Commit feec7040 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: Make context access check generic 



Always check context access if the register we're operating on is
PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX. This allows
simplifying the arg_type checking section of the function.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-8-lmb@cloudflare.com
parent 02f7c958

kernel/bpf/verifier.c

+4 −3
Original line number Diff line number Diff line
@@ -4021,9 +4021,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 
		      arg_type == ARG_PTR_TO_CTX_OR_NULL)) {

			if (type != expected_type)

				goto err_type;

			err = check_ctx_reg(env, reg, regno);

			if (err < 0)

				return err;

		}

	} else if (arg_type == ARG_PTR_TO_SOCK_COMMON) {

		expected_type = PTR_TO_SOCK_COMMON;
@@ -4107,6 +4104,10 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 
				regno);

			return -EACCES;

		}

	} else if (type == PTR_TO_CTX) {

		err = check_ctx_reg(env, reg, regno);

		if (err < 0)

			return err;

	}



	if (reg->ref_obj_id) {