Instead of having to pass multiple arguments that describe the register,
pass the bpf_reg_state into the btf_struct_access callback. Currently,
all call sites simply reuse the btf and btf_id of the reg they want to
check the access of. The only exception to this pattern is the callsite
in check_ptr_to_map_access, hence for that case create a dummy reg to
simulate PTR_TO_BTF_ID access.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
include/linux/bpf.h | 17 ++++++++--------
include/linux/filter.h | 8 ++++----
kernel/bpf/btf.c | 11 +++++++----
kernel/bpf/verifier.c | 12 ++++++-----
net/bpf/bpf_dummy_struct_ops.c | 14 ++++++-------
net/core/filter.c | 34 +++++++++++++-------------------
net/ipv4/bpf_tcp_ca.c | 13 ++++++------
net/netfilter/nf_conntrack_bpf.c | 17 +++++++---------
8 files changed, 60 insertions(+), 66 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index afc1c51b59ff..49f9d2bec401 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -771,6 +771,7 @@ struct bpf_prog_ops {
union bpf_attr __user *uattr);
};
+struct bpf_reg_state;
struct bpf_verifier_ops {
/* return eBPF function prototype for verification */
const struct bpf_func_proto *
@@ -792,9 +793,8 @@ struct bpf_verifier_ops {
struct bpf_insn *dst,
struct bpf_prog *prog, u32 *target_size);
int (*btf_struct_access)(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
u32 *next_btf_id, enum bpf_type_flag *flag);
};
@@ -2080,9 +2080,9 @@ static inline bool bpf_tracing_btf_ctx_access(int off, int size,
return btf_ctx_access(off, size, type, prog, info);
}
-int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype,
+int btf_struct_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
u32 *next_btf_id, enum bpf_type_flag *flag);
bool btf_struct_ids_match(struct bpf_verifier_log *log,
const struct btf *btf, u32 id, int off,
@@ -2333,9 +2333,8 @@ static inline struct bpf_prog *bpf_prog_by_id(u32 id)
}
static inline int btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
u32 *next_btf_id, enum bpf_type_flag *flag)
{
return -EACCES;
diff --git a/include/linux/filter.h b/include/linux/filter.h
index efc42a6e3aed..787d35dbf5b0 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -568,10 +568,10 @@ struct sk_filter {
DECLARE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
extern struct mutex nf_conn_btf_access_lock;
-extern int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype, u32 *next_btf_id,
- enum bpf_type_flag *flag);
+extern int (*nfct_btf_struct_access)(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag);
typedef unsigned int (*bpf_dispatcher_fn)(const void *ctx,
const struct bpf_insn *insnsi,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index c0d73d71c539..875355ff3718 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6017,15 +6017,18 @@ static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
return -EINVAL;
}
-int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype __maybe_unused,
+int btf_struct_access(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype __maybe_unused,
u32 *next_btf_id, enum bpf_type_flag *flag)
{
+ const struct btf *btf = reg->btf;
enum bpf_type_flag tmp_flag = 0;
+ const struct btf_type *t;
+ u32 id = reg->btf_id;
int err;
- u32 id;
+ t = btf_type_by_id(btf, id);
do {
err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c588e5483540..5e74f460dfd0 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4688,16 +4688,14 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
}
if (env->ops->btf_struct_access) {
- ret = env->ops->btf_struct_access(&env->log, reg->btf, t,
- off, size, atype, &btf_id, &flag);
+ ret = env->ops->btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
} else {
if (atype != BPF_READ) {
verbose(env, "only read is supported\n");
return -EACCES;
}
- ret = btf_struct_access(&env->log, reg->btf, t, off, size,
- atype, &btf_id, &flag);
+ ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
}
if (ret < 0)
@@ -4723,6 +4721,7 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
{
struct bpf_reg_state *reg = regs + regno;
struct bpf_map *map = reg->map_ptr;
+ struct bpf_reg_state map_reg;
enum bpf_type_flag flag = 0;
const struct btf_type *t;
const char *tname;
@@ -4761,7 +4760,10 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
return -EACCES;
}
- ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag);
+ /* Simulate access to a PTR_TO_BTF_ID */
+ memset(&map_reg, 0, sizeof(map_reg));
+ mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
+ ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag);
if (ret < 0)
return ret;
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index e78dadfc5829..2d434c1f4617 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -156,29 +156,29 @@ static bool bpf_dummy_ops_is_valid_access(int off, int size,
}
static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off,
- int size, enum bpf_access_type atype,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
u32 *next_btf_id,
enum bpf_type_flag *flag)
{
const struct btf_type *state;
+ const struct btf_type *t;
s32 type_id;
int err;
- type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state",
+ type_id = btf_find_by_name_kind(reg->btf, "bpf_dummy_ops_state",
BTF_KIND_STRUCT);
if (type_id < 0)
return -EINVAL;
- state = btf_type_by_id(btf, type_id);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
+ state = btf_type_by_id(reg->btf, type_id);
if (t != state) {
bpf_log(log, "only access to bpf_dummy_ops_state is supported\n");
return -EACCES;
}
- err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id,
- flag);
+ err = btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
if (err < 0)
return err;
diff --git a/net/core/filter.c b/net/core/filter.c
index 6dd2baf5eeb2..37fad5a9b752 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8651,28 +8651,25 @@ static bool tc_cls_act_is_valid_access(int off, int size,
DEFINE_MUTEX(nf_conn_btf_access_lock);
EXPORT_SYMBOL_GPL(nf_conn_btf_access_lock);
-int (*nfct_btf_struct_access)(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, int off, int size,
- enum bpf_access_type atype, u32 *next_btf_id,
- enum bpf_type_flag *flag);
+int (*nfct_btf_struct_access)(struct bpf_verifier_log *log,
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag);
EXPORT_SYMBOL_GPL(nfct_btf_struct_access);
static int tc_cls_act_btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off,
- int size, enum bpf_access_type atype,
- u32 *next_btf_id,
- enum bpf_type_flag *flag)
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag)
{
int ret = -EACCES;
if (atype == BPF_READ)
- return btf_struct_access(log, btf, t, off, size, atype, next_btf_id,
- flag);
+ return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
mutex_lock(&nf_conn_btf_access_lock);
if (nfct_btf_struct_access)
- ret = nfct_btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag);
+ ret = nfct_btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
mutex_unlock(&nf_conn_btf_access_lock);
return ret;
@@ -8738,21 +8735,18 @@ void bpf_warn_invalid_xdp_action(struct net_device *dev, struct bpf_prog *prog,
EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);
static int xdp_btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off,
- int size, enum bpf_access_type atype,
- u32 *next_btf_id,
- enum bpf_type_flag *flag)
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag)
{
int ret = -EACCES;
if (atype == BPF_READ)
- return btf_struct_access(log, btf, t, off, size, atype, next_btf_id,
- flag);
+ return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
mutex_lock(&nf_conn_btf_access_lock);
if (nfct_btf_struct_access)
- ret = nfct_btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag);
+ ret = nfct_btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
mutex_unlock(&nf_conn_btf_access_lock);
return ret;
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 6da16ae6a962..d15c91de995f 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -69,18 +69,17 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size,
}
static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off,
- int size, enum bpf_access_type atype,
- u32 *next_btf_id,
- enum bpf_type_flag *flag)
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag)
{
+ const struct btf_type *t;
size_t end;
if (atype == BPF_READ)
- return btf_struct_access(log, btf, t, off, size, atype, next_btf_id,
- flag);
+ return btf_struct_access(log, reg, off, size, atype, next_btf_id, flag);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
if (t != tcp_sock_type) {
bpf_log(log, "only read is supported\n");
return -EACCES;
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index 8639e7efd0e2..24002bc61e07 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -191,19 +191,16 @@ BTF_ID(struct, nf_conn___init)
/* Check writes into `struct nf_conn` */
static int _nf_conntrack_btf_struct_access(struct bpf_verifier_log *log,
- const struct btf *btf,
- const struct btf_type *t, int off,
- int size, enum bpf_access_type atype,
- u32 *next_btf_id,
- enum bpf_type_flag *flag)
+ const struct bpf_reg_state *reg,
+ int off, int size, enum bpf_access_type atype,
+ u32 *next_btf_id, enum bpf_type_flag *flag)
{
- const struct btf_type *ncit;
- const struct btf_type *nct;
+ const struct btf_type *ncit, *nct, *t;
size_t end;
- ncit = btf_type_by_id(btf, btf_nf_conn_ids[1]);
- nct = btf_type_by_id(btf, btf_nf_conn_ids[0]);
-
+ ncit = btf_type_by_id(reg->btf, btf_nf_conn_ids[1]);
+ nct = btf_type_by_id(reg->btf, btf_nf_conn_ids[0]);
+ t = btf_type_by_id(reg->btf, reg->btf_id);
if (t != nct && t != ncit) {
bpf_log(log, "only read is supported\n");
return -EACCES;
--
2.38.1
