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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 <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-8-lmb@cloudflare.com
This commit is contained in:
Lorenz Bauer 2020-09-21 13:12:23 +01:00 committed by Alexei Starovoitov
parent 02f7c9585d
commit feec704016
1 changed files with 4 additions and 3 deletions
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7
kernel/bpf/verifier.c
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@ -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) {