Merge tag 'fsnotify_for_v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "Support for auditing decisions regarding fanotify permission events"

* tag 'fsnotify_for_v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify,audit: Allow audit to use the full permission event response
  fanotify: define struct members to hold response decision context
  fanotify: Ensure consistent variable type for response

3 files changed, 39 insertions, 5 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 3608992848d3..31086a72e32a 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -14,6 +14,7 @@
 #include <linux/audit_arch.h>
 #include <uapi/linux/audit.h>
 #include <uapi/linux/netfilter/nf_tables.h>
+#include <uapi/linux/fanotify.h>
 
 #define AUDIT_INO_UNSET ((unsigned long)-1)
 #define AUDIT_DEV_UNSET ((dev_t)-1)
@@ -416,7 +417,7 @@ extern void __audit_log_capset(const struct cred *new, const struct cred *old);
 extern void __audit_mmap_fd(int fd, int flags);
 extern void __audit_openat2_how(struct open_how *how);
 extern void __audit_log_kern_module(char *name);
-extern void __audit_fanotify(unsigned int response);
+extern void __audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar);
 extern void __audit_tk_injoffset(struct timespec64 offset);
 extern void __audit_ntp_log(const struct audit_ntp_data *ad);
 extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries,
@@ -523,10 +524,10 @@ static inline void audit_log_kern_module(char *name)
 		__audit_log_kern_module(name);
 }
 
-static inline void audit_fanotify(unsigned int response)
+static inline void audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar)
 {
 	if (!audit_dummy_context())
-		__audit_fanotify(response);
+		__audit_fanotify(response, friar);
 }
 
 static inline void audit_tk_injoffset(struct timespec64 offset)
@@ -679,7 +680,7 @@ static inline void audit_log_kern_module(char *name)
 {
 }
 
-static inline void audit_fanotify(unsigned int response)
+static inline void audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar)
 { }
 
 static inline void audit_tk_injoffset(struct timespec64 offset)
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 8ad743def6f3..4f1c4f603118 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -122,6 +122,11 @@
 #define ALL_FANOTIFY_EVENT_BITS		(FANOTIFY_OUTGOING_EVENTS | \
 					 FANOTIFY_EVENT_FLAGS)
 
+/* These masks check for invalid bits in permission responses. */
+#define FANOTIFY_RESPONSE_ACCESS (FAN_ALLOW | FAN_DENY)
+#define FANOTIFY_RESPONSE_FLAGS (FAN_AUDIT | FAN_INFO)
+#define FANOTIFY_RESPONSE_VALID_MASK (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS)
+
 /* Do not use these old uapi constants internally */
 #undef FAN_ALL_CLASS_BITS
 #undef FAN_ALL_INIT_FLAGS
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 436258214bb0..cd14c94e9a1e 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -188,15 +188,43 @@ struct fanotify_event_info_error {
 	__u32 error_count;
 };
 
+/*
+ * User space may need to record additional information about its decision.
+ * The extra information type records what kind of information is included.
+ * The default is none. We also define an extra information buffer whose
+ * size is determined by the extra information type.
+ *
+ * If the information type is Audit Rule, then the information following
+ * is the rule number that triggered the user space decision that
+ * requires auditing.
+ */
+
+#define FAN_RESPONSE_INFO_NONE		0
+#define FAN_RESPONSE_INFO_AUDIT_RULE	1
+
 struct fanotify_response {
 	__s32 fd;
 	__u32 response;
 };
 
+struct fanotify_response_info_header {
+	__u8 type;
+	__u8 pad;
+	__u16 len;
+};
+
+struct fanotify_response_info_audit_rule {
+	struct fanotify_response_info_header hdr;
+	__u32 rule_number;
+	__u32 subj_trust;
+	__u32 obj_trust;
+};
+
 /* Legit userspace responses to a _PERM event */
 #define FAN_ALLOW	0x01
 #define FAN_DENY	0x02
-#define FAN_AUDIT	0x10	/* Bit mask to create audit record for result */
+#define FAN_AUDIT	0x10	/* Bitmask to create audit record for result */
+#define FAN_INFO	0x20	/* Bitmask to indicate additional information */
 
 /* No fd set in event */
 #define FAN_NOFD	-1