usbloadergx/source/libntfs/efs.c

/**
 * efs.c - Limited processing of encrypted files
 *
 *	This module is part of ntfs-3g library
 *
 * Copyright (c)      2009 Martin Bene
 * Copyright (c)      2009-2010 Jean-Pierre Andre
 *
 * This program/include file 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/include file 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 (in the main directory of the NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif

#ifdef HAVE_SETXATTR
#include <sys/xattr.h>
#endif

#ifdef HAVE_SYS_SYSMACROS_H
#include <sys/sysmacros.h>
#endif

#include "types.h"
#include "debug.h"
#include "attrib.h"
#include "inode.h"
#include "dir.h"
#include "efs.h"
#include "index.h"
#include "logging.h"
#include "misc.h"
#include "efs.h"

#ifdef HAVE_SETXATTR	/* extended attributes interface required */

static ntfschar logged_utility_stream_name[] =
{
    const_cpu_to_le16('$'),
    const_cpu_to_le16('E'),
    const_cpu_to_le16('F'),
    const_cpu_to_le16('S'),
    const_cpu_to_le16(0)
};

/*
 *		Get the ntfs EFS info into an extended attribute
 */

int ntfs_get_efs_info(ntfs_inode *ni, char *value, size_t size)
{
    EFS_ATTR_HEADER *efs_info;
    s64 attr_size = 0;

    if (ni)
    {
        if (ni->flags & FILE_ATTR_ENCRYPTED)
        {
            efs_info = (EFS_ATTR_HEADER*)ntfs_attr_readall(ni,
                    AT_LOGGED_UTILITY_STREAM,(ntfschar*)NULL, 0,
                    &attr_size);
            if (efs_info
                    && (le32_to_cpu(efs_info->length) == attr_size))
            {
                if (attr_size <= (s64)size)
                {
                    if (value)
                    memcpy(value,efs_info,attr_size);
                    else
                    {
                        errno = EFAULT;
                        attr_size = 0;
                    }
                }
                else
                if (size)
                {
                    errno = ERANGE;
                    attr_size = 0;
                }
                free (efs_info);
            }
            else
            {
                if (efs_info)
                {
                    free(efs_info);
                    ntfs_log_error("Bad efs_info for inode %lld\n",
                            (long long)ni->mft_no);
                }
                else
                {
                    ntfs_log_error("Could not get efsinfo"
                            " for inode %lld\n",
                            (long long)ni->mft_no);
                }
                errno = EIO;
                attr_size = 0;
            }
        }
        else
        {
            errno = ENODATA;
            ntfs_log_trace("Inode %lld is not encrypted\n",
                    (long long)ni->mft_no);
        }
    }
    return (attr_size ? (int)attr_size : -errno);
}

/*
 *		Fix all encrypted AT_DATA attributes of an inode
 *
 *	The fix may require making an attribute non resident, which
 *	requires more space in the MFT record, and may cause some
 *	attribute to be expelled and the full record to be reorganized.
 *	When this happens, the search for data attributes has to be
 *	reinitialized.
 *
 *	Returns zero if successful.
 *		-1 if there is a problem.
 */

static int fixup_loop(ntfs_inode *ni)
{
    ntfs_attr_search_ctx *ctx;
    ntfs_attr *na;
    ATTR_RECORD *a;
    BOOL restart;
    BOOL first;
    int cnt;
    int maxcnt;
    int res = 0;

    maxcnt = 0;
    do
    {
        restart = FALSE;
        ctx = ntfs_attr_get_search_ctx(ni, NULL);
        if (!ctx)
        {
            ntfs_log_error("Failed to get ctx for efs\n");
            res = -1;
        }
        cnt = 0;
        while (!restart && !res
                && !ntfs_attr_lookup(AT_DATA, NULL, 0,
                        CASE_SENSITIVE, 0, NULL, 0, ctx))
        {
            cnt++;
            a = ctx->attr;
            na = ntfs_attr_open(ctx->ntfs_ino, AT_DATA,
                    (ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)),
                    a->name_length);
            if (!na)
            {
                ntfs_log_error("can't open DATA Attribute\n");
                res = -1;
            }
            if (na && !(ctx->attr->flags & ATTR_IS_ENCRYPTED))
            {
                if (!NAttrNonResident(na)
                        && ntfs_attr_make_non_resident(na, ctx))
                {
                    /*
                     * ntfs_attr_make_non_resident fails if there
                     * is not enough space in the MFT record.
                     * When this happens, force making non-resident
                     * so that some other attribute is expelled.
                     */
                    if (ntfs_attr_force_non_resident(na))
                    {
                        res = -1;
                    }
                    else
                    {
                        /* make sure there is some progress */
                        if (cnt <= maxcnt)
                        {
                            errno = EIO;
                            ntfs_log_error("Multiple failure"
                                    " making non resident\n");
                            res = -1;
                        }
                        else
                        {
                            ntfs_attr_put_search_ctx(ctx);
                            ctx = (ntfs_attr_search_ctx*)NULL;
                            restart = TRUE;
                            maxcnt = cnt;
                        }
                    }
                }
                if (!restart && !res
                        && ntfs_efs_fixup_attribute(ctx, na))
                {
                    ntfs_log_error("Error in efs fixup of AT_DATA Attribute\n");
                    res = -1;
                }
            }
            if (na)
            ntfs_attr_close(na);
        }
        first = FALSE;
    }while (restart && !res);
    if (ctx)
    ntfs_attr_put_search_ctx(ctx);
    return (res);
}

/*
 *		Set the efs data from an extended attribute
 *	Warning : the new data is not checked
 *	Returns 0, or -1 if there is a problem
 */

int ntfs_set_efs_info(ntfs_inode *ni, const char *value, size_t size,
        int flags)

{
    int res;
    int written;
    ntfs_attr *na;
    const EFS_ATTR_HEADER *info_header;

    res = 0;
    if (ni && value && size)
    {
        if (ni->flags & (FILE_ATTR_ENCRYPTED | FILE_ATTR_COMPRESSED))
        {
            if (ni->flags & FILE_ATTR_ENCRYPTED)
            {
                ntfs_log_trace("Inode %lld already encrypted\n",
                        (long long)ni->mft_no);
                errno = EEXIST;
            }
            else
            {
                /*
                 * Possible problem : if encrypted file was
                 * restored in a compressed directory, it was
                 * restored as compressed.
                 * TODO : decompress first.
                 */
                ntfs_log_error("Inode %lld cannot be encrypted and compressed\n",
                        (long long)ni->mft_no);
                errno = EIO;
            }
            return -1;
        }
        info_header = (const EFS_ATTR_HEADER*)value;
        /* make sure we get a likely efsinfo */
        if (le32_to_cpu(info_header->length) != size)
        {
            errno = EINVAL;
            return (-1);
        }
        if (!ntfs_attr_exist(ni,AT_LOGGED_UTILITY_STREAM,
                        (ntfschar*)NULL,0))
        {
            if (!(flags & XATTR_REPLACE))
            {
                /*
                 * no logged_utility_stream attribute : add one,
                 * apparently, this does not feed the new value in
                 */
                res = ntfs_attr_add(ni,AT_LOGGED_UTILITY_STREAM,
                        logged_utility_stream_name,4,
                        (u8*)NULL,(s64)size);
            }
            else
            {
                errno = ENODATA;
                res = -1;
            }
        }
        else
        {
            errno = EEXIST;
            res = -1;
        }
        if (!res)
        {
            /*
             * open and update the existing efs data
             */
            na = ntfs_attr_open(ni, AT_LOGGED_UTILITY_STREAM,
                    logged_utility_stream_name, 4);
            if (na)
            {
                /* resize attribute */
                res = ntfs_attr_truncate(na, (s64)size);
                /* overwrite value if any */
                if (!res && value)
                {
                    written = (int)ntfs_attr_pwrite(na,
                            (s64)0, (s64)size, value);
                    if (written != (s64)size)
                    {
                        ntfs_log_error("Failed to "
                                "update efs data\n");
                        errno = EIO;
                        res = -1;
                    }
                }
                ntfs_attr_close(na);
            }
            else
            res = -1;
        }
        if (!res)
        {
            /* Don't handle AT_DATA Attribute(s) if inode is a directory */
            if (!(ni->mrec->flags & MFT_RECORD_IS_DIRECTORY))
            {
                /* iterate over AT_DATA attributes */
                /* set encrypted flag, truncate attribute to match padding bytes */

                if (fixup_loop(ni))
                return -1;
            }
            ni->flags |= FILE_ATTR_ENCRYPTED;
            NInoSetDirty(ni);
            NInoFileNameSetDirty(ni);
        }
    }
    else
    {
        errno = EINVAL;
        res = -1;
    }
    return (res ? -1 : 0);
}

/*
 *              Fixup raw encrypted AT_DATA Attribute
 *     read padding length from last two bytes
 *     truncate attribute, make non-resident,
 *     set data size to match padding length
 *     set ATTR_IS_ENCRYPTED flag on attribute 
 *
 *	Return 0 if successful
 *		-1 if failed (errno tells why)
 */

int ntfs_efs_fixup_attribute(ntfs_attr_search_ctx *ctx, ntfs_attr *na)
{
    u64 newsize;
    u64 oldsize;
    le16 appended_bytes;
    u16 padding_length;
    ntfs_inode *ni;
    BOOL close_ctx = FALSE;

    if (!na)
    {
        ntfs_log_error("no na specified for efs_fixup_attribute\n");
        goto err_out;
    }
    if (!ctx)
    {
        ctx = ntfs_attr_get_search_ctx(na->ni, NULL);
        if (!ctx)
        {
            ntfs_log_error("Failed to get ctx for efs\n");
            goto err_out;
        }
        close_ctx = TRUE;
        if (ntfs_attr_lookup(AT_DATA, na->name, na->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx))
        {
            ntfs_log_error("attr lookup for AT_DATA attribute failed in efs fixup\n");
            goto err_out;
        }
    }
    else
    {
        if (!NAttrNonResident(na))
        {
            ntfs_log_error("Cannot make non resident"
                    " when a context has been allocated\n");
            goto err_out;
        }
    }

    /* no extra bytes are added to void attributes */
    oldsize = na->data_size;
    if (oldsize)
    {
        /* make sure size is valid for a raw encrypted stream */
        if ((oldsize & 511) != 2)
        {
            ntfs_log_error("Bad raw encrypted stream\n");
            goto err_out;
        }
        /* read padding length from last two bytes of attribute */
        if (ntfs_attr_pread(na, oldsize - 2, 2, &appended_bytes) != 2)
        {
            ntfs_log_error("Error reading padding length\n");
            goto err_out;
        }
        padding_length = le16_to_cpu(appended_bytes);
        if (padding_length > 511 || padding_length > na->data_size-2)
        {
            errno = EINVAL;
            ntfs_log_error("invalid padding length %d for data_size %lld\n",
                    padding_length, (long long)oldsize);
            goto err_out;
        }
        newsize = oldsize - padding_length - 2;
        /*
         * truncate attribute to possibly free clusters allocated
         * for the last two bytes, but do not truncate to new size
         * to avoid losing useful data
         */
        if (ntfs_attr_truncate(na, oldsize - 2))
        {
            ntfs_log_error("Error truncating attribute\n");
            goto err_out;
        }
    }
    else
    newsize = 0;

    /*
     * Encrypted AT_DATA Attributes MUST be non-resident
     * This has to be done after the attribute is resized, as
     * resizing down to zero may cause the attribute to be made
     * resident.
     */
    if (!NAttrNonResident(na)
            && ntfs_attr_make_non_resident(na, ctx))
    {
        if (!close_ctx
                || ntfs_attr_force_non_resident(na))
        {
            ntfs_log_error("Error making DATA attribute non-resident\n");
            goto err_out;
        }
        else
        {
            /*
             * must reinitialize context after forcing
             * non-resident. We need a context for updating
             * the state, and at this point, we are sure
             * the context is not used elsewhere.
             */
            ntfs_attr_reinit_search_ctx(ctx);
            if (ntfs_attr_lookup(AT_DATA, na->name, na->name_len,
                            CASE_SENSITIVE, 0, NULL, 0, ctx))
            {
                ntfs_log_error("attr lookup for AT_DATA attribute failed in efs fixup\n");
                goto err_out;
            }
        }
    }
    ni = na->ni;
    if (!na->name_len)
    {
        ni->data_size = newsize;
        ni->allocated_size = na->allocated_size;
    }
    NInoSetDirty(ni);
    NInoFileNameSetDirty(ni);

    ctx->attr->data_size = cpu_to_le64(newsize);
    if (le64_to_cpu(ctx->attr->initialized_size) > newsize)
    ctx->attr->initialized_size = ctx->attr->data_size;
    ctx->attr->flags |= ATTR_IS_ENCRYPTED;
    if (close_ctx)
    ntfs_attr_put_search_ctx(ctx);

    return (0);
    err_out:
    if (close_ctx && ctx)
    ntfs_attr_put_search_ctx(ctx);
    return (-1);
}

#endif /* HAVE_SETXATTR */