code in rpc.svcgssd treats date as signed 32-bit

[Charles Hedrick]

Upstream patch eb3a145789b9eedd39b56e1d76f412435abaa747 adds code to rpc.svcgssd to set an expiration date for nfs contexts. (It doesn't work, but that's the subject of a different bug.) That code treats the date is int32. It is sent into the kernel using code that ends up as a printf %d. In 2038 the date will go negative. Because the kernel uses 64-bit dates I believe that will produce the wrong result.

The code should use data_t, not int32_t.

This is complicated by the fact that it gets the date from a Kerberos ticket. Kerberos declares date as int32. For historical reaosns, they have decided to retain it as int32, but whenever there's a comparison or arithemtic that would break, they cast it (date_t)(u_int32_t). I believe the code in svcgssdd should do the same. All variables should be date_t. Anything retrieved from a Kerberos ticket should be cast (date_t)(u_int32_t).

THis is actually a problem upstream. But it's not clear that upstream has any reason to fix it. Redhat is no longer using rpc.svcgssd. They're using gssproxy to handle the upcall from the kernel. So it's not clear that there's any significant use of svcgssd other than Ubuntu.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: nfs-common 1:1.3.4-2.5ubuntu3.3 [modified: usr/sbin/rpc.svcgssd]
ProcVersionSignature: Ubuntu 5.4.0-65.73-generic 5.4.78
Uname: Linux 5.4.0-65-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckResult: skip
Date: Tue Mar 9 12:46:12 2021
InstallationDate: Installed on 2020-03-25 (348 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
ProcEnviron:
 TERM=vt100
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/tcsh
SourcePackage: nfs-utils
UpgradeStatus: Upgraded to focal on 2020-12-21 (78 days ago)
modified.conffile..etc.default.apport: [modified]
mtime.conffile..etc.default.apport: 2020-08-10T17:26:17.512725
mtime.conffile..etc.default.nfs-common: 2020-04-16T16:03:31.356462