selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 131 insertions, 0 deletions

diff --git a/fs/smb/server/smbacl.h b/fs/smb/server/smbacl.h
new file mode 100644
index 000000000..ab21ba2cd
--- /dev/null
+++ b/fs/smb/server/smbacl.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/*
+ *   Copyright (c) International Business Machines  Corp., 2007
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *   Modified by Namjae Jeon (linkinjeon@kernel.org)
+ */
+
+#ifndef _SMBACL_H
+#define _SMBACL_H
+
+#include "../common/smbacl.h"
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/posix_acl.h>
+#include <linux/mnt_idmapping.h>
+
+#include "mgmt/tree_connect.h"
+
+/* Revision for ACLs */
+#define SD_REVISION	1
+
+/* Control flags for Security Descriptor */
+#define OWNER_DEFAULTED		0x0001
+#define GROUP_DEFAULTED		0x0002
+#define DACL_PRESENT		0x0004
+#define DACL_DEFAULTED		0x0008
+#define SACL_PRESENT		0x0010
+#define SACL_DEFAULTED		0x0020
+#define DACL_TRUSTED		0x0040
+#define SERVER_SECURITY		0x0080
+#define DACL_AUTO_INHERIT_REQ	0x0100
+#define SACL_AUTO_INHERIT_REQ	0x0200
+#define DACL_AUTO_INHERITED	0x0400
+#define SACL_AUTO_INHERITED	0x0800
+#define DACL_PROTECTED		0x1000
+#define SACL_PROTECTED		0x2000
+#define RM_CONTROL_VALID	0x4000
+#define SELF_RELATIVE		0x8000
+
+struct ksmbd_conn;
+
+struct smb_fattr {
+	kuid_t	cf_uid;
+	kgid_t	cf_gid;
+	umode_t	cf_mode;
+	__le32 daccess;
+	struct posix_acl *cf_acls;
+	struct posix_acl *cf_dacls;
+};
+
+struct posix_ace_state {
+	u32 allow;
+	u32 deny;
+};
+
+struct posix_user_ace_state {
+	union {
+		kuid_t uid;
+		kgid_t gid;
+	};
+	struct posix_ace_state perms;
+};
+
+struct posix_ace_state_array {
+	int n;
+	struct posix_user_ace_state aces[];
+};
+
+/*
+ * while processing the nfsv4 ace, this maintains the partial permissions
+ * calculated so far:
+ */
+
+struct posix_acl_state {
+	struct posix_ace_state owner;
+	struct posix_ace_state group;
+	struct posix_ace_state other;
+	struct posix_ace_state everyone;
+	struct posix_ace_state mask; /* deny unused in this case */
+	struct posix_ace_state_array *users;
+	struct posix_ace_state_array *groups;
+};
+
+int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd,
+		   int acl_len, struct smb_fattr *fattr);
+int build_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd,
+		   struct smb_ntsd *ppntsd, int ppntsd_size, int addition_info,
+		   __u32 *secdesclen, struct smb_fattr *fattr);
+int init_acl_state(struct posix_acl_state *state, u16 cnt);
+void free_acl_state(struct posix_acl_state *state);
+void posix_state_to_acl(struct posix_acl_state *state,
+			struct posix_acl_entry *pace);
+int compare_sids(const struct smb_sid *ctsid, const struct smb_sid *cwsid);
+bool smb_inherit_flags(int flags, bool is_dir);
+int smb_inherit_dacl(struct ksmbd_conn *conn, const struct path *path,
+		     unsigned int uid, unsigned int gid);
+int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path,
+			__le32 *pdaccess, int uid);
+int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon,
+		 const struct path *path, struct smb_ntsd *pntsd, int ntsd_len,
+		 bool type_check, bool get_write);
+void id_to_sid(unsigned int cid, uint sidtype, struct smb_sid *ssid);
+void ksmbd_init_domain(u32 *sub_auth);
+size_t smb_acl_sec_desc_scratch_len(struct smb_fattr *fattr,
+		struct smb_ntsd *ppntsd, int ppntsd_size, int addition_info);
+
+static inline uid_t posix_acl_uid_translate(struct mnt_idmap *idmap,
+					    struct posix_acl_entry *pace)
+{
+	vfsuid_t vfsuid;
+
+	/* If this is an idmapped mount, apply the idmapping. */
+	vfsuid = make_vfsuid(idmap, &init_user_ns, pace->e_uid);
+
+	/* Translate the kuid into a userspace id ksmbd would see. */
+	return from_kuid(&init_user_ns, vfsuid_into_kuid(vfsuid));
+}
+
+static inline gid_t posix_acl_gid_translate(struct mnt_idmap *idmap,
+					    struct posix_acl_entry *pace)
+{
+	vfsgid_t vfsgid;
+
+	/* If this is an idmapped mount, apply the idmapping. */
+	vfsgid = make_vfsgid(idmap, &init_user_ns, pace->e_gid);
+
+	/* Translate the kgid into a userspace id ksmbd would see. */
+	return from_kgid(&init_user_ns, vfsgid_into_kgid(vfsgid));
+}
+
+#endif /* _SMBACL_H */