bpf: Fix propagation of 32-bit signed bounds from 64-bit bounds.
The 64-bit signed bounds should not affect 32-bit signed bounds unless the verifier knows that upper 32-bits are either all 1s or all 0s. For example the register with smin_value==1 doesn't mean that s32_min_value is also equal to 1, since smax_value could be larger than 32-bit subregister can hold. The verifier refines the smax/s32_max return value from certain helpers in do_refine_retval_range(). Teach the verifier to recognize that smin/s32_min value is also bounded. When both smin and smax bounds fit into 32-bit subregister the verifier can propagate those bounds. Fixes: 3f50f132 ("bpf: Verifier, do explicit ALU32 bounds tracking") Reported-by:Jean-Philippe Brucker <jean-philippe@linaro.org> Acked-by:
John Fastabend <john.fastabend@gmail.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
parent
4e083fdf
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