| Message ID | 156710348066.10009.17986469867635955040.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Keyrings, Block and USB notifications [ver #6] | expand |
On 8/29/19 2:31 PM, David Howells wrote: > Implement the watch_key security hook to make sure that a key grants the > caller View permission in order to set a watch on a key. > > For the moment, the watch_devices security hook is left unimplemented as > it's not obvious what the object should be since the queue is global and > didn't previously exist. > > Signed-off-by: David Howells <dhowells@redhat.com> > --- > > security/selinux/hooks.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 74dd46de01b6..371f2ebc879b 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -6533,6 +6533,20 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer) > *_buffer = context; > return rc; > } > + > +#ifdef CONFIG_KEY_NOTIFICATIONS > +static int selinux_watch_key(struct watch *watch, struct key *key) > +{ > + struct key_security_struct *ksec; > + u32 sid; > + > + sid = cred_sid(watch->cred); Can watch->cred ever differ from current's cred here? If not, why can't we just use current_sid() here and why do we need the watch object at all? > + ksec = key->security; > + > + return avc_has_perm(&selinux_state, > + sid, ksec->sid, SECCLASS_KEY, KEY_NEED_VIEW, NULL); > +} > +#endif > #endif > > #ifdef CONFIG_SECURITY_INFINIBAND > @@ -6965,6 +6979,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { > LSM_HOOK_INIT(key_free, selinux_key_free), > LSM_HOOK_INIT(key_permission, selinux_key_permission), > LSM_HOOK_INIT(key_getsecurity, selinux_key_getsecurity), > +#ifdef CONFIG_KEY_NOTIFICATIONS > + LSM_HOOK_INIT(watch_key, selinux_watch_key), > +#endif > #endif > > #ifdef CONFIG_AUDIT >
Stephen Smalley <sds@tycho.nsa.gov> wrote: > Can watch->cred ever differ from current's cred here? If not, why can't we > just use current_sid() here Um. Not currently. I'm not sure whether its ever likely to be otherwise. Probably we could just use that and fix it up later if we do find otherwise. > and why do we need the watch object at all? It carries more than just the creds for the caller of keyctl_watch_key(), it also carries information about the queue to which notifications will be written, including the creds that were active when that was set up. Note that there's no requirement that the process that opened /dev/watch_queue be the one that sets the watch. In the keyutils testsuite, I 'leak' a file descriptor from the session wrangler into the program that it runs so that tests running inside the test script can add watches to it. David
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 74dd46de01b6..371f2ebc879b 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -6533,6 +6533,20 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer) *_buffer = context; return rc; } + +#ifdef CONFIG_KEY_NOTIFICATIONS +static int selinux_watch_key(struct watch *watch, struct key *key) +{ + struct key_security_struct *ksec; + u32 sid; + + sid = cred_sid(watch->cred); + ksec = key->security; + + return avc_has_perm(&selinux_state, + sid, ksec->sid, SECCLASS_KEY, KEY_NEED_VIEW, NULL); +} +#endif #endif #ifdef CONFIG_SECURITY_INFINIBAND @@ -6965,6 +6979,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(key_free, selinux_key_free), LSM_HOOK_INIT(key_permission, selinux_key_permission), LSM_HOOK_INIT(key_getsecurity, selinux_key_getsecurity), +#ifdef CONFIG_KEY_NOTIFICATIONS + LSM_HOOK_INIT(watch_key, selinux_watch_key), +#endif #endif #ifdef CONFIG_AUDIT
Implement the watch_key security hook to make sure that a key grants the caller View permission in order to set a watch on a key. For the moment, the watch_devices security hook is left unimplemented as it's not obvious what the object should be since the queue is global and didn't previously exist. Signed-off-by: David Howells <dhowells@redhat.com> --- security/selinux/hooks.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)