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    Subject[ 04/91] vfs: make AIO use the proper rw_verify_area() area helpers
    3.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Linus Torvalds <torvalds@linux-foundation.org>

    commit a70b52ec1aaeaf60f4739edb1b422827cb6f3893 upstream.

    We had for some reason overlooked the AIO interface, and it didn't use
    the proper rw_verify_area() helper function that checks (for example)
    mandatory locking on the file, and that the size of the access doesn't
    cause us to overflow the provided offset limits etc.

    Instead, AIO did just the security_file_permission() thing (that
    rw_verify_area() also does) directly.

    This fixes it to do all the proper helper functions, which not only
    means that now mandatory file locking works with AIO too, we can
    actually remove lines of code.

    Reported-by: Manish Honap <manish_honap_vit@yahoo.co.in>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/aio.c | 30 ++++++++++++++----------------
    1 file changed, 14 insertions(+), 16 deletions(-)

    --- a/fs/aio.c
    +++ b/fs/aio.c
    @@ -1456,6 +1456,10 @@ static ssize_t aio_setup_vectored_rw(int
    if (ret < 0)
    goto out;

    + ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret);
    + if (ret < 0)
    + goto out;
    +
    kiocb->ki_nr_segs = kiocb->ki_nbytes;
    kiocb->ki_cur_seg = 0;
    /* ki_nbytes/left now reflect bytes instead of segs */
    @@ -1467,11 +1471,17 @@ out:
    return ret;
    }

    -static ssize_t aio_setup_single_vector(struct kiocb *kiocb)
    +static ssize_t aio_setup_single_vector(int type, struct file * file, struct kiocb *kiocb)
    {
    + int bytes;
    +
    + bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left);
    + if (bytes < 0)
    + return bytes;
    +
    kiocb->ki_iovec = &kiocb->ki_inline_vec;
    kiocb->ki_iovec->iov_base = kiocb->ki_buf;
    - kiocb->ki_iovec->iov_len = kiocb->ki_left;
    + kiocb->ki_iovec->iov_len = bytes;
    kiocb->ki_nr_segs = 1;
    kiocb->ki_cur_seg = 0;
    return 0;
    @@ -1496,10 +1506,7 @@ static ssize_t aio_setup_iocb(struct kio
    if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
    kiocb->ki_left)))
    break;
    - ret = security_file_permission(file, MAY_READ);
    - if (unlikely(ret))
    - break;
    - ret = aio_setup_single_vector(kiocb);
    + ret = aio_setup_single_vector(READ, file, kiocb);
    if (ret)
    break;
    ret = -EINVAL;
    @@ -1514,10 +1521,7 @@ static ssize_t aio_setup_iocb(struct kio
    if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
    kiocb->ki_left)))
    break;
    - ret = security_file_permission(file, MAY_WRITE);
    - if (unlikely(ret))
    - break;
    - ret = aio_setup_single_vector(kiocb);
    + ret = aio_setup_single_vector(WRITE, file, kiocb);
    if (ret)
    break;
    ret = -EINVAL;
    @@ -1528,9 +1532,6 @@ static ssize_t aio_setup_iocb(struct kio
    ret = -EBADF;
    if (unlikely(!(file->f_mode & FMODE_READ)))
    break;
    - ret = security_file_permission(file, MAY_READ);
    - if (unlikely(ret))
    - break;
    ret = aio_setup_vectored_rw(READ, kiocb, compat);
    if (ret)
    break;
    @@ -1542,9 +1543,6 @@ static ssize_t aio_setup_iocb(struct kio
    ret = -EBADF;
    if (unlikely(!(file->f_mode & FMODE_WRITE)))
    break;
    - ret = security_file_permission(file, MAY_WRITE);
    - if (unlikely(ret))
    - break;
    ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
    if (ret)
    break;



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