[pkg-gnupg-maint] Bug#829366: doesn't allow for creation of keys with 90-year expiry

[Luke Faraone]

Package: gnupg2
Version: 2.1.11-7
Severity: normal

Creating a key that expires in 89 years correctly sets an expiry of 2105, but
attempting to set an expiry of 90 years or greater results in an expirty date
that wraps around to 1970.

Curiously, the time on such wrapped-around expiries is always 13:09:41.

  -- Luke

# gpg2 --full-gen-key
gpg (GnuPG) 2.1.11; Copyright (C) 2016 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Please select what kind of key you want:
   (1) RSA and RSA (default)
   (2) DSA and Elgamal
   (3) DSA (sign only)
   (4) RSA (sign only)
Your selection? 4
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) 
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) 89y
Key expires at Thu Jun 11 19:37:57 2105 UTC
Is this correct? (y/N) n
Key is valid for? (0) 90y
Key expires at Tue May  5 13:09:41 1970 UTC
invalid value
Key is valid for? (0) 99y
Key expires at Thu May  3 13:09:41 1979 UTC
invalid value
Key is valid for? (0) 


-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.4.0-28-generic (SMP w/32 CPU cores)
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnupg2 depends on:
ii  dpkg           1.18.7
ii  gnupg-agent    2.1.11-7
ii  libassuan0     2.4.2-3
ii  libbz2-1.0     1.0.6-8
ii  libc6          2.22-13
ii  libgcrypt20    1.7.1-2
ii  libgpg-error0  1.23-1
ii  libksba8       1.3.4-3
ii  libreadline6   6.3-8+b4
ii  libsqlite3-0   3.13.0-1
ii  zlib1g         1:1.2.8.dfsg-2+b1

Versions of packages gnupg2 recommends:
ii  dirmngr  2.1.11-7

Versions of packages gnupg2 suggests:
pn  gnupg-doc   <none>
pn  parcimonie  <none>
pn  xloadimage  <none>

-- no debconf information