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    Subject[PATCH] ext3: htree entry integrity checking
     This patch adds integrity checking to two htree paths that are missing it.

    Currently, if a corrupted directory entry with rec_len=0 is encountered,
    we still trust that the data is valid. This can cause an infinite loop
    in htree_dirblock_to_tree() since the iteration loop will never make any
    progress.

    I initially had written a ext3_check_htree_entry(), but saw that
    ext3_dir_entry_2 is used for both htree and regular directory entries. Since
    ext3_check_dir_entry() is used for checking ext3_dir_entry_2, I used that.
    Can someone confirm that this is correct? There are other places where
    de->rec_len == 0 is used by itself and I'd be fine doing that too, but I
    figure more integrity checking isn't a bad thing.

    This fixes the problem described at:
    http://projects.info-pull.com/mokb/MOKB-10-11-2006.html

    Signed-off-by: Jeff Mahoney <jeffm@suse.com>

    diff -ruNpX ../dontdiff linux-2.6.18.orig/fs/ext3/namei.c linux-2.6.18.orig.devel/fs/ext3/namei.c
    --- linux-2.6.18.orig/fs/ext3/namei.c 2006-11-09 00:06:37.000000000 -0500
    +++ linux-2.6.18.orig.devel/fs/ext3/namei.c 2006-11-12 20:15:19.000000000 -0500
    @@ -551,6 +551,11 @@ static int htree_dirblock_to_tree(struct
    dir->i_sb->s_blocksize -
    EXT3_DIR_REC_LEN(0));
    for (; de < top; de = ext3_next_entry(de)) {
    + if (!ext3_check_dir_entry(__FUNCTION__, dir, de, bh,
    + (char *)de - bh->b_data)) {
    + brelse(bh);
    + return ERR_BAD_DX_DIR;
    + }
    ext3fs_dirhash(de->name, de->name_len, hinfo);
    if ((hinfo->hash < start_hash) ||
    ((hinfo->hash == start_hash) &&
    @@ -617,6 +622,11 @@ int ext3_htree_fill_tree(struct file *di
    if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
    de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data;
    de = ext3_next_entry(de);
    + if (!ext3_check_dir_entry(__FUNCTION__, dir, de, frames[0].bh,
    + (char *)de - frames[0].bh->b_data)) {
    + err = ERR_BAD_DX_DIR;
    + goto errout;
    + }
    if ((err = ext3_htree_store_dirent(dir_file, 2, 0, de)) != 0)
    goto errout;
    count++;
    --
    Jeff Mahoney
    -
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