seccomp: Fix ioctl number for SECCOMP_IOCTL_NOTIF_ID_VALID

When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced it had the wrong
direction flag set. While this isn't a big deal as nothing currently
enforces these bits in the kernel, it should be defined correctly. Fix
the define and provide support for the old command until it is no longer
needed for backward compatibility.

Fixes: 6a21cc50f0c7 ("seccomp: add a return code to trap to userspace")
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
index c173545..965290f 100644 (file)
--- a/include/uapi/linux/seccomp.h
+++ b/include/uapi/linux/seccomp.h
@@ -123,5 +123,6 @@ struct seccomp_notif_resp {
 #define SECCOMP_IOCTL_NOTIF_RECV       SECCOMP_IOWR(0, struct seccomp_notif)
 #define SECCOMP_IOCTL_NOTIF_SEND       SECCOMP_IOWR(1, \
                                                struct seccomp_notif_resp)
-#define SECCOMP_IOCTL_NOTIF_ID_VALID   SECCOMP_IOR(2, __u64)
+#define SECCOMP_IOCTL_NOTIF_ID_VALID   SECCOMP_IOW(2, __u64)
+
 #endif /* _UAPI_LINUX_SECCOMP_H */

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 5f0e3f3..0ed57e8 100644 (file)
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -44,6 +44,14 @@
 #include <linux/anon_inodes.h>
 #include <linux/lockdep.h>
 
+/*
+ * When SECCOMP_IOCTL_NOTIF_ID_VALID was first introduced, it had the
+ * wrong direction flag in the ioctl number. This is the broken one,
+ * which the kernel needs to keep supporting until all userspaces stop
+ * using the wrong command number.
+ */
+#define SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR SECCOMP_IOR(2, __u64)
+
 enum notify_state {
        SECCOMP_NOTIFY_INIT,
        SECCOMP_NOTIFY_SENT,
@@ -1236,6 +1244,7 @@ static long seccomp_notify_ioctl(struct file *file, unsigned int cmd,
                return seccomp_notify_recv(filter, buf);
        case SECCOMP_IOCTL_NOTIF_SEND:
                return seccomp_notify_send(filter, buf);
+       case SECCOMP_IOCTL_NOTIF_ID_VALID_WRONG_DIR:
        case SECCOMP_IOCTL_NOTIF_ID_VALID:
                return seccomp_notify_id_valid(filter, buf);
        default:

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 43884b6..61f9ac2 100644 (file)
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -186,7 +186,7 @@ struct seccomp_metadata {
 #define SECCOMP_IOCTL_NOTIF_RECV       SECCOMP_IOWR(0, struct seccomp_notif)
 #define SECCOMP_IOCTL_NOTIF_SEND       SECCOMP_IOWR(1, \
                                                struct seccomp_notif_resp)
-#define SECCOMP_IOCTL_NOTIF_ID_VALID   SECCOMP_IOR(2, __u64)
+#define SECCOMP_IOCTL_NOTIF_ID_VALID   SECCOMP_IOW(2, __u64)
 
 struct seccomp_notif {
        __u64 id;