Can't write explicitly tagged sets

[jethrogb]

I don't think it's possible to generate the following with yasna right now:

$ openssl asn1parse -i
-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----
    0:d=0  hl=4 l= 727 cons: SEQUENCE          
    4:d=1  hl=4 l= 447 cons:  SEQUENCE          
    8:d=2  hl=2 l=   1 prim:   INTEGER           :00
   11:d=2  hl=2 l=  69 cons:   SEQUENCE          
   13:d=3  hl=2 l=  11 cons:    SET               
   15:d=4  hl=2 l=   9 cons:     SEQUENCE          
   17:d=5  hl=2 l=   3 prim:      OBJECT            :countryName
   22:d=5  hl=2 l=   2 prim:      PRINTABLESTRING   :AU
   26:d=3  hl=2 l=  19 cons:    SET               
   28:d=4  hl=2 l=  17 cons:     SEQUENCE          
   30:d=5  hl=2 l=   3 prim:      OBJECT            :stateOrProvinceName
   35:d=5  hl=2 l=  10 prim:      UTF8STRING        :Some-State
   47:d=3  hl=2 l=  33 cons:    SET               
   49:d=4  hl=2 l=  31 cons:     SEQUENCE          
   51:d=5  hl=2 l=   3 prim:      OBJECT            :organizationName
   56:d=5  hl=2 l=  24 prim:      UTF8STRING        :Internet Widgits Pty Ltd
   82:d=2  hl=4 l= 290 cons:   SEQUENCE          
   86:d=3  hl=2 l=  13 cons:    SEQUENCE          
   88:d=4  hl=2 l=   9 prim:     OBJECT            :rsaEncryption
   99:d=4  hl=2 l=   0 prim:     NULL              
  101:d=3  hl=4 l= 271 prim:    BIT STRING        
  376:d=2  hl=2 l=  77 cons:   cont [ 0 ]        
  378:d=3  hl=2 l=  16 cons:    SEQUENCE          
  380:d=4  hl=2 l=   9 prim:     OBJECT            :unstructuredName
  391:d=4  hl=2 l=   3 cons:     SET               
  393:d=5  hl=2 l=   1 prim:      UTF8STRING        :x
  396:d=3  hl=2 l=  16 cons:    SEQUENCE          
  398:d=4  hl=2 l=   9 prim:     OBJECT            :challengePassword
  409:d=4  hl=2 l=   3 cons:     SET               
  411:d=5  hl=2 l=   1 prim:      UTF8STRING        :x
  414:d=3  hl=2 l=  39 cons:    SEQUENCE          
  416:d=4  hl=2 l=   9 prim:     OBJECT            :Extension Request
  427:d=4  hl=2 l=  26 cons:     SET               
  429:d=5  hl=2 l=  24 cons:      SEQUENCE          
  431:d=6  hl=2 l=   9 cons:       SEQUENCE          
  433:d=7  hl=2 l=   3 prim:        OBJECT            :X509v3 Basic Constraints
  438:d=7  hl=2 l=   2 prim:        OCTET STRING      [HEX DUMP]:3000
  442:d=6  hl=2 l=  11 cons:       SEQUENCE          
  444:d=7  hl=2 l=   3 prim:        OBJECT            :X509v3 Key Usage
  449:d=7  hl=2 l=   4 prim:        OCTET STRING      [HEX DUMP]:030205E0
  455:d=1  hl=2 l=  13 cons:  SEQUENCE          
  457:d=2  hl=2 l=   9 prim:   OBJECT            :sha256WithRSAEncryption
  468:d=2  hl=2 l=   0 prim:   NULL              
  470:d=1  hl=4 l= 257 prim:  BIT STRING        

At offset 376 is a [0] SET OF SEQUENCE { ... }, see https://tools.ietf.org/html/rfc2986#section-4. DERWriter::write_tagged has a callback with a DERWriter, not DERWriterSeq or DERWriterSet, so I don't see how to emit the multiple sequences in the set.

[qnighy]

Isn't this an implicit tag (declared as DEFINITIONS IMPLICIT TAGS ::= in the RFC), for which yasna has a corresponding API write_tagged_implicit?

[jethrogb]

Yes, you're right. Solution:

w.write_tagged_implicit(|w|w.write_set(|w|
  for _ in ... {
    writer.next().write_...(...)
  }
));