bpf: consider types listed in reg2btf_ids as trusted

The reg2btf_ids array contains a list of types for which we can (and need)
to find a corresponding static BTF id. All the types in the list can be
considered as trusted for purposes of kfuncs.

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230719092952.41202-2-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0b9da95..05123fe 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5413,12 +5413,24 @@ static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
        return reg->type == PTR_TO_FLOW_KEYS;
 }
 
+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
+};
+
 static bool is_trusted_reg(const struct bpf_reg_state *reg)
 {
        /* A referenced register is always trusted. */
        if (reg->ref_obj_id)
                return true;
 
+       /* Types listed in the reg2btf_ids are always trusted */
+       if (reg2btf_ids[base_type(reg->type)])
+               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
@@ -10052,15 +10064,6 @@ 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
-};
-
 enum kfunc_ptr_arg_type {
        KF_ARG_PTR_TO_CTX,
        KF_ARG_PTR_TO_ALLOC_BTF_ID,    /* Allocated object */