selinux: rework security_netlbl_secattr_to_sid

security_netlbl_secattr_to_sid is difficult to follow, especially the
return codes.  Try to make the function obvious.

Signed-off-by: Eric Paris <eparis@redhat.com>

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 84e2a98..ab6dbce 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -3041,7 +3041,7 @@ static void security_netlbl_cache_add(struct netlbl_lsm_secattr *secattr,
 int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
                                   u32 *sid)
 {
-       int rc = -EIDRM;
+       int rc;
        struct context *ctx;
        struct context ctx_new;
 
@@ -3052,16 +3052,15 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
 
        read_lock(&policy_rwlock);
 
-       if (secattr->flags & NETLBL_SECATTR_CACHE) {
+       if (secattr->flags & NETLBL_SECATTR_CACHE)
                *sid = *(u32 *)secattr->cache->data;
-               rc = 0;
-       } else if (secattr->flags & NETLBL_SECATTR_SECID) {
+       else if (secattr->flags & NETLBL_SECATTR_SECID)
                *sid = secattr->attr.secid;
-               rc = 0;
-       } else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
+       else if (secattr->flags & NETLBL_SECATTR_MLS_LVL) {
+               rc = -EIDRM;
                ctx = sidtab_search(&sidtab, SECINITSID_NETMSG);
                if (ctx == NULL)
-                       goto netlbl_secattr_to_sid_return;
+                       goto out;
 
                context_init(&ctx_new);
                ctx_new.user = ctx->user;
@@ -3069,34 +3068,35 @@ int security_netlbl_secattr_to_sid(struct netlbl_lsm_secattr *secattr,
                ctx_new.type = ctx->type;
                mls_import_netlbl_lvl(&ctx_new, secattr);
                if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
-                       if (ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
-                                                 secattr->attr.mls.cat) != 0)
-                               goto netlbl_secattr_to_sid_return;
+                       rc = ebitmap_netlbl_import(&ctx_new.range.level[0].cat,
+                                                  secattr->attr.mls.cat);
+                       if (rc)
+                               goto out;
                        memcpy(&ctx_new.range.level[1].cat,
                               &ctx_new.range.level[0].cat,
                               sizeof(ctx_new.range.level[0].cat));
                }
-               if (mls_context_isvalid(&policydb, &ctx_new) != 1)
-                       goto netlbl_secattr_to_sid_return_cleanup;
+               rc = -EIDRM;
+               if (!mls_context_isvalid(&policydb, &ctx_new))
+                       goto out_free;
 
                rc = sidtab_context_to_sid(&sidtab, &ctx_new, sid);
-               if (rc != 0)
-                       goto netlbl_secattr_to_sid_return_cleanup;
+               if (rc)
+                       goto out_free;
 
                security_netlbl_cache_add(secattr, *sid);
 
                ebitmap_destroy(&ctx_new.range.level[0].cat);
-       } else {
+       } else
                *sid = SECSID_NULL;
-               rc = 0;
-       }
 
-netlbl_secattr_to_sid_return:
        read_unlock(&policy_rwlock);
-       return rc;
-netlbl_secattr_to_sid_return_cleanup:
+       return 0;
+out_free:
        ebitmap_destroy(&ctx_new.range.level[0].cat);
-       goto netlbl_secattr_to_sid_return;
+out:
+       read_unlock(&policy_rwlock);
+       return rc;
 }
 
 /**