tree e566c233ebb068375c7a463d7d2f1dc6cfa680b2
parent 8854c5d450905974ab57366eccc4aa0f5e17c8b3
author Gilles Peskine <Gilles.Peskine@arm.com> 1623331050 +0200
committer Gilles Peskine <Gilles.Peskine@arm.com> 1624380517 +0200

Overhaul testing of mbedtls_mpi_copy

Replace the two test functions mbedtls_mpi_copy_sint (supporting signed
inputs but always with exactly one limb) and mbedtls_mpi_copy_binary
(supporting arbitrary-sized inputs but not negative inputs) by a single
function that supports both arbitrary-sized inputs and arbitrary-signed
inputs. This will allows testing combinations like negative source and
zero-sized destination.

Also generalize mpi_copy_self to support arbitrary inputs.

Generate a new list of test cases systematically enumerating all
possibilities among various categories: zero with 0 or 1 limb, negative or
positive with 1 limb, negative or positive with >1 limb. I used the
following Perl script:

```
sub rhs { $_ = $_[0]; s/bead/beef/; s/ca5cadedb01dfaceacc01ade/face1e55ca11ab1ecab005e5/; $_ }
%v = (
    "zero (null)" => "",
    "zero (1 limb)" => "0",
    "small positive" => "bead",
    "large positive" => "ca5cadedb01dfaceacc01ade",
    "small negative" => "-bead",
    "large negative" => "-ca5cadedb01dfaceacc01ade",
);
foreach $s (sort keys %v) {
    foreach $d (sort keys %v) {
        printf "Copy %s to %s\nmbedtls_mpi_copy:\"%s\":\"%s\"\n\n",
               $s, $d, $v{$s}, rhs($v{$d});
    }
}
foreach $s (sort keys %v) {
    printf "Copy self: %s\nmpi_copy_self:\"%s\"\n\n", $s, $v{$s};
}
```

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>