bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/net/x25/Kconfig b/net/x25/Kconfig
new file mode 100644
index 000000000..dc72302cb
--- /dev/null
+++ b/net/x25/Kconfig
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# CCITT X.25 Packet Layer
+#
+
+config X25
+	tristate "CCITT X.25 Packet Layer"
+	help
+	  X.25 is a set of standardized network protocols, similar in scope to
+	  frame relay; the one physical line from your box to the X.25 network
+	  entry point can carry several logical point-to-point connections
+	  (called "virtual circuits") to other computers connected to the X.25
+	  network. Governments, banks, and other organizations tend to use it
+	  to connect to each other or to form Wide Area Networks (WANs). Many
+	  countries have public X.25 networks. X.25 consists of two
+	  protocols: the higher level Packet Layer Protocol (PLP) (say Y here
+	  if you want that) and the lower level data link layer protocol LAPB
+	  (say Y to "LAPB Data Link Driver" below if you want that).
+
+	  Information about X.25 for Linux is contained in the files
+	  <file:Documentation/networking/x25.rst> and
+	  <file:Documentation/networking/x25-iface.rst>.
+
+	  One connects to an X.25 network either with a dedicated network card
+	  using the X.21 protocol (not yet supported by Linux) or one can do
+	  X.25 over a standard telephone line using an ordinary modem (say Y
+	  to "X.25 async driver" below) or over Ethernet using an ordinary
+	  Ethernet card and the LAPB over Ethernet (say Y to "LAPB Data Link
+	  Driver" and "LAPB over Ethernet driver" below).
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called x25. If unsure, say N.