@@ -1507,7 +1507,7 @@ struct bpf_prog_aux {
u32 max_rdonly_access;
u32 max_rdwr_access;
struct btf *attach_btf;
- const struct bpf_ctx_arg_aux *ctx_arg_info;
+ struct bpf_ctx_arg_aux *ctx_arg_info;
void __percpu *priv_stack_ptr;
struct mutex dst_mutex; /* protects dst_* pointers below, *after* prog becomes visible */
struct bpf_prog *dst_prog;
@@ -1945,6 +1945,9 @@ static inline void bpf_struct_ops_desc_release(struct bpf_struct_ops_desc *st_op
#endif
+int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog,
+ const struct bpf_ctx_arg_aux *info, u32 cnt);
+
#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
int cgroup_atype);
@@ -2546,7 +2549,7 @@ struct bpf_iter__bpf_map_elem {
int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info);
void bpf_iter_unreg_target(const struct bpf_iter_reg *reg_info);
-bool bpf_iter_prog_supported(struct bpf_prog *prog);
+int bpf_iter_prog_supported(struct bpf_prog *prog);
const struct bpf_func_proto *
bpf_iter_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog);
int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_prog *prog);
@@ -335,7 +335,7 @@ static void cache_btf_id(struct bpf_iter_target_info *tinfo,
tinfo->btf_id = prog->aux->attach_btf_id;
}
-bool bpf_iter_prog_supported(struct bpf_prog *prog)
+int bpf_iter_prog_supported(struct bpf_prog *prog)
{
const char *attach_fname = prog->aux->attach_func_name;
struct bpf_iter_target_info *tinfo = NULL, *iter;
@@ -344,7 +344,7 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog)
int prefix_len = strlen(prefix);
if (strncmp(attach_fname, prefix, prefix_len))
- return false;
+ return -EINVAL;
mutex_lock(&targets_mutex);
list_for_each_entry(iter, &targets, list) {
@@ -360,12 +360,11 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog)
}
mutex_unlock(&targets_mutex);
- if (tinfo) {
- prog->aux->ctx_arg_info_size = tinfo->reg_info->ctx_arg_info_size;
- prog->aux->ctx_arg_info = tinfo->reg_info->ctx_arg_info;
- }
+ if (!tinfo)
+ return -EINVAL;
- return tinfo != NULL;
+ return bpf_prog_ctx_arg_info_init(prog, tinfo->reg_info->ctx_arg_info,
+ tinfo->reg_info->ctx_arg_info_size);
}
const struct bpf_func_proto *
@@ -22377,6 +22377,18 @@ static void print_verification_stats(struct bpf_verifier_env *env)
env->peak_states, env->longest_mark_read_walk);
}
+int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog,
+ const struct bpf_ctx_arg_aux *info, u32 cnt)
+{
+ prog->aux->ctx_arg_info = kcalloc(cnt, sizeof(*info), GFP_KERNEL);
+ if (!prog->aux->ctx_arg_info)
+ return -ENOMEM;
+
+ memcpy(prog->aux->ctx_arg_info, info, sizeof(*info) * cnt);
+ prog->aux->ctx_arg_info_size = cnt;
+ return 0;
+}
+
static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
{
const struct btf_type *t, *func_proto;
@@ -22457,17 +22469,12 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
return -EACCES;
}
- /* btf_ctx_access() used this to provide argument type info */
- prog->aux->ctx_arg_info =
- st_ops_desc->arg_info[member_idx].info;
- prog->aux->ctx_arg_info_size =
- st_ops_desc->arg_info[member_idx].cnt;
-
prog->aux->attach_func_proto = func_proto;
prog->aux->attach_func_name = mname;
env->ops = st_ops->verifier_ops;
- return 0;
+ return bpf_prog_ctx_arg_info_init(prog, st_ops_desc->arg_info[member_idx].info,
+ st_ops_desc->arg_info[member_idx].cnt);
}
#define SECURITY_PREFIX "security_"
@@ -22917,9 +22924,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->aux->attach_btf_trace = true;
return 0;
} else if (prog->expected_attach_type == BPF_TRACE_ITER) {
- if (!bpf_iter_prog_supported(prog))
- return -EINVAL;
- return 0;
+ return bpf_iter_prog_supported(prog);
}
if (prog->type == BPF_PROG_TYPE_LSM) {
Currently, ctx_arg_info is read-only in the view of the verifier since it is shared among programs of the same attach type. Make each program have their own copy of ctx_arg_info so that we can use it to store program specific information. In the next patch where we support acquiring a referenced kptr through a struct_ops argument tagged with "__ref", ctx_arg_info->ref_obj_id will be used to store the unique reference object id of the argument. This avoids creating a requirement in the verifier that "__ref" tagged arguments must be the first set of references acquired [0]. [0] https://lore.kernel.org/bpf/20241220195619.2022866-2-amery.hung@gmail.com/ Signed-off-by: Amery Hung <ameryhung@gmail.com> --- include/linux/bpf.h | 7 +++++-- kernel/bpf/bpf_iter.c | 13 ++++++------- kernel/bpf/verifier.c | 25 +++++++++++++++---------- 3 files changed, 26 insertions(+), 19 deletions(-)