openssl-1.0.2r build fails on CE-X86 platform because of warning

[Metpalli, Ashwinkumar]

Dear OpenSSL Users,

This is my first interaction in this community.

While am trying to build the latest openssl-1.0.2r code on CE-X86 platform, it fails with the below error:

rsa_pk1.c
.\crypto\rsa\rsa_pk1.c(296) : warning C4761: integral size mismatch in argument
conversion supplied
.\crypto\rsa\rsa_pk1.c(296) : error C2220: warning treated as error - no object
file generated
NMAKE : fatal error U1077: 'cl.exe' : return code '0x2'

The below is the failing line (Line# 296) in rsa_pk1.c

               to[i] = constant_time_select_8(mask, from[i], to[i]); (Here the second parameter takes a unsigned char data type while the passed one is a const unsigned char )

Can I fix this just by type casting to unsigned char using a Perl patch? Is there a better way to fix this?

NOTE:


  1.  The above line doesn't exist in older code (1.0.2.q) and so no issues on older builds.
  2.  This new code builds fine on CE-Arm, CE-Shx, NT-VS10, NT-VS15 platforms however fails on CE-X86 platform alone and that too because of the warning.
  3.  We need to fix this warning and can't simply use something like Treat Warnings as Errors to No.
  4.  There seems to be similar other occurrences in other files which could also flag warning (For instance, s3_cbc.c).

Please advise.

Thank you,
Ashwin
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