[PATCH] keys: Add tracepoints for the keyrings facility

From: David Howells
Date: Mon Jul 22 2024 - 19:20:51 EST

Add some tracepoints to aid in debuggin the keyrings facility and
applications that use it. A number of events and operations are traceable,
including:

- Allocation
- Refcounting
- Instantiation and negative instantiation/rejection
- Update
- Detection of key being dead
- Key quota changes
- Key quota failure
- Link, unlink and move
- Keyring clearance
- Revocation and invalidation
- Garbage collection

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
cc: keyrings@xxxxxxxxxxxxxxx
cc: linux-security-module@xxxxxxxxxxxxxxx
---
Documentation/security/keys/core.rst | 1
crypto/asymmetric_keys/restrict.c | 6
include/keys/key_user.h | 35 +++
include/linux/key.h | 16 -
include/trace/events/key.h | 401 +++++++++++++++++++++++++++++++++++
security/keys/gc.c | 4
security/keys/internal.h | 41 ---
security/keys/key.c | 66 +++++
security/keys/keyctl.c | 2
security/keys/keyring.c | 45 +++
security/keys/process_keys.c | 15 -
11 files changed, 562 insertions(+), 70 deletions(-)

diff --git a/Documentation/security/keys/core.rst b/Documentation/security/keys/core.rst
index 326b8a973828..0b179540d885 100644
--- a/Documentation/security/keys/core.rst
+++ b/Documentation/security/keys/core.rst
@@ -1217,7 +1217,6 @@ payload contents" for more information.
* Extra references can be made to a key by calling one of the following
functions::

- struct key *__key_get(struct key *key);
struct key *key_get(struct key *key);

Keys so references will need to be disposed of by calling key_put() when
diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index afcd4d101ac5..1ea7bfd4e5d7 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -267,20 +267,20 @@ static int key_or_keyring_common(struct key *dest_keyring,
if (!sig->auth_ids[0] && !sig->auth_ids[1]) {
if (asymmetric_key_id_same(signer_ids[2],
sig->auth_ids[2]))
- key = __key_get(trusted);
+ key = key_get(trusted);

} else if (!sig->auth_ids[0] || !sig->auth_ids[1]) {
const struct asymmetric_key_id *auth_id;

auth_id = sig->auth_ids[0] ?: sig->auth_ids[1];
if (match_either_id(signer_ids, auth_id))
- key = __key_get(trusted);
+ key = key_get(trusted);

} else if (asymmetric_key_id_same(signer_ids[1],
sig->auth_ids[1]) &&
match_either_id(signer_ids,
sig->auth_ids[0])) {
- key = __key_get(trusted);
+ key = key_get(trusted);
}
} else {
return -EOPNOTSUPP;
diff --git a/include/keys/key_user.h b/include/keys/key_user.h
new file mode 100644
index 000000000000..e9c383d8116e
--- /dev/null
+++ b/include/keys/key_user.h
@@ -0,0 +1,35 @@
+/* User quota tracking for keys.
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _KEYS_KEY_USER_H
+#define _KEYS_KEY_USER_H
+
+/*
+ * Keep track of keys for a user.
+ *
+ * This needs to be separate to user_struct to avoid a refcount-loop
+ * (user_struct pins some keyrings which pin this struct).
+ *
+ * We also keep track of keys under request from userspace for this UID here.
+ */
+struct key_user {
+ struct rb_node node;
+ struct mutex cons_lock; /* construction initiation lock */
+ spinlock_t lock;
+ refcount_t usage; /* for accessing qnkeys & qnbytes */
+ atomic_t nkeys; /* number of keys */
+ atomic_t nikeys; /* number of instantiated keys */
+ kuid_t uid;
+ int qnkeys; /* number of keys allocated to this user */
+ int qnbytes; /* number of bytes allocated to this user */
+};
+
+#endif /* _KEYS_KEY_USER_H */
diff --git a/include/linux/key.h b/include/linux/key.h
index 943a432da3ae..4e5baf3e7286 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -299,24 +299,20 @@ extern struct key *key_alloc(struct key_type *type,

extern void key_revoke(struct key *key);
extern void key_invalidate(struct key *key);
+struct key *key_get(struct key *key);
+struct key *key_try_get(struct key *key);
extern void key_put(struct key *key);
extern bool key_put_tag(struct key_tag *tag);
extern void key_remove_domain(struct key_tag *domain_tag);

-static inline struct key *__key_get(struct key *key)
-{
- refcount_inc(&key->usage);
- return key;
-}
-
-static inline struct key *key_get(struct key *key)
+static inline void key_ref_put(key_ref_t key_ref)
{
- return key ? __key_get(key) : key;
+ key_put(key_ref_to_ptr(key_ref));
}

-static inline void key_ref_put(key_ref_t key_ref)
+static inline void key_ref_get(key_ref_t key_ref)
{
- key_put(key_ref_to_ptr(key_ref));
+ key_get(key_ref_to_ptr(key_ref));
}

extern struct key *request_key_tag(struct key_type *type,
diff --git a/include/trace/events/key.h b/include/trace/events/key.h
new file mode 100644
index 000000000000..b3f8c39cc0e8
--- /dev/null
+++ b/include/trace/events/key.h
@@ -0,0 +1,401 @@
+/* Keyrings tracepoints
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@xxxxxxxxxx)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM key
+
+#if !defined(_TRACE_KEY_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KEY_H
+
+#include <linux/tracepoint.h>
+
+struct key;
+
+/*
+ * Declare tracing information enums and their string mappings for display.
+ */
+#define key_ref_traces \
+ EM(key_trace_ref_alloc, "ALLOC") \
+ EM(key_trace_ref_free, "FREE ") \
+ EM(key_trace_ref_gc, "GC ") \
+ EM(key_trace_ref_get, "GET ") \
+ EM(key_trace_ref_put, "PUT ") \
+ E_(key_trace_ref_try_get, "GET ")
+
+#define key_dead_traces \
+ EM(key_trace_dead_type_removed, "TYPR") \
+ EM(key_trace_dead_domain_removed, "DOMR") \
+ EM(key_trace_dead_expired, "EXPD") \
+ E_(key_trace_dead_invalidated, "INVL")
+
+/*
+ * Generate enums for tracing information.
+ */
+#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY
+
+#undef EM
+#undef E_
+#define EM(a, b) a,
+#define E_(a, b) a
+
+enum key_dead_trace { key_dead_traces } __mode(byte);
+enum key_ref_trace { key_ref_traces } __mode(byte);
+
+#endif /* end __RXRPC_DECLARE_TRACE_ENUMS_ONCE_ONLY */
+
+/*
+ * Export enum symbols via userspace.
+ */
+#undef EM
+#undef E_
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define E_(a, b) TRACE_DEFINE_ENUM(a);
+
+key_dead_traces;
+key_ref_traces;
+
+/*
+ * Now redefine the EM() and E_() macros to map the enums to the strings that
+ * will be printed in the output.
+ */
+#undef EM
+#undef E_
+#define EM(a, b) { a, b },
+#define E_(a, b) { a, b }
+
+TRACE_EVENT(key_alloc,
+ TP_PROTO(const struct key *key),
+
+ TP_ARGS(key),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(uid_t, uid)
+ __array(char, type, 8)
+ __array(char, desc, 24)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key->serial;
+ __entry->uid = from_kuid(&init_user_ns, key->uid);
+ strncpy(__entry->type, key->type->name, sizeof(__entry->type) - 1);
+ strncpy(__entry->desc, key->description ?: "", sizeof(__entry->desc) - 1);
+ __entry->type[sizeof(__entry->type) - 1] = 0;
+ __entry->desc[sizeof(__entry->desc) - 1] = 0;
+ ),
+
+ TP_printk("key=%08x uid=%08x t=%s d=%s",
+ __entry->key,
+ __entry->uid,
+ __entry->type,
+ __entry->desc)
+ );
+
+TRACE_EVENT(key_ref,
+ TP_PROTO(key_serial_t key, unsigned int ref, enum key_ref_trace trace,
+ const void *where),
+
+ TP_ARGS(key, ref, trace, where),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(enum key_ref_trace, trace)
+ __field(unsigned int, ref)
+ __field(const void *, where)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key;
+ __entry->trace = trace;
+ __entry->ref = ref;
+ __entry->where = where;
+ ),
+
+ TP_printk("key=%08x %s r=%d pc=%pSR",
+ __entry->key,
+ __print_symbolic(__entry->trace, key_ref_traces),
+ __entry->ref,
+ __entry->where)
+ );
+
+TRACE_EVENT(key_instantiate,
+ TP_PROTO(const struct key *key, const struct key_preparsed_payload *prep),
+
+ TP_ARGS(key, prep),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(unsigned int, datalen)
+ __field(unsigned int, quotalen)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key->serial;
+ __entry->datalen = prep->datalen;
+ __entry->quotalen = prep->quotalen;
+ ),
+
+ TP_printk("key=%08x dlen=%u qlen=%u",
+ __entry->key,
+ __entry->datalen,
+ __entry->quotalen)
+ );
+
+TRACE_EVENT(key_reject,
+ TP_PROTO(const struct key *key, int error),
+
+ TP_ARGS(key, error),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(int, error)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key->serial;
+ __entry->error = error;
+ ),
+
+ TP_printk("key=%08x err=%d",
+ __entry->key,
+ __entry->error)
+ );
+
+TRACE_EVENT(key_update,
+ TP_PROTO(const struct key *key, const struct key_preparsed_payload *prep),
+
+ TP_ARGS(key, prep),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(unsigned int, datalen)
+ __field(unsigned int, quotalen)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key->serial;
+ __entry->datalen = prep->datalen;
+ __entry->quotalen = prep->quotalen;
+ ),
+
+ TP_printk("key=%08x dlen=%u qlen=%u",
+ __entry->key,
+ __entry->datalen,
+ __entry->quotalen)
+ );
+
+TRACE_EVENT(key_dead,
+ TP_PROTO(const struct key *key, enum key_dead_trace trace),
+
+ TP_ARGS(key, trace),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ __field(enum key_dead_trace, trace)
+ ),
+
+ TP_fast_assign(
+ __entry->key = key->serial;
+ __entry->trace = trace;
+ ),
+
+ TP_printk("key=%08x %s",
+ __entry->key,
+ __print_symbolic(__entry->trace, key_dead_traces))
+ );
+
+TRACE_EVENT(key_quota,
+ TP_PROTO(const struct key_user *user, int change_keys, int change_bytes),
+
+ TP_ARGS(user, change_keys, change_bytes),
+
+ TP_STRUCT__entry(
+ __field(uid_t, uid)
+ __field(unsigned int, nkeys)
+ __field(unsigned int, nikeys)
+ __field(unsigned int, qnkeys)
+ __field(unsigned int, qnbytes)
+ __field(int, change_keys)
+ __field(int, change_bytes)
+ ),
+
+ TP_fast_assign(
+ __entry->uid = from_kuid(&init_user_ns, user->uid);
+ __entry->nkeys = atomic_read(&user->nkeys);
+ __entry->nikeys = atomic_read(&user->nikeys);
+ __entry->qnkeys = user->qnkeys;
+ __entry->qnbytes = user->qnbytes;
+ __entry->change_keys = change_keys;
+ __entry->change_bytes = change_bytes;
+ ),
+
+ TP_printk("uid=%d nkeys=%u/%u qkeys=%u qpay=%u ckeys=%d cpay=%d",
+ __entry->uid,
+ __entry->nikeys, __entry->nkeys,
+ __entry->qnkeys,
+ __entry->qnbytes,
+ __entry->change_keys, __entry->change_bytes)
+ );
+
+TRACE_EVENT(key_edquot,
+ TP_PROTO(const struct key_user *user, unsigned int maxkeys,
+ unsigned int maxbytes, unsigned int reqbytes),
+
+ TP_ARGS(user, maxkeys, maxbytes, reqbytes),
+
+ TP_STRUCT__entry(
+ __field(uid_t, uid)
+ __field(unsigned int, nkeys)
+ __field(unsigned int, nikeys)
+ __field(unsigned int, qnkeys)
+ __field(unsigned int, qnbytes)
+ __field(unsigned int, maxkeys)
+ __field(unsigned int, maxbytes)
+ __field(unsigned int, reqbytes)
+ ),
+
+ TP_fast_assign(
+ __entry->uid = from_kuid(&init_user_ns, user->uid);
+ __entry->nkeys = atomic_read(&user->nkeys);
+ __entry->nikeys = atomic_read(&user->nikeys);
+ __entry->qnkeys = user->qnkeys;
+ __entry->qnbytes = user->qnbytes;
+ __entry->maxkeys = maxkeys;
+ __entry->maxbytes = maxbytes;
+ __entry->reqbytes = reqbytes;
+ ),
+
+ TP_printk("u=%d nkeys=%u/%u qkeys=%u/%u qpay=%u/%u cpay=%u",
+ __entry->uid,
+ __entry->nikeys, __entry->nkeys,
+ __entry->qnkeys, __entry->maxkeys,
+ __entry->qnbytes, __entry->maxbytes,
+ __entry->reqbytes)
+ );
+
+TRACE_EVENT(key_link,
+ TP_PROTO(const struct key *keyring, const struct key *key),
+
+ TP_ARGS(keyring, key),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, keyring)
+ __field(key_serial_t, key)
+ ),
+
+ TP_fast_assign(
+ __entry->keyring = keyring->serial;
+ __entry->key = key->serial;
+ ),
+
+ TP_printk("key=%08x to=%08x",
+ __entry->key, __entry->keyring)
+ );
+
+TRACE_EVENT(key_unlink,
+ TP_PROTO(const struct key *keyring, const struct key *key),
+
+ TP_ARGS(keyring, key),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, keyring)
+ __field(key_serial_t, key)
+ ),
+
+ TP_fast_assign(
+ __entry->keyring = keyring->serial;
+ __entry->key = key->serial;
+ ),
+
+ TP_printk("key=%08x from=%08x",
+ __entry->key, __entry->keyring)
+ );
+
+TRACE_EVENT(key_move,
+ TP_PROTO(const struct key *from, const struct key *to,
+ const struct key *key),
+
+ TP_ARGS(from, to, key),
+
+ TP_STRUCT__entry(
+ __field(key_serial_t, from)
+ __field(key_serial_t, to)
+ __field(key_serial_t, key)
+ ),
+
+ TP_fast_assign(
+ __entry->from = from->serial;
+ __entry->to = to->serial;
+ __entry->key = key->serial;
+ ),
+
+ TP_printk("key=%08x from=%08x to=%08x",
+ __entry->key, __entry->from, __entry->to)
+ );
+
+TRACE_EVENT(key_clear,
+ TP_PROTO(const struct key *keyring),
+ TP_ARGS(keyring),
+ TP_STRUCT__entry(
+ __field(key_serial_t, keyring)
+ ),
+ TP_fast_assign(
+ __entry->keyring = keyring->serial;
+ ),
+ TP_printk("key=%08x",
+ __entry->keyring)
+ );
+
+TRACE_EVENT(key_revoke,
+ TP_PROTO(const struct key *key),
+ TP_ARGS(key),
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ ),
+ TP_fast_assign(
+ __entry->key = key->serial;
+ ),
+ TP_printk("key=%08x",
+ __entry->key)
+ );
+
+TRACE_EVENT(key_invalidate,
+ TP_PROTO(const struct key *key),
+ TP_ARGS(key),
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ ),
+ TP_fast_assign(
+ __entry->key = key->serial;
+ ),
+ TP_printk("key=%08x",
+ __entry->key)
+ );
+
+TRACE_EVENT(key_gc,
+ TP_PROTO(const struct key *key),
+ TP_ARGS(key),
+ TP_STRUCT__entry(
+ __field(key_serial_t, key)
+ ),
+ TP_fast_assign(
+ __entry->key = key->serial;
+ ),
+ TP_printk("key=%08x",
+ __entry->key)
+ );
+
+#undef EM
+#undef E_
+#endif /* _TRACE_KEY_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 7d687b0962b1..47f857653854 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -141,6 +141,7 @@ static noinline void key_gc_unused_keys(struct list_head *keys)

list_del(&key->graveyard_link);

+ trace_key_gc(key);
kdebug("- %u", key->serial);
key_check(key);

@@ -163,6 +164,8 @@ static noinline void key_gc_unused_keys(struct list_head *keys)
key_put_tag(key->domain_tag);
kfree(key->description);

+ trace_key_ref(key->serial, refcount_read(&key->usage),
+ key_trace_ref_free, 0);
memzero_explicit(key, sizeof(*key));
kmem_cache_free(key_jar, key);
}
@@ -331,6 +334,7 @@ static void key_garbage_collector(struct work_struct *work)
*/
found_unreferenced_key:
kdebug("unrefd key %d", key->serial);
+ trace_key_ref(key->serial, refcount_read(&key->usage), key_trace_ref_gc, 0);
rb_erase(&key->serial_node, &key_serial_tree);
spin_unlock(&key_serial_lock);

diff --git a/security/keys/internal.h b/security/keys/internal.h
index 2cffa6dc8255..87600683a7f5 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -19,6 +19,8 @@
#include <linux/compat.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
+#include <keys/key_user.h>
+#include <trace/events/key.h>

struct iovec;

@@ -43,25 +45,6 @@ extern struct key_type key_type_user;
extern struct key_type key_type_logon;

/*****************************************************************************/
-/*
- * Keep track of keys for a user.
- *
- * This needs to be separate to user_struct to avoid a refcount-loop
- * (user_struct pins some keyrings which pin this struct).
- *
- * We also keep track of keys under request from userspace for this UID here.
- */
-struct key_user {
- struct rb_node node;
- struct mutex cons_lock; /* construction initiation lock */
- spinlock_t lock;
- refcount_t usage; /* for accessing qnkeys & qnbytes */
- atomic_t nkeys; /* number of keys */
- atomic_t nikeys; /* number of instantiated keys */
- kuid_t uid;
- int qnkeys; /* number of keys allocated to this user */
- int qnbytes; /* number of bytes allocated to this user */
-};

extern struct rb_root key_user_tree;
extern spinlock_t key_user_lock;
@@ -211,26 +194,6 @@ extern struct key *request_key_auth_new(struct key *target,

extern struct key *key_get_instantiation_authkey(key_serial_t target_id);

-/*
- * Determine whether a key is dead.
- */
-static inline bool key_is_dead(const struct key *key, time64_t limit)
-{
- time64_t expiry = key->expiry;
-
- if (expiry != TIME64_MAX) {
- if (!(key->type->flags & KEY_TYPE_INSTANT_REAP))
- expiry += key_gc_delay;
- if (expiry <= limit)
- return true;
- }
-
- return
- key->flags & ((1 << KEY_FLAG_DEAD) |
- (1 << KEY_FLAG_INVALIDATED)) ||
- key->domain_tag->removed;
-}
-
/*
* keyctl() functions
*/
diff --git a/security/keys/key.c b/security/keys/key.c
index 3d7d185019d3..28a4128ff103 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -14,6 +14,7 @@
#include <linux/workqueue.h>
#include <linux/random.h>
#include <linux/err.h>
+#define CREATE_TRACE_POINTS
#include "internal.h"

struct kmem_cache *key_jar;
@@ -264,12 +265,15 @@ struct key *key_alloc(struct key_type *type, const char *desc,
if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
if (user->qnkeys + 1 > maxkeys ||
user->qnbytes + quotalen > maxbytes ||
- user->qnbytes + quotalen < user->qnbytes)
+ user->qnbytes + quotalen < user->qnbytes) {
+ trace_key_edquot(user, maxkeys, maxbytes, quotalen);
goto no_quota;
+ }
}

user->qnkeys++;
user->qnbytes += quotalen;
+ trace_key_quota(user, +1, quotalen);
spin_unlock_irqrestore(&user->lock, irqflags);
}

@@ -319,7 +323,10 @@ struct key *key_alloc(struct key_type *type, const char *desc,
/* publish the key by giving it a serial number */
refcount_inc(&key->domain_tag->usage);
atomic_inc(&user->nkeys);
+ trace_key_quota(user, 0, 0);
key_alloc_serial(key);
+ trace_key_alloc(key);
+ trace_key_ref(key->serial, 1, key_trace_ref_alloc, __builtin_return_address(0));

error:
return key;
@@ -331,6 +338,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
spin_lock_irqsave(&user->lock, irqflags);
user->qnkeys--;
user->qnbytes -= quotalen;
+ trace_key_quota(user, -1, -quotalen);
spin_unlock_irqrestore(&user->lock, irqflags);
}
key_user_put(user);
@@ -344,6 +352,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
spin_lock_irqsave(&user->lock, irqflags);
user->qnkeys--;
user->qnbytes -= quotalen;
+ trace_key_quota(user, -1, quotalen);
spin_unlock_irqrestore(&user->lock, irqflags);
}
key_user_put(user);
@@ -388,11 +397,13 @@ int key_payload_reserve(struct key *key, size_t datalen)
if (delta > 0 &&
(key->user->qnbytes + delta > maxbytes ||
key->user->qnbytes + delta < key->user->qnbytes)) {
+ trace_key_edquot(key->user, 0, maxbytes, datalen);
ret = -EDQUOT;
}
else {
key->user->qnbytes += delta;
key->quotalen += delta;
+ trace_key_quota(key->user, 0, delta);
}
spin_unlock_irqrestore(&key->user->lock, flags);
}
@@ -447,6 +458,7 @@ static int __key_instantiate_and_link(struct key *key,
if (ret == 0) {
/* mark the key as being instantiated */
atomic_inc(&key->user->nikeys);
+ trace_key_instantiate(key, prep);
mark_key_instantiated(key, 0);
notify_key(key, NOTIFY_KEY_INSTANTIATED, 0);

@@ -604,6 +616,7 @@ int key_reject_and_link(struct key *key,
if (key->state == KEY_IS_UNINSTANTIATED) {
/* mark the key as being negatively instantiated */
atomic_inc(&key->user->nikeys);
+ trace_key_reject(key, -error);
mark_key_instantiated(key, -error);
notify_key(key, NOTIFY_KEY_INSTANTIATED, -error);
key_set_expiry(key, ktime_get_real_seconds() + timeout);
@@ -635,6 +648,39 @@ int key_reject_and_link(struct key *key,
}
EXPORT_SYMBOL(key_reject_and_link);

+/**
+ * key_get - Get a reference on a key
+ * @key: The key to get a reference on.
+ *
+ * Get a reference on a key, if not NULL, and return the parameter.
+ */
+noinline struct key *key_get(struct key *key)
+{
+ if (key) {
+ int r;
+
+ __refcount_inc(&key->usage, &r);
+ trace_key_ref(key->serial, r + 1, key_trace_ref_get,
+ __builtin_return_address(0));
+ }
+ return key;
+}
+EXPORT_SYMBOL(key_get);
+
+/*
+ * Get a ref on a key if its refcount is not non-zero.
+ */
+noinline struct key *key_try_get(struct key *key)
+{
+ int r;
+
+ if (!__refcount_inc_not_zero(&key->usage, &r))
+ return NULL;
+ trace_key_ref(key->serial, r + 1, key_trace_ref_try_get,
+ __builtin_return_address(0));
+ return key;
+}
+
/**
* key_put - Discard a reference to a key.
* @key: The key to discard a reference from.
@@ -643,12 +689,19 @@ EXPORT_SYMBOL(key_reject_and_link);
* schedule the cleanup task to come and pull it out of the tree in process
* context at some later time.
*/
-void key_put(struct key *key)
+noinline void key_put(struct key *key)
{
if (key) {
+ key_serial_t serial = key->serial;
+ bool zero;
+ int r;
+
key_check(key);

- if (refcount_dec_and_test(&key->usage)) {
+ zero = __refcount_dec_and_test(&key->usage, &r);
+ trace_key_ref(serial, r - 1, key_trace_ref_put,
+ __builtin_return_address(0));
+ if (zero) {
unsigned long flags;

/* deal with the user's key tracking and quota */
@@ -656,6 +709,7 @@ void key_put(struct key *key)
spin_lock_irqsave(&key->user->lock, flags);
key->user->qnkeys--;
key->user->qnbytes -= key->quotalen;
+ trace_key_quota(key->user, -1, -key->quotalen);
spin_unlock_irqrestore(&key->user->lock, flags);
}
schedule_work(&key_gc_work);
@@ -695,7 +749,7 @@ struct key *key_lookup(key_serial_t id)
/* A key is allowed to be looked up only if someone still owns a
* reference to it - otherwise it's awaiting the gc.
*/
- if (!refcount_inc_not_zero(&key->usage))
+ if (!key_try_get(key))
goto not_found;

error:
@@ -779,6 +833,7 @@ static inline key_ref_t __key_update(key_ref_t key_ref,
ret = key->type->update(key, prep);
if (ret == 0) {
/* Updating a negative key positively instantiates it */
+ trace_key_update(key, prep);
mark_key_instantiated(key, 0);
notify_key(key, NOTIFY_KEY_UPDATED, 0);
}
@@ -1103,6 +1158,7 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen)
ret = key->type->update(key, &prep);
if (ret == 0) {
/* Updating a negative key positively instantiates it */
+ trace_key_update(key, &prep);
mark_key_instantiated(key, 0);
notify_key(key, NOTIFY_KEY_UPDATED, 0);
}
@@ -1138,6 +1194,7 @@ void key_revoke(struct key *key)
*/
down_write_nested(&key->sem, 1);
if (!test_and_set_bit(KEY_FLAG_REVOKED, &key->flags)) {
+ trace_key_revoke(key);
notify_key(key, NOTIFY_KEY_REVOKED, 0);
if (key->type->revoke)
key->type->revoke(key);
@@ -1170,6 +1227,7 @@ void key_invalidate(struct key *key)
if (!test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
down_write_nested(&key->sem, 1);
if (!test_and_set_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
+ trace_key_invalidate(key);
notify_key(key, NOTIFY_KEY_INVALIDATED, 0);
key_schedule_gc_links();
}
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 4bc3e9398ee3..8fa4ced5c915 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1020,11 +1020,13 @@ long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)

newowner->qnkeys++;
newowner->qnbytes += key->quotalen;
+ trace_key_quota(newowner, +1, key->quotalen);
spin_unlock_irqrestore(&newowner->lock, flags);

spin_lock_irqsave(&key->user->lock, flags);
key->user->qnkeys--;
key->user->qnbytes -= key->quotalen;
+ trace_key_quota(newowner, -1, -key->quotalen);
spin_unlock_irqrestore(&key->user->lock, flags);
}

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 4448758f643a..d67a60142318 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -920,7 +920,7 @@ key_ref_t keyring_search_rcu(key_ref_t keyring_ref,

ctx->now = ktime_get_real_seconds();
if (search_nested_keyrings(keyring, ctx))
- __key_get(key_ref_to_ptr(ctx->result));
+ key_ref_get(ctx->result);
return ctx->result;
}

@@ -1122,7 +1122,7 @@ key_ref_t find_key_to_update(key_ref_t keyring_ref,
kleave(" = NULL [x]");
return NULL;
}
- __key_get(key);
+ key_get(key);
kleave(" = {%d}", key->serial);
return make_key_ref(key, is_key_possessed(keyring_ref));
}
@@ -1174,7 +1174,7 @@ struct key *find_keyring_by_name(const char *name, bool uid_keyring)
/* we've got a match but we might end up racing with
* key_cleanup() if the keyring is currently 'dead'
* (ie. it has a zero usage count) */
- if (!refcount_inc_not_zero(&keyring->usage))
+ if (!key_try_get(keyring))
continue;
keyring->last_used_at = ktime_get_real_seconds();
goto out;
@@ -1367,7 +1367,8 @@ int __key_link_check_live_key(struct key *keyring, struct key *key)
void __key_link(struct key *keyring, struct key *key,
struct assoc_array_edit **_edit)
{
- __key_get(key);
+ key_get(key);
+ trace_key_link(keyring, key);
assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key));
assoc_array_apply_edit(*_edit);
*_edit = NULL;
@@ -1506,6 +1507,7 @@ static int __key_unlink_begin(struct key *keyring, struct key *key,
static void __key_unlink(struct key *keyring, struct key *key,
struct assoc_array_edit **_edit)
{
+ trace_key_unlink(keyring, key);
assoc_array_apply_edit(*_edit);
notify_key(keyring, NOTIFY_KEY_UNLINKED, key_serial(key));
*_edit = NULL;
@@ -1625,6 +1627,7 @@ int key_move(struct key *key,
if (ret < 0)
goto error;

+ trace_key_move(from_keyring, to_keyring, key);
__key_unlink(from_keyring, key, &from_edit);
__key_link(to_keyring, key, &to_edit);
error:
@@ -1654,6 +1657,7 @@ int keyring_clear(struct key *keyring)

down_write(&keyring->sem);

+ trace_key_clear(keyring);
edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
if (IS_ERR(edit)) {
ret = PTR_ERR(edit);
@@ -1687,6 +1691,39 @@ static void keyring_revoke(struct key *keyring)
}
}

+/*
+ * Determine whether a key is dead.
+ */
+static bool key_is_dead(const struct key *key, time64_t limit)
+{
+ time64_t expiry = key->expiry;
+
+ if (expiry != TIME64_MAX) {
+ if (!(key->type->flags & KEY_TYPE_INSTANT_REAP))
+ expiry += key_gc_delay;
+ if (expiry <= limit) {
+ trace_key_dead(key, key_trace_dead_expired);
+ return true;
+ }
+ }
+
+ if (test_bit(KEY_FLAG_DEAD, &key->flags)) {
+ trace_key_dead(key, key_trace_dead_type_removed);
+ return true;
+ }
+
+ if (test_bit(KEY_FLAG_INVALIDATED, &key->flags)) {
+ trace_key_dead(key, key_trace_dead_invalidated);
+ return true;
+ }
+
+ if (key->domain_tag->removed) {
+ trace_key_dead(key, key_trace_dead_domain_removed);
+ return true;
+ }
+ return false;
+}
+
static bool keyring_gc_select_iterator(void *object, void *iterator_data)
{
struct key *key = keyring_ptr_to_key(object);
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index b5d5333ab330..01291b2d0888 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -333,7 +333,7 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
if (IS_ERR(keyring))
return PTR_ERR(keyring);
} else {
- __key_get(keyring);
+ key_get(keyring);
}

/* install the keyring */
@@ -641,7 +641,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
}

key = ctx.cred->thread_keyring;
- __key_get(key);
+ key_get(key);
key_ref = make_key_ref(key, 1);
break;

@@ -658,8 +658,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
goto reget_creds;
}

- key = ctx.cred->process_keyring;
- __key_get(key);
+ key = key_get(ctx.cred->process_keyring);
key_ref = make_key_ref(key, 1);
break;

@@ -688,8 +687,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
goto reget_creds;
}

- key = ctx.cred->session_keyring;
- __key_get(key);
+ key = key_get(ctx.cred->session_keyring);
key_ref = make_key_ref(key, 1);
break;

@@ -717,7 +715,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
if (!key)
goto error;

- __key_get(key);
+ key_get(key);
key_ref = make_key_ref(key, 1);
break;

@@ -732,8 +730,7 @@ key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
key = NULL;
} else {
rka = ctx.cred->request_key_auth->payload.data[0];
- key = rka->dest_keyring;
- __key_get(key);
+ key = key_get(rka->dest_keyring);
}
up_read(&ctx.cred->request_key_auth->sem);
if (!key)