NAME;
                _SEH2_LEAVE;
            }
        }

        // Now add EA entries to the inode
        for (FullEa = (PFILE_FULL_EA_INFORMATION)UserBuffer;
            FullEa < (PFILE_FULL_EA_INFORMATION)&UserBuffer[UserBufferLength];
            FullEa = (PFILE_FULL_EA_INFORMATION)(FullEa->NextEntryOffset == 0 ?
                &UserBuffer[UserBufferLength] :
                (PCHAR)FullEa + FullEa->NextEntryOffset)) {

                int ret;
                OEM_STRING EaName;

                EaName.MaximumLength = EaName.Length = FullEa->EaNameLength;
                EaName.Buffer = &FullEa->EaName[0];

                Status = Ext2WinntError(ret =
                    ext4_fs_set_xattr_ordered(&xattr_ref,
                        EXT4_XATTR_INDEX_USER,
                        EaName.Buffer,
                        EaName.Length,
                        &FullEa->EaName[0] + FullEa->EaNameLength + 1,
                        FullEa->EaValueLength));
                if (!NT_SUCCESS(Status))
                    _SEH2_LEAVE;

        }
    } _SEH2_FINALLY {

        if (XattrRefAcquired) {
            if (!NT_SUCCESS(Status)) {
                xattr_ref.dirty = FALSE;
                ext4_fs_put_xattr_ref(&xattr_ref);
            } else
                Status = Ext2WinntError(ext4_fs_put_xattr_ref(&xattr_ref));
        }

        if (FcbLockAcquired) {
            ExReleaseResourceLite(&Vcb->FcbLock);
            FcbLockAcquired = FALSE;
        }

        if (MainResourceAcquired) {
            ExReleaseResourceLite(&Fcb->MainResource);
        }

        if (NT_SUCCESS(Status)) {
            Ext2NotifyReportChange(
                IrpContext,
                Vcb,
                Mcb,
                FILE_NOTIFY_CHANGE_EA,
                FILE_ACTION_MODIFIED);
        }

        if (!_SEH2_AbnormalTermination()) {
            if (Status == STATUS_PENDING || Status == STATUS_CANT_WAIT) {
                Status = Ext2QueueRequest(IrpContext);
            }
            else {
                Ext2CompleteIrpContext(IrpContext, Status);
            }
        }
    } _SEH2_END;
    return Status;
}

Referenced by Ext2DispatchRequest().