KEYS: Move KEY_LOOKUP_ to include/linux/key.h and define KEY_LOOKUP_ALL

In preparation for the patch that introduces the bpf_lookup_user_key() eBPF
kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to
validate the kfunc parameters. Add them to enum key_lookup_flag, so that
all the current ones and the ones defined in the future are automatically
exported through BTF and available to eBPF programs.

Also, add KEY_LOOKUP_ALL to the enum, with the logical OR of currently
defined flags as value, to facilitate checking whether a variable contains
only those flags.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/r/20220920075951.929132-7-roberto.sassu@huaweicloud.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

include/linux/key.h

@@ -88,6 +88,12 @@ enum key_need_perm {
 	KEY_DEFER_PERM_CHECK,	/* Special: permission check is deferred */
 };
 
+enum key_lookup_flag {
+	KEY_LOOKUP_CREATE = 0x01,
+	KEY_LOOKUP_PARTIAL = 0x02,
+	KEY_LOOKUP_ALL = (KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL),
+};
+
 struct seq_file;
 struct user_struct;
 struct signal_struct;

security/keys/internal.h

@@ -165,8 +165,6 @@ extern struct key *request_key_and_link(struct key_type *type,
 
 extern bool lookup_user_key_possessed(const struct key *key,
 				      const struct key_match_data *match_data);
-#define KEY_LOOKUP_CREATE	0x01
-#define KEY_LOOKUP_PARTIAL	0x02
 
 extern long join_session_keyring(const char *name);
 extern void key_change_session_keyring(struct callback_head *twork);