RPC: svc_register() authentication error; why = client credential too weak

[Scott Duckworth]

Simple RPC programs will not work without running rpcbind in insecure mode (rpcbind -i). The error that is given when running the RPC server is:

Cannot register service: RPC: Authentication error; why = Client credential too weak
unable to register (SIMP_PROG, SIMP_VERSION, udp).

strace shows where the problem happens:

socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_UDP) = 4
bind(4, {sa_family=AF_INET, sin_port=htons(861), sin_addr=inet_addr("0.0.0.0")}, 16) = -1 EACCES (Permission denied)
setsockopt(4, SOL_IP, IP_RECVERR, [1], 4) = 0
sendto(4, "h_\202\356\0\0\0\0\0\0\0\2\0\1\206\240\0\0\0\2\0\0\0\1\0\0\0\0\0\0\0\0"..., 56, 0, {sa_family=AF_INET, sin_port=htons(111), sin_addr=inet_addr("127.0.0.1")}, 16) = 56
poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}])
recvfrom(4, "h_\202\356\0\0\0\1\0\0\0\1\0\0\0\1\0\0\0\5", 400, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(111), sin_addr=inet_addr("127.0.0.1")}, [16]) = 20
write(2, "Cannot register service: RPC: Au"..., 85Cannot register service: RPC: Authentication error; why = Client credential too weak
) = 85
close(4) = 0
write(2, "unable to register (SIMP_PROG, S"..., 50unable to register (SIMP_PROG, SIMP_VERSION, udp).) = 50
exit_group(1) = ?

The same program works fine on CentOS 5 and CentOS 6. strace on the same program on CentOS 6 (libc 2.12) shows a different behavior:

socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_UDP) = 4
bind(4, {sa_family=AF_INET, sin_port=htons(613), sin_addr=inet_addr("0.0.0.0")}, 16) = -1 EACCES (Permission denied)
setsockopt(4, SOL_IP, IP_RECVERR, [1], 4) = 0
sendto(4, "\f\330A\n\0\0\0\0\0\0\0\2\0\1\206\240\0\0\0\2\0\0\0\1\0\0\0\0\0\0\0\0"..., 56, 0, {sa_family=AF_INET, sin_port=htons(111), sin_addr=inet_addr("127.0.0.1")}, 16) = 56
poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}])
recvfrom(4, "\f\330A\n\0\0\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1", 400, MSG_DONTWAIT, {sa_family=AF_INET, sin_port=htons(111), sin_addr=inet_addr("127.0.0.1")}, [16]) = 28
close(4) = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 4
bind(4, {sa_family=AF_INET, sin_port=htons(614), sin_addr=inet_addr("0.0.0.0")}, 16) = -1 EACCES (Permission denied)
bind(4, {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("0.0.0.0")}, 16) = 0
getsockname(4, {sa_family=AF_INET, sin_port=htons(41111), sin_addr=inet_addr("0.0.0.0")}, [16]) = 0
listen(4, 128) = 0
... (the program keeps running as expected) ...

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: libc6 2.15-0ubuntu10.5
ProcVersionSignature: Ubuntu 3.2.0-56.86-generic 3.2.51
Uname: Linux 3.2.0-56-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Fri Nov 22 17:27:24 2013
MarkForUpload: True
ProcEnviron:
 SHELL=/bin/bash
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 LANGUAGE=en_US:
SourcePackage: eglibc
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.