selinux: fix the labeled xfrm/IPsec reference count handling

The SELinux labeled IPsec code was improperly handling its reference
counting, dropping a reference on a delete operation instead of on a
free/release operation.

Reported-by: Ondrej Moris <omoris@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 20 deletions

diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index 8ab295154517..d03081886214 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -316,6 +316,7 @@ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
 
                 memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
                 memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
+                atomic_inc(&selinux_xfrm_refcount);
                 *new_ctxp = new_ctx;
         }
         return 0;
@@ -326,6 +327,7 @@ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
  */
 void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
 {
+        atomic_dec(&selinux_xfrm_refcount);
         kfree(ctx);
 }
 
@@ -335,17 +337,13 @@ void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
 int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
 {
         const struct task_security_struct *tsec = current_security();
-        int rc = 0;
 
-        if (ctx) {
-                rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
-                                  SECCLASS_ASSOCIATION,
-                                  ASSOCIATION__SETCONTEXT, NULL);
-                if (rc == 0)
-                        atomic_dec(&selinux_xfrm_refcount);
-        }
+        if (!ctx)
+                return 0;
 
-        return rc;
+        return avc_has_perm(tsec->sid, ctx->ctx_sid,
+                            SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
+                            NULL);
 }
 
 /*
@@ -370,8 +368,8 @@ int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uct
  */
 void selinux_xfrm_state_free(struct xfrm_state *x)
 {
-        struct xfrm_sec_ctx *ctx = x->security;
-        kfree(ctx);
+        atomic_dec(&selinux_xfrm_refcount);
+        kfree(x->security);
 }
 
  /*
@@ -381,17 +379,13 @@ int selinux_xfrm_state_delete(struct xfrm_state *x)
 {
         const struct task_security_struct *tsec = current_security();
         struct xfrm_sec_ctx *ctx = x->security;
-        int rc = 0;
 
-        if (ctx) {
-                rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
-                                  SECCLASS_ASSOCIATION,
-                                  ASSOCIATION__SETCONTEXT, NULL);
-                if (rc == 0)
-                        atomic_dec(&selinux_xfrm_refcount);
-        }
+        if (!ctx)
+                return 0;
 
-        return rc;
+        return avc_has_perm(tsec->sid, ctx->ctx_sid,
+                            SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
+                            NULL);
 }
 
 /*