[PATCH bpf-next v2 0/4] Generalizing bpf_local_storage

[PATCH bpf-next v2 0/4] Generalizing bpf_local_storage

[KP Singh]

From: KP Singh <kpsingh@google.com>

# v1 -> v2

* Use the security blob pointer instead of dedicated member in
  struct inode.
* Better code re-use as suggested by Alexei.
* Dropped the inode count arithmetic as pointed out by Alexei.
* Minor bug fixes and rebase.

bpf_sk_storage can already be used by some BPF program types to annotate
socket objects. These annotations are managed with the life-cycle of the
object (i.e. freed when the object is freed) which makes BPF programs
much simpler and less prone to errors and leaks.

This patch series:

* Generalizes the bpf_sk_storage infrastructure to allow easy
  implementation of local storage for other objects
* Implements local storage for inodes
* Makes both bpf_{sk, inode}_storage available to LSM programs.

Local storage is safe to use in LSM programs as the attachment sites are
limited and the owning object won't be freed, however, this is not the
case for tracing. Usage in tracing is expected to follow a white-list
based approach similar to the d_path helper
(https://lore.kernel.org/bpf/20200506132946.2164578-1-jolsa@kernel.org).

Access to local storage would allow LSM programs to implement stateful
detections like detecting the unlink of a running executable from the
examples shared as a part of the KRSI series
https://lore.kernel.org/bpf/20200329004356.27286-1-kpsingh@chromium.org/
and
https://github.com/sinkap/linux-krsi/blob/patch/v1/examples/samples/bpf/lsm_detect_exec_unlink.c

KP Singh (4):
  bpf: Generalize bpf_sk_storage
  bpf: Implement bpf_local_storage for inodes
  bpf: Allow local storage to be used from LSM programs
  bpf: Add selftests for local_storage

 .../bpf_local_storage.h}                      |  15 +-
 include/linux/bpf_lsm.h                       |  21 +
 include/linux/bpf_types.h                     |   1 +
 include/net/sock.h                            |   4 +-
 include/uapi/linux/bpf.h                      |  56 +-
 kernel/bpf/Makefile                           |   1 +
 .../bpf/bpf_local_storage.c                   | 933 ++++++++++++------
 kernel/bpf/bpf_lsm.c                          |  20 +-
 kernel/bpf/cgroup.c                           |   2 +-
 kernel/bpf/syscall.c                          |   3 +-
 kernel/bpf/verifier.c                         |  10 +
 net/bpf/test_run.c                            |   2 +-
 net/core/Makefile                             |   1 -
 net/core/filter.c                             |   2 +-
 net/core/sock.c                               |   2 +-
 net/ipv4/bpf_tcp_ca.c                         |   2 +-
 net/ipv4/inet_diag.c                          |   2 +-
 security/bpf/hooks.c                          |   7 +
 tools/bpf/bpftool/map.c                       |   1 +
 tools/include/uapi/linux/bpf.h                |  56 +-
 tools/lib/bpf/libbpf_probes.c                 |   5 +-
 .../bpf/prog_tests/test_local_storage.c       |  60 ++
 .../selftests/bpf/progs/local_storage.c       | 137 +++
 23 files changed, 1038 insertions(+), 305 deletions(-)
 rename include/{net/bpf_sk_storage.h => linux/bpf_local_storage.h} (72%)
 rename net/core/bpf_sk_storage.c => kernel/bpf/bpf_local_storage.c (50%)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/local_storage.c

-- 
2.27.0.111.gc72c7da667-goog

[PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[KP Singh]

From: KP Singh <kpsingh@google.com>

Refactor the functionality in bpf_sk_storage.c so that concept of
storage linked to kernel objects can be extended to other objects like
inode, task_struct etc.

bpf_sk_storage is updated to be bpf_local_storage with a union that
contains a pointer to the owner object. The type of the
bpf_local_storage can be determined using the newly added
bpf_local_storage_type enum.

Each new local storage will still be a separate map and provide its own
set of helpers. This allows for future object specific extensions and
still share a lot of the underlying implementation.

Signed-off-by: KP Singh <kpsingh@google.com>
---
 .../bpf_local_storage.h}                      |   6 +-
 include/net/sock.h                            |   4 +-
 include/uapi/linux/bpf.h                      |  12 +-
 kernel/bpf/Makefile                           |   1 +
 .../bpf/bpf_local_storage.c                   | 652 ++++++++++--------
 kernel/bpf/cgroup.c                           |   2 +-
 net/bpf/test_run.c                            |   2 +-
 net/core/Makefile                             |   1 -
 net/core/filter.c                             |   2 +-
 net/core/sock.c                               |   2 +-
 net/ipv4/bpf_tcp_ca.c                         |   2 +-
 net/ipv4/inet_diag.c                          |   2 +-
 tools/include/uapi/linux/bpf.h                |  12 +-
 13 files changed, 405 insertions(+), 295 deletions(-)
 rename include/{net/bpf_sk_storage.h => linux/bpf_local_storage.h} (93%)
 rename net/core/bpf_sk_storage.c => kernel/bpf/bpf_local_storage.c (60%)

diff --git a/include/net/bpf_sk_storage.h b/include/linux/bpf_local_storage.h
similarity index 93%
rename from include/net/bpf_sk_storage.h
rename to include/linux/bpf_local_storage.h
index 5036c94c0503..85524f18cd91 100644
--- a/include/net/bpf_sk_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /* Copyright (c) 2019 Facebook */
-#ifndef _BPF_SK_STORAGE_H
-#define _BPF_SK_STORAGE_H
+#ifndef _BPF_LOCAL_STORAGE_H
+#define _BPF_LOCAL_STORAGE_H
 
 struct sock;
 
@@ -47,4 +47,4 @@ static inline int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
 }
 #endif
 
-#endif /* _BPF_SK_STORAGE_H */
+#endif /* _BPF_LOCAL_STORAGE_H */
diff --git a/include/net/sock.h b/include/net/sock.h
index c53cc42b5ab9..105e08a3e994 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -245,7 +245,7 @@ struct sock_common {
 	/* public: */
 };
 
-struct bpf_sk_storage;
+struct bpf_local_storage;
 
 /**
   *	struct sock - network layer representation of sockets
@@ -516,7 +516,7 @@ struct sock {
 	void                    (*sk_destruct)(struct sock *sk);
 	struct sock_reuseport __rcu	*sk_reuseport_cb;
 #ifdef CONFIG_BPF_SYSCALL
-	struct bpf_sk_storage __rcu	*sk_bpf_storage;
+	struct bpf_local_storage __rcu	*sk_bpf_storage;
 #endif
 	struct rcu_head		sk_rcu;
 };
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 19684813faae..6218677daaa2 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2798,10 +2798,10 @@ union bpf_attr {
  *		"type". The bpf-local-storage "type" (i.e. the *map*) is
  *		searched against all bpf-local-storages residing at *sk*.
  *
- *		An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
+ *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
  *		used such that a new bpf-local-storage will be
  *		created if one does not exist.  *value* can be used
- *		together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
+ *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
  *		the initial value of a bpf-local-storage.  If *value* is
  *		**NULL**, the new bpf-local-storage will be zero initialized.
  *	Return
@@ -3498,9 +3498,13 @@ enum {
 	BPF_F_SYSCTL_BASE_NAME		= (1ULL << 0),
 };
 
-/* BPF_FUNC_sk_storage_get flags */
+/* BPF_FUNC_<local>_storage_get flags */
 enum {
-	BPF_SK_STORAGE_GET_F_CREATE	= (1ULL << 0),
+	BPF_LOCAL_STORAGE_GET_F_CREATE	= (1ULL << 0),
+	/* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
+	 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
+	 */
+	BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
 };
 
 /* BPF_FUNC_read_branch_records flags. */
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 1131a921e1a6..0acb8f8a6042 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_BPF_JIT) += dispatcher.o
 ifeq ($(CONFIG_NET),y)
 obj-$(CONFIG_BPF_SYSCALL) += devmap.o
 obj-$(CONFIG_BPF_SYSCALL) += cpumap.o
+obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o
 obj-$(CONFIG_BPF_SYSCALL) += offload.o
 obj-$(CONFIG_BPF_SYSCALL) += net_namespace.o
 endif
diff --git a/net/core/bpf_sk_storage.c b/kernel/bpf/bpf_local_storage.c
similarity index 60%
rename from net/core/bpf_sk_storage.c
rename to kernel/bpf/bpf_local_storage.c
index d2c4d16dadba..314a923569d5 100644
--- a/net/core/bpf_sk_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -1,19 +1,22 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2019 Facebook  */
+#include "linux/bpf.h"
+#include "asm-generic/bug.h"
+#include "linux/err.h"
 #include <linux/rculist.h>
 #include <linux/list.h>
 #include <linux/hash.h>
 #include <linux/types.h>
 #include <linux/spinlock.h>
 #include <linux/bpf.h>
-#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
 #include <net/sock.h>
 #include <uapi/linux/sock_diag.h>
 #include <uapi/linux/btf.h>
 
 static atomic_t cache_idx;
 
-#define SK_STORAGE_CREATE_FLAG_MASK					\
+#define LOCAL_STORAGE_CREATE_FLAG_MASK					\
 	(BPF_F_NO_PREALLOC | BPF_F_CLONE)
 
 struct bucket {
@@ -21,11 +24,15 @@ struct bucket {
 	raw_spinlock_t lock;
 };
 
-/* Thp map is not the primary owner of a bpf_sk_storage_elem.
+enum bpf_local_storage_type {
+	BPF_LOCAL_STORAGE_SK,
+};
+
+/* Thp map is not the primary owner of a bpf_local_storage_elem.
  * Instead, the sk->sk_bpf_storage is.
  *
- * The map (bpf_sk_storage_map) is for two purposes
- * 1. Define the size of the "sk local storage".  It is
+ * The map (bpf_local_storage_map) is for two purposes
+ * 1. Define the size of the "local storage".  It is
  *    the map's value_size.
  *
  * 2. Maintain a list to keep track of all elems such
@@ -34,12 +41,12 @@ struct bucket {
  * When a bpf local storage is being looked up for a
  * particular sk,  the "bpf_map" pointer is actually used
  * as the "key" to search in the list of elem in
- * sk->sk_bpf_storage.
+ * the respective bpf_local_storage owned by the object.
  *
- * Hence, consider sk->sk_bpf_storage is the mini-map
- * with the "bpf_map" pointer as the searching key.
+ * e.g. sk->sk_bpf_storage is the mini-map with the "bpf_map" pointer
+ * as the searching key.
  */
-struct bpf_sk_storage_map {
+struct bpf_local_storage_map {
 	struct bpf_map map;
 	/* Lookup elem does not require accessing the map.
 	 *
@@ -53,46 +60,51 @@ struct bpf_sk_storage_map {
 	u16 cache_idx;
 };
 
-struct bpf_sk_storage_data {
+struct bpf_local_storage_data {
 	/* smap is used as the searching key when looking up
 	 * from sk->sk_bpf_storage.
 	 *
 	 * Put it in the same cacheline as the data to minimize
 	 * the number of cachelines access during the cache hit case.
 	 */
-	struct bpf_sk_storage_map __rcu *smap;
+	struct bpf_local_storage_map __rcu *smap;
 	u8 data[] __aligned(8);
 };
 
-/* Linked to bpf_sk_storage and bpf_sk_storage_map */
-struct bpf_sk_storage_elem {
-	struct hlist_node map_node;	/* Linked to bpf_sk_storage_map */
-	struct hlist_node snode;	/* Linked to bpf_sk_storage */
-	struct bpf_sk_storage __rcu *sk_storage;
+/* Linked to bpf_local_storage and bpf_local_storage_map */
+struct bpf_local_storage_elem {
+	struct hlist_node map_node;	/* Linked to bpf_local_storage_map */
+	struct hlist_node snode;	/* Linked to bpf_local_storage */
+	struct bpf_local_storage __rcu *local_storage;
 	struct rcu_head rcu;
 	/* 8 bytes hole */
 	/* The data is stored in aother cacheline to minimize
 	 * the number of cachelines access during a cache hit.
 	 */
-	struct bpf_sk_storage_data sdata ____cacheline_aligned;
+	struct bpf_local_storage_data sdata ____cacheline_aligned;
 };
 
-#define SELEM(_SDATA) container_of((_SDATA), struct bpf_sk_storage_elem, sdata)
+#define SELEM(_SDATA)                                                          \
+	container_of((_SDATA), struct bpf_local_storage_elem, sdata)
 #define SDATA(_SELEM) (&(_SELEM)->sdata)
-#define BPF_SK_STORAGE_CACHE_SIZE	16
-
-struct bpf_sk_storage {
-	struct bpf_sk_storage_data __rcu *cache[BPF_SK_STORAGE_CACHE_SIZE];
-	struct hlist_head list;	/* List of bpf_sk_storage_elem */
-	struct sock *sk;	/* The sk that owns the the above "list" of
-				 * bpf_sk_storage_elem.
-				 */
+#define BPF_STORAGE_CACHE_SIZE	16
+
+struct bpf_local_storage {
+	struct bpf_local_storage_data __rcu *cache[BPF_STORAGE_CACHE_SIZE];
+	struct hlist_head list;		/* List of bpf_local_storage_elem */
+	/* The object that owns the the above "list" of
+	 * bpf_local_storage_elem
+	 */
+	union {
+		struct sock *sk;
+	};
 	struct rcu_head rcu;
 	raw_spinlock_t lock;	/* Protect adding/removing from the "list" */
+	enum bpf_local_storage_type stype;
 };
 
-static struct bucket *select_bucket(struct bpf_sk_storage_map *smap,
-				    struct bpf_sk_storage_elem *selem)
+static struct bucket *select_bucket(struct bpf_local_storage_map *smap,
+				    struct bpf_local_storage_elem *selem)
 {
 	return &smap->buckets[hash_ptr(selem, smap->bucket_log)];
 }
@@ -109,24 +121,20 @@ static int omem_charge(struct sock *sk, unsigned int size)
 	return -ENOMEM;
 }
 
-static bool selem_linked_to_sk(const struct bpf_sk_storage_elem *selem)
+static bool selem_linked_to_node(const struct bpf_local_storage_elem *selem)
 {
 	return !hlist_unhashed(&selem->snode);
 }
 
-static bool selem_linked_to_map(const struct bpf_sk_storage_elem *selem)
+static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem)
 {
 	return !hlist_unhashed(&selem->map_node);
 }
 
-static struct bpf_sk_storage_elem *selem_alloc(struct bpf_sk_storage_map *smap,
-					       struct sock *sk, void *value,
-					       bool charge_omem)
+static struct bpf_local_storage_elem *selem_alloc(
+	struct bpf_local_storage_map *smap, void *value)
 {
-	struct bpf_sk_storage_elem *selem;
-
-	if (charge_omem && omem_charge(sk, smap->elem_size))
-		return NULL;
+	struct bpf_local_storage_elem *selem;
 
 	selem = kzalloc(smap->elem_size, GFP_ATOMIC | __GFP_NOWARN);
 	if (selem) {
@@ -135,94 +143,102 @@ static struct bpf_sk_storage_elem *selem_alloc(struct bpf_sk_storage_map *smap,
 		return selem;
 	}
 
+	return NULL;
+}
+
+static struct bpf_local_storage_elem *sk_selem_alloc(
+	struct bpf_local_storage_map *smap, struct sock *sk, void *value,
+	bool charge_omem)
+{
+	struct bpf_local_storage_elem *selem;
+
+	if (charge_omem && omem_charge(sk, smap->elem_size))
+		return NULL;
+
+	selem = selem_alloc(smap, value);
+	if (selem)
+		return selem;
+
 	if (charge_omem)
 		atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
 
 	return NULL;
 }
 
-/* sk_storage->lock must be held and selem->sk_storage == sk_storage.
+static void __unlink_local_storage(struct bpf_local_storage *local_storage,
+				   bool uncharge_omem)
+{
+	struct sock *sk;
+
+	switch (local_storage->stype) {
+	case BPF_LOCAL_STORAGE_SK:
+		sk = local_storage->sk;
+		if (uncharge_omem)
+			atomic_sub(sizeof(struct bpf_local_storage),
+				   &sk->sk_omem_alloc);
+
+		/* After this RCU_INIT, sk may be freed and cannot be used */
+		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
+		local_storage->sk = NULL;
+		break;
+	}
+}
+
+/* local_storage->lock must be held and selem->local_storage == local_storage.
  * The caller must ensure selem->smap is still valid to be
  * dereferenced for its smap->elem_size and smap->cache_idx.
+ *
+ * uncharge_omem is only relevant when:
+ *
+ *	local_storage->stype == BPF_LOCAL_STORAGE_SK
  */
-static bool __selem_unlink_sk(struct bpf_sk_storage *sk_storage,
-			      struct bpf_sk_storage_elem *selem,
-			      bool uncharge_omem)
+static bool __selem_unlink(struct bpf_local_storage *local_storage,
+			   struct bpf_local_storage_elem *selem,
+			   bool uncharge_omem)
 {
-	struct bpf_sk_storage_map *smap;
-	bool free_sk_storage;
-	struct sock *sk;
+	struct bpf_local_storage_map *smap;
+	bool free_local_storage;
 
 	smap = rcu_dereference(SDATA(selem)->smap);
-	sk = sk_storage->sk;
-
-	/* All uncharging on sk->sk_omem_alloc must be done first.
-	 * sk may be freed once the last selem is unlinked from sk_storage.
+	free_local_storage = hlist_is_singular_node(&selem->snode,
+						    &local_storage->list);
+
+	/* local_storage is not freed now.  local_storage->lock is
+	 * still held and raw_spin_unlock_bh(&local_storage->lock)
+	 * will be done by the caller.
+	 * Although the unlock will be done under
+	 * rcu_read_lock(),  it is more intutivie to
+	 * read if kfree_rcu(local_storage, rcu) is done
+	 * after the raw_spin_unlock_bh(&local_storage->lock).
+	 *
+	 * Hence, a "bool free_local_storage" is returned
+	 * to the caller which then calls the kfree_rcu()
+	 * after unlock.
 	 */
-	if (uncharge_omem)
-		atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
+	if (free_local_storage)
+		__unlink_local_storage(local_storage, uncharge_omem);
 
-	free_sk_storage = hlist_is_singular_node(&selem->snode,
-						 &sk_storage->list);
-	if (free_sk_storage) {
-		atomic_sub(sizeof(struct bpf_sk_storage), &sk->sk_omem_alloc);
-		sk_storage->sk = NULL;
-		/* After this RCU_INIT, sk may be freed and cannot be used */
-		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
 
-		/* sk_storage is not freed now.  sk_storage->lock is
-		 * still held and raw_spin_unlock_bh(&sk_storage->lock)
-		 * will be done by the caller.
-		 *
-		 * Although the unlock will be done under
-		 * rcu_read_lock(),  it is more intutivie to
-		 * read if kfree_rcu(sk_storage, rcu) is done
-		 * after the raw_spin_unlock_bh(&sk_storage->lock).
-		 *
-		 * Hence, a "bool free_sk_storage" is returned
-		 * to the caller which then calls the kfree_rcu()
-		 * after unlock.
-		 */
-	}
 	hlist_del_init_rcu(&selem->snode);
-	if (rcu_access_pointer(sk_storage->cache[smap->cache_idx]) ==
+	if (rcu_access_pointer(local_storage->cache[smap->cache_idx]) ==
 	    SDATA(selem))
-		RCU_INIT_POINTER(sk_storage->cache[smap->cache_idx], NULL);
+		RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL);
 
 	kfree_rcu(selem, rcu);
 
-	return free_sk_storage;
+	return free_local_storage;
 }
 
-static void selem_unlink_sk(struct bpf_sk_storage_elem *selem)
+static void __selem_link(struct bpf_local_storage *local_storage,
+			    struct bpf_local_storage_elem *selem)
 {
-	struct bpf_sk_storage *sk_storage;
-	bool free_sk_storage = false;
-
-	if (unlikely(!selem_linked_to_sk(selem)))
-		/* selem has already been unlinked from sk */
-		return;
-
-	sk_storage = rcu_dereference(selem->sk_storage);
-	raw_spin_lock_bh(&sk_storage->lock);
-	if (likely(selem_linked_to_sk(selem)))
-		free_sk_storage = __selem_unlink_sk(sk_storage, selem, true);
-	raw_spin_unlock_bh(&sk_storage->lock);
-
-	if (free_sk_storage)
-		kfree_rcu(sk_storage, rcu);
-}
-
-static void __selem_link_sk(struct bpf_sk_storage *sk_storage,
-			    struct bpf_sk_storage_elem *selem)
-{
-	RCU_INIT_POINTER(selem->sk_storage, sk_storage);
-	hlist_add_head(&selem->snode, &sk_storage->list);
+	RCU_INIT_POINTER(selem->local_storage, local_storage);
+	hlist_add_head(&selem->snode, &local_storage->list);
 }
 
-static void selem_unlink_map(struct bpf_sk_storage_elem *selem)
+static void selem_unlink_map(struct bpf_local_storage_elem *selem)
 {
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage_map *smap;
 	struct bucket *b;
 
 	if (unlikely(!selem_linked_to_map(selem)))
@@ -237,8 +253,8 @@ static void selem_unlink_map(struct bpf_sk_storage_elem *selem)
 	raw_spin_unlock_bh(&b->lock);
 }
 
-static void selem_link_map(struct bpf_sk_storage_map *smap,
-			   struct bpf_sk_storage_elem *selem)
+static void selem_link_map(struct bpf_local_storage_map *smap,
+			   struct bpf_local_storage_elem *selem)
 {
 	struct bucket *b = select_bucket(smap, selem);
 
@@ -248,31 +264,46 @@ static void selem_link_map(struct bpf_sk_storage_map *smap,
 	raw_spin_unlock_bh(&b->lock);
 }
 
-static void selem_unlink(struct bpf_sk_storage_elem *selem)
+static void selem_unlink(struct bpf_local_storage_elem *selem)
 {
-	/* Always unlink from map before unlinking from sk_storage
+	struct bpf_local_storage *local_storage;
+	bool free_local_storage = false;
+
+	/* Always unlink from map before unlinking from local_storage
 	 * because selem will be freed after successfully unlinked from
-	 * the sk_storage.
+	 * the local_storage.
 	 */
 	selem_unlink_map(selem);
-	selem_unlink_sk(selem);
+
+	if (unlikely(!selem_linked_to_node(selem)))
+		/* selem has already been unlinked from its owner */
+		return;
+
+	local_storage = rcu_dereference(selem->local_storage);
+	raw_spin_lock_bh(&local_storage->lock);
+	if (likely(selem_linked_to_node(selem)))
+		free_local_storage = __selem_unlink(local_storage, selem, true);
+	raw_spin_unlock_bh(&local_storage->lock);
+
+	if (free_local_storage)
+		kfree_rcu(local_storage, rcu);
 }
 
-static struct bpf_sk_storage_data *
-__sk_storage_lookup(struct bpf_sk_storage *sk_storage,
-		    struct bpf_sk_storage_map *smap,
+static struct bpf_local_storage_data *
+__local_storage_lookup(struct bpf_local_storage *local_storage,
+		    struct bpf_local_storage_map *smap,
 		    bool cacheit_lockit)
 {
-	struct bpf_sk_storage_data *sdata;
-	struct bpf_sk_storage_elem *selem;
+	struct bpf_local_storage_data *sdata;
+	struct bpf_local_storage_elem *selem;
 
 	/* Fast path (cache hit) */
-	sdata = rcu_dereference(sk_storage->cache[smap->cache_idx]);
+	sdata = rcu_dereference(local_storage->cache[smap->cache_idx]);
 	if (sdata && rcu_access_pointer(sdata->smap) == smap)
 		return sdata;
 
 	/* Slow path (cache miss) */
-	hlist_for_each_entry_rcu(selem, &sk_storage->list, snode)
+	hlist_for_each_entry_rcu(selem, &local_storage->list, snode)
 		if (rcu_access_pointer(SDATA(selem)->smap) == smap)
 			break;
 
@@ -284,33 +315,33 @@ __sk_storage_lookup(struct bpf_sk_storage *sk_storage,
 		/* spinlock is needed to avoid racing with the
 		 * parallel delete.  Otherwise, publishing an already
 		 * deleted sdata to the cache will become a use-after-free
-		 * problem in the next __sk_storage_lookup().
+		 * problem in the next __local_storage_lookup().
 		 */
-		raw_spin_lock_bh(&sk_storage->lock);
-		if (selem_linked_to_sk(selem))
-			rcu_assign_pointer(sk_storage->cache[smap->cache_idx],
-					   sdata);
-		raw_spin_unlock_bh(&sk_storage->lock);
+		raw_spin_lock_bh(&local_storage->lock);
+		if (selem_linked_to_node(selem))
+			rcu_assign_pointer(
+				local_storage->cache[smap->cache_idx], sdata);
+		raw_spin_unlock_bh(&local_storage->lock);
 	}
 
 	return sdata;
 }
 
-static struct bpf_sk_storage_data *
+static struct bpf_local_storage_data *
 sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
 {
-	struct bpf_sk_storage *sk_storage;
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage *sk_storage;
+	struct bpf_local_storage_map *smap;
 
 	sk_storage = rcu_dereference(sk->sk_bpf_storage);
 	if (!sk_storage)
 		return NULL;
 
-	smap = (struct bpf_sk_storage_map *)map;
-	return __sk_storage_lookup(sk_storage, smap, cacheit_lockit);
+	smap = (struct bpf_local_storage_map *)map;
+	return __local_storage_lookup(sk_storage, smap, cacheit_lockit);
 }
 
-static int check_flags(const struct bpf_sk_storage_data *old_sdata,
+static int check_flags(const struct bpf_local_storage_data *old_sdata,
 		       u64 map_flags)
 {
 	if (old_sdata && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
@@ -324,127 +355,190 @@ static int check_flags(const struct bpf_sk_storage_data *old_sdata,
 	return 0;
 }
 
-static int sk_storage_alloc(struct sock *sk,
-			    struct bpf_sk_storage_map *smap,
-			    struct bpf_sk_storage_elem *first_selem)
+static struct bpf_local_storage *
+bpf_local_storage_alloc(struct bpf_local_storage_map *smap)
 {
-	struct bpf_sk_storage *prev_sk_storage, *sk_storage;
-	int err;
+	struct bpf_local_storage *storage;
 
-	err = omem_charge(sk, sizeof(*sk_storage));
-	if (err)
-		return err;
+	storage = kzalloc(sizeof(*storage), GFP_ATOMIC | __GFP_NOWARN);
+	if (!storage)
+		return NULL;
 
-	sk_storage = kzalloc(sizeof(*sk_storage), GFP_ATOMIC | __GFP_NOWARN);
-	if (!sk_storage) {
-		err = -ENOMEM;
-		goto uncharge;
-	}
-	INIT_HLIST_HEAD(&sk_storage->list);
-	raw_spin_lock_init(&sk_storage->lock);
-	sk_storage->sk = sk;
+	INIT_HLIST_HEAD(&storage->list);
+	raw_spin_lock_init(&storage->lock);
+	return storage;
+}
 
-	__selem_link_sk(sk_storage, first_selem);
-	selem_link_map(smap, first_selem);
-	/* Publish sk_storage to sk.  sk->sk_lock cannot be acquired.
-	 * Hence, atomic ops is used to set sk->sk_bpf_storage
-	 * from NULL to the newly allocated sk_storage ptr.
-	 *
-	 * From now on, the sk->sk_bpf_storage pointer is protected
-	 * by the sk_storage->lock.  Hence,  when freeing
-	 * the sk->sk_bpf_storage, the sk_storage->lock must
-	 * be held before setting sk->sk_bpf_storage to NULL.
-	 */
-	prev_sk_storage = cmpxchg((struct bpf_sk_storage **)&sk->sk_bpf_storage,
-				  NULL, sk_storage);
-	if (unlikely(prev_sk_storage)) {
-		selem_unlink_map(first_selem);
-		err = -EAGAIN;
-		goto uncharge;
+/* Publish local_storage to the address.  This is used because we are already
+ * in a region where we cannot grab a lock on the object owning the storage (
+ * (e.g sk->sk_lock). Hence, atomic ops is used.
+ *
+ * From now on, the addr pointer is protected
+ * by the local_storage->lock.  Hence, upon freeing,
+ * the local_storage->lock must be held before unlinking the storage from the
+ * owner.
+ */
+static int publish_local_storage(struct bpf_local_storage_elem *first_selem,
+				 struct bpf_local_storage **addr,
+				 struct bpf_local_storage *curr)
+{
+	struct bpf_local_storage *prev;
 
+	prev = cmpxchg(addr, NULL, curr);
+	if (unlikely(prev)) {
 		/* Note that even first_selem was linked to smap's
 		 * bucket->list, first_selem can be freed immediately
 		 * (instead of kfree_rcu) because
-		 * bpf_sk_storage_map_free() does a
+		 * bpf_local_storage_map_free() does a
 		 * synchronize_rcu() before walking the bucket->list.
 		 * Hence, no one is accessing selem from the
 		 * bucket->list under rcu_read_lock().
 		 */
+		selem_unlink_map(first_selem);
+		return -EAGAIN;
 	}
 
 	return 0;
+}
+
+static int sk_storage_alloc(struct sock *sk,
+			    struct bpf_local_storage_map *smap,
+			    struct bpf_local_storage_elem *first_selem)
+{
+	struct bpf_local_storage *curr;
+	int err;
+
+	err = omem_charge(sk, sizeof(*curr));
+	if (err)
+		return err;
+
+	curr = bpf_local_storage_alloc(smap);
+	if (!curr) {
+		err = -ENOMEM;
+		goto uncharge;
+	}
+
+	curr->sk = sk;
+	curr->stype = BPF_LOCAL_STORAGE_SK;
+
+	__selem_link(curr, first_selem);
+	selem_link_map(smap, first_selem);
+
+	err = publish_local_storage(first_selem,
+		(struct bpf_local_storage **)&sk->sk_bpf_storage, curr);
+	if (err)
+		goto uncharge;
+
+	return 0;
 
 uncharge:
-	kfree(sk_storage);
-	atomic_sub(sizeof(*sk_storage), &sk->sk_omem_alloc);
+	kfree(curr);
+	atomic_sub(sizeof(*curr), &sk->sk_omem_alloc);
 	return err;
 }
 
+static int check_update_flags(struct bpf_map *map, u64 map_flags)
+{
+	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) ||
+	    /* BPF_F_LOCK can only be used in a value with spin_lock */
+	    unlikely((map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int map_to_storage_type(struct bpf_map *map)
+{
+	switch (map->map_type) {
+	case BPF_MAP_TYPE_SK_STORAGE:
+		return BPF_LOCAL_STORAGE_SK;
+	default:
+		return -EINVAL;
+	}
+}
+
 /* sk cannot be going away because it is linking new elem
  * to sk->sk_bpf_storage. (i.e. sk->sk_refcnt cannot be 0).
  * Otherwise, it will become a leak (and other memory issues
  * during map destruction).
  */
-static struct bpf_sk_storage_data *sk_storage_update(struct sock *sk,
-						     struct bpf_map *map,
-						     void *value,
-						     u64 map_flags)
+static struct bpf_local_storage_data *local_storage_update(
+	void *owner, struct bpf_map *map, void *value, u64 map_flags)
 {
-	struct bpf_sk_storage_data *old_sdata = NULL;
-	struct bpf_sk_storage_elem *selem;
-	struct bpf_sk_storage *sk_storage;
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage_data *old_sdata = NULL;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *local_storage;
+	struct bpf_local_storage_map *smap;
+	enum bpf_local_storage_type stype;
+	struct sock *sk;
 	int err;
 
-	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
-	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST) ||
-	    /* BPF_F_LOCK can only be used in a value with spin_lock */
-	    unlikely((map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)))
+	err = check_update_flags(map, map_flags);
+	if (err)
+		return ERR_PTR(err);
+
+	stype = map_to_storage_type(map);
+	if (stype < 0)
+		return ERR_PTR(stype);
+
+	smap = (struct bpf_local_storage_map *)map;
+
+	switch (stype) {
+	case BPF_LOCAL_STORAGE_SK:
+		sk = owner;
+		local_storage = rcu_dereference(sk->sk_bpf_storage);
+		break;
+	default:
+		WARN_ON_ONCE(1);
 		return ERR_PTR(-EINVAL);
+	}
 
-	smap = (struct bpf_sk_storage_map *)map;
-	sk_storage = rcu_dereference(sk->sk_bpf_storage);
-	if (!sk_storage || hlist_empty(&sk_storage->list)) {
-		/* Very first elem for this sk */
+	if (!local_storage || hlist_empty(&local_storage->list)) {
+		/* Very first elem */
 		err = check_flags(NULL, map_flags);
 		if (err)
 			return ERR_PTR(err);
 
-		selem = selem_alloc(smap, sk, value, true);
-		if (!selem)
-			return ERR_PTR(-ENOMEM);
+		switch (stype) {
+		case BPF_LOCAL_STORAGE_SK:
+			selem = sk_selem_alloc(smap, sk, value, true);
+			if (!selem)
+				return ERR_PTR(-ENOMEM);
+
+			err = sk_storage_alloc(sk, smap, selem);
+			if (err) {
+				kfree(selem);
+				atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
+				return ERR_PTR(err);
+			}
 
-		err = sk_storage_alloc(sk, smap, selem);
-		if (err) {
-			kfree(selem);
-			atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
-			return ERR_PTR(err);
+			return SDATA(selem);
 		}
-
-		return SDATA(selem);
 	}
 
 	if ((map_flags & BPF_F_LOCK) && !(map_flags & BPF_NOEXIST)) {
 		/* Hoping to find an old_sdata to do inline update
-		 * such that it can avoid taking the sk_storage->lock
+		 * such that it can avoid taking the local_storage->lock
 		 * and changing the lists.
 		 */
-		old_sdata = __sk_storage_lookup(sk_storage, smap, false);
+		old_sdata = __local_storage_lookup(local_storage, smap, false);
 		err = check_flags(old_sdata, map_flags);
 		if (err)
 			return ERR_PTR(err);
-		if (old_sdata && selem_linked_to_sk(SELEM(old_sdata))) {
+
+		if (old_sdata && selem_linked_to_node(SELEM(old_sdata))) {
 			copy_map_value_locked(map, old_sdata->data,
 					      value, false);
 			return old_sdata;
 		}
 	}
 
-	raw_spin_lock_bh(&sk_storage->lock);
+	raw_spin_lock_bh(&local_storage->lock);
 
-	/* Recheck sk_storage->list under sk_storage->lock */
-	if (unlikely(hlist_empty(&sk_storage->list))) {
-		/* A parallel del is happening and sk_storage is going
+	/* Recheck local_storage->list under local_storage->lock */
+	if (unlikely(hlist_empty(&local_storage->list))) {
+		/* A parallel del is happening and local_storage is going
 		 * away.  It has just been checked before, so very
 		 * unlikely.  Return instead of retry to keep things
 		 * simple.
@@ -453,7 +547,7 @@ static struct bpf_sk_storage_data *sk_storage_update(struct sock *sk,
 		goto unlock_err;
 	}
 
-	old_sdata = __sk_storage_lookup(sk_storage, smap, false);
+	old_sdata = __local_storage_lookup(local_storage, smap, false);
 	err = check_flags(old_sdata, map_flags);
 	if (err)
 		goto unlock_err;
@@ -464,44 +558,48 @@ static struct bpf_sk_storage_data *sk_storage_update(struct sock *sk,
 		goto unlock;
 	}
 
-	/* sk_storage->lock is held.  Hence, we are sure
+	/* local_storage->lock is held.  Hence, we are sure
 	 * we can unlink and uncharge the old_sdata successfully
 	 * later.  Hence, instead of charging the new selem now
 	 * and then uncharge the old selem later (which may cause
 	 * a potential but unnecessary charge failure),  avoid taking
 	 * a charge at all here (the "!old_sdata" check) and the
-	 * old_sdata will not be uncharged later during __selem_unlink_sk().
+	 * old_sdata will not be uncharged later during __selem_unlink().
 	 */
-	selem = selem_alloc(smap, sk, value, !old_sdata);
-	if (!selem) {
-		err = -ENOMEM;
-		goto unlock_err;
+	switch (stype) {
+	case BPF_LOCAL_STORAGE_SK:
+		selem = sk_selem_alloc(smap, sk, value, !old_sdata);
+		if (!selem) {
+			err = -ENOMEM;
+			goto unlock_err;
+		}
+		break;
 	}
 
 	/* First, link the new selem to the map */
 	selem_link_map(smap, selem);
 
-	/* Second, link (and publish) the new selem to sk_storage */
-	__selem_link_sk(sk_storage, selem);
+	/* Second, link (and publish) the new selem to local_storage */
+	__selem_link(local_storage, selem);
 
 	/* Third, remove old selem, SELEM(old_sdata) */
 	if (old_sdata) {
 		selem_unlink_map(SELEM(old_sdata));
-		__selem_unlink_sk(sk_storage, SELEM(old_sdata), false);
+		__selem_unlink(local_storage, SELEM(old_sdata), false);
 	}
 
 unlock:
-	raw_spin_unlock_bh(&sk_storage->lock);
+	raw_spin_unlock_bh(&local_storage->lock);
 	return SDATA(selem);
 
 unlock_err:
-	raw_spin_unlock_bh(&sk_storage->lock);
+	raw_spin_unlock_bh(&local_storage->lock);
 	return ERR_PTR(err);
 }
 
 static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
 {
-	struct bpf_sk_storage_data *sdata;
+	struct bpf_local_storage_data *sdata;
 
 	sdata = sk_storage_lookup(sk, map, false);
 	if (!sdata)
@@ -515,8 +613,8 @@ static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
 /* Called by __sk_destruct() & bpf_sk_storage_clone() */
 void bpf_sk_storage_free(struct sock *sk)
 {
-	struct bpf_sk_storage_elem *selem;
-	struct bpf_sk_storage *sk_storage;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *sk_storage;
 	bool free_sk_storage = false;
 	struct hlist_node *n;
 
@@ -530,9 +628,9 @@ void bpf_sk_storage_free(struct sock *sk)
 	/* Netiher the bpf_prog nor the bpf-map's syscall
 	 * could be modifying the sk_storage->list now.
 	 * Thus, no elem can be added-to or deleted-from the
-	 * sk_storage->list by the bpf_prog or by the bpf-map's syscall.
+	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
 	 *
-	 * It is racing with bpf_sk_storage_map_free() alone
+	 * It is racing with bpf_local_storage_map_free() alone
 	 * when unlinking elem from the sk_storage->list and
 	 * the map's bucket->list.
 	 */
@@ -542,7 +640,7 @@ void bpf_sk_storage_free(struct sock *sk)
 		 * sk_storage.
 		 */
 		selem_unlink_map(selem);
-		free_sk_storage = __selem_unlink_sk(sk_storage, selem, true);
+		free_sk_storage = __selem_unlink(sk_storage, selem, true);
 	}
 	raw_spin_unlock_bh(&sk_storage->lock);
 	rcu_read_unlock();
@@ -551,14 +649,14 @@ void bpf_sk_storage_free(struct sock *sk)
 		kfree_rcu(sk_storage, rcu);
 }
 
-static void bpf_sk_storage_map_free(struct bpf_map *map)
+static void bpf_local_storage_map_free(struct bpf_map *map)
 {
-	struct bpf_sk_storage_elem *selem;
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map *smap;
 	struct bucket *b;
 	unsigned int i;
 
-	smap = (struct bpf_sk_storage_map *)map;
+	smap = (struct bpf_local_storage_map *)map;
 
 	/* Note that this map might be concurrently cloned from
 	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
@@ -569,11 +667,11 @@ static void bpf_sk_storage_map_free(struct bpf_map *map)
 
 	/* bpf prog and the userspace can no longer access this map
 	 * now.  No new selem (of this map) can be added
-	 * to the sk->sk_bpf_storage or to the map bucket's list.
+	 * to the bpf_local_storage or to the map bucket's list.
 	 *
 	 * The elem of this map can be cleaned up here
-	 * or
-	 * by bpf_sk_storage_free() during __sk_destruct().
+	 * or by bpf_local_storage_free() during the destruction of the
+	 * owner object. eg. __sk_destruct.
 	 */
 	for (i = 0; i < (1U << smap->bucket_log); i++) {
 		b = &smap->buckets[i];
@@ -581,7 +679,7 @@ static void bpf_sk_storage_map_free(struct bpf_map *map)
 		rcu_read_lock();
 		/* No one is adding to b->list now */
 		while ((selem = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(&b->list)),
-						 struct bpf_sk_storage_elem,
+						 struct bpf_local_storage_elem,
 						 map_node))) {
 			selem_unlink(selem);
 			cond_resched_rcu();
@@ -589,17 +687,17 @@ static void bpf_sk_storage_map_free(struct bpf_map *map)
 		rcu_read_unlock();
 	}
 
-	/* bpf_sk_storage_free() may still need to access the map.
-	 * e.g. bpf_sk_storage_free() has unlinked selem from the map
+	/* bpf_local_storage_free() may still need to access the map.
+	 * e.g. bpf_local_storage_free() has unlinked selem from the map
 	 * which then made the above while((selem = ...)) loop
 	 * exited immediately.
 	 *
-	 * However, the bpf_sk_storage_free() still needs to access
+	 * However, the bpf_local_storage_free() still needs to access
 	 * the smap->elem_size to do the uncharging in
-	 * __selem_unlink_sk().
+	 * __selem_unlink().
 	 *
 	 * Hence, wait another rcu grace period for the
-	 * bpf_sk_storage_free() to finish.
+	 * bpf_local_storage_free() to finish.
 	 */
 	synchronize_rcu();
 
@@ -612,12 +710,13 @@ static void bpf_sk_storage_map_free(struct bpf_map *map)
  */
 #define MAX_VALUE_SIZE							\
 	min_t(u32,							\
-	      (KMALLOC_MAX_SIZE - MAX_BPF_STACK - sizeof(struct bpf_sk_storage_elem)), \
-	      (U16_MAX - sizeof(struct bpf_sk_storage_elem)))
+	      (KMALLOC_MAX_SIZE - MAX_BPF_STACK -			\
+	       sizeof(struct bpf_local_storage_elem)),			\
+	      (U16_MAX - sizeof(struct bpf_local_storage_elem)))
 
-static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
+static int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
 {
-	if (attr->map_flags & ~SK_STORAGE_CREATE_FLAG_MASK ||
+	if (attr->map_flags & ~LOCAL_STORAGE_CREATE_FLAG_MASK ||
 	    !(attr->map_flags & BPF_F_NO_PREALLOC) ||
 	    attr->max_entries ||
 	    attr->key_size != sizeof(int) || !attr->value_size ||
@@ -634,9 +733,11 @@ static int bpf_sk_storage_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
-static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
+
+static struct bpf_map *
+bpf_local_storage_map_alloc(union bpf_attr *attr)
 {
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage_map *smap;
 	unsigned int i;
 	u32 nbuckets;
 	u64 cost;
@@ -672,9 +773,10 @@ static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
 		raw_spin_lock_init(&smap->buckets[i].lock);
 	}
 
-	smap->elem_size = sizeof(struct bpf_sk_storage_elem) + attr->value_size;
+	smap->elem_size =
+		sizeof(struct bpf_local_storage_elem) + attr->value_size;
 	smap->cache_idx = (unsigned int)atomic_inc_return(&cache_idx) %
-		BPF_SK_STORAGE_CACHE_SIZE;
+		BPF_STORAGE_CACHE_SIZE;
 
 	return &smap->map;
 }
@@ -685,7 +787,7 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
 	return -ENOTSUPP;
 }
 
-static int bpf_sk_storage_map_check_btf(const struct bpf_map *map,
+static int bpf_local_storage_map_check_btf(const struct bpf_map *map,
 					const struct btf *btf,
 					const struct btf_type *key_type,
 					const struct btf_type *value_type)
@@ -702,11 +804,11 @@ static int bpf_sk_storage_map_check_btf(const struct bpf_map *map,
 	return 0;
 }
 
-static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key)
+static void *bpf_sk_storage_lookup_elem(struct bpf_map *map, void *key)
 {
-	struct bpf_sk_storage_data *sdata;
+	struct bpf_local_storage_data *sdata;
 	struct socket *sock;
-	int fd, err;
+	int fd, err = -EINVAL;
 
 	fd = *(int *)key;
 	sock = sockfd_lookup(fd, &err);
@@ -719,17 +821,17 @@ static void *bpf_fd_sk_storage_lookup_elem(struct bpf_map *map, void *key)
 	return ERR_PTR(err);
 }
 
-static int bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key,
+static int bpf_sk_storage_update_elem(struct bpf_map *map, void *key,
 					 void *value, u64 map_flags)
 {
-	struct bpf_sk_storage_data *sdata;
+	struct bpf_local_storage_data *sdata;
 	struct socket *sock;
 	int fd, err;
 
 	fd = *(int *)key;
 	sock = sockfd_lookup(fd, &err);
 	if (sock) {
-		sdata = sk_storage_update(sock->sk, map, value, map_flags);
+		sdata = local_storage_update(sock->sk, map, value, map_flags);
 		sockfd_put(sock);
 		return PTR_ERR_OR_ZERO(sdata);
 	}
@@ -737,7 +839,7 @@ static int bpf_fd_sk_storage_update_elem(struct bpf_map *map, void *key,
 	return err;
 }
 
-static int bpf_fd_sk_storage_delete_elem(struct bpf_map *map, void *key)
+static int bpf_sk_storage_delete_elem(struct bpf_map *map, void *key)
 {
 	struct socket *sock;
 	int fd, err;
@@ -747,20 +849,19 @@ static int bpf_fd_sk_storage_delete_elem(struct bpf_map *map, void *key)
 	if (sock) {
 		err = sk_storage_delete(sock->sk, map);
 		sockfd_put(sock);
-		return err;
 	}
 
 	return err;
 }
 
-static struct bpf_sk_storage_elem *
+static struct bpf_local_storage_elem *
 bpf_sk_storage_clone_elem(struct sock *newsk,
-			  struct bpf_sk_storage_map *smap,
-			  struct bpf_sk_storage_elem *selem)
+			  struct bpf_local_storage_map *smap,
+			  struct bpf_local_storage_elem *selem)
 {
-	struct bpf_sk_storage_elem *copy_selem;
+	struct bpf_local_storage_elem *copy_selem;
 
-	copy_selem = selem_alloc(smap, newsk, NULL, true);
+	copy_selem = sk_selem_alloc(smap, newsk, NULL, true);
 	if (!copy_selem)
 		return NULL;
 
@@ -776,9 +877,9 @@ bpf_sk_storage_clone_elem(struct sock *newsk,
 
 int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 {
-	struct bpf_sk_storage *new_sk_storage = NULL;
-	struct bpf_sk_storage *sk_storage;
-	struct bpf_sk_storage_elem *selem;
+	struct bpf_local_storage *new_sk_storage = NULL;
+	struct bpf_local_storage *sk_storage;
+	struct bpf_local_storage_elem *selem;
 	int ret = 0;
 
 	RCU_INIT_POINTER(newsk->sk_bpf_storage, NULL);
@@ -790,8 +891,8 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 		goto out;
 
 	hlist_for_each_entry_rcu(selem, &sk_storage->list, snode) {
-		struct bpf_sk_storage_elem *copy_selem;
-		struct bpf_sk_storage_map *smap;
+		struct bpf_local_storage_elem *copy_selem;
+		struct bpf_local_storage_map *smap;
 		struct bpf_map *map;
 
 		smap = rcu_dereference(SDATA(selem)->smap);
@@ -799,7 +900,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 			continue;
 
 		/* Note that for lockless listeners adding new element
-		 * here can race with cleanup in bpf_sk_storage_map_free.
+		 * here can race with cleanup in bpf_local_storage_map_free.
 		 * Try to grab map refcnt to make sure that it's still
 		 * alive and prevent concurrent removal.
 		 */
@@ -816,7 +917,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 
 		if (new_sk_storage) {
 			selem_link_map(smap, copy_selem);
-			__selem_link_sk(new_sk_storage, copy_selem);
+			__selem_link(new_sk_storage, copy_selem);
 		} else {
 			ret = sk_storage_alloc(newsk, smap, copy_selem);
 			if (ret) {
@@ -827,7 +928,8 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 				goto out;
 			}
 
-			new_sk_storage = rcu_dereference(copy_selem->sk_storage);
+			new_sk_storage =
+				rcu_dereference(copy_selem->local_storage);
 		}
 		bpf_map_put(map);
 	}
@@ -836,7 +938,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 	rcu_read_unlock();
 
 	/* In case of an error, don't free anything explicitly here, the
-	 * caller is responsible to call bpf_sk_storage_free.
+	 * caller is responsible to call bpf_local_storage_free.
 	 */
 
 	return ret;
@@ -845,7 +947,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
 BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
 	   void *, value, u64, flags)
 {
-	struct bpf_sk_storage_data *sdata;
+	struct bpf_local_storage_data *sdata;
 
 	if (flags > BPF_SK_STORAGE_GET_F_CREATE)
 		return (unsigned long)NULL;
@@ -854,14 +956,14 @@ BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
 	if (sdata)
 		return (unsigned long)sdata->data;
 
-	if (flags == BPF_SK_STORAGE_GET_F_CREATE &&
+	if (flags == BPF_LOCAL_STORAGE_GET_F_CREATE &&
 	    /* Cannot add new elem to a going away sk.
 	     * Otherwise, the new elem may become a leak
 	     * (and also other memory issues during map
 	     *  destruction).
 	     */
 	    refcount_inc_not_zero(&sk->sk_refcnt)) {
-		sdata = sk_storage_update(sk, map, value, BPF_NOEXIST);
+		sdata = local_storage_update(sk, map, value, BPF_NOEXIST);
 		/* sk must be a fullsock (guaranteed by verifier),
 		 * so sock_gen_put() is unnecessary.
 		 */
@@ -887,14 +989,14 @@ BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
 }
 
 const struct bpf_map_ops sk_storage_map_ops = {
-	.map_alloc_check = bpf_sk_storage_map_alloc_check,
-	.map_alloc = bpf_sk_storage_map_alloc,
-	.map_free = bpf_sk_storage_map_free,
+	.map_alloc_check = bpf_local_storage_map_alloc_check,
+	.map_alloc = bpf_local_storage_map_alloc,
+	.map_free = bpf_local_storage_map_free,
 	.map_get_next_key = notsupp_get_next_key,
-	.map_lookup_elem = bpf_fd_sk_storage_lookup_elem,
-	.map_update_elem = bpf_fd_sk_storage_update_elem,
-	.map_delete_elem = bpf_fd_sk_storage_delete_elem,
-	.map_check_btf = bpf_sk_storage_map_check_btf,
+	.map_lookup_elem = bpf_sk_storage_lookup_elem,
+	.map_update_elem = bpf_sk_storage_update_elem,
+	.map_delete_elem = bpf_sk_storage_delete_elem,
+	.map_check_btf = bpf_local_storage_map_check_btf,
 };
 
 const struct bpf_func_proto bpf_sk_storage_get_proto = {
@@ -975,7 +1077,7 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
 	u32 nr_maps = 0;
 	int rem, err;
 
-	/* bpf_sk_storage_map is currently limited to CAP_SYS_ADMIN as
+	/* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as
 	 * the map_alloc_check() side also does.
 	 */
 	if (!bpf_capable())
@@ -1025,10 +1127,10 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
 }
 EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
 
-static int diag_get(struct bpf_sk_storage_data *sdata, struct sk_buff *skb)
+static int diag_get(struct bpf_local_storage_data *sdata, struct sk_buff *skb)
 {
 	struct nlattr *nla_stg, *nla_value;
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage_map *smap;
 
 	/* It cannot exceed max nlattr's payload */
 	BUILD_BUG_ON(U16_MAX - NLA_HDRLEN < MAX_VALUE_SIZE);
@@ -1067,9 +1169,9 @@ static int bpf_sk_storage_diag_put_all(struct sock *sk, struct sk_buff *skb,
 {
 	/* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
 	unsigned int diag_size = nla_total_size(0);
-	struct bpf_sk_storage *sk_storage;
-	struct bpf_sk_storage_elem *selem;
-	struct bpf_sk_storage_map *smap;
+	struct bpf_local_storage *sk_storage;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map *smap;
 	struct nlattr *nla_stgs;
 	unsigned int saved_len;
 	int err = 0;
@@ -1122,8 +1224,8 @@ int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
 {
 	/* stg_array_type (e.g. INET_DIAG_BPF_SK_STORAGES) */
 	unsigned int diag_size = nla_total_size(0);
-	struct bpf_sk_storage *sk_storage;
-	struct bpf_sk_storage_data *sdata;
+	struct bpf_local_storage *sk_storage;
+	struct bpf_local_storage_data *sdata;
 	struct nlattr *nla_stgs;
 	unsigned int saved_len;
 	int err = 0;
@@ -1150,8 +1252,8 @@ int bpf_sk_storage_diag_put(struct bpf_sk_storage_diag *diag,
 
 	saved_len = skb->len;
 	for (i = 0; i < diag->nr_maps; i++) {
-		sdata = __sk_storage_lookup(sk_storage,
-				(struct bpf_sk_storage_map *)diag->maps[i],
+		sdata = __local_storage_lookup(sk_storage,
+				(struct bpf_local_storage_map *)diag->maps[i],
 				false);
 
 		if (!sdata)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 4d76f16524cc..0c54fa7d2e51 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -14,8 +14,8 @@
 #include <linux/string.h>
 #include <linux/bpf.h>
 #include <linux/bpf-cgroup.h>
+#include <linux/bpf_local_storage.h>
 #include <net/sock.h>
-#include <net/bpf_sk_storage.h>
 
 #include "../cgroup/cgroup-internal.h"
 
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index bfd4ccd80847..b1547efcc842 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -7,7 +7,7 @@
 #include <linux/etherdevice.h>
 #include <linux/filter.h>
 #include <linux/sched/signal.h>
-#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 #include <linux/error-injection.h>
diff --git a/net/core/Makefile b/net/core/Makefile
index 3e2c378e5f31..9ddc2f3ecd97 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -34,4 +34,3 @@ obj-$(CONFIG_HWBM) += hwbm.o
 obj-$(CONFIG_NET_DEVLINK) += devlink.o
 obj-$(CONFIG_GRO_CELLS) += gro_cells.o
 obj-$(CONFIG_FAILOVER) += failover.o
-obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o
diff --git a/net/core/filter.c b/net/core/filter.c
index 73395384afe2..f60b0ba8b529 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -72,7 +72,7 @@
 #include <net/seg6_local.h>
 #include <net/lwtunnel.h>
 #include <net/ipv6_stubs.h>
-#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
 
 /**
  *	sk_filter_trim_cap - run a packet through a socket filter
diff --git a/net/core/sock.c b/net/core/sock.c
index 6c4acf1f0220..68693484ff77 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -130,8 +130,8 @@
 #include <linux/sock_diag.h>
 
 #include <linux/filter.h>
+#include <linux/bpf_local_storage.h>
 #include <net/sock_reuseport.h>
-#include <net/bpf_sk_storage.h>
 
 #include <trace/events/sock.h>
 
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index e3939f76b024..075abf1c6d7e 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -7,7 +7,7 @@
 #include <linux/btf.h>
 #include <linux/filter.h>
 #include <net/tcp.h>
-#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
 
 static u32 optional_ops[] = {
 	offsetof(struct tcp_congestion_ops, init),
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 125f4f8a36b4..ce22867cce5d 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -23,7 +23,7 @@
 #include <net/inet_hashtables.h>
 #include <net/inet_timewait_sock.h>
 #include <net/inet6_hashtables.h>
-#include <net/bpf_sk_storage.h>
+#include <linux/bpf_local_storage.h>
 #include <net/netlink.h>
 
 #include <linux/inet.h>
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 19684813faae..6218677daaa2 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2798,10 +2798,10 @@ union bpf_attr {
  *		"type". The bpf-local-storage "type" (i.e. the *map*) is
  *		searched against all bpf-local-storages residing at *sk*.
  *
- *		An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
+ *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
  *		used such that a new bpf-local-storage will be
  *		created if one does not exist.  *value* can be used
- *		together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
+ *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
  *		the initial value of a bpf-local-storage.  If *value* is
  *		**NULL**, the new bpf-local-storage will be zero initialized.
  *	Return
@@ -3498,9 +3498,13 @@ enum {
 	BPF_F_SYSCTL_BASE_NAME		= (1ULL << 0),
 };
 
-/* BPF_FUNC_sk_storage_get flags */
+/* BPF_FUNC_<local>_storage_get flags */
 enum {
-	BPF_SK_STORAGE_GET_F_CREATE	= (1ULL << 0),
+	BPF_LOCAL_STORAGE_GET_F_CREATE	= (1ULL << 0),
+	/* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
+	 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
+	 */
+	BPF_SK_STORAGE_GET_F_CREATE  = BPF_LOCAL_STORAGE_GET_F_CREATE,
 };
 
 /* BPF_FUNC_read_branch_records flags. */
-- 
2.27.0.111.gc72c7da667-goog

Re: [PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[Martin KaFai Lau]

On Wed, Jun 17, 2020 at 10:29:38PM +0200, KP Singh wrote:
> From: KP Singh <kpsingh@google.com>
> 
> Refactor the functionality in bpf_sk_storage.c so that concept of
> storage linked to kernel objects can be extended to other objects like
> inode, task_struct etc.
> 
> bpf_sk_storage is updated to be bpf_local_storage with a union that
> contains a pointer to the owner object. The type of the
> bpf_local_storage can be determined using the newly added
> bpf_local_storage_type enum.
> 
> Each new local storage will still be a separate map and provide its own
> set of helpers. This allows for future object specific extensions and
> still share a lot of the underlying implementation.
Thanks for taking up this effort to refactor sk_local_storage.

I took a quick look.  I have some comments and would like to explore
some thoughts.

> --- a/net/core/bpf_sk_storage.c
> +++ b/kernel/bpf/bpf_local_storage.c
> @@ -1,19 +1,22 @@
>  // SPDX-License-Identifier: GPL-2.0
>  /* Copyright (c) 2019 Facebook  */
> +#include "linux/bpf.h"
> +#include "asm-generic/bug.h"
> +#include "linux/err.h"
"<" ">"

>  #include <linux/rculist.h>
>  #include <linux/list.h>
>  #include <linux/hash.h>
>  #include <linux/types.h>
>  #include <linux/spinlock.h>
>  #include <linux/bpf.h>
> -#include <net/bpf_sk_storage.h>
> +#include <linux/bpf_local_storage.h>
>  #include <net/sock.h>
>  #include <uapi/linux/sock_diag.h>
>  #include <uapi/linux/btf.h>
>  
>  static atomic_t cache_idx;
inode local storage and sk local storage probably need a separate
cache_idx.  An improvement on picking cache_idx has just been
landed also.

[ ... ]

> +struct bpf_local_storage {
> +	struct bpf_local_storage_data __rcu *cache[BPF_STORAGE_CACHE_SIZE];
> +	struct hlist_head list;		/* List of bpf_local_storage_elem */
> +	/* The object that owns the the above "list" of
> +	 * bpf_local_storage_elem
> +	 */
> +	union {
> +		struct sock *sk;
> +	};
>  	struct rcu_head rcu;
>  	raw_spinlock_t lock;	/* Protect adding/removing from the "list" */
> +	enum bpf_local_storage_type stype;
>  };

[ ... ]

> +static struct bpf_local_storage_elem *sk_selem_alloc(
> +	struct bpf_local_storage_map *smap, struct sock *sk, void *value,
> +	bool charge_omem)
> +{
> +	struct bpf_local_storage_elem *selem;
> +
> +	if (charge_omem && omem_charge(sk, smap->elem_size))
> +		return NULL;
> +
> +	selem = selem_alloc(smap, value);
> +	if (selem)
> +		return selem;
> +
>  	if (charge_omem)
>  		atomic_sub(smap->elem_size, &sk->sk_omem_alloc);
>  
>  	return NULL;
>  }
>  
> -/* sk_storage->lock must be held and selem->sk_storage == sk_storage.
> +static void __unlink_local_storage(struct bpf_local_storage *local_storage,
> +				   bool uncharge_omem)
Nit. indent is off.  There are a few more cases like this.

> +{
> +	struct sock *sk;
> +
> +	switch (local_storage->stype) {
Does it need a new bpf_local_storage_type?  Is map_type as good?

Instead of adding any new member (e.g. stype) to
"struct bpf_local_storage",  can the smap pointer be directly used
here instead?

For example in __unlink_local_storage() here, it should
have a hold to the selem which then has a hold to smap.

> +	case BPF_LOCAL_STORAGE_SK:
> +		sk = local_storage->sk;
> +		if (uncharge_omem)
> +			atomic_sub(sizeof(struct bpf_local_storage),
> +				   &sk->sk_omem_alloc);
> +
> +		/* After this RCU_INIT, sk may be freed and cannot be used */
> +		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
> +		local_storage->sk = NULL;
> +		break;
> +	}
Another thought on the stype switch cases.

Instead of having multiple switches on stype in bpf_local_storage.c which may
not be scalable soon if we are planning to support a few more kernel objects,
have you considered putting them into its own "ops".  May be a few new
ops can be added to bpf_map_ops to do local storage unlink/update/alloc...etc.

> +}
> +
> +/* local_storage->lock must be held and selem->local_storage == local_storage.
>   * The caller must ensure selem->smap is still valid to be
>   * dereferenced for its smap->elem_size and smap->cache_idx.
> + *
> + * uncharge_omem is only relevant when:
> + *
> + *	local_storage->stype == BPF_LOCAL_STORAGE_SK
>   */

[ ... ]

> @@ -845,7 +947,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk)
>  BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
>  	   void *, value, u64, flags)
>  {
> -	struct bpf_sk_storage_data *sdata;
> +	struct bpf_local_storage_data *sdata;
>  
>  	if (flags > BPF_SK_STORAGE_GET_F_CREATE)
>  		return (unsigned long)NULL;
> @@ -854,14 +956,14 @@ BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
>  	if (sdata)
>  		return (unsigned long)sdata->data;
>  
> -	if (flags == BPF_SK_STORAGE_GET_F_CREATE &&
> +	if (flags == BPF_LOCAL_STORAGE_GET_F_CREATE &&
>  	    /* Cannot add new elem to a going away sk.
>  	     * Otherwise, the new elem may become a leak
>  	     * (and also other memory issues during map
>  	     *  destruction).
>  	     */
>  	    refcount_inc_not_zero(&sk->sk_refcnt)) {
> -		sdata = sk_storage_update(sk, map, value, BPF_NOEXIST);
> +		sdata = local_storage_update(sk, map, value, BPF_NOEXIST);
>  		/* sk must be a fullsock (guaranteed by verifier),
>  		 * so sock_gen_put() is unnecessary.
>  		 */
> @@ -887,14 +989,14 @@ BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
>  }
>  
>  const struct bpf_map_ops sk_storage_map_ops = {
> -	.map_alloc_check = bpf_sk_storage_map_alloc_check,
> -	.map_alloc = bpf_sk_storage_map_alloc,
> -	.map_free = bpf_sk_storage_map_free,
> +	.map_alloc_check = bpf_local_storage_map_alloc_check,
> +	.map_alloc = bpf_local_storage_map_alloc,
> +	.map_free = bpf_local_storage_map_free,
>  	.map_get_next_key = notsupp_get_next_key,
> -	.map_lookup_elem = bpf_fd_sk_storage_lookup_elem,
> -	.map_update_elem = bpf_fd_sk_storage_update_elem,
> -	.map_delete_elem = bpf_fd_sk_storage_delete_elem,
> -	.map_check_btf = bpf_sk_storage_map_check_btf,
> +	.map_lookup_elem = bpf_sk_storage_lookup_elem,
> +	.map_update_elem = bpf_sk_storage_update_elem,
> +	.map_delete_elem = bpf_sk_storage_delete_elem,
> +	.map_check_btf = bpf_local_storage_map_check_btf,
>  };
>  
>  const struct bpf_func_proto bpf_sk_storage_get_proto = {
> @@ -975,7 +1077,7 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
>  	u32 nr_maps = 0;
>  	int rem, err;
>  
> -	/* bpf_sk_storage_map is currently limited to CAP_SYS_ADMIN as
> +	/* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as
>  	 * the map_alloc_check() side also does.
>  	 */
>  	if (!bpf_capable())
> @@ -1025,10 +1127,10 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
>  }
>  EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
Would it be cleaner to leave bpf_sk specific function, map_ops, and func_proto
in net/core/bpf_sk_storage.c?

There is a test in map_tests/sk_storage_map.c, in case you may not notice.

Re: [PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[KP Singh]

Thanks for your feedback! Apologies it took some time for me
to incorporate this into another revision.

On 18-Jun 23:43, Martin KaFai Lau wrote:
> On Wed, Jun 17, 2020 at 10:29:38PM +0200, KP Singh wrote:
> > From: KP Singh <kpsingh@google.com>
> > 
> > Refactor the functionality in bpf_sk_storage.c so that concept of
> > storage linked to kernel objects can be extended to other objects like
> > inode, task_struct etc.
> > 
> > bpf_sk_storage is updated to be bpf_local_storage with a union that
> > contains a pointer to the owner object. The type of the
> > bpf_local_storage can be determined using the newly added
> > bpf_local_storage_type enum.
> > 
> > Each new local storage will still be a separate map and provide its own
> > set of helpers. This allows for future object specific extensions and
> > still share a lot of the underlying implementation.
> Thanks for taking up this effort to refactor sk_local_storage.
> 
> I took a quick look.  I have some comments and would like to explore
> some thoughts.
> 
> > --- a/net/core/bpf_sk_storage.c
> > +++ b/kernel/bpf/bpf_local_storage.c
> > @@ -1,19 +1,22 @@
> >  // SPDX-License-Identifier: GPL-2.0
> >  /* Copyright (c) 2019 Facebook  */
> > +#include "linux/bpf.h"
> > +#include "asm-generic/bug.h"
> > +#include "linux/err.h"
> "<" ">"
> 
> >  #include <linux/rculist.h>
> >  #include <linux/list.h>
> >  #include <linux/hash.h>
> >  #include <linux/types.h>
> >  #include <linux/spinlock.h>
> >  #include <linux/bpf.h>
> > -#include <net/bpf_sk_storage.h>
> > +#include <linux/bpf_local_storage.h>
> >  #include <net/sock.h>
> >  #include <uapi/linux/sock_diag.h>
> >  #include <uapi/linux/btf.h>
> >  
> >  static atomic_t cache_idx;
> inode local storage and sk local storage probably need a separate
> cache_idx.  An improvement on picking cache_idx has just been
> landed also.

I see, thanks! I rebased and I now see that cache_idx is now a:

  static u64 cache_idx_usage_counts[BPF_STORAGE_CACHE_SIZE];

which tracks the free cache slots rather than using a single atomic
cache_idx. I guess all types of local storage can share this now
right?

> 
> [ ... ]
> 
> > +struct bpf_local_storage {
> > +	struct bpf_local_storage_data __rcu *cache[BPF_STORAGE_CACHE_SIZE];
> >  	return NULL;

[...]

> >  }
> >  
> > -/* sk_storage->lock must be held and selem->sk_storage == sk_storage.
> > +static void __unlink_local_storage(struct bpf_local_storage *local_storage,
> > +				   bool uncharge_omem)
> Nit. indent is off.  There are a few more cases like this.

Thanks, will fix this. (note to self: don't trust the editor's
clang-format blindly).

> 
> > +{
> > +	struct sock *sk;
> > +
> > +	switch (local_storage->stype) {
> Does it need a new bpf_local_storage_type?  Is map_type as good?
> 
> Instead of adding any new member (e.g. stype) to
> "struct bpf_local_storage",  can the smap pointer be directly used
> here instead?
> 
> For example in __unlink_local_storage() here, it should
> have a hold to the selem which then has a hold to smap.

Good point, Updated to using the map->map_type.

> 
> > +	case BPF_LOCAL_STORAGE_SK:
> > +		sk = local_storage->sk;
> > +		if (uncharge_omem)
> > +			atomic_sub(sizeof(struct bpf_local_storage),
> > +				   &sk->sk_omem_alloc);
> > +
> > +		/* After this RCU_INIT, sk may be freed and cannot be used */
> > +		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
> > +		local_storage->sk = NULL;
> > +		break;
> > +	}
> Another thought on the stype switch cases.
> 
> Instead of having multiple switches on stype in bpf_local_storage.c which may
> not be scalable soon if we are planning to support a few more kernel objects,
> have you considered putting them into its own "ops".  May be a few new
> ops can be added to bpf_map_ops to do local storage unlink/update/alloc...etc.

Good idea, I was able to refactor this with the following ops:

        /* Functions called by bpf_local_storage maps */
	void (*map_local_storage_unlink)(struct bpf_local_storage *local_storage,
                                         bool uncharge_omem);
	struct bpf_local_storage_elem *(*map_selem_alloc)(
		struct bpf_local_storage_map *smap, void *owner, void *value,
		bool charge_omem);
	struct bpf_local_storage_data *(*map_local_storage_update)(
		void  *owner, struct bpf_map *map, void *value, u64 flags);
	int (*map_local_storage_alloc)(void *owner,
				       struct bpf_local_storage_map *smap,
				       struct bpf_local_storage_elem *elem);

Let me know if you have any particular thoughts/suggestions about
this.

> 
> > +}
> > +
> > +/* local_storage->lock must be held and selem->local_storage == local_storage.
> >   * The caller must ensure selem->smap is still valid to be
> >   * dereferenced for its smap->elem_size and smap->cache_idx.
> > + *
> > + * uncharge_omem is only relevant when:

[...]

> > +	/* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as
> >  	 * the map_alloc_check() side also does.
> >  	 */
> >  	if (!bpf_capable())
> > @@ -1025,10 +1127,10 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
> >  }
> >  EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
> Would it be cleaner to leave bpf_sk specific function, map_ops, and func_proto
> in net/core/bpf_sk_storage.c?

Sure, I can also keep the sk_clone code their as well for now.

> 
> There is a test in map_tests/sk_storage_map.c, in case you may not notice.

I will try to make it generic as a part of this series. If it takes
too much time, I will send a separate patch for testing
inode_storage_map and till then we have some assurance with
test_local_storage in test_progs.

- KP

Re: [PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[Martin KaFai Lau]

On Mon, Jun 29, 2020 at 06:01:00PM +0200, KP Singh wrote:
> Thanks for your feedback! Apologies it took some time for me
> to incorporate this into another revision.
> 
> On 18-Jun 23:43, Martin KaFai Lau wrote:
> > On Wed, Jun 17, 2020 at 10:29:38PM +0200, KP Singh wrote:
> > > From: KP Singh <kpsingh@google.com>
> > > 
> > > Refactor the functionality in bpf_sk_storage.c so that concept of
> > > storage linked to kernel objects can be extended to other objects like
> > > inode, task_struct etc.
> > > 
> > > bpf_sk_storage is updated to be bpf_local_storage with a union that
> > > contains a pointer to the owner object. The type of the
> > > bpf_local_storage can be determined using the newly added
> > > bpf_local_storage_type enum.
> > > 
> > > Each new local storage will still be a separate map and provide its own
> > > set of helpers. This allows for future object specific extensions and
> > > still share a lot of the underlying implementation.
> > Thanks for taking up this effort to refactor sk_local_storage.
> > 
> > I took a quick look.  I have some comments and would like to explore
> > some thoughts.
> > 
> > > --- a/net/core/bpf_sk_storage.c
> > > +++ b/kernel/bpf/bpf_local_storage.c
> > > @@ -1,19 +1,22 @@
> > >  // SPDX-License-Identifier: GPL-2.0
> > >  /* Copyright (c) 2019 Facebook  */
> > > +#include "linux/bpf.h"
> > > +#include "asm-generic/bug.h"
> > > +#include "linux/err.h"
> > "<" ">"
> > 
> > >  #include <linux/rculist.h>
> > >  #include <linux/list.h>
> > >  #include <linux/hash.h>
> > >  #include <linux/types.h>
> > >  #include <linux/spinlock.h>
> > >  #include <linux/bpf.h>
> > > -#include <net/bpf_sk_storage.h>
> > > +#include <linux/bpf_local_storage.h>
> > >  #include <net/sock.h>
> > >  #include <uapi/linux/sock_diag.h>
> > >  #include <uapi/linux/btf.h>
> > >  
> > >  static atomic_t cache_idx;
> > inode local storage and sk local storage probably need a separate
> > cache_idx.  An improvement on picking cache_idx has just been
> > landed also.
> 
> I see, thanks! I rebased and I now see that cache_idx is now a:
> 
>   static u64 cache_idx_usage_counts[BPF_STORAGE_CACHE_SIZE];
> 
> which tracks the free cache slots rather than using a single atomic
> cache_idx. I guess all types of local storage can share this now
> right?
I believe they have to be separated.  A sk-storage will not be cached/stored
in inode.  Caching a sk-storage at idx=0 of a sk should not stop
an inode-storage to be cached at the same idx of a inode.

> 
> > 
> > [ ... ]
> > 
> > > +struct bpf_local_storage {
> > > +	struct bpf_local_storage_data __rcu *cache[BPF_STORAGE_CACHE_SIZE];
> > >  	return NULL;
> 
> [...]
> 
> > >  }
> > >  
> > > -/* sk_storage->lock must be held and selem->sk_storage == sk_storage.
> > > +static void __unlink_local_storage(struct bpf_local_storage *local_storage,
> > > +				   bool uncharge_omem)
> > Nit. indent is off.  There are a few more cases like this.
> 
> Thanks, will fix this. (note to self: don't trust the editor's
> clang-format blindly).
> 
> > 
> > > +{
> > > +	struct sock *sk;
> > > +
> > > +	switch (local_storage->stype) {
> > Does it need a new bpf_local_storage_type?  Is map_type as good?
> > 
> > Instead of adding any new member (e.g. stype) to
> > "struct bpf_local_storage",  can the smap pointer be directly used
> > here instead?
> > 
> > For example in __unlink_local_storage() here, it should
> > have a hold to the selem which then has a hold to smap.
> 
> Good point, Updated to using the map->map_type.
> 
> > 
> > > +	case BPF_LOCAL_STORAGE_SK:
> > > +		sk = local_storage->sk;
> > > +		if (uncharge_omem)
> > > +			atomic_sub(sizeof(struct bpf_local_storage),
> > > +				   &sk->sk_omem_alloc);
> > > +
> > > +		/* After this RCU_INIT, sk may be freed and cannot be used */
> > > +		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
> > > +		local_storage->sk = NULL;
> > > +		break;
> > > +	}
> > Another thought on the stype switch cases.
> > 
> > Instead of having multiple switches on stype in bpf_local_storage.c which may
> > not be scalable soon if we are planning to support a few more kernel objects,
> > have you considered putting them into its own "ops".  May be a few new
> > ops can be added to bpf_map_ops to do local storage unlink/update/alloc...etc.
> 
> Good idea, I was able to refactor this with the following ops:
> 
>         /* Functions called by bpf_local_storage maps */
> 	void (*map_local_storage_unlink)(struct bpf_local_storage *local_storage,
>                                          bool uncharge_omem);
> 	struct bpf_local_storage_elem *(*map_selem_alloc)(
> 		struct bpf_local_storage_map *smap, void *owner, void *value,
> 		bool charge_omem);
> 	struct bpf_local_storage_data *(*map_local_storage_update)(
> 		void  *owner, struct bpf_map *map, void *value, u64 flags);
> 	int (*map_local_storage_alloc)(void *owner,
> 				       struct bpf_local_storage_map *smap,
> 				       struct bpf_local_storage_elem *elem);
> 
> Let me know if you have any particular thoughts/suggestions about
> this.
Make sense to me.

It seems the fast-path's lookup can all be done within __local_storage_lookup().
No indirect call is needed, so should be good.

> 
> > 
> > > +}
> > > +
> > > +/* local_storage->lock must be held and selem->local_storage == local_storage.
> > >   * The caller must ensure selem->smap is still valid to be
> > >   * dereferenced for its smap->elem_size and smap->cache_idx.
> > > + *
> > > + * uncharge_omem is only relevant when:
> 
> [...]
> 
> > > +	/* bpf_local_storage_map is currently limited to CAP_SYS_ADMIN as
> > >  	 * the map_alloc_check() side also does.
> > >  	 */
> > >  	if (!bpf_capable())
> > > @@ -1025,10 +1127,10 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs)
> > >  }
> > >  EXPORT_SYMBOL_GPL(bpf_sk_storage_diag_alloc);
> > Would it be cleaner to leave bpf_sk specific function, map_ops, and func_proto
> > in net/core/bpf_sk_storage.c?
> 
> Sure, I can also keep the sk_clone code their as well for now.
Just came to my mind.  For easier review purpose, may be
first do the refactoring/renaming within bpf_sk_storage.c first and
then create another patch to move the common parts to a new
file bpf_local_storage.c.

Not sure if it will be indeed easier to read the diff in practice.
I probably should be able to follow it either way.

> 
> > 
> > There is a test in map_tests/sk_storage_map.c, in case you may not notice.
> 
> I will try to make it generic as a part of this series. If it takes
> too much time, I will send a separate patch for testing
> inode_storage_map and till then we have some assurance with
> test_local_storage in test_progs.
Sure. no problem.  It is mostly for you to test sk_storage to ensure things ;)
Also give some ideas on what racing conditions have
been considered in the sk_storage test and may be the inode storage
test want to stress similar code path.

Re: [PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[KP Singh]

On Tue, Jun 30, 2020 at 9:35 PM Martin KaFai Lau <kafai@fb.com> wrote:
>
> On Mon, Jun 29, 2020 at 06:01:00PM +0200, KP Singh wrote:
> > > >

[...]

> > > >  static atomic_t cache_idx;
> > > inode local storage and sk local storage probably need a separate
> > > cache_idx.  An improvement on picking cache_idx has just been
> > > landed also.
> >
> > I see, thanks! I rebased and I now see that cache_idx is now a:
> >
> >   static u64 cache_idx_usage_counts[BPF_STORAGE_CACHE_SIZE];
> >
> > which tracks the free cache slots rather than using a single atomic
> > cache_idx. I guess all types of local storage can share this now
> > right?
> I believe they have to be separated.  A sk-storage will not be cached/stored
> in inode.  Caching a sk-storage at idx=0 of a sk should not stop
> an inode-storage to be cached at the same idx of a inode.

Ah yes, I see.

I came up with some macros to solve this. Let me know what you think:
(this is on top of the refactoring I did, so some function names may seem new,
but it should, hopefully, convey the general idea).

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 3067774cc640..1dc2e6d72091 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -79,6 +79,26 @@ struct bpf_local_storage_elem {
 #define SDATA(_SELEM) (&(_SELEM)->sdata)
 #define BPF_STORAGE_CACHE_SIZE	16
 
+u16 bpf_ls_cache_idx_get(spinlock_t *cache_idx_lock,
+			   u64 *cache_idx_usage_count);
+
+void bpf_ls_cache_idx_free(spinlock_t *cache_idx_lock,
+			   u64 *cache_idx_usage_counts, u16 idx);
+
+#define DEFINE_BPF_STORAGE_CACHE(type)					\
+static DEFINE_SPINLOCK(cache_idx_lock_##type);				\
+static u64 cache_idx_usage_counts_##type[BPF_STORAGE_CACHE_SIZE];	\
+static u16 cache_idx_get_##type(void)					\
+{									\
+	return bpf_ls_cache_idx_get(&cache_idx_lock_##type,		\
+				    cache_idx_usage_counts_##type);	\
+}									\
+static void cache_idx_free_##type(u16 idx)				\
+{									\
+	return bpf_ls_cache_idx_free(&cache_idx_lock_##type,		\
+				     cache_idx_usage_counts_##type,	\
+				     idx);				\
+}
 
 /* U16_MAX is much more than enough for sk local storage
  * considering a tcp_sock is ~2k.
@@ -105,13 +125,14 @@ struct bpf_local_storage {
 
 /* Helper functions for bpf_local_storage */
 int bpf_local_storage_map_alloc_check(union bpf_attr *attr);
-struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr);
+struct bpf_local_storage_map *
+bpf_local_storage_map_alloc(union bpf_attr *attr);
 
 struct bpf_local_storage_data *
 bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
 	struct bpf_local_storage_map *smap, bool cacheit_lockit);
 
-void bpf_local_storage_map_free(struct bpf_map *map);
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap);
 
 int bpf_local_storage_map_check_btf(const struct bpf_map *map,
 	const struct btf *btf, const struct btf_type *key_type,
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index fb589a5715f5..2bc04f8d1e35 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -17,9 +17,6 @@
 	container_of((_SDATA), struct bpf_local_storage_elem, sdata)
 #define SDATA(_SELEM) (&(_SELEM)->sdata)
 
-static DEFINE_SPINLOCK(cache_idx_lock);
-static u64 cache_idx_usage_counts[BPF_STORAGE_CACHE_SIZE];
-
 static struct bucket *select_bucket(struct bpf_local_storage_map *smap,
 				    struct bpf_local_storage_elem *selem)
 {
@@ -460,12 +457,13 @@ static struct bpf_local_storage_data *inode_storage_update(
 					map_flags);
 }
 
-static u16 cache_idx_get(void)
+u16 bpf_ls_cache_idx_get(spinlock_t *cache_idx_lock,
+			 u64 *cache_idx_usage_counts)
 {
 	u64 min_usage = U64_MAX;
 	u16 i, res = 0;
 
-	spin_lock(&cache_idx_lock);
+	spin_lock(cache_idx_lock);
 
 	for (i = 0; i < BPF_STORAGE_CACHE_SIZE; i++) {
 		if (cache_idx_usage_counts[i] < min_usage) {
@@ -479,16 +477,17 @@ static u16 cache_idx_get(void)
 	}
 	cache_idx_usage_counts[res]++;
 
-	spin_unlock(&cache_idx_lock);
+	spin_unlock(cache_idx_lock);
 
 	return res;
 }
 
-static void cache_idx_free(u16 idx)
+void bpf_ls_cache_idx_free(spinlock_t *cache_idx_lock,
+			   u64 *cache_idx_usage_counts, u16 idx)
 {
-	spin_lock(&cache_idx_lock);
+	spin_lock(cache_idx_lock);
 	cache_idx_usage_counts[idx]--;
-	spin_unlock(&cache_idx_lock);
+	spin_unlock(cache_idx_lock);
 }
 
 static int inode_storage_delete(struct inode *inode, struct bpf_map *map)
@@ -552,17 +551,12 @@ void bpf_inode_storage_free(struct inode *inode)
 		kfree_rcu(local_storage, rcu);
 }
 
-void bpf_local_storage_map_free(struct bpf_map *map)
+void bpf_local_storage_map_free(struct bpf_local_storage_map *smap)
 {
 	struct bpf_local_storage_elem *selem;
-	struct bpf_local_storage_map *smap;
 	struct bucket *b;
 	unsigned int i;
 
-	smap = (struct bpf_local_storage_map *)map;
-
-	cache_idx_free(smap->cache_idx);
-
 	/* Note that this map might be concurrently cloned from
 	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
 	 * RCU read section to finish before proceeding. New RCU
@@ -607,7 +601,7 @@ void bpf_local_storage_map_free(struct bpf_map *map)
 	synchronize_rcu();
 
 	kvfree(smap->buckets);
-	kfree(map);
+	kfree(smap);
 }
 
 int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
@@ -629,8 +623,7 @@ int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
-
-struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
+struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
 {
 	struct bpf_local_storage_map *smap;
 	unsigned int i;
@@ -670,9 +663,8 @@ struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
 
 	smap->elem_size =
 		sizeof(struct bpf_local_storage_elem) + attr->value_size;
-	smap->cache_idx = cache_idx_get();
 
-	return &smap->map;
+	return smap;
 }
 
 int bpf_local_storage_map_check_btf(const struct bpf_map *map,
@@ -768,11 +760,34 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
 	return -ENOTSUPP;
 }
 
+DEFINE_BPF_STORAGE_CACHE(inode);
+
+struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = bpf_local_storage_map_alloc(attr);
+	if (IS_ERR(smap))
+		return ERR_CAST(smap);
+
+	smap->cache_idx = cache_idx_get_inode();
+	return &smap->map;
+}
+
+void inode_storage_map_free(struct bpf_map *map)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = (struct bpf_local_storage_map *)map;
+	cache_idx_free_inode(smap->cache_idx);
+	bpf_local_storage_map_free(smap);
+}
+
 static int inode_storage_map_btf_id;
 const struct bpf_map_ops inode_storage_map_ops = {
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
-	.map_alloc = bpf_local_storage_map_alloc,
-	.map_free = bpf_local_storage_map_free,
+	.map_alloc = inode_storage_map_alloc,
+	.map_free = inode_storage_map_free,
 	.map_get_next_key = notsupp_get_next_key,
 	.map_lookup_elem = bpf_inode_storage_lookup_elem,
 	.map_update_elem = bpf_inode_storage_update_elem,
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 0ec44e819bfe..add0340e9ad3 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -396,11 +396,34 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
 	return -ENOTSUPP;
 }
 
+DEFINE_BPF_STORAGE_CACHE(sk);
+
+struct bpf_map *sk_storage_map_alloc(union bpf_attr *attr)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = bpf_local_storage_map_alloc(attr);
+	if (IS_ERR(smap))
+		return ERR_CAST(smap);
+
+	smap->cache_idx = cache_idx_get_sk();
+	return &smap->map;
+}
+
+void sk_storage_map_free(struct bpf_map *map)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = (struct bpf_local_storage_map *)map;
+	cache_idx_free_sk(smap->cache_idx);
+	bpf_local_storage_map_free(smap);
+}
+
 static int sk_storage_map_btf_id;
 const struct bpf_map_ops sk_storage_map_ops = {
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
-	.map_alloc = bpf_local_storage_map_alloc,
-	.map_free = bpf_local_storage_map_free,
+	.map_alloc = sk_storage_map_alloc,
+	.map_free = sk_storage_map_free,
 	.map_get_next_key = notsupp_get_next_key,
 	.map_lookup_elem = bpf_sk_storage_lookup_elem,
 	.map_update_elem = bpf_sk_storage_update_elem,

>

[...]

> >
> > Sure, I can also keep the sk_clone code their as well for now.
> Just came to my mind.  For easier review purpose, may be
> first do the refactoring/renaming within bpf_sk_storage.c first and
> then create another patch to move the common parts to a new
> file bpf_local_storage.c.
>
> Not sure if it will be indeed easier to read the diff in practice.
> I probably should be able to follow it either way.

Since I already refactored it. I will send the next version with the refactoring
and split done as a part of the Generalize bpf_sk_storage patch.
If it becomes too hard to review, please let me know and I can split it. :)


>
> >
> > >
> > > There is a test in map_tests/sk_storage_map.c, in case you may not notice.
> >
> > I will try to make it generic as a part of this series. If it takes
> > too much time, I will send a separate patch for testing
> > inode_storage_map and till then we have some assurance with
> > test_local_storage in test_progs.
> Sure. no problem.  It is mostly for you to test sk_storage to ensure things ;)
> Also give some ideas on what racing conditions have
> been considered in the sk_storage test and may be the inode storage
> test want to stress similar code path.

Thanks! I ran test_maps and it passes. I will send a separate patch
that generalizes the sk_storage_map.c.

- KP

Re: [PATCH bpf-next v2 1/4] bpf: Generalize bpf_sk_storage

[Martin KaFai Lau]

On Tue, Jun 30, 2020 at 10:00:18PM +0000, KP Singh wrote:
> 
> 
> On Tue, Jun 30, 2020 at 9:35 PM Martin KaFai Lau <kafai@fb.com> wrote:
> >
> > On Mon, Jun 29, 2020 at 06:01:00PM +0200, KP Singh wrote:
> > > > >
> 
> [...]
> 
> > > > >  static atomic_t cache_idx;
> > > > inode local storage and sk local storage probably need a separate
> > > > cache_idx.  An improvement on picking cache_idx has just been
> > > > landed also.
> > >
> > > I see, thanks! I rebased and I now see that cache_idx is now a:
> > >
> > >   static u64 cache_idx_usage_counts[BPF_STORAGE_CACHE_SIZE];
> > >
> > > which tracks the free cache slots rather than using a single atomic
> > > cache_idx. I guess all types of local storage can share this now
> > > right?
> > I believe they have to be separated.  A sk-storage will not be cached/stored
> > in inode.  Caching a sk-storage at idx=0 of a sk should not stop
> > an inode-storage to be cached at the same idx of a inode.
> 
> Ah yes, I see.
> 
> I came up with some macros to solve this. Let me know what you think:
> (this is on top of the refactoring I did, so some function names may seem new,
> but it should, hopefully, convey the general idea).
> 
> diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
> index 3067774cc640..1dc2e6d72091 100644
> --- a/include/linux/bpf_local_storage.h
> +++ b/include/linux/bpf_local_storage.h
> @@ -79,6 +79,26 @@ struct bpf_local_storage_elem {
>  #define SDATA(_SELEM) (&(_SELEM)->sdata)
>  #define BPF_STORAGE_CACHE_SIZE	16
>  
> +u16 bpf_ls_cache_idx_get(spinlock_t *cache_idx_lock,
> +			   u64 *cache_idx_usage_count);
> +
> +void bpf_ls_cache_idx_free(spinlock_t *cache_idx_lock,
> +			   u64 *cache_idx_usage_counts, u16 idx);
> +
> +#define DEFINE_BPF_STORAGE_CACHE(type)					\
> +static DEFINE_SPINLOCK(cache_idx_lock_##type);				\
> +static u64 cache_idx_usage_counts_##type[BPF_STORAGE_CACHE_SIZE];	\
> +static u16 cache_idx_get_##type(void)					\
> +{									\
> +	return bpf_ls_cache_idx_get(&cache_idx_lock_##type,		\
> +				    cache_idx_usage_counts_##type);	\
> +}									\
> +static void cache_idx_free_##type(u16 idx)				\
> +{									\
> +	return bpf_ls_cache_idx_free(&cache_idx_lock_##type,		\
> +				     cache_idx_usage_counts_##type,	\
> +				     idx);				\
> +}
Sorry for the late reply.  I missed this email.

The above looks reasonable.

[PATCH bpf-next v2 2/4] bpf: Implement bpf_local_storage for inodes

[KP Singh]

From: KP Singh <kpsingh@google.com>

Similar to bpf_local_storage for sockets, add local storage for inodes.
The life-cycle of storage is managed with the life-cycle of the inode.
i.e. the storage is destroyed along with the owning inode.

The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the
security blob which are now stackable and can co-exist with other LSMs.

Signed-off-by: KP Singh <kpsingh@google.com>
---
 include/linux/bpf_local_storage.h |   7 +
 include/linux/bpf_lsm.h           |  21 +++
 include/linux/bpf_types.h         |   1 +
 include/uapi/linux/bpf.h          |  40 ++++-
 kernel/bpf/bpf_local_storage.c    | 261 +++++++++++++++++++++++++++++-
 kernel/bpf/syscall.c              |   3 +-
 kernel/bpf/verifier.c             |  10 ++
 security/bpf/hooks.c              |   7 +
 tools/bpf/bpftool/map.c           |   1 +
 tools/include/uapi/linux/bpf.h    |  40 ++++-
 tools/lib/bpf/libbpf_probes.c     |   5 +-
 11 files changed, 390 insertions(+), 6 deletions(-)

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 85524f18cd91..7488487b1099 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -4,11 +4,14 @@
 #define _BPF_LOCAL_STORAGE_H
 
 struct sock;
+struct inode;
 
 void bpf_sk_storage_free(struct sock *sk);
 
 extern const struct bpf_func_proto bpf_sk_storage_get_proto;
 extern const struct bpf_func_proto bpf_sk_storage_delete_proto;
+extern const struct bpf_func_proto bpf_inode_storage_get_proto;
+extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
 
 struct bpf_sk_storage_diag;
 struct sk_buff;
@@ -16,6 +19,7 @@ struct nlattr;
 struct sock;
 
 #ifdef CONFIG_BPF_SYSCALL
+void bpf_inode_storage_free(struct inode *inode);
 int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk);
 struct bpf_sk_storage_diag *
 bpf_sk_storage_diag_alloc(const struct nlattr *nla_stgs);
@@ -35,6 +39,9 @@ bpf_sk_storage_diag_alloc(const struct nlattr *nla)
 {
 	return NULL;
 }
+static inline void void bpf_inode_storage_free(struct inode *inode)
+{
+}
 static inline void bpf_sk_storage_diag_free(struct bpf_sk_storage_diag *diag)
 {
 }
diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
index af74712af585..8efd7562e3de 100644
--- a/include/linux/bpf_lsm.h
+++ b/include/linux/bpf_lsm.h
@@ -17,9 +17,24 @@
 #include <linux/lsm_hook_defs.h>
 #undef LSM_HOOK
 
+struct bpf_storage_blob {
+	struct bpf_local_storage __rcu *storage;
+};
+
+extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
+
 int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 			const struct bpf_prog *prog);
 
+static inline struct bpf_storage_blob *bpf_inode(
+	const struct inode *inode)
+{
+	if (unlikely(!inode->i_security))
+		return NULL;
+
+	return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
+}
+
 #else /* !CONFIG_BPF_LSM */
 
 static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
@@ -28,6 +43,12 @@ static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 	return -EOPNOTSUPP;
 }
 
+static inline struct bpf_storage_blob *bpf_inode_storage(
+	const struct inode *inode)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_BPF_LSM */
 
 #endif /* _LINUX_BPF_LSM_H */
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index a18ae82a298a..881e7954c956 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -101,6 +101,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP, dev_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, dev_map_hash_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_SK_STORAGE, sk_storage_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops)
 #if defined(CONFIG_BPF_STREAM_PARSER)
 BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKMAP, sock_map_ops)
 BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6218677daaa2..679a50562e72 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -148,6 +148,7 @@ enum bpf_map_type {
 	BPF_MAP_TYPE_DEVMAP_HASH,
 	BPF_MAP_TYPE_STRUCT_OPS,
 	BPF_MAP_TYPE_RINGBUF,
+	BPF_MAP_TYPE_INODE_STORAGE,
 };
 
 /* Note that tracing related programs such as
@@ -3252,6 +3253,41 @@ union bpf_attr {
  * 		case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
  * 		is returned or the error code -EACCES in case the skb is not
  * 		subject to CHECKSUM_UNNECESSARY.
+ * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
+ *	Description
+ *		Get a bpf_local_storage from an *inode*.
+ *
+ *		Logically, it could be thought of as getting the value from
+ *		a *map* with *inode* as the **key**.  From this
+ *		perspective,  the usage is not much different from
+ *		**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
+ *		helper enforces the key must be an inode and the map must also
+ *		be a **BPF_MAP_TYPE_INODE_STORAGE**.
+ *
+ *		Underneath, the value is stored locally at *inode* instead of
+ *		the *map*.  The *map* is used as the bpf-local-storage
+ *		"type". The bpf-local-storage "type" (i.e. the *map*) is
+ *		searched against all bpf_local_storage residing at *inode*.
+ *
+ *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ *		used such that a new bpf_local_storage will be
+ *		created if one does not exist.  *value* can be used
+ *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ *		the initial value of a bpf_local_storage.  If *value* is
+ *		**NULL**, the new bpf_local_storage will be zero initialized.
+ *	Return
+ *		A bpf_local_storage pointer is returned on success.
+ *
+ *		**NULL** if not found or there was an error in adding
+ *		a new bpf_local_storage.
+ *
+ * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
+ *	Description
+ *		Delete a bpf_local_storage from an *inode*.
+ *	Return
+ *		0 on success.
+ *
+ *		**-ENOENT** if the bpf_local_storage cannot be found.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3389,7 +3425,9 @@ union bpf_attr {
 	FN(ringbuf_submit),		\
 	FN(ringbuf_discard),		\
 	FN(ringbuf_query),		\
-	FN(csum_level),
+	FN(csum_level),			\
+	FN(inode_storage_get),		\
+	FN(inode_storage_delete),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 314a923569d5..572ed711c3fd 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -3,6 +3,7 @@
 #include "linux/bpf.h"
 #include "asm-generic/bug.h"
 #include "linux/err.h"
+#include "linux/fs.h"
 #include <linux/rculist.h>
 #include <linux/list.h>
 #include <linux/hash.h>
@@ -13,6 +14,7 @@
 #include <net/sock.h>
 #include <uapi/linux/sock_diag.h>
 #include <uapi/linux/btf.h>
+#include <linux/bpf_lsm.h>
 
 static atomic_t cache_idx;
 
@@ -26,6 +28,7 @@ struct bucket {
 
 enum bpf_local_storage_type {
 	BPF_LOCAL_STORAGE_SK,
+	BPF_LOCAL_STORAGE_INODE,
 };
 
 /* Thp map is not the primary owner of a bpf_local_storage_elem.
@@ -97,6 +100,7 @@ struct bpf_local_storage {
 	 */
 	union {
 		struct sock *sk;
+		struct inode *inode;
 	};
 	struct rcu_head rcu;
 	raw_spinlock_t lock;	/* Protect adding/removing from the "list" */
@@ -168,6 +172,8 @@ static struct bpf_local_storage_elem *sk_selem_alloc(
 static void __unlink_local_storage(struct bpf_local_storage *local_storage,
 				   bool uncharge_omem)
 {
+	struct bpf_storage_blob *bsb;
+	struct inode *inode;
 	struct sock *sk;
 
 	switch (local_storage->stype) {
@@ -181,6 +187,15 @@ static void __unlink_local_storage(struct bpf_local_storage *local_storage,
 		RCU_INIT_POINTER(sk->sk_bpf_storage, NULL);
 		local_storage->sk = NULL;
 		break;
+	case BPF_LOCAL_STORAGE_INODE:
+		inode = local_storage->inode;
+		bsb = bpf_inode(inode);
+		if (!bsb)
+			return;
+
+		RCU_INIT_POINTER(bsb->storage, NULL);
+		local_storage->inode = NULL;
+		break;
 	}
 }
 
@@ -341,6 +356,25 @@ sk_storage_lookup(struct sock *sk, struct bpf_map *map, bool cacheit_lockit)
 	return __local_storage_lookup(sk_storage, smap, cacheit_lockit);
 }
 
+static struct bpf_local_storage_data *inode_storage_lookup(
+	struct inode *inode, struct bpf_map *map, bool cacheit_lockit)
+{
+	struct bpf_local_storage *inode_storage;
+	struct bpf_local_storage_map *smap;
+	struct bpf_storage_blob *bsb;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return ERR_PTR(-ENOENT);
+
+	inode_storage = rcu_dereference(bsb->storage);
+	if (!inode_storage)
+		return NULL;
+
+	smap = (struct bpf_local_storage_map *)map;
+	return __local_storage_lookup(inode_storage, smap, cacheit_lockit);
+}
+
 static int check_flags(const struct bpf_local_storage_data *old_sdata,
 		       u64 map_flags)
 {
@@ -437,6 +471,38 @@ static int sk_storage_alloc(struct sock *sk,
 	return err;
 }
 
+static int inode_storage_alloc(struct inode *inode,
+			       struct bpf_local_storage_map *smap,
+			       struct bpf_local_storage_elem *first_selem)
+{
+	struct bpf_storage_blob *bsb;
+	struct bpf_local_storage *curr;
+	int err;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return -EINVAL;
+
+	curr = bpf_local_storage_alloc(smap);
+	if (!curr)
+		return -ENOMEM;
+
+	curr->inode = inode;
+	curr->stype = BPF_LOCAL_STORAGE_INODE;
+
+	__selem_link(curr, first_selem);
+	selem_link_map(smap, first_selem);
+
+	err = publish_local_storage(first_selem,
+		(struct bpf_local_storage **)&bsb->storage, curr);
+	if (err) {
+		kfree(curr);
+		return err;
+	}
+
+	return 0;
+}
+
 static int check_update_flags(struct bpf_map *map, u64 map_flags)
 {
 	/* BPF_EXIST and BPF_NOEXIST cannot be both set */
@@ -453,6 +519,8 @@ static int map_to_storage_type(struct bpf_map *map)
 	switch (map->map_type) {
 	case BPF_MAP_TYPE_SK_STORAGE:
 		return BPF_LOCAL_STORAGE_SK;
+	case BPF_MAP_TYPE_INODE_STORAGE:
+		return BPF_LOCAL_STORAGE_INODE;
 	default:
 		return -EINVAL;
 	}
@@ -471,6 +539,8 @@ static struct bpf_local_storage_data *local_storage_update(
 	struct bpf_local_storage *local_storage;
 	struct bpf_local_storage_map *smap;
 	enum bpf_local_storage_type stype;
+	struct bpf_storage_blob *bsb;
+	struct inode *inode;
 	struct sock *sk;
 	int err;
 
@@ -489,6 +559,11 @@ static struct bpf_local_storage_data *local_storage_update(
 		sk = owner;
 		local_storage = rcu_dereference(sk->sk_bpf_storage);
 		break;
+	case BPF_LOCAL_STORAGE_INODE:
+		inode = owner;
+		bsb = bpf_inode(inode);
+		local_storage = rcu_dereference(bsb->storage);
+		break;
 	default:
 		WARN_ON_ONCE(1);
 		return ERR_PTR(-EINVAL);
@@ -513,6 +588,18 @@ static struct bpf_local_storage_data *local_storage_update(
 				return ERR_PTR(err);
 			}
 
+			return SDATA(selem);
+		case BPF_LOCAL_STORAGE_INODE:
+			selem = selem_alloc(smap, value);
+			if (!selem)
+				return ERR_PTR(-ENOMEM);
+
+			err = inode_storage_alloc(inode, smap, selem);
+			if (err) {
+				kfree(selem);
+				return ERR_PTR(err);
+			}
+
 			return SDATA(selem);
 		}
 	}
@@ -574,6 +661,13 @@ static struct bpf_local_storage_data *local_storage_update(
 			goto unlock_err;
 		}
 		break;
+	case BPF_LOCAL_STORAGE_INODE:
+		selem = selem_alloc(smap, value);
+		if (!selem) {
+			err = -ENOMEM;
+			goto unlock_err;
+		}
+		break;
 	}
 
 	/* First, link the new selem to the map */
@@ -610,6 +704,19 @@ static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
 	return 0;
 }
 
+static int inode_storage_delete(struct inode *inode, struct bpf_map *map)
+{
+	struct bpf_local_storage_data *sdata;
+
+	sdata = inode_storage_lookup(inode, map, false);
+	if (!sdata)
+		return -ENOENT;
+
+	selem_unlink(SELEM(sdata));
+
+	return 0;
+}
+
 /* Called by __sk_destruct() & bpf_sk_storage_clone() */
 void bpf_sk_storage_free(struct sock *sk)
 {
@@ -649,6 +756,55 @@ void bpf_sk_storage_free(struct sock *sk)
 		kfree_rcu(sk_storage, rcu);
 }
 
+/* Called by __destroy_inode() */
+void bpf_inode_storage_free(struct inode *inode)
+{
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage *local_storage;
+	bool free_inode_storage = false;
+	struct bpf_storage_blob *bsb;
+	struct hlist_node *n;
+
+	bsb = bpf_inode(inode);
+	if (!bsb)
+		return;
+
+	rcu_read_lock();
+
+	local_storage = rcu_dereference(bsb->storage);
+	if (!local_storage) {
+		rcu_read_unlock();
+		return;
+	}
+
+	/* Netiher the bpf_prog nor the bpf-map's syscall
+	 * could be modifying the local_storage->list now.
+	 * Thus, no elem can be added-to or deleted-from the
+	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
+	 *
+	 * It is racing with bpf_local_storage_map_free() alone
+	 * when unlinking elem from the local_storage->list and
+	 * the map's bucket->list.
+	 */
+	raw_spin_lock_bh(&local_storage->lock);
+	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
+		/* Always unlink from map before unlinking from
+		 * local_storage.
+		 */
+		selem_unlink_map(selem);
+		free_inode_storage =
+			__selem_unlink(local_storage, selem, false);
+	}
+	raw_spin_unlock_bh(&local_storage->lock);
+	rcu_read_unlock();
+
+	/* free_inoode_storage should always be true as long as
+	 * local_storage->list was non-empty.
+	 */
+	if (free_inode_storage)
+		kfree_rcu(local_storage, rcu);
+}
+
 static void bpf_local_storage_map_free(struct bpf_map *map)
 {
 	struct bpf_local_storage_elem *selem;
@@ -671,7 +827,7 @@ static void bpf_local_storage_map_free(struct bpf_map *map)
 	 *
 	 * The elem of this map can be cleaned up here
 	 * or by bpf_local_storage_free() during the destruction of the
-	 * owner object. eg. __sk_destruct.
+	 * owner object. eg. __sk_destruct or __destroy_inode.
 	 */
 	for (i = 0; i < (1U << smap->bucket_log); i++) {
 		b = &smap->buckets[i];
@@ -821,6 +977,21 @@ static void *bpf_sk_storage_lookup_elem(struct bpf_map *map, void *key)
 	return ERR_PTR(err);
 }
 
+static void *bpf_inode_storage_lookup_elem(struct bpf_map *map, void *key)
+{
+	struct bpf_local_storage_data *sdata;
+	struct inode *inode;
+	int err = -EINVAL;
+
+	if (key) {
+		inode = *(struct inode **)(key);
+		sdata = inode_storage_lookup(inode, map, true);
+		return sdata ? sdata->data : NULL;
+	}
+
+	return ERR_PTR(err);
+}
+
 static int bpf_sk_storage_update_elem(struct bpf_map *map, void *key,
 					 void *value, u64 map_flags)
 {
@@ -839,6 +1010,21 @@ static int bpf_sk_storage_update_elem(struct bpf_map *map, void *key,
 	return err;
 }
 
+static int bpf_inode_storage_update_elem(struct bpf_map *map, void *key,
+					 void *value, u64 map_flags)
+{
+	struct bpf_local_storage_data *sdata;
+	struct inode *inode;
+	int err = -EINVAL;
+
+	if (key) {
+		inode = *(struct inode **)(key);
+		sdata = local_storage_update(inode, map, value, map_flags);
+		return PTR_ERR_OR_ZERO(sdata);
+	}
+	return err;
+}
+
 static int bpf_sk_storage_delete_elem(struct bpf_map *map, void *key)
 {
 	struct socket *sock;
@@ -854,6 +1040,19 @@ static int bpf_sk_storage_delete_elem(struct bpf_map *map, void *key)
 	return err;
 }
 
+static int bpf_inode_storage_delete_elem(struct bpf_map *map, void *key)
+{
+	struct inode *inode;
+	int err = -EINVAL;
+
+	if (key) {
+		inode = *(struct inode **)(key);
+		err = inode_storage_delete(inode, map);
+	}
+
+	return err;
+}
+
 static struct bpf_local_storage_elem *
 bpf_sk_storage_clone_elem(struct sock *newsk,
 			  struct bpf_local_storage_map *smap,
@@ -975,6 +1174,27 @@ BPF_CALL_4(bpf_sk_storage_get, struct bpf_map *, map, struct sock *, sk,
 	return (unsigned long)NULL;
 }
 
+BPF_CALL_4(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode,
+	   void *, value, u64, flags)
+{
+	struct bpf_local_storage_data *sdata;
+
+	if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
+		return (unsigned long)NULL;
+
+	sdata = inode_storage_lookup(inode, map, true);
+	if (sdata)
+		return (unsigned long)sdata->data;
+
+	if (flags & BPF_LOCAL_STORAGE_GET_F_CREATE) {
+		sdata = local_storage_update(inode, map, value, BPF_NOEXIST);
+		return IS_ERR(sdata) ?
+			(unsigned long)NULL : (unsigned long)sdata->data;
+	}
+
+	return (unsigned long)NULL;
+}
+
 BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
 {
 	if (refcount_inc_not_zero(&sk->sk_refcnt)) {
@@ -988,6 +1208,12 @@ BPF_CALL_2(bpf_sk_storage_delete, struct bpf_map *, map, struct sock *, sk)
 	return -ENOENT;
 }
 
+BPF_CALL_2(bpf_inode_storage_delete,
+	   struct bpf_map *, map, struct inode *, inode)
+{
+	return inode_storage_delete(inode, map);
+}
+
 const struct bpf_map_ops sk_storage_map_ops = {
 	.map_alloc_check = bpf_local_storage_map_alloc_check,
 	.map_alloc = bpf_local_storage_map_alloc,
@@ -999,6 +1225,17 @@ const struct bpf_map_ops sk_storage_map_ops = {
 	.map_check_btf = bpf_local_storage_map_check_btf,
 };
 
+const struct bpf_map_ops inode_storage_map_ops = {
+	.map_alloc_check = bpf_local_storage_map_alloc_check,
+	.map_alloc = bpf_local_storage_map_alloc,
+	.map_free = bpf_local_storage_map_free,
+	.map_get_next_key = notsupp_get_next_key,
+	.map_lookup_elem = bpf_inode_storage_lookup_elem,
+	.map_update_elem = bpf_inode_storage_update_elem,
+	.map_delete_elem = bpf_inode_storage_delete_elem,
+	.map_check_btf = bpf_local_storage_map_check_btf,
+};
+
 const struct bpf_func_proto bpf_sk_storage_get_proto = {
 	.func		= bpf_sk_storage_get,
 	.gpl_only	= false,
@@ -1017,6 +1254,28 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = {
 	.arg2_type	= ARG_PTR_TO_SOCKET,
 };
 
+static int bpf_inode_storage_get_btf_ids[4];
+const struct bpf_func_proto bpf_inode_storage_get_proto = {
+	.func		= bpf_inode_storage_get,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.arg3_type	= ARG_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+	.btf_id		= bpf_inode_storage_get_btf_ids,
+};
+
+static int bpf_inode_storage_delete_btf_ids[2];
+const struct bpf_func_proto bpf_inode_storage_delete_proto = {
+	.func		= bpf_sk_storage_delete,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.btf_id		= bpf_inode_storage_delete_btf_ids,
+};
+
 struct bpf_sk_storage_diag {
 	u32 nr_maps;
 	struct bpf_map *maps[];
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8da159936bab..a685ec4c7b99 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -768,7 +768,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
 		if (map->map_type != BPF_MAP_TYPE_HASH &&
 		    map->map_type != BPF_MAP_TYPE_ARRAY &&
 		    map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
-		    map->map_type != BPF_MAP_TYPE_SK_STORAGE)
+		    map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
 			return -ENOTSUPP;
 		if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
 		    map->value_size) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 34cde841ab68..52936d24271d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4090,6 +4090,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 		    func_id != BPF_FUNC_sk_storage_delete)
 			goto error;
 		break;
+	case BPF_MAP_TYPE_INODE_STORAGE:
+		if (func_id != BPF_FUNC_inode_storage_get &&
+		    func_id != BPF_FUNC_inode_storage_delete)
+			goto error;
+		break;
 	default:
 		break;
 	}
@@ -4163,6 +4168,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 		if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
 			goto error;
 		break;
+	case BPF_FUNC_inode_storage_get:
+	case BPF_FUNC_inode_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
+			goto error;
+		break;
 	default:
 		break;
 	}
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index 32d32d485451..35f9b19259e5 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -3,6 +3,7 @@
 /*
  * Copyright (C) 2020 Google LLC.
  */
+#include <linux/bpf_local_storage.h>
 #include <linux/lsm_hooks.h>
 #include <linux/bpf_lsm.h>
 
@@ -11,6 +12,7 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(NAME, bpf_lsm_##NAME),
 	#include <linux/lsm_hook_defs.h>
 	#undef LSM_HOOK
+	LSM_HOOK_INIT(inode_free_security, bpf_inode_storage_free),
 };
 
 static int __init bpf_lsm_init(void)
@@ -20,7 +22,12 @@ static int __init bpf_lsm_init(void)
 	return 0;
 }
 
+struct lsm_blob_sizes bpf_lsm_blob_sizes __lsm_ro_after_init = {
+	.lbs_inode = sizeof(struct bpf_storage_blob),
+};
+
 DEFINE_LSM(bpf) = {
 	.name = "bpf",
 	.init = bpf_lsm_init,
+	.blobs = &bpf_lsm_blob_sizes
 };
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index c5fac8068ba1..e8fbafb3e87b 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -49,6 +49,7 @@ const char * const map_type_name[] = {
 	[BPF_MAP_TYPE_STACK]			= "stack",
 	[BPF_MAP_TYPE_SK_STORAGE]		= "sk_storage",
 	[BPF_MAP_TYPE_STRUCT_OPS]		= "struct_ops",
+	[BPF_MAP_TYPE_INODE_STORAGE]		= "inode_storage",
 };
 
 const size_t map_type_name_size = ARRAY_SIZE(map_type_name);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 6218677daaa2..679a50562e72 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -148,6 +148,7 @@ enum bpf_map_type {
 	BPF_MAP_TYPE_DEVMAP_HASH,
 	BPF_MAP_TYPE_STRUCT_OPS,
 	BPF_MAP_TYPE_RINGBUF,
+	BPF_MAP_TYPE_INODE_STORAGE,
 };
 
 /* Note that tracing related programs such as
@@ -3252,6 +3253,41 @@ union bpf_attr {
  * 		case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
  * 		is returned or the error code -EACCES in case the skb is not
  * 		subject to CHECKSUM_UNNECESSARY.
+ * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
+ *	Description
+ *		Get a bpf_local_storage from an *inode*.
+ *
+ *		Logically, it could be thought of as getting the value from
+ *		a *map* with *inode* as the **key**.  From this
+ *		perspective,  the usage is not much different from
+ *		**bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
+ *		helper enforces the key must be an inode and the map must also
+ *		be a **BPF_MAP_TYPE_INODE_STORAGE**.
+ *
+ *		Underneath, the value is stored locally at *inode* instead of
+ *		the *map*.  The *map* is used as the bpf-local-storage
+ *		"type". The bpf-local-storage "type" (i.e. the *map*) is
+ *		searched against all bpf_local_storage residing at *inode*.
+ *
+ *		An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ *		used such that a new bpf_local_storage will be
+ *		created if one does not exist.  *value* can be used
+ *		together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ *		the initial value of a bpf_local_storage.  If *value* is
+ *		**NULL**, the new bpf_local_storage will be zero initialized.
+ *	Return
+ *		A bpf_local_storage pointer is returned on success.
+ *
+ *		**NULL** if not found or there was an error in adding
+ *		a new bpf_local_storage.
+ *
+ * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
+ *	Description
+ *		Delete a bpf_local_storage from an *inode*.
+ *	Return
+ *		0 on success.
+ *
+ *		**-ENOENT** if the bpf_local_storage cannot be found.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -3389,7 +3425,9 @@ union bpf_attr {
 	FN(ringbuf_submit),		\
 	FN(ringbuf_discard),		\
 	FN(ringbuf_query),		\
-	FN(csum_level),
+	FN(csum_level),			\
+	FN(inode_storage_get),		\
+	FN(inode_storage_delete),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 10cd8d1891f5..b859558ce290 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -170,7 +170,7 @@ int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
 	return btf_fd;
 }
 
-static int load_sk_storage_btf(void)
+static int load_local_storage_btf(void)
 {
 	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
 	/* struct bpf_spin_lock {
@@ -229,12 +229,13 @@ bool bpf_probe_map_type(enum bpf_map_type map_type, __u32 ifindex)
 		key_size	= 0;
 		break;
 	case BPF_MAP_TYPE_SK_STORAGE:
+	case BPF_MAP_TYPE_INODE_STORAGE:
 		btf_key_type_id = 1;
 		btf_value_type_id = 3;
 		value_size = 8;
 		max_entries = 0;
 		map_flags = BPF_F_NO_PREALLOC;
-		btf_fd = load_sk_storage_btf();
+		btf_fd = load_local_storage_btf();
 		if (btf_fd < 0)
 			return false;
 		break;
-- 
2.27.0.111.gc72c7da667-goog

Re: [PATCH bpf-next v2 2/4] bpf: Implement bpf_local_storage for inodes

[Martin KaFai Lau]

On Wed, Jun 17, 2020 at 10:29:39PM +0200, KP Singh wrote:
[ ... ]

> diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
> index af74712af585..8efd7562e3de 100644
> --- a/include/linux/bpf_lsm.h
> +++ b/include/linux/bpf_lsm.h
> @@ -17,9 +17,24 @@
>  #include <linux/lsm_hook_defs.h>
>  #undef LSM_HOOK
>  
> +struct bpf_storage_blob {
> +	struct bpf_local_storage __rcu *storage;
> +};
> +
> +extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
> +
>  int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
>  			const struct bpf_prog *prog);
>  
> +static inline struct bpf_storage_blob *bpf_inode(
> +	const struct inode *inode)
> +{
> +	if (unlikely(!inode->i_security))
> +		return NULL;
> +
> +	return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
> +}
> +
>  #else /* !CONFIG_BPF_LSM */
>  
>  static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> @@ -28,6 +43,12 @@ static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
>  	return -EOPNOTSUPP;
>  }
>  
> +static inline struct bpf_storage_blob *bpf_inode_storage(
This does not seem to match the newly added "bpf_inode()"
above for the "CONFIG_BPF_LSM" case.

A typo?  May be a good idea to test compiling with !CONFIG_BPF_LSM.

> +	const struct inode *inode)
> +{
> +	return NULL;
> +}
> +
>  #endif /* CONFIG_BPF_LSM */
>  
>  #endif /* _LINUX_BPF_LSM_H */
> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> index a18ae82a298a..881e7954c956 100644
> --- a/include/linux/bpf_types.h
> +++ b/include/linux/bpf_types.h
> @@ -101,6 +101,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP, dev_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, dev_map_hash_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SK_STORAGE, sk_storage_map_ops)
> +BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops)
sk_storage is under CONFIG_NET.

inode_storage should be CONFIG_BPF_LSM?

>  #if defined(CONFIG_BPF_STREAM_PARSER)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKMAP, sock_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops)

Re: [PATCH bpf-next v2 2/4] bpf: Implement bpf_local_storage for inodes

[KP Singh]

On 18-Jun 23:52, Martin KaFai Lau wrote:
> On Wed, Jun 17, 2020 at 10:29:39PM +0200, KP Singh wrote:
> [ ... ]
> 
> > diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
> > index af74712af585..8efd7562e3de 100644
> > --- a/include/linux/bpf_lsm.h
> > +++ b/include/linux/bpf_lsm.h
> > @@ -17,9 +17,24 @@
> >  #include <linux/lsm_hook_defs.h>
> >  #undef LSM_HOOK
> >  
> > +struct bpf_storage_blob {
> > +	struct bpf_local_storage __rcu *storage;
> > +};
> > +
> > +extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
> > +
> >  int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> >  			const struct bpf_prog *prog);
> >  
> > +static inline struct bpf_storage_blob *bpf_inode(
> > +	const struct inode *inode)
> > +{
> > +	if (unlikely(!inode->i_security))
> > +		return NULL;
> > +
> > +	return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
> > +}
> > +
> >  #else /* !CONFIG_BPF_LSM */
> >  
> >  static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> > @@ -28,6 +43,12 @@ static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> >  	return -EOPNOTSUPP;
> >  }
> >  
> > +static inline struct bpf_storage_blob *bpf_inode_storage(
> This does not seem to match the newly added "bpf_inode()"
> above for the "CONFIG_BPF_LSM" case.
> 
> A typo?  May be a good idea to test compiling with !CONFIG_BPF_LSM.

Sorry about that, yeah it was a last minute lazy rename. Will
compile test the series with !CONFIG_BPF_LSM and !CONFIG_NET. Thanks.

> 
> > +	const struct inode *inode)
> > +{
> > +	return NULL;
> > +}
> > +
> >  #endif /* CONFIG_BPF_LSM */
> >  
> >  #endif /* _LINUX_BPF_LSM_H */
> > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> > index a18ae82a298a..881e7954c956 100644
> > --- a/include/linux/bpf_types.h
> > +++ b/include/linux/bpf_types.h
> > @@ -101,6 +101,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
> >  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP, dev_map_ops)
> >  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, dev_map_hash_ops)
> >  BPF_MAP_TYPE(BPF_MAP_TYPE_SK_STORAGE, sk_storage_map_ops)
> > +BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops)
> sk_storage is under CONFIG_NET.
> 
> inode_storage should be CONFIG_BPF_LSM?

Thanks, updated.

- KP

> 
> >  #if defined(CONFIG_BPF_STREAM_PARSER)
> >  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKMAP, sock_map_ops)
> >  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops)

Re: [PATCH bpf-next v2 2/4] bpf: Implement bpf_local_storage for inodes

[Quentin Monnet]

2020-06-17 22:29 UTC+0200 ~ KP Singh <kpsingh@chromium.org>
> From: KP Singh <kpsingh@google.com>
> 
> Similar to bpf_local_storage for sockets, add local storage for inodes.
> The life-cycle of storage is managed with the life-cycle of the inode.
> i.e. the storage is destroyed along with the owning inode.
> 
> The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the
> security blob which are now stackable and can co-exist with other LSMs.
> 
> Signed-off-by: KP Singh <kpsingh@google.com>

> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index c5fac8068ba1..e8fbafb3e87b 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -49,6 +49,7 @@ const char * const map_type_name[] = {
>  	[BPF_MAP_TYPE_STACK]			= "stack",
>  	[BPF_MAP_TYPE_SK_STORAGE]		= "sk_storage",
>  	[BPF_MAP_TYPE_STRUCT_OPS]		= "struct_ops",
> +	[BPF_MAP_TYPE_INODE_STORAGE]		= "inode_storage",
>  };
>  
>  const size_t map_type_name_size = ARRAY_SIZE(map_type_name);

Thanks for the update on bpftool map types, could you also change the
relevant help message, man page and bash completion please? (See below.)

Best regards,
Quentin

------

diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index 31101643e57c..a9cd15ed7187 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
@@ -49,7 +49,7 @@ MAP COMMANDS
 |		| **lru_percpu_hash** | **lpm_trie** | **array_of_maps** | **hash_of_maps**
 |		| **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash**
 |		| **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage**
-|		| **queue** | **stack** | **sk_storage** | **struct_ops** }
+|		| **queue** | **stack** | **sk_storage** | **struct_ops** | **inode_storage** }
 
 DESCRIPTION
 ===========
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 25b25aca1112..34cadc081a78 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -688,7 +688,8 @@ _bpftool()
                                 lru_percpu_hash lpm_trie array_of_maps \
                                 hash_of_maps devmap devmap_hash sockmap cpumap \
                                 xskmap sockhash cgroup_storage reuseport_sockarray \
-                                percpu_cgroup_storage queue stack' -- \
+                                percpu_cgroup_storage queue stack sk_storage \
+                                struct_ops inode_storage' -- \
                                                    "$cur" ) )
                             return 0
                             ;;
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index c5fac8068ba1..f1b48a97b378 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1590,7 +1590,7 @@ static int do_help(int argc, char **argv)
 		"                 lru_percpu_hash | lpm_trie | array_of_maps | hash_of_maps |\n"
 		"                 devmap | devmap_hash | sockmap | cpumap | xskmap | sockhash |\n"
 		"                 cgroup_storage | reuseport_sockarray | percpu_cgroup_storage |\n"
-		"                 queue | stack | sk_storage | struct_ops }\n"
+		"                 queue | stack | sk_storage | struct_ops | inode_storage }\n"
 		"       " HELP_SPEC_OPTIONS "\n"
 		"",
 		bin_name, argv[-2]);

[PATCH bpf-next v2 3/4] bpf: Allow local storage to be used from LSM programs

[KP Singh]

From: KP Singh <kpsingh@google.com>

Adds support for both bpf_{sk, inode}_storage_{get, delete} to be used
in LSM programs. These helpers are not used for tracing programs
(currently) as their usage is tied to the life-cycle of the object and
should only be used where the owning object won't be freed (when the
owning object is passed as an argument to the LSM hook). Thus, they
are safer to use in LSM hooks than tracing. Usage of local storage in
tracing programs will probably follow a per function based whitelist
approach.

Since the UAPI helper signature for bpf_sk_storage expect a bpf_sock,
it, leads to a compilation warning for LSM programs, it's also updated
to accept a void * pointer instead.

Signed-off-by: KP Singh <kpsingh@google.com>
---
 include/linux/bpf_local_storage.h |  2 ++
 include/uapi/linux/bpf.h          |  4 ++--
 kernel/bpf/bpf_local_storage.c    | 22 ++++++++++++++++++++++
 kernel/bpf/bpf_lsm.c              | 20 +++++++++++++++++++-
 tools/include/uapi/linux/bpf.h    |  4 ++--
 5 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 7488487b1099..cf43ed0b6c3b 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -10,6 +10,8 @@ void bpf_sk_storage_free(struct sock *sk);
 
 extern const struct bpf_func_proto bpf_sk_storage_get_proto;
 extern const struct bpf_func_proto bpf_sk_storage_delete_proto;
+extern const struct bpf_func_proto sk_storage_get_btf_proto;
+extern const struct bpf_func_proto sk_storage_delete_btf_proto;
 extern const struct bpf_func_proto bpf_inode_storage_get_proto;
 extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
 
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 679a50562e72..6867e24f8c77 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2783,7 +2783,7 @@ union bpf_attr {
  *
  *		**-ERANGE** if resulting value was out of range.
  *
- * void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags)
+ * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
  *	Description
  *		Get a bpf-local-storage from a *sk*.
  *
@@ -2811,7 +2811,7 @@ union bpf_attr {
  *		**NULL** if not found or there was an error in adding
  *		a new bpf-local-storage.
  *
- * int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk)
+ * int bpf_sk_storage_delete(struct bpf_map *map, void *sk)
  *	Description
  *		Delete a bpf-local-storage from a *sk*.
  *	Return
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 572ed711c3fd..c944fc0cc81d 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -1276,6 +1276,28 @@ const struct bpf_func_proto bpf_inode_storage_delete_proto = {
 	.btf_id		= bpf_inode_storage_delete_btf_ids,
 };
 
+static int sk_storage_get_btf_ids[4];
+const struct bpf_func_proto sk_storage_get_btf_proto = {
+	.func		= bpf_sk_storage_get,
+	.gpl_only	= false,
+	.ret_type	= RET_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.arg3_type	= ARG_PTR_TO_MAP_VALUE_OR_NULL,
+	.arg4_type	= ARG_ANYTHING,
+	.btf_id		= sk_storage_get_btf_ids,
+};
+
+static int sk_storage_delete_btf_ids[2];
+const struct bpf_func_proto sk_storage_delete_btf_proto = {
+	.func		= bpf_sk_storage_delete,
+	.gpl_only	= false,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_CONST_MAP_PTR,
+	.arg2_type	= ARG_PTR_TO_BTF_ID,
+	.btf_id		= sk_storage_delete_btf_ids,
+};
+
 struct bpf_sk_storage_diag {
 	u32 nr_maps;
 	struct bpf_map *maps[];
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index fb278144e9fd..e97dbbf56285 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -11,6 +11,7 @@
 #include <linux/bpf_lsm.h>
 #include <linux/kallsyms.h>
 #include <linux/bpf_verifier.h>
+#include <linux/bpf_local_storage.h>
 
 /* For every LSM hook that allows attachment of BPF programs, declare a nop
  * function where a BPF program can be attached.
@@ -45,10 +46,27 @@ int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 	return 0;
 }
 
+static const struct bpf_func_proto *
+bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	switch (func_id) {
+	case BPF_FUNC_inode_storage_get:
+		return &bpf_inode_storage_get_proto;
+	case BPF_FUNC_inode_storage_delete:
+		return &bpf_inode_storage_delete_proto;
+	case BPF_FUNC_sk_storage_get:
+		return &sk_storage_get_btf_proto;
+	case BPF_FUNC_sk_storage_delete:
+		return &sk_storage_delete_btf_proto;
+	default:
+		return tracing_prog_func_proto(func_id, prog);
+	}
+}
+
 const struct bpf_prog_ops lsm_prog_ops = {
 };
 
 const struct bpf_verifier_ops lsm_verifier_ops = {
-	.get_func_proto = tracing_prog_func_proto,
+	.get_func_proto = bpf_lsm_func_proto,
 	.is_valid_access = btf_ctx_access,
 };
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 679a50562e72..6867e24f8c77 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2783,7 +2783,7 @@ union bpf_attr {
  *
  *		**-ERANGE** if resulting value was out of range.
  *
- * void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags)
+ * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
  *	Description
  *		Get a bpf-local-storage from a *sk*.
  *
@@ -2811,7 +2811,7 @@ union bpf_attr {
  *		**NULL** if not found or there was an error in adding
  *		a new bpf-local-storage.
  *
- * int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk)
+ * int bpf_sk_storage_delete(struct bpf_map *map, void *sk)
  *	Description
  *		Delete a bpf-local-storage from a *sk*.
  *	Return
-- 
2.27.0.111.gc72c7da667-goog

[PATCH bpf-next v2 4/4] bpf: Add selftests for local_storage

[KP Singh]

From: KP Singh <kpsingh@google.com>

inode_local_storage:

* Hook to the file_open and inode_unlink LSM hooks.
* Create and unlink a temporary file.
* Store some information in the inode's bpf_local_storage during
  file_open.
* Verify that this information exists when the file is unlinked.

sk_local_storage:

* Hook to the socket_post_create and socket_bind LSM hooks.
* Open and bind a socket and set the sk_storage in the
  socket_post_create hook using the start_server helper.
* Verify if the information is set in the socket_bind hook.

Signed-off-by: KP Singh <kpsingh@google.com>
---
 .../bpf/prog_tests/test_local_storage.c       |  60 ++++++++
 .../selftests/bpf/progs/local_storage.c       | 137 ++++++++++++++++++
 2 files changed, 197 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/test_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/local_storage.c

diff --git a/tools/testing/selftests/bpf/prog_tests/test_local_storage.c b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
new file mode 100644
index 000000000000..ee4e27473c1d
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_local_storage.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2020 Google LLC.
+ */
+
+#include <test_progs.h>
+#include <linux/limits.h>
+
+#include "local_storage.skel.h"
+#include "network_helpers.h"
+
+int create_and_unlink_file(void)
+{
+	char fname[PATH_MAX] = "/tmp/fileXXXXXX";
+	int fd;
+
+	fd = mkstemp(fname);
+	if (fd < 0)
+		return fd;
+
+	close(fd);
+	unlink(fname);
+	return 0;
+}
+
+void test_test_local_storage(void)
+{
+	struct local_storage *skel = NULL;
+	int err, duration = 0, serv_sk = -1;
+
+	skel = local_storage__open_and_load();
+	if (CHECK(!skel, "skel_load", "lsm skeleton failed\n"))
+		goto close_prog;
+
+	err = local_storage__attach(skel);
+	if (CHECK(err, "attach", "lsm attach failed: %d\n", err))
+		goto close_prog;
+
+	skel->bss->monitored_pid = getpid();
+
+	err = create_and_unlink_file();
+	if (CHECK(err < 0, "exec_cmd", "err %d errno %d\n", err, errno))
+		goto close_prog;
+
+	CHECK(!skel->bss->inode_storage_result, "inode_storage_result",
+	      "inode_local_storage not set");
+
+	serv_sk = start_server(AF_INET6, SOCK_STREAM);
+	if (CHECK(serv_sk < 0, "start_server", "failed to start server\n"))
+		goto close_prog;
+
+	CHECK(!skel->bss->sk_storage_result, "sk_storage_result",
+	      "sk_local_storage not set");
+
+	close(serv_sk);
+
+close_prog:
+	local_storage__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c
new file mode 100644
index 000000000000..38954e6a1edc
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/local_storage.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2020 Google LLC.
+ */
+
+#include <errno.h>
+#include <linux/bpf.h>
+#include <stdbool.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+__u32 _version SEC("version") = 1;
+
+#define DUMMY_STORAGE_VALUE 0xdeadbeef
+
+int monitored_pid = 0;
+bool inode_storage_result = false;
+bool sk_storage_result = false;
+
+struct dummy_storage {
+	__u32 value;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_INODE_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, struct dummy_storage);
+} inode_storage_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
+	__type(key, int);
+	__type(value, struct dummy_storage);
+} sk_storage_map SEC(".maps");
+
+/* TODO Use vmlinux.h once BTF pruning for embedded types is fixed.
+ */
+struct sock {} __attribute__((preserve_access_index));
+struct sockaddr {} __attribute__((preserve_access_index));
+struct socket {
+	struct sock *sk;
+} __attribute__((preserve_access_index));
+
+struct inode {} __attribute__((preserve_access_index));
+struct dentry {
+	struct inode *d_inode;
+} __attribute__((preserve_access_index));
+struct file {
+	struct inode *f_inode;
+} __attribute__((preserve_access_index));
+
+
+SEC("lsm/inode_unlink")
+int BPF_PROG(unlink_hook, struct inode *dir, struct dentry *victim)
+{
+	__u32 pid = bpf_get_current_pid_tgid() >> 32;
+	struct dummy_storage *storage;
+
+	if (pid != monitored_pid)
+		return 0;
+
+	storage = bpf_inode_storage_get(&inode_storage_map, victim->d_inode, 0,
+				     BPF_SK_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 0;
+
+	if (storage->value == DUMMY_STORAGE_VALUE)
+		inode_storage_result = true;
+
+	return 0;
+}
+
+SEC("lsm/socket_bind")
+int BPF_PROG(socket_bind, struct socket *sock, struct sockaddr *address,
+	     int addrlen)
+{
+	__u32 pid = bpf_get_current_pid_tgid() >> 32;
+	struct dummy_storage *storage;
+
+	if (pid != monitored_pid)
+		return 0;
+
+	storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0,
+				     BPF_SK_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 0;
+
+	if (storage->value == DUMMY_STORAGE_VALUE)
+		sk_storage_result = true;
+
+	return 0;
+}
+
+SEC("lsm/socket_post_create")
+int BPF_PROG(socket_post_create, struct socket *sock, int family, int type,
+	     int protocol, int kern)
+{
+	__u32 pid = bpf_get_current_pid_tgid() >> 32;
+	struct dummy_storage *storage;
+
+	if (pid != monitored_pid)
+		return 0;
+
+	storage = bpf_sk_storage_get(&sk_storage_map, sock->sk, 0,
+				     BPF_SK_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 0;
+
+	storage->value = DUMMY_STORAGE_VALUE;
+
+	return 0;
+}
+
+SEC("lsm/file_open")
+int BPF_PROG(test_int_hook, struct file *file)
+{
+	__u32 pid = bpf_get_current_pid_tgid() >> 32;
+	struct dummy_storage *storage;
+
+	if (pid != monitored_pid)
+		return 0;
+
+	if (!file->f_inode)
+		return 0;
+
+	storage = bpf_inode_storage_get(&inode_storage_map, file->f_inode, 0,
+				     BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!storage)
+		return 0;
+
+	storage->value = DUMMY_STORAGE_VALUE;
+	return 0;
+}
-- 
2.27.0.111.gc72c7da667-goog

Re: [PATCH bpf-next v2 4/4] bpf: Add selftests for local_storage

[Andrii Nakryiko]

On Wed, Jun 17, 2020 at 1:31 PM KP Singh <kpsingh@chromium.org> wrote:
>
> From: KP Singh <kpsingh@google.com>
>
> inode_local_storage:
>
> * Hook to the file_open and inode_unlink LSM hooks.
> * Create and unlink a temporary file.
> * Store some information in the inode's bpf_local_storage during
>   file_open.
> * Verify that this information exists when the file is unlinked.
>
> sk_local_storage:
>
> * Hook to the socket_post_create and socket_bind LSM hooks.
> * Open and bind a socket and set the sk_storage in the
>   socket_post_create hook using the start_server helper.
> * Verify if the information is set in the socket_bind hook.
>
> Signed-off-by: KP Singh <kpsingh@google.com>
> ---
>  .../bpf/prog_tests/test_local_storage.c       |  60 ++++++++
>  .../selftests/bpf/progs/local_storage.c       | 137 ++++++++++++++++++
>  2 files changed, 197 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/test_local_storage.c
>  create mode 100644 tools/testing/selftests/bpf/progs/local_storage.c
>

[...]

> diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c
> new file mode 100644
> index 000000000000..38954e6a1edc
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/local_storage.c
> @@ -0,0 +1,137 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Copyright 2020 Google LLC.
> + */
> +
> +#include <errno.h>
> +#include <linux/bpf.h>
> +#include <stdbool.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +
> +char _license[] SEC("license") = "GPL";
> +__u32 _version SEC("version") = 1;

version is anachronism, please drop it.

Otherwise, LGTM.

Acked-by: Andrii Nakryiko <andriin@fb.com>

[...]

Re: [PATCH bpf-next v2 4/4] bpf: Add selftests for local_storage

[KP Singh]

On 18-Jun 11:16, Andrii Nakryiko wrote:
> On Wed, Jun 17, 2020 at 1:31 PM KP Singh <kpsingh@chromium.org> wrote:
> >
> > From: KP Singh <kpsingh@google.com>
> >
> > inode_local_storage:
> >
> > * Hook to the file_open and inode_unlink LSM hooks.
> > * Create and unlink a temporary file.
> > * Store some information in the inode's bpf_local_storage during
> >   file_open.
> > * Verify that this information exists when the file is unlinked.
> >
> > sk_local_storage:
> >
> > * Hook to the socket_post_create and socket_bind LSM hooks.
> > * Open and bind a socket and set the sk_storage in the
> >   socket_post_create hook using the start_server helper.
> > * Verify if the information is set in the socket_bind hook.
> >
> > Signed-off-by: KP Singh <kpsingh@google.com>
> > ---
> >  .../bpf/prog_tests/test_local_storage.c       |  60 ++++++++
> >  .../selftests/bpf/progs/local_storage.c       | 137 ++++++++++++++++++
> >  2 files changed, 197 insertions(+)
> >  create mode 100644 tools/testing/selftests/bpf/prog_tests/test_local_storage.c
> >  create mode 100644 tools/testing/selftests/bpf/progs/local_storage.c
> >
> 
> [...]
> 
> > diff --git a/tools/testing/selftests/bpf/progs/local_storage.c b/tools/testing/selftests/bpf/progs/local_storage.c
> > new file mode 100644
> > index 000000000000..38954e6a1edc
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/progs/local_storage.c
> > @@ -0,0 +1,137 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +/*
> > + * Copyright 2020 Google LLC.
> > + */
> > +
> > +#include <errno.h>
> > +#include <linux/bpf.h>
> > +#include <stdbool.h>
> > +#include <bpf/bpf_helpers.h>
> > +#include <bpf/bpf_tracing.h>
> > +
> > +char _license[] SEC("license") = "GPL";
> > +__u32 _version SEC("version") = 1;
> 
> version is anachronism, please drop it.

Removed.

> 
> Otherwise, LGTM.

Thanks

- KP

> 
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> 
> [...]