HeaderEval::check_header_count_range() not working correctly?

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HeaderEval::check_header_count_range() not working correctly?

Philip Prindeville
Hi.

I’m looking at:

# Return true if the count of $hdr headers are within the given range
sub check_header_count_range {
 my ($self, $pms, $hdr, $min, $max) = @_;
 my %uniq = ();
 my @hdrs = grep(!$uniq{$_}++, $pms->{msg}->get_header ($hdr));
 return (scalar @hdrs >= $min && scalar @hdrs <= $max);
}

in HeaderEval.pm and I’m not getting it.  It inserts (once and only once) each occurrence of a unique RHS for the header X.  So if I had:

X-yzzy: A
X-yzzy: A
X-yzzy: B
X-yzzy: C

Then $uniq{A} would be 2, $uniq${B} would be 1, and $uniq{C} would be 1, so the number of elements in @hdrs would be 3, once each for ‘A’, ‘B’, and ‘C’.

But if I have:

X-yzzy: A
X-yzzy: A
X-yzzy: A
X-yzzy: A

then $uniq{A} is 4, but the number of elements in @hdrs would be 1 (because of the ‘!’ which only passes the first).

This seems counter-intuitive.  What if I want to count the absolute number of headers of type ‘X-yzzy:’ regardless of their RHS?

I’ve been seeing a lot of Spam recently with duplicative Received-SPF: lines, but since they are all identical, it’s not nudging the number of @hdrs past one.

Thanks,

-Philip

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Re: HeaderEval::check_header_count_range() not working correctly?

Philip Prindeville
What would be the downsize of having:

  my @hdrs = grep($uniq{$_}++, $pms->{msg}->get_header ($hdr));

instead and counting ALL instances of $hdr, not just the unique RHS’s?



> On Nov 3, 2019, at 1:51 PM, Philip Prindeville <[hidden email]> wrote:
>
> Hi.
>
> I’m looking at:
>
> # Return true if the count of $hdr headers are within the given range
> sub check_header_count_range {
> my ($self, $pms, $hdr, $min, $max) = @_;
> my %uniq = ();
> my @hdrs = grep(!$uniq{$_}++, $pms->{msg}->get_header ($hdr));
> return (scalar @hdrs >= $min && scalar @hdrs <= $max);
> }
>
> in HeaderEval.pm and I’m not getting it.  It inserts (once and only once) each occurrence of a unique RHS for the header X.  So if I had:
>
> X-yzzy: A
> X-yzzy: A
> X-yzzy: B
> X-yzzy: C
>
> Then $uniq{A} would be 2, $uniq${B} would be 1, and $uniq{C} would be 1, so the number of elements in @hdrs would be 3, once each for ‘A’, ‘B’, and ‘C’.
>
> But if I have:
>
> X-yzzy: A
> X-yzzy: A
> X-yzzy: A
> X-yzzy: A
>
> then $uniq{A} is 4, but the number of elements in @hdrs would be 1 (because of the ‘!’ which only passes the first).
>
> This seems counter-intuitive.  What if I want to count the absolute number of headers of type ‘X-yzzy:’ regardless of their RHS?
>
> I’ve been seeing a lot of Spam recently with duplicative Received-SPF: lines, but since they are all identical, it’s not nudging the number of @hdrs past one.
>
> Thanks,
>
> -Philip
>

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Re: HeaderEval::check_header_count_range() not working correctly?

Philip Prindeville
Sigh… “downside”.


> On Nov 3, 2019, at 2:32 PM, Philip Prindeville <[hidden email]> wrote:
>
> What would be the downsize of having:
>
>  my @hdrs = grep($uniq{$_}++, $pms->{msg}->get_header ($hdr));
>
> instead and counting ALL instances of $hdr, not just the unique RHS’s?
>
>
>
>> On Nov 3, 2019, at 1:51 PM, Philip Prindeville <[hidden email]> wrote:
>>
>> Hi.
>>
>> I’m looking at:
>>
>> # Return true if the count of $hdr headers are within the given range
>> sub check_header_count_range {
>> my ($self, $pms, $hdr, $min, $max) = @_;
>> my %uniq = ();
>> my @hdrs = grep(!$uniq{$_}++, $pms->{msg}->get_header ($hdr));
>> return (scalar @hdrs >= $min && scalar @hdrs <= $max);
>> }
>>
>> in HeaderEval.pm and I’m not getting it.  It inserts (once and only once) each occurrence of a unique RHS for the header X.  So if I had:
>>
>> X-yzzy: A
>> X-yzzy: A
>> X-yzzy: B
>> X-yzzy: C
>>
>> Then $uniq{A} would be 2, $uniq${B} would be 1, and $uniq{C} would be 1, so the number of elements in @hdrs would be 3, once each for ‘A’, ‘B’, and ‘C’.
>>
>> But if I have:
>>
>> X-yzzy: A
>> X-yzzy: A
>> X-yzzy: A
>> X-yzzy: A
>>
>> then $uniq{A} is 4, but the number of elements in @hdrs would be 1 (because of the ‘!’ which only passes the first).
>>
>> This seems counter-intuitive.  What if I want to count the absolute number of headers of type ‘X-yzzy:’ regardless of their RHS?
>>
>> I’ve been seeing a lot of Spam recently with duplicative Received-SPF: lines, but since they are all identical, it’s not nudging the number of @hdrs past one.
>>
>> Thanks,
>>
>> -Philip
>>
>

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Re: HeaderEval::check_header_count_range() not working correctly?

RW-15
In reply to this post by Philip Prindeville
On Sun, 3 Nov 2019 13:51:19 -0700
Philip Prindeville wrote:

> then $uniq{A} is 4, but the number of elements in @hdrs would be 1
> (because of the ‘!’ which only passes the first).
>
> This seems counter-intuitive.  What if I want to count the absolute
> number of headers of type ‘X-yzzy:’ regardless of their RHS?
>
> I’ve been seeing a lot of Spam recently with duplicative
> Received-SPF: lines, but since they are all identical, it’s not
> nudging the number of @hdrs past one.

You shouldn't need perl for this. Header tests run on a string that
contains all the RHS's for the named header, so something like the
following should do it:


header __RECSPF_COUNT   Received-SPF =~ /^.*$/m
tflags __RECSP__COUNT   multiple