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, 85 insertions, 0 deletions

diff --git a/fs/lockd/xdr.h b/fs/lockd/xdr.h
new file mode 100644
index 000000000..a1126cca9
--- /dev/null
+++ b/fs/lockd/xdr.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * XDR types for the NLM protocol
+ *
+ * Copyright (C) 1996 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#ifndef _LOCKD_XDR_H
+#define _LOCKD_XDR_H
+
+#include <linux/fs.h>
+#include <linux/filelock.h>
+#include <linux/nfs.h>
+#include <linux/sunrpc/xdr.h>
+
+#define SM_MAXSTRLEN		1024
+#define SM_PRIV_SIZE		16
+
+struct nsm_private {
+	unsigned char		data[SM_PRIV_SIZE];
+};
+
+#define NLM_MAXCOOKIELEN    	32
+#define NLM_MAXSTRLEN		1024
+
+#define	nlm_granted		cpu_to_be32(NLM_LCK_GRANTED)
+#define	nlm_lck_denied		cpu_to_be32(NLM_LCK_DENIED)
+#define	nlm_lck_denied_nolocks	cpu_to_be32(NLM_LCK_DENIED_NOLOCKS)
+#define	nlm_lck_blocked		cpu_to_be32(NLM_LCK_BLOCKED)
+#define	nlm_lck_denied_grace_period	cpu_to_be32(NLM_LCK_DENIED_GRACE_PERIOD)
+
+/* Lock info passed via NLM */
+struct lockd_lock {
+	char *			caller;
+	unsigned int		len; 	/* length of "caller" */
+	struct nfs_fh		fh;
+	struct xdr_netobj	oh;
+	u32			svid;
+	u64			lock_start;
+	u64			lock_len;
+	struct file_lock	fl;
+};
+
+/*
+ *	NLM cookies. Technically they can be 1K, but Linux only uses 8 bytes.
+ *	FreeBSD uses 16, Apple Mac OS X 10.3 uses 20. Therefore we set it to
+ *	32 bytes.
+ */
+
+struct lockd_cookie {
+	unsigned char data[NLM_MAXCOOKIELEN];
+	unsigned int len;
+};
+
+/*
+ * Generic lockd arguments for all but sm_notify
+ */
+struct lockd_args {
+	struct lockd_cookie	cookie;
+	struct lockd_lock	lock;
+	u32			block;
+	u32			reclaim;
+	u32			state;
+};
+
+/*
+ * Generic lockd result
+ */
+struct lockd_res {
+	struct lockd_cookie	cookie;
+	__be32			status;
+	struct lockd_lock	lock;
+};
+
+/*
+ * statd callback when client has rebooted
+ */
+struct lockd_reboot {
+	char			*mon;
+	unsigned int		len;
+	u32			state;
+	struct nsm_private	priv;
+};
+
+#endif /* _LOCKD_XDR_H */