linux/security/selinux
Christian Brauner 1bdeb21862
selinux: implement get, set and remove acl hook
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

So far posix acls were passed as a void blob to the security and
integrity modules. Some of them like evm then proceed to interpret the
void pointer and convert it into the kernel internal struct posix acl
representation to perform their integrity checking magic. This is
obviously pretty problematic as that requires knowledge that only the
vfs is guaranteed to have and has lead to various bugs. Add a proper
security hook for setting posix acls and pass down the posix acls in
their appropriate vfs format instead of hacking it through a void
pointer stored in the uapi format.

I spent considerate time in the security module infrastructure and
audited all codepaths. SELinux has no restrictions based on the posix
acl values passed through it. The capability hook doesn't need to be
called either because it only has restrictions on security.* xattrs. So
these are all fairly simply hooks for SELinux.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:28 +02:00
..
include lsm/stable-6.1 PR 20221003 2022-10-03 17:51:52 -07:00
ss selinux: declare read-only parameters const 2022-08-30 17:14:36 -04:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
avc.c selinux: declare data arrays const 2022-05-03 15:53:49 -04:00
hooks.c selinux: implement get, set and remove acl hook 2022-10-20 10:13:28 +02:00
ibpkey.c selinux: various sparse fixes 2022-02-01 19:08:28 -05:00
ima.c selinux/stable-5.18 PR 20220321 2022-03-21 20:47:54 -07:00
Kconfig Documentation,selinux: deprecate setting checkreqprot to 1 2020-02-10 10:49:01 -05:00
Makefile selinux: include a consumer of the new IMA critical data hook 2021-01-14 23:41:46 -05:00
netif.c selinux: remove unused global variables 2021-01-12 09:49:01 -05:00
netlabel.c security: pass asoc to sctp_assoc_request and sctp_sk_clone 2021-11-03 11:09:20 +00:00
netlink.c selinux: mark some global variables __ro_after_init 2021-01-12 10:08:55 -05:00
netnode.c selinux: various sparse fixes 2022-02-01 19:08:28 -05:00
netport.c selinux: various sparse fixes 2022-02-01 19:08:28 -05:00
nlmsgtab.c selinux: resolve checkpatch errors 2022-05-03 13:59:15 -04:00
selinuxfs.c selinux: use int arrays for boolean values 2022-08-30 17:03:33 -04:00
status.c selinux: move status variables out of selinux_ss 2020-02-10 10:49:01 -05:00
xfrm.c selinux: use correct type for context length 2022-02-18 10:45:54 -05:00