[PATCH bpf-next 2/4] bpf: Make bpf inode storage available to tracing program
Song Liu
song at kernel.org
Tue Nov 12 08:25:56 UTC 2024
inode storage can be useful for non-LSM program. For example, file* tools
from bcc/libbpf-tools can use inode storage instead of hash map; fanotify
fastpath [1] can also use inode storage to store useful data.
Make inode storage available for tracing program. Move bpf inode storage
from a security blob to inode->i_bpf_storage, and adjust related code
accordingly.
[1] https://lore.kernel.org/linux-fsdevel/20241029231244.2834368-1-song@kernel.org/
Signed-off-by: Song Liu <song at kernel.org>
---
fs/inode.c | 1 +
include/linux/bpf.h | 9 +++++++++
include/linux/bpf_lsm.h | 29 -----------------------------
include/linux/fs.h | 4 ++++
kernel/bpf/Makefile | 3 +--
kernel/bpf/bpf_inode_storage.c | 32 +++++---------------------------
kernel/bpf/bpf_lsm.c | 4 ----
kernel/trace/bpf_trace.c | 4 ++++
security/bpf/hooks.c | 6 ------
9 files changed, 24 insertions(+), 68 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 8dabb224f941..3c679578169f 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -286,6 +286,7 @@ static struct inode *alloc_inode(struct super_block *sb)
void __destroy_inode(struct inode *inode)
{
BUG_ON(inode_has_buffers(inode));
+ bpf_inode_storage_free(inode);
inode_detach_wb(inode);
security_inode_free(inode);
fsnotify_inode_delete(inode);
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1b84613b10ac..0b31d2e74df6 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2672,6 +2672,7 @@ struct bpf_link *bpf_link_by_id(u32 id);
const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id,
const struct bpf_prog *prog);
void bpf_task_storage_free(struct task_struct *task);
+void bpf_inode_storage_free(struct inode *inode);
void bpf_cgrp_storage_free(struct cgroup *cgroup);
bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog);
const struct btf_func_model *
@@ -2942,6 +2943,10 @@ static inline void bpf_task_storage_free(struct task_struct *task)
{
}
+static inline void bpf_inode_storage_free(struct inode *inode)
+{
+}
+
static inline bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
{
return false;
@@ -3305,6 +3310,10 @@ extern const struct bpf_func_proto bpf_task_storage_get_recur_proto;
extern const struct bpf_func_proto bpf_task_storage_get_proto;
extern const struct bpf_func_proto bpf_task_storage_delete_recur_proto;
extern const struct bpf_func_proto bpf_task_storage_delete_proto;
+extern const struct bpf_func_proto bpf_inode_storage_get_proto;
+extern const struct bpf_func_proto bpf_inode_storage_get_recur_proto;
+extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
+extern const struct bpf_func_proto bpf_inode_storage_delete_recur_proto;
extern const struct bpf_func_proto bpf_for_each_map_elem_proto;
extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto;
extern const struct bpf_func_proto bpf_sk_setsockopt_proto;
diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
index aefcd6564251..a819c2f0a062 100644
--- a/include/linux/bpf_lsm.h
+++ b/include/linux/bpf_lsm.h
@@ -19,31 +19,12 @@
#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);
bool bpf_lsm_is_sleepable_hook(u32 btf_id);
bool bpf_lsm_is_trusted(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;
-}
-
-extern const struct bpf_func_proto bpf_inode_storage_get_proto;
-extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
-void bpf_inode_storage_free(struct inode *inode);
-
void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func);
int bpf_lsm_get_retval_range(const struct bpf_prog *prog,
@@ -66,16 +47,6 @@ static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
return -EOPNOTSUPP;
}
-static inline struct bpf_storage_blob *bpf_inode(
- const struct inode *inode)
-{
- return NULL;
-}
-
-static inline void bpf_inode_storage_free(struct inode *inode)
-{
-}
-
static inline void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
bpf_func_t *bpf_func)
{
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3559446279c1..479097e4dd5b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -79,6 +79,7 @@ struct fs_context;
struct fs_parameter_spec;
struct fileattr;
struct iomap_ops;
+struct bpf_local_storage;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -648,6 +649,9 @@ struct inode {
#ifdef CONFIG_SECURITY
void *i_security;
#endif
+#ifdef CONFIG_BPF_SYSCALL
+ struct bpf_local_storage __rcu *i_bpf_storage;
+#endif
/* Stat data, not accessed from path walking */
unsigned long i_ino;
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 105328f0b9c0..73604c7130f1 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -10,8 +10,7 @@ obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o log.o
obj-$(CONFIG_BPF_SYSCALL) += bpf_iter.o map_iter.o task_iter.o prog_iter.o link_iter.o
obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o bloom_filter.o
obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o
-obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o
-obj-${CONFIG_BPF_LSM} += bpf_inode_storage.o
+obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o bpf_inode_storage.o
obj-$(CONFIG_BPF_SYSCALL) += disasm.o mprog.o
obj-$(CONFIG_BPF_JIT) += trampoline.o
obj-$(CONFIG_BPF_SYSCALL) += btf.o memalloc.o
diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 44ccebc745e5..8d5a9bfe6643 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -21,16 +21,11 @@
DEFINE_BPF_STORAGE_CACHE(inode_cache);
-static struct bpf_local_storage __rcu **
-inode_storage_ptr(void *owner)
+static struct bpf_local_storage __rcu **inode_storage_ptr(void *owner)
{
struct inode *inode = owner;
- struct bpf_storage_blob *bsb;
- bsb = bpf_inode(inode);
- if (!bsb)
- return NULL;
- return &bsb->storage;
+ return &inode->i_bpf_storage;
}
static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
@@ -39,14 +34,9 @@ static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
{
struct bpf_local_storage *inode_storage;
struct bpf_local_storage_map *smap;
- struct bpf_storage_blob *bsb;
-
- bsb = bpf_inode(inode);
- if (!bsb)
- return NULL;
inode_storage =
- rcu_dereference_check(bsb->storage, bpf_rcu_lock_held());
+ rcu_dereference_check(inode->i_bpf_storage, bpf_rcu_lock_held());
if (!inode_storage)
return NULL;
@@ -57,15 +47,10 @@ static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
void bpf_inode_storage_free(struct inode *inode)
{
struct bpf_local_storage *local_storage;
- struct bpf_storage_blob *bsb;
-
- bsb = bpf_inode(inode);
- if (!bsb)
- return;
rcu_read_lock();
- local_storage = rcu_dereference(bsb->storage);
+ local_storage = rcu_dereference(inode->i_bpf_storage);
if (!local_storage) {
rcu_read_unlock();
return;
@@ -95,8 +80,6 @@ static long bpf_fd_inode_storage_update_elem(struct bpf_map *map, void *key,
if (fd_empty(f))
return -EBADF;
- if (!inode_storage_ptr(file_inode(fd_file(f))))
- return -EBADF;
sdata = bpf_local_storage_update(file_inode(fd_file(f)),
(struct bpf_local_storage_map *)map,
@@ -136,12 +119,7 @@ BPF_CALL_5(bpf_inode_storage_get, struct bpf_map *, map, struct inode *, inode,
if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
return (unsigned long)NULL;
- /* explicitly check that the inode_storage_ptr is not
- * NULL as inode_storage_lookup returns NULL in this case and
- * bpf_local_storage_update expects the owner to have a
- * valid storage pointer.
- */
- if (!inode || !inode_storage_ptr(inode))
+ if (!inode)
return (unsigned long)NULL;
sdata = inode_storage_lookup(inode, map, true);
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index 3bc61628ab25..6b6e0730e515 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -231,10 +231,6 @@ 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;
#ifdef CONFIG_NET
case BPF_FUNC_sk_storage_get:
return &bpf_sk_storage_get_proto;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 949a3870946c..262bd101ea0b 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1553,6 +1553,10 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
if (bpf_prog_check_recur(prog))
return &bpf_task_storage_delete_recur_proto;
return &bpf_task_storage_delete_proto;
+ 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_for_each_map_elem:
return &bpf_for_each_map_elem_proto;
case BPF_FUNC_snprintf:
diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
index db759025abe1..67719a04bb0b 100644
--- a/security/bpf/hooks.c
+++ b/security/bpf/hooks.c
@@ -12,7 +12,6 @@ static struct security_hook_list bpf_lsm_hooks[] __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 const struct lsm_id bpf_lsmid = {
@@ -28,12 +27,7 @@ static int __init bpf_lsm_init(void)
return 0;
}
-struct lsm_blob_sizes bpf_lsm_blob_sizes __ro_after_init = {
- .lbs_inode = sizeof(struct bpf_storage_blob),
-};
-
DEFINE_LSM(bpf) = {
.name = "bpf",
.init = bpf_lsm_init,
- .blobs = &bpf_lsm_blob_sizes
};
--
2.43.5
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