1 files changed, 49 insertions, 5 deletions

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ea94527e5d70..9291e2b2c950 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6203,7 +6203,8 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 				    const struct btf *btf, u32 func_id,
 				    struct bpf_reg_state *regs,
 				    bool ptr_to_mem_ok,
-				    u32 kfunc_flags)
+				    u32 kfunc_flags,
+				    bool processing_call)
 {
 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
 	bool rel = false, kptr_get = false, trusted_arg = false;
@@ -6389,7 +6390,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 					reg_ref_tname);
 				return -EINVAL;
 			}
-		} else if (ptr_to_mem_ok) {
+		} else if (ptr_to_mem_ok && processing_call) {
 			const struct btf_type *resolve_ret;
 			u32 type_size;
 
@@ -6464,7 +6465,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 	return rel ? ref_regno : 0;
 }
 
-/* Compare BTF of a function with given bpf_reg_state.
+/* Compare BTF of a function declaration with given bpf_reg_state.
  * Returns:
  * EFAULT - there is a verifier bug. Abort verification.
  * EINVAL - there is a type mismatch or BTF is not available.
@@ -6491,7 +6492,50 @@ int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
 		return -EINVAL;
 
 	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
-	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0);
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0, false);
+
+	/* Compiler optimizations can remove arguments from static functions
+	 * or mismatched type can be passed into a global function.
+	 * In such cases mark the function as unreliable from BTF point of view.
+	 */
+	if (err)
+		prog->aux->func_info_aux[subprog].unreliable = true;
+	return err;
+}
+
+/* Compare BTF of a function call with given bpf_reg_state.
+ * Returns:
+ * EFAULT - there is a verifier bug. Abort verification.
+ * EINVAL - there is a type mismatch or BTF is not available.
+ * 0 - BTF matches with what bpf_reg_state expects.
+ * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
+ *
+ * NOTE: the code is duplicated from btf_check_subprog_arg_match()
+ * because btf_check_func_arg_match() is still doing both. Once that
+ * function is split in 2, we can call from here btf_check_subprog_arg_match()
+ * first, and then treat the calling part in a new code path.
+ */
+int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
+			   struct bpf_reg_state *regs)
+{
+	struct bpf_prog *prog = env->prog;
+	struct btf *btf = prog->aux->btf;
+	bool is_global;
+	u32 btf_id;
+	int err;
+
+	if (!prog->aux->func_info)
+		return -EINVAL;
+
+	btf_id = prog->aux->func_info[subprog].type_id;
+	if (!btf_id)
+		return -EFAULT;
+
+	if (prog->aux->func_info_aux[subprog].unreliable)
+		return -EINVAL;
+
+	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, 0, true);
 
 	/* Compiler optimizations can remove arguments from static functions
 	 * or mismatched type can be passed into a global function.
@@ -6507,7 +6551,7 @@ int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
 			      struct bpf_reg_state *regs,
 			      u32 kfunc_flags)
 {
-	return btf_check_func_arg_match(env, btf, func_id, regs, true, kfunc_flags);
+	return btf_check_func_arg_match(env, btf, func_id, regs, true, kfunc_flags, true);
 }
 
 /* Convert BTF of a function into bpf_reg_state if possible