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    SubjectRe: [PATCH v4 00/19] LSM: Module stacking for SARA and Landlock
    On 9/24/2018 8:01 AM, Stephen Smalley wrote:
    > On 09/23/2018 01:09 PM, Casey Schaufler wrote:
    >> On 9/23/2018 8:59 AM, Tetsuo Handa wrote:
    >>> On 2018/09/23 11:43, Kees Cook wrote:
    >>>>>> I'm excited about getting this landed!
    >>>>> Soon. Real soon. I hope. I would very much like for
    >>>>> someone from the SELinux camp to chime in, especially on
    >>>>> the selinux_is_enabled() removal.
    >>>> Agreed.
    >>> This patchset from Casey lands before the patchset from Kees, doesn't it?
    >> That is up for negotiation. We may end up combining them.
    >>> OK, a few comments (if I didn't overlook something).
    >>>    lsm_early_cred()/lsm_early_task() are called from only __init functions.
    >> True.
    >>>    lsm_cred_alloc()/lsm_file_alloc() are called from only security/security.c .
    >> Also true.
    >>>    lsm_early_inode() should be avoided because it is not appropriate to
    >>>    call panic() when lsm_early_inode() is called after __init phase.
    >> You're correct. In fact, lsm_early_inode() isn't needed at all
    >> until multiple inode using modules are supported.
    >>>    Since all free hooks are called when one of init hooks failed, each
    >>>    free hook needs to check whether init hook was called. An example is
    >>>    inode_free_security() in security/selinux/hooks.c (but not addressed in
    >>>    this patch).
    >> I *think* that selinux_inode_free_security() is safe in this
    >> case because the blob will be zeroed, hence isec->list will
    >> be NULL.
    > That's not safe - look more closely at what list_empty_careful() tests, and then think about what happens when list_del_init() gets called on that isec->list.  selinux_inode_free_security() presumes that selinux_inode_alloc_security() has been called already.  If you are breaking that assumption, you have to fix it.

    Yup. I misread the macro my first time around. Easy fix.

    > Is there a reason you can't make inode_alloc_security() return void since you moved the allocation to the framework?

    No reason with any of the existing modules, But I could see someone
    doing unnatural things during allocation that might result in a

    > Unfortunate that inode_init_security name is already in use for another purpose since essentially you have reduced these hooks to initialization only.

    I considered that but decided that it makes more sense for the module hook names
    to match the infrastructure name. Having security_inode_alloc() call
    selinux_inode_setup_security() starts to get confusing.

     \ /
      Last update: 2018-09-24 18:15    [W:4.607 / U:0.024 seconds]
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