Commit 13e3c779 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 

Daniel Borkmann says:

====================
pull-request: bpf 2022-12-16

We've added 7 non-merge commits during the last 2 day(s) which contain
a total of 9 files changed, 119 insertions(+), 36 deletions(-).

1) Fix for recent syzkaller XDP dispatcher update splat, from Jiri Olsa.

2) Fix BPF program refcount leak in LSM attachment failure path,
   from Milan Landaverde.

3) Fix BPF program type in map compatibility check for fext,
   from Toke Høiland-Jørgensen.

4) Fix a BPF selftest compilation error under !CONFIG_SMP config,
   from Yonghong Song.

5) Fix CI to enable CONFIG_FUNCTION_ERROR_INJECTION after it got changed
   to a prompt, from Song Liu.

6) Various BPF documentation fixes for socket local storage,
   from Donald Hunter.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Add a test for using a cpumap from an freplace-to-XDP program
  bpf: Resolve fext program type when checking map compatibility
  bpf: Synchronize dispatcher update with bpf_dispatcher_xdp_func
  bpf: prevent leak of lsm program after failed attach
  selftests/bpf: Select CONFIG_FUNCTION_ERROR_INJECTION
  selftests/bpf: Fix a selftest compilation error with CONFIG_SMP=n
  docs/bpf: Reword docs for BPF_MAP_TYPE_SK_STORAGE
====================

Link: https://lore.kernel.org/r/20221216174540.16598-1-daniel@iogearbox.net


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 68bb1010 f506439e

Documentation/bpf/map_sk_storage.rst

+30 −26
Original line number Diff line number Diff line
@@ -34,13 +34,12 @@ bpf_sk_storage_get() 


   void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)



Socket-local storage can be retrieved using the ``bpf_sk_storage_get()``

helper. The helper gets the storage from ``sk`` that is associated with ``map``.

If the ``BPF_LOCAL_STORAGE_GET_F_CREATE`` flag is used then

``bpf_sk_storage_get()`` will create the storage for ``sk`` if it does not

already exist. ``value`` can be used together with

``BPF_LOCAL_STORAGE_GET_F_CREATE`` to initialize the storage value, otherwise it

will be zero initialized. Returns a pointer to the storage on success, or

Socket-local storage for ``map`` can be retrieved from socket ``sk`` using the

``bpf_sk_storage_get()`` helper. If the ``BPF_LOCAL_STORAGE_GET_F_CREATE``

flag is used then ``bpf_sk_storage_get()`` will create the storage for ``sk``

if it does not already exist. ``value`` can be used together with

``BPF_LOCAL_STORAGE_GET_F_CREATE`` to initialize the storage value, otherwise

it will be zero initialized. Returns a pointer to the storage on success, or

``NULL`` in case of failure.



.. note::
@@ -54,9 +53,9 @@ bpf_sk_storage_delete() 


   long bpf_sk_storage_delete(struct bpf_map *map, void *sk)



Socket-local storage can be deleted using the ``bpf_sk_storage_delete()``

helper. The helper deletes the storage from ``sk`` that is identified by

``map``. Returns ``0`` on success, or negative error in case of failure.

Socket-local storage for ``map`` can be deleted from socket ``sk`` using the

``bpf_sk_storage_delete()`` helper. Returns ``0`` on success, or negative

error in case of failure.



User space

----------
@@ -68,16 +67,20 @@ bpf_map_update_elem() 


   int bpf_map_update_elem(int map_fd, const void *key, const void *value, __u64 flags)



Socket-local storage for the socket identified by ``key`` belonging to

``map_fd`` can be added or updated using the ``bpf_map_update_elem()`` libbpf

function. ``key`` must be a pointer to a valid ``fd`` in the user space

program. The ``flags`` parameter can be used to control the update behaviour:

Socket-local storage for map ``map_fd`` can be added or updated locally to a

socket using the ``bpf_map_update_elem()`` libbpf function. The socket is

identified by a `socket` ``fd`` stored in the pointer ``key``. The pointer

``value`` has the data to be added or updated to the socket ``fd``. The type

and size of ``value`` should be the same as the value type of the map

definition.



- ``BPF_ANY`` will create storage for ``fd`` or update existing storage.

- ``BPF_NOEXIST`` will create storage for ``fd`` only if it did not already

  exist, otherwise the call will fail with ``-EEXIST``.

- ``BPF_EXIST`` will update existing storage for ``fd`` if it already exists,

  otherwise the call will fail with ``-ENOENT``.

The ``flags`` parameter can be used to control the update behaviour:



- ``BPF_ANY`` will create storage for `socket` ``fd`` or update existing storage.

- ``BPF_NOEXIST`` will create storage for `socket` ``fd`` only if it did not

  already exist, otherwise the call will fail with ``-EEXIST``.

- ``BPF_EXIST`` will update existing storage for `socket` ``fd`` if it already

  exists, otherwise the call will fail with ``-ENOENT``.



Returns ``0`` on success, or negative error in case of failure.
@@ -88,10 +91,10 @@ bpf_map_lookup_elem() 


   int bpf_map_lookup_elem(int map_fd, const void *key, void *value)



Socket-local storage for the socket identified by ``key`` belonging to

``map_fd`` can be retrieved using the ``bpf_map_lookup_elem()`` libbpf

function. ``key`` must be a pointer to a valid ``fd`` in the user space

program. Returns ``0`` on success, or negative error in case of failure.

Socket-local storage for map ``map_fd`` can be retrieved from a socket using

the ``bpf_map_lookup_elem()`` libbpf function. The storage is retrieved from

the socket identified by a `socket` ``fd`` stored in the pointer

``key``. Returns ``0`` on success, or negative error in case of failure.



bpf_map_delete_elem()

~~~~~~~~~~~~~~~~~~~~~
@@ -100,9 +103,10 @@ bpf_map_delete_elem() 


   int bpf_map_delete_elem(int map_fd, const void *key)



Socket-local storage for the socket identified by ``key`` belonging to

``map_fd`` can be deleted using the ``bpf_map_delete_elem()`` libbpf

function. Returns ``0`` on success, or negative error in case of failure.

Socket-local storage for map ``map_fd`` can be deleted from a socket using the

``bpf_map_delete_elem()`` libbpf function. The storage is deleted from the

socket identified by a `socket` ``fd`` stored in the pointer ``key``. Returns

``0`` on success, or negative error in case of failure.



Examples

========

kernel/bpf/core.c

+3 −2
Original line number Diff line number Diff line
@@ -2092,6 +2092,7 @@ static unsigned int __bpf_prog_ret0_warn(const void *ctx, 
bool bpf_prog_map_compatible(struct bpf_map *map,

			     const struct bpf_prog *fp)

{

	enum bpf_prog_type prog_type = resolve_prog_type(fp);

	bool ret;



	if (fp->kprobe_override)
@@ -2102,12 +2103,12 @@ bool bpf_prog_map_compatible(struct bpf_map *map, 
		/* There's no owner yet where we could check for

		 * compatibility.

		 */

		map->owner.type  = fp->type;

		map->owner.type  = prog_type;

		map->owner.jited = fp->jited;

		map->owner.xdp_has_frags = fp->aux->xdp_has_frags;

		ret = true;

	} else {

		ret = map->owner.type  == fp->type &&

		ret = map->owner.type  == prog_type &&

		      map->owner.jited == fp->jited &&

		      map->owner.xdp_has_frags == fp->aux->xdp_has_frags;

	}

kernel/bpf/dispatcher.c

+5 −0
Original line number Diff line number Diff line
@@ -125,6 +125,11 @@ static void bpf_dispatcher_update(struct bpf_dispatcher *d, int prev_num_progs) 


	__BPF_DISPATCHER_UPDATE(d, new ?: (void *)&bpf_dispatcher_nop_func);



	/* Make sure all the callers executing the previous/old half of the

	 * image leave it, so following update call can modify it safely.

	 */

	synchronize_rcu();



	if (new)

		d->image_off = noff;

}

kernel/bpf/syscall.c

+3 −3
Original line number Diff line number Diff line
@@ -3518,8 +3518,8 @@ static int bpf_prog_attach(const union bpf_attr *attr) 
	case BPF_PROG_TYPE_LSM:

		if (ptype == BPF_PROG_TYPE_LSM &&

		    prog->expected_attach_type != BPF_LSM_CGROUP)

			return -EINVAL;



			ret = -EINVAL;

		else

			ret = cgroup_bpf_prog_attach(attr, ptype, prog);

		break;

	default:

tools/testing/selftests/bpf/config

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ CONFIG_CRYPTO_USER_API_HASH=y 
CONFIG_DYNAMIC_FTRACE=y

CONFIG_FPROBE=y

CONFIG_FTRACE_SYSCALLS=y

CONFIG_FUNCTION_ERROR_INJECTION=y

CONFIG_FUNCTION_TRACER=y

CONFIG_GENEVE=y

CONFIG_IKCONFIG=y