Messages in this thread | | | Subject | Re: [PATCH v2 2/3] Teach SELinux about anonymous inodes | From | Stephen Smalley <> | Date | Thu, 26 Mar 2020 13:37:36 -0400 |
| |
On 3/25/20 7:02 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 : file uffd_t "[userfaultfd]"; > allow sysadm_t uffd_t:file { create };
These should use :anon_inode rather than :file since the class is no longer file.
> > (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);
You should use isec->sclass == SECCLASS_ANON_INODE instead of SECCLASS_FILE here.
| |