Re: [PATCH v20 05/23] net: Prepare UDS for security module stacking
On Wed, Aug 26, 2020 at 11:07 AM Casey Schaufler <casey(a)schaufler-ca.com> wrote:
Change the data used in UDS SO_PEERSEC processing from a
secid to a more general struct lsmblob. Update the
security_socket_getpeersec_dgram() interface to use the
lsmblob. There is a small amount of scaffolding code
that will come out when the security_secid_to_secctx()
code is brought in line with the lsmblob.
Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com>
---
include/linux/security.h | 7 +++++--
include/net/af_unix.h | 2 +-
include/net/scm.h | 8 +++++---
net/ipv4/ip_sockglue.c | 8 +++++---
net/unix/af_unix.c | 6 +++---
security/security.c | 18 +++++++++++++++---
6 files changed, 34 insertions(+), 15 deletions(-)
...
diff --git a/include/net/af_unix.h b/include/net/af_unix.h
index f42fdddecd41..a86da0cb5ec1 100644
--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -36,7 +36,7 @@ struct unix_skb_parms {
kgid_t gid;
struct scm_fp_list *fp; /* Passed files */
#ifdef CONFIG_SECURITY_NETWORK
- u32 secid; /* Security ID */
+ struct lsmblob lsmblob; /* Security LSM data */
As mentioned in a previous revision, I remain concerned that this is
going to become a problem due to the size limit on unix_skb_parms. I
would need to redo the math to be certain, but if I recall correctly
this would limit us to five LSMs assuming both that we don't need to
grow the per-LSM size of lsmblob *and* the netdev folks don't decide
to add more fields to the unix_skb_parms.
I lost track of that earlier discussion so I'm not sure where it ended
up, but if there is a viable alternative it might be a good idea to
pursue it.
--
paul moore
www.paul-moore.com