lkml.org 
[lkml]   [2017]   [Oct]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH 07/27] kexec_file: Disable at runtime if securelevel has been set
    From
    Date
    On Thu, 2017-10-26 at 15:42 +0800, joeyli wrote:
    > Hi Mimi,
    >
    > Thank you for reviewing.
    >
    > On Mon, Oct 23, 2017 at 11:54:43AM -0400, Mimi Zohar wrote:
    > > On Thu, 2017-10-19 at 15:51 +0100, David Howells wrote:
    > > > From: Chun-Yi Lee <joeyli.kernel@gmail.com>
    > > >
    > > > When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image
    > > > through kexec_file systemcall if securelevel has been set.
    > >
    > > The patch title and description needs to be updated to refer to
    > > lockdown, not securelevel.
    > >
    > > As previously mentioned the last time these patches were posted, this
    > > leaves out testing to see if the integrity subsystem is enabled.
    > >
    > > Commit 503ceaef8e2e "ima: define a set of appraisal rules requiring
    > > file signatures" was upstreamed.  An additional patch could force
    > > these rules to be added to the custom policy, if lockdown is enabled.
    > >  This and other patches in this series could then check to see if
    > > is_ima_appraise_enabled() is true.
    > >
    > > Mimi
    > >
    >
    > I have updated the patch title and description, and I also added
    > is_ima_appraise_enabled() as the following. Is it good to you?

    Yes, that works.  Thanks!  Remember is_ima_appraise_enabled() is
    dependent on the "ima: require secure_boot rules in lockdown mode"
    patch - http://kernsec.org/pipermail/linux-security-module-archive/201
    7-October/003910.html.

    The IMA "secure_boot" policy can be specified on the boot command line
    as ima_policy="secure_boot".  It requires kernel modules, firmware,
    kexec kernel image and the IMA custom policy to be signed.  In
    lockdown mode, these rules are enabled by default and added to the
    custom policy.

    > On the other hand, I am not good on IMA. I have traced the code path
    > in kimage_file_prepare_segments(). Looks that the READING_KEXEC_IMAGE
    > doesn't show in selinux_kernel_read_file(). Where is the exact code
    > in IMA for checking the signature when loading crash kernel file?

    kernel_read_file_from_fd() calls the security_kernel_read_file() and
    security_kernel_post_read_file() hooks, which call ima_read_file() and
    ima_post_read_file() respectively.

    Mimi

    \
     
     \ /
      Last update: 2017-10-26 16:19    [W:4.158 / U:0.012 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site