Update: Failing tests: Re: RFC: [PATCH] SCM_CREDS support

[Svante Signell]

On Sun, 2015-09-20 at 20:28 +0200, Samuel Thibault wrote:
> Samuel Thibault, le Sun 20 Sep 2015 13:17:36 +0200, a écrit :
> > I'll have a stab at cleaning your patches.
> 
> I have pushed the result on the t/sendmsg-SCM_CREDS branch.  Note that I
> have refactored the t/sendmsg-SCM_RIGHTS branch, so make sure to update
> your SCM_RIGHTS patch from that branch.
> 
> I'll probably try to upload a glibc soon.

Working on a patch for a piece of software using SCM_CREDS code I tried the old
tests for SCM_RIGHTS and SCM_CREDS again with a recent glibc. 

Running the code reveals that the current implementation in glibc is buggy:

./scm_rights+creds_recv
Number of SCM_RIGHTS [<=3], SCM_CREDS [<=2]: [1,1] 
Input error: Using defaults: 
NRIGHTS = 1, NCREDS = 1
scm_rights+creds_send.c: msgh.msg_controllen = 112 (from control_un)
Receiving via datagram socket
recvmsg: (os/kern) invalid right

 ./scm_rights+creds_send
Number of SCM_RIGHTS [<=3], SCM_CREDS [<=2]: [1,1] 
Input error: Using defaults: 
NRIGHTS = 1, NCREDS = 1
scm_rights+creds_send.c: msgh.msg_controllen = 112 (from control_un)
Sent data = 12345

scm_rights+creds_send.c: Sending SCM_RIGHTS data
scm_rights+creds_send.c: cmhp[0]->cmsg_len = 16
scm_rights+creds_send.c: CMSG_SPACE (sizeof(int))[0] = 16
scm_rights+creds_send.c: fd[0]=3

scm_rights+creds_send.c: Sending SCM_CREDS data
scm_rights+creds_send.c: cmhp[1]->cmsg_len = 96
scm_rights+creds_send.c: CMSG_SPACE (sz)[1] = 96
Sent credentials: cmcred_pid=11071, cmcred_uid=1000, cmcred_euid=1000,
cmcred_gid=1000
scm_rights+creds_send.c: msgh.msg_controllen = 112
Sending via datagram socket
sendmsg() sent 4 bytes


Case 0,1 works, 0,2 does not. Neither does x,1 where x=1,2,3

Attached is the test code packaged into a small tar file.

test_SCM_RIGHTS+CREDS.tar.gz
Description: application/compressed-tar