selinux: libsepol: remove dead code in check_avtab_hierarchy_callback()

This patch revert the commit of 7d52a155e38d5a165759dbbee656455861bf7801
which removed a part of type_attribute_bounds_av as a dead code.
However, at that time, we didn't find out the target side boundary allows
to handle some of pseudo /proc/<pid>/* entries with its process's security
context well.

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>

--
 security/selinux/ss/services.c |   43 ++++++++++++++++++++++++++++++++++++---
 1 files changed, 39 insertions(+), 4 deletions(-)
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 39 insertions, 4 deletions

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 0e5c3a422a8e..cf27b3ee1a95 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -525,14 +525,16 @@ static void type_attribute_bounds_av(struct context *scontext,
                                      u16 tclass,
                                      struct av_decision *avd)
 {
+        struct context lo_scontext;
+        struct context lo_tcontext;
+        struct av_decision lo_avd;
         struct type_datum *source
                 = policydb.type_val_to_struct[scontext->type - 1];
+        struct type_datum *target
+                = policydb.type_val_to_struct[tcontext->type - 1];
+        u32 masked = 0;
 
         if (source->bounds) {
-                struct context lo_scontext;
-                struct av_decision lo_avd;
-                u32 masked;
-
                 memset(&lo_avd, 0, sizeof(lo_avd));
 
                 memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
@@ -545,7 +547,40 @@ static void type_attribute_bounds_av(struct context *scontext,
                 if ((lo_avd.allowed & avd->allowed) == avd->allowed)
                         return;         /* no masked permission */
                 masked = ~lo_avd.allowed & avd->allowed;
+        }
+
+        if (target->bounds) {
+                memset(&lo_avd, 0, sizeof(lo_avd));
+
+                memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
+                lo_tcontext.type = target->bounds;
+
+                context_struct_compute_av(scontext,
+                                          &lo_tcontext,
+                                          tclass,
+                                          &lo_avd);
+                if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+                        return;         /* no masked permission */
+                masked = ~lo_avd.allowed & avd->allowed;
+        }
+
+        if (source->bounds && target->bounds) {
+                memset(&lo_avd, 0, sizeof(lo_avd));
+                /*
+                 * lo_scontext and lo_tcontext are already
+                 * set up.
+                 */
+
+                context_struct_compute_av(&lo_scontext,
+                                          &lo_tcontext,
+                                          tclass,
+                                          &lo_avd);
+                if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+                        return;         /* no masked permission */
+                masked = ~lo_avd.allowed & avd->allowed;
+        }
 
+        if (masked) {
                 /* mask violated permissions */
                 avd->allowed &= ~masked;