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Make secure_compare fail on undef or empty string #1292

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Make secure_compare fail on undef or empty string #1292

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4 changes: 2 additions & 2 deletions lib/Mojo/Util.pm
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Original file line number Diff line number Diff line change
Expand Up @@ -264,8 +264,8 @@ sub quote {
}

sub secure_compare {
my ($one, $two) = @_;
return undef if length $one != length $two;
my ($one, $two) = (shift // '', shift // '');
return undef if !length $one or length $one != length $two;
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To avoid failing faster for ('', '1') than ('1', '') due to the shortcut conditional on $one only, you could multiply both lengths ensuring an equal operation on both $one and $two.

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return undef if !length $one or length $one != length $two;
return undef if !(length $one * length $two) or length $one != length $two;

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I'd rather see something like this

Suggested change
return undef if !length $one or length $one != length $two;
return undef if !length $one != length $two;
return undef unless length $one;

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@karenetheridge karenetheridge Dec 7, 2018 •
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The new line 268 is confusing to read without more parentheses. I'm not sure what part of the expression the ! in front of length is intending to surround.

my $r = 0;
$r |= ord(substr $one, $_) ^ ord(substr $two, $_) for 0 .. length($one) - 1;
return $r == 0;
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3 changes: 3 additions & 0 deletions t/mojo/util.t
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Expand Up @@ -427,6 +427,9 @@ ok !secure_compare('0♥', '♥'), 'values are not equal';
ok !secure_compare('0♥1', '1♥0'), 'values are not equal';
ok !secure_compare('', '♥'), 'values are not equal';
ok !secure_compare('♥', ''), 'values are not equal';
ok !secure_compare(undef, undef), 'values are not equal';
ok !secure_compare(undef, ''), 'values are not equal';
ok !secure_compare('', ''), 'values are not equal';

# xor_encode
is xor_encode('hello', 'foo'), "\x0e\x0a\x03\x0a\x00", 'right result';
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