Patch verifier to regard values of type CONST_PTR_TO_MAP as trusted
pointers to struct bpf_map. This allows kfuncs to work with `struct
bpf_map *` arguments.
Save some bytes by defining btf_bpf_map_id as BTF_ID_LIST_GLOBAL_SINGLE
(which is u32[1]), not as BTF_ID_LIST (which is u32[64]).
Signed-off-by: Anton Protopopov <aspsk@xxxxxxxxxxxxx>
---
include/linux/btf_ids.h | 1 +
kernel/bpf/map_iter.c | 3 +--
kernel/bpf/verifier.c | 5 ++++-
3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 00950cc03bff..a3462a9b8e18 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -267,5 +267,6 @@ MAX_BTF_TRACING_TYPE,
extern u32 btf_tracing_ids[];
extern u32 bpf_cgroup_btf_id[];
extern u32 bpf_local_storage_map_btf_id[];
+extern u32 btf_bpf_map_id[];
#endif
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
index d06d3b7150e5..b67996147895 100644
--- a/kernel/bpf/map_iter.c
+++ b/kernel/bpf/map_iter.c
@@ -78,8 +78,7 @@ static const struct seq_operations bpf_map_seq_ops = {
.show = bpf_map_seq_show,
};
-BTF_ID_LIST(btf_bpf_map_id)
-BTF_ID(struct, bpf_map)
+BTF_ID_LIST_GLOBAL_SINGLE(btf_bpf_map_id, struct, bpf_map)
static const struct bpf_iter_seq_info bpf_map_seq_info = {
.seq_ops = &bpf_map_seq_ops,
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0b9da95331d7..5663f97ef292 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5419,6 +5419,9 @@ static bool is_trusted_reg(const struct bpf_reg_state *reg)
if (reg->ref_obj_id)
return true;
+ if (reg->type == CONST_PTR_TO_MAP)
+ return true;
+
/* If a register is not referenced, it is trusted if it has the
* MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the
* other type modifiers may be safe, but we elect to take an opt-in
@@ -10052,13 +10055,13 @@ static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
return true;
}
-
static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
#ifdef CONFIG_NET
[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
[PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
[PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
#endif
+ [CONST_PTR_TO_MAP] = btf_bpf_map_id,
};
enum kfunc_ptr_arg_type {
--
2.34.1
