From feec70401672bd9b0268ae59ec5efd15d86ae138 Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Mon, 21 Sep 2020 13:12:23 +0100 Subject: [PATCH] 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: Lorenz Bauer Signed-off-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200921121227.255763-8-lmb@cloudflare.com --- kernel/bpf/verifier.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a4549b2..fc795ba 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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) { -- 2.7.4