Commit 47cc0ed5 authored May 15, 2020 by Daniel Borkmann Committed by Alexei Starovoitov May 15, 2020

bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range



Given bpf_probe_read{,str}() BPF helpers are now only available under
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE, we need to add the drop-in
replacements of bpf_probe_read_{kernel,user}_str() to do_refine_retval_range()
as well to avoid hitting the same issue as in 849fa506 ("bpf/verifier:
refine retval R0 state for bpf_get_stack helper").

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-3-daniel@iogearbox.net

parent 0ebeea8c

kernel/bpf/verifier.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4340,7 +4340,9 @@ static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,

		if (ret_type != RET_INTEGER \|\|
		(func_id != BPF_FUNC_get_stack &&
		func_id != BPF_FUNC_probe_read_str))
		func_id != BPF_FUNC_probe_read_str &&
		func_id != BPF_FUNC_probe_read_kernel_str &&
		func_id != BPF_FUNC_probe_read_user_str))
		return;

		ret_reg->smax_value = meta->msize_max_value;

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