Re: [PATCH v22 12/23] LSM: Specify which LSM to display

On Fri, Nov 06, 2020 at 04:20:43PM -0800, Casey Schaufler wrote: > On 11/5/2020 1:22 AM, Greg KH wrote: >> On Wed, Nov 04, 2020 at 03:41:03PM -0800, Casey Schaufler wrote: >>> Create a new entry "display" in the procfs attr directory for >>> controlling which LSM security information is displayed for a >>> process. A process can only read or write its own display value. >>> >>> The name of an active LSM that supplies hooks for >>> human readable data may be written to "display" to set the >>> value. The name of the LSM currently in use can be read from >>> "display". At this point there can only be one LSM capable >>> of display active. A helper function lsm_task_display() is >>> provided to get the display slot for a task_struct. >>> >>> Setting the "display" requires that all security modules using >>> setprocattr hooks allow the action. Each security module is >>> responsible for defining its policy. >>> >>> AppArmor hook provided by John Johansen <john.johansen(a)canonical.com&gt; >>> SELinux hook provided by Stephen Smalley <sds(a)tycho.nsa.gov&gt; >>> >>> Reviewed-by: Kees Cook <keescook(a)chromium.org&gt; >>> Acked-by: Stephen Smalley <sds(a)tycho.nsa.gov&gt; >>> Acked-by: Paul Moore <paul(a)paul-moore.com&gt; >>> Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt; >>> Cc: linux-api(a)vger.kernel.org >>> --- >>> fs/proc/base.c | 1 + >>> include/linux/lsm_hooks.h | 17 +++ >>> security/apparmor/include/apparmor.h | 3 +- >>> security/apparmor/lsm.c | 32 +++++ >>> security/security.c | 169 ++++++++++++++++++++++++--- >>> security/selinux/hooks.c | 11 ++ >>> security/selinux/include/classmap.h | 2 +- >>> security/smack/smack_lsm.c | 7 ++ >>> 8 files changed, 223 insertions(+), 19 deletions(-) >>> >>> diff --git a/fs/proc/base.c b/fs/proc/base.c >>> index 0f707003dda5..7432f24f0132 100644 >>> --- a/fs/proc/base.c >>> +++ b/fs/proc/base.c >>> @@ -2806,6 +2806,7 @@ static const struct pid_entry attr_dir_stuff[] = { >>> ATTR(NULL, "fscreate", 0666), >>> ATTR(NULL, "keycreate", 0666), >>> ATTR(NULL, "sockcreate", 0666), >>> + ATTR(NULL, "display", 0666), >> That's a vague name, any chance it can be more descriptive? > > Sure. How about lsm_display, or display_lsm? I wouldn't say that > any of the files in /proc/*/attr have especially descriptive names, > but that's hardly an excuse. I still don't understand what "display" means in this context. Perhaps

documentation will help clear it up?

thanks, greg k-h