On 10/11/17 20:16, Acee Lindem (acee) wrote:
____
There are several patterns in the YANG definition that perform significant
restriction of numbers (e.g., to ensure they don't fall outside the range
that
can be stored in 16 or 32 bits). In many cases, these patterns include the
ability to zero-prefix some (but not all) decimal values. For example, the
production for route-origin would allow leading zeros in "2:0100:0555"
but not
in "2:04294967295:065535" (even though "2:4294967295:65535" is okay). I
don't
know offhand whether it makes sense to allow leading zeros in these
fields, but
I would argue that the production should be consistent in allowing or
disallowing them. This issue arises in various forms in route-target,
ipv6-route-target, route-origin, and ipv6-route-origin.
We’ll look at this and get back to you - a lot of time has already gone
into formulating and testing these patterns.
Yes, and it would be a shame if that work resulted in publishing
patterns with known issues.
This flaw arises in three formulations (each of which appear multiple
times), and would be quite easy to fix. These fixes should be obvious by
inspection.
32 bits (0-4,294,967,295)
Replace: [0-3]?[0-9]{0,8}[0-9]
With: [1-3][0-9]{9}|[1-9][0-9]{0,8}|0
16 bits (0-65535)
Replace: [0-5]?[0-9]{0,3}[0-9]
With: [1-5][0-9]{4}|[1-9][0-9]{0,3}|0
8 bits (0-255)
Replace: [01]?[0-9]?[0-9]
With: 1[0-9]{2}|[1-9]?[0-9]
____
As an aside: replacing "[0-9]" with "\d" everywhere would make these
patterns easier to read in general, but this is merely a readability
improvement rather than a bug fix. Compare:
+ '(2:(429496729[0-5]|42949672[0-8][0-9]|'
+ '4294967[01][0-9]{2}|'
+ '429496[0-6][0-9]{3}|42949[0-5][0-9]{4}|'
+ '4294[0-8][0-9]{5}|'
+ '429[0-3][0-9]{6}|42[0-8][0-9]{7}|4[01][0-9]{8}|'
+ '[1-3][0-9]{9}|[1-9][0-9]{0,8}|0):'
+ '(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|'
+ '6[0-4][0-9]{3}|'
+ '[1-5][0-9]{4}|[1-9][0-9]{0,3}|0))|'
Becomes:
+ '(2:(429496729[0-5]|42949672[0-8]\d|'
+ '4294967[01]\d{2}|'
+ '429496[0-6]\d{3}|42949[0-5]\d{4}|'
+ '4294[0-8]\d{5}|'
+ '429[0-3]\d{6}|42[0-8]\d{7}|4[01]\d{8}|'
+ '[1-3]\d{9}|[1-9]\d{0,8}|0):'
+ '(6553[0-5]|655[0-2]\d|65[0-4]\d{2}|'
+ '6[0-4]\d{3}|'
+ '[1-5]\d{4}|[1-9]\d{0,3}|0))|'
/a
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