[PATCH] selinux: add support for range transitions on object classes

Introduces support for policy version 21.  This version of the binary
kernel policy allows for defining range transitions on security classes
other than the process security class.  As always, backwards compatibility
for older formats is retained.  The security class is read in as specified
when using the new format, while the "process" security class is assumed
when using an older policy format.

Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 34 insertions, 21 deletions

diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 119bd6078ba1..c713af23250a 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -530,22 +530,21 @@ int mls_compute_sid(struct context *scontext,
                     u32 specified,
                     struct context *newcontext)
 {
+        struct range_trans *rtr;
+
         if (!selinux_mls_enabled)
                 return 0;
 
         switch (specified) {
         case AVTAB_TRANSITION:
-                if (tclass == SECCLASS_PROCESS) {
-                        struct range_trans *rangetr;
-                        /* Look for a range transition rule. */
-                        for (rangetr = policydb.range_tr; rangetr;
-                             rangetr = rangetr->next) {
-                                if (rangetr->dom == scontext->type &&
-                                    rangetr->type == tcontext->type) {
-                                        /* Set the range from the rule */
-                                        return mls_range_set(newcontext,
-                                                             &rangetr->range);
-                                }
+                /* Look for a range transition rule. */
+                for (rtr = policydb.range_tr; rtr; rtr = rtr->next) {
+                        if (rtr->source_type == scontext->type &&
+                            rtr->target_type == tcontext->type &&
+                            rtr->target_class == tclass) {
+                                /* Set the range from the rule */
+                                return mls_range_set(newcontext,
+                                                     &rtr->target_range);
                         }
                 }
                 /* Fallthrough */
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index f03960e697ce..b18895302555 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -96,6 +96,11 @@ static struct policydb_compat_info policydb_compat[] = {
                 .sym_num        = SYM_NUM,
                 .ocon_num       = OCON_NUM,
         },
+        {
+                .version        = POLICYDB_VERSION_RANGETRANS,
+                .sym_num        = SYM_NUM,
+                .ocon_num       = OCON_NUM,
+        },
 };
 
 static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -645,15 +650,15 @@ void policydb_destroy(struct policydb *p)
 
         for (rt = p->range_tr; rt; rt = rt -> next) {
                 if (lrt) {
-                        ebitmap_destroy(&lrt->range.level[0].cat);
-                        ebitmap_destroy(&lrt->range.level[1].cat);
+                        ebitmap_destroy(&lrt->target_range.level[0].cat);
+                        ebitmap_destroy(&lrt->target_range.level[1].cat);
                         kfree(lrt);
                 }
                 lrt = rt;
         }
         if (lrt) {
-                ebitmap_destroy(&lrt->range.level[0].cat);
-                ebitmap_destroy(&lrt->range.level[1].cat);
+                ebitmap_destroy(&lrt->target_range.level[0].cat);
+                ebitmap_destroy(&lrt->target_range.level[1].cat);
                 kfree(lrt);
         }
 
@@ -1829,6 +1834,7 @@ int policydb_read(struct policydb *p, void *fp)
         }
 
         if (p->policyvers >= POLICYDB_VERSION_MLS) {
+                int new_rangetr = p->policyvers >= POLICYDB_VERSION_RANGETRANS;
                 rc = next_entry(buf, fp, sizeof(u32));
                 if (rc < 0)
                         goto bad;
@@ -1847,9 +1853,16 @@ int policydb_read(struct policydb *p, void *fp)
                         rc = next_entry(buf, fp, (sizeof(u32) * 2));
                         if (rc < 0)
                                 goto bad;
-                        rt->dom = le32_to_cpu(buf[0]);
-                        rt->type = le32_to_cpu(buf[1]);
-                        rc = mls_read_range_helper(&rt->range, fp);
+                        rt->source_type = le32_to_cpu(buf[0]);
+                        rt->target_type = le32_to_cpu(buf[1]);
+                        if (new_rangetr) {
+                                rc = next_entry(buf, fp, sizeof(u32));
+                                if (rc < 0)
+                                        goto bad;
+                                rt->target_class = le32_to_cpu(buf[0]);
+                        } else
+                                rt->target_class = SECCLASS_PROCESS;
+                        rc = mls_read_range_helper(&rt->target_range, fp);
                         if (rc)
                                 goto bad;
                         lrt = rt;
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index b1340711f721..8319d5ff5944 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -106,9 +106,10 @@ struct cat_datum {
 };
 
 struct range_trans {
-        u32 dom;                        /* current process domain */
-        u32 type;                       /* program executable type */
-        struct mls_range range;         /* new range */
+        u32 source_type;
+        u32 target_type;
+        u32 target_class;
+        struct mls_range target_range;
         struct range_trans *next;
 };