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    Subject[PATCH 3.14 10/21] Revert "ecryptfs: forbid opening files without mmap handler"
    Date
    3.14-stable review patch.  If anyone has any objections, please let me know.

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

    From: Jeff Mahoney <jeffm@suse.com>

    commit 78c4e172412de5d0456dc00d2b34050aa0b683b5 upstream.

    This reverts commit 2f36db71009304b3f0b95afacd8eba1f9f046b87.

    It fixed a local root exploit but also introduced a dependency on
    the lower file system implementing an mmap operation just to open a file,
    which is a bit of a heavy hammer. The right fix is to have mmap depend
    on the existence of the mmap handler instead.

    Signed-off-by: Jeff Mahoney <jeffm@suse.com>
    Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    fs/ecryptfs/kthread.c | 13 ++-----------
    1 file changed, 2 insertions(+), 11 deletions(-)

    --- a/fs/ecryptfs/kthread.c
    +++ b/fs/ecryptfs/kthread.c
    @@ -25,7 +25,6 @@
    #include <linux/slab.h>
    #include <linux/wait.h>
    #include <linux/mount.h>
    -#include <linux/file.h>
    #include "ecryptfs_kernel.h"

    struct ecryptfs_open_req {
    @@ -148,7 +147,7 @@ int ecryptfs_privileged_open(struct file
    flags |= IS_RDONLY(lower_dentry->d_inode) ? O_RDONLY : O_RDWR;
    (*lower_file) = dentry_open(&req.path, flags, cred);
    if (!IS_ERR(*lower_file))
    - goto have_file;
    + goto out;
    if ((flags & O_ACCMODE) == O_RDONLY) {
    rc = PTR_ERR((*lower_file));
    goto out;
    @@ -166,16 +165,8 @@ int ecryptfs_privileged_open(struct file
    mutex_unlock(&ecryptfs_kthread_ctl.mux);
    wake_up(&ecryptfs_kthread_ctl.wait);
    wait_for_completion(&req.done);
    - if (IS_ERR(*lower_file)) {
    + if (IS_ERR(*lower_file))
    rc = PTR_ERR(*lower_file);
    - goto out;
    - }
    -have_file:
    - if ((*lower_file)->f_op->mmap == NULL) {
    - fput(*lower_file);
    - *lower_file = NULL;
    - rc = -EMEDIUMTYPE;
    - }
    out:
    return rc;
    }

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