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    Subject[PATCH 5.4 25/92] fuse: verify attributes
    Date
    From: Miklos Szeredi <mszeredi@redhat.com>

    commit eb59bd17d2fa6e5e84fba61a5ebdea984222e6d5 upstream.

    If a filesystem returns negative inode sizes, future reads on the file were
    causing the cpu to spin on truncate_pagecache.

    Create a helper to validate the attributes. This now does two things:

    - check the file mode
    - check if the file size fits in i_size without overflowing

    Reported-by: Arijit Banerjee <arijit@rubrik.com>
    Fixes: d8a5ba45457e ("[PATCH] FUSE - core")
    Cc: <stable@vger.kernel.org> # v2.6.14
    Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/fuse/dir.c | 22 ++++++++++++++++------
    fs/fuse/fuse_i.h | 2 ++
    fs/fuse/readdir.c | 2 +-
    3 files changed, 19 insertions(+), 7 deletions(-)

    --- a/fs/fuse/dir.c
    +++ b/fs/fuse/dir.c
    @@ -248,7 +248,8 @@ static int fuse_dentry_revalidate(struct
    kfree(forget);
    if (ret == -ENOMEM)
    goto out;
    - if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
    + if (ret || fuse_invalid_attr(&outarg.attr) ||
    + (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
    goto invalid;

    forget_all_cached_acls(inode);
    @@ -319,6 +320,12 @@ int fuse_valid_type(int m)
    S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
    }

    +bool fuse_invalid_attr(struct fuse_attr *attr)
    +{
    + return !fuse_valid_type(attr->mode) ||
    + attr->size > LLONG_MAX;
    +}
    +
    int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
    struct fuse_entry_out *outarg, struct inode **inode)
    {
    @@ -350,7 +357,7 @@ int fuse_lookup_name(struct super_block
    err = -EIO;
    if (!outarg->nodeid)
    goto out_put_forget;
    - if (!fuse_valid_type(outarg->attr.mode))
    + if (fuse_invalid_attr(&outarg->attr))
    goto out_put_forget;

    *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
    @@ -475,7 +482,8 @@ static int fuse_create_open(struct inode
    goto out_free_ff;

    err = -EIO;
    - if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
    + if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
    + fuse_invalid_attr(&outentry.attr))
    goto out_free_ff;

    ff->fh = outopen.fh;
    @@ -583,7 +591,7 @@ static int create_new_entry(struct fuse_
    goto out_put_forget_req;

    err = -EIO;
    - if (invalid_nodeid(outarg.nodeid))
    + if (invalid_nodeid(outarg.nodeid) || fuse_invalid_attr(&outarg.attr))
    goto out_put_forget_req;

    if ((outarg.attr.mode ^ mode) & S_IFMT)
    @@ -943,7 +951,8 @@ static int fuse_do_getattr(struct inode
    args.out_args[0].value = &outarg;
    err = fuse_simple_request(fc, &args);
    if (!err) {
    - if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
    + if (fuse_invalid_attr(&outarg.attr) ||
    + (inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
    make_bad_inode(inode);
    err = -EIO;
    } else {
    @@ -1564,7 +1573,8 @@ int fuse_do_setattr(struct dentry *dentr
    goto error;
    }

    - if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
    + if (fuse_invalid_attr(&outarg.attr) ||
    + (inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
    make_bad_inode(inode);
    err = -EIO;
    goto error;
    --- a/fs/fuse/fuse_i.h
    +++ b/fs/fuse/fuse_i.h
    @@ -989,6 +989,8 @@ void fuse_ctl_remove_conn(struct fuse_co
    */
    int fuse_valid_type(int m);

    +bool fuse_invalid_attr(struct fuse_attr *attr);
    +
    /**
    * Is current process allowed to perform filesystem operation?
    */
    --- a/fs/fuse/readdir.c
    +++ b/fs/fuse/readdir.c
    @@ -184,7 +184,7 @@ static int fuse_direntplus_link(struct f

    if (invalid_nodeid(o->nodeid))
    return -EIO;
    - if (!fuse_valid_type(o->attr.mode))
    + if (fuse_invalid_attr(&o->attr))
    return -EIO;

    fc = get_fuse_conn(dir);

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