On 12/03/2016 09:31 PM, Alexei Starovoitov wrote:
From: Gianluca Borello <g.bore...@gmail.com>
Occasionally, clang (e.g. version 3.8.1) translates a sum between two
constant operands using a BPF_OR instead of a BPF_ADD. The verifier is
currently not handling this scenario, and the destination register type
becomes UNKNOWN_VALUE even if it's still storing a constant. As a result,
the destination register cannot be used as argument to a helper function
expecting a ARG_CONST_STACK_*, limiting some use cases.
Modify the verifier to handle this case, and add a few tests to make sure
all combinations are supported, and stack boundaries are still verified
even with BPF_OR.
Signed-off-by: Gianluca Borello <g.bore...@gmail.com>
Signed-off-by: Alexei Starovoitov <a...@kernel.org>
Acked-by: Daniel Borkmann <dan...@iogearbox.net>
