lkml.org 
[lkml]   [2020]   [Mar]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 2/3] Teach SELinux about anonymous inodes
From
Date
On 3/26/20 2:14 PM, Daniel Colascione wrote:
> This change uses the anon_inodes and LSM infrastructure introduced in
> the previous patch to give SELinux the ability to control
> anonymous-inode files that are created using the new _secure()
> anon_inodes functions.
>
> A SELinux policy author detects and controls these anonymous inodes by
> adding a name-based type_transition rule that assigns a new security
> type to anonymous-inode files created in some domain. The name used
> for the name-based transition is the name associated with the
> anonymous inode for file listings --- e.g., "[userfaultfd]" or
> "[perf_event]".
>
> Example:
>
> type uffd_t;
> type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]";
> allow sysadm_t uffd_t:anon_inode { create };
>
> (The next patch in this series is necessary for making userfaultfd
> support this new interface. The example above is just
> for exposition.)
>
> Signed-off-by: Daniel Colascione <dancol@google.com>
> ---
> security/selinux/hooks.c | 54 +++++++++++++++++++++++++++++
> security/selinux/include/classmap.h | 2 ++
> 2 files changed, 56 insertions(+)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 1659b59fb5d7..b9eb45c2e4e5 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2915,6 +2915,59 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
> return 0;
> }
>
> +static int selinux_inode_init_security_anon(struct inode *inode,
> + const struct qstr *name,
> + const struct file_operations *fops,
> + const struct inode *context_inode)
> +{
> + const struct task_security_struct *tsec = selinux_cred(current_cred());
> + struct common_audit_data ad;
> + struct inode_security_struct *isec;
> + int rc;
> +
> + if (unlikely(!selinux_state.initialized))
> + return 0;
> +
> + isec = selinux_inode(inode);
> +
> + /*
> + * We only get here once per ephemeral inode. The inode has
> + * been initialized via inode_alloc_security but is otherwise
> + * untouched.
> + */
> +
> + if (context_inode) {
> + struct inode_security_struct *context_isec =
> + selinux_inode(context_inode);
> + isec->sclass = context_isec->sclass;
> + isec->sid = context_isec->sid;
> + } else {
> + isec->sclass = SECCLASS_ANON_INODE;
> + rc = security_transition_sid(
> + &selinux_state, tsec->sid, tsec->sid,
> + SECCLASS_FILE, name, &isec->sid);

I guess you missed the 2nd comment in my reply to v2 of this patch:
You should use isec->sclass aka SECCLASS_ANON_INODE instead of
SECCLASS_FILE here.

\
 
 \ /
  Last update: 2020-03-26 20:09    [W:0.072 / U:22.080 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site