Re: [PATCH] Implement file posix capabilities

["Serge E. Hallyn" <serue@us.ibm.com>]

Quoting Bill O'Donnell (billodo@sgi.com):
> The memory fault when setfcaps is run as noted in #4 below also occurs
> on RHEL5 IA64 (2.6.18 kernel-2.6.18-1.2747.el5 with Serge's capability patch,
> and Kaigai's userspace tools installed).
> 
> On Wed, Nov 29, 2006 at 02:40:13PM -0600, Bill O'Donnell wrote:
> | Once again, running into problems when trying this patch on SLES-10 IA64,
> | (Linux certify 2.6.18 #2 SMP PREEMPT Wed Nov 29 13:11:28 CST 2006 ia64)
> |
> | 1) replaced the ancient /lib/libcap.so.1.92 with less ancient libcap.so.1.10
> |
> | 2) successfully applied Serge's patch to SLES 2.6.18 sources and rebooted
> |
> | 3) installed Kaigai's userspace tools... no problems evident
> |
> | 4) ran setfcaps to see capabilities... (note Memory fault):
> |
> | certify:~/libcap-1.10 # setfcaps
> | usage: setfcaps <capabilities> <file> ...
> |         cap_chown, cap_dac_override, cap_dac_read_search, cap_fowner
> | 	cap_fsetid, cap_kill, cap_setgid, cap_setuid
> | 	cap_setpcap, cap_linux_immutable,
> | 	cap_net_bind_service, cap_net_broadcast
> |         cap_net_admin, cap_net_raw, cap_ipc_lock, cap_ipc_owner
> | 	cap_sys_module, cap_sys_rawio, cap_sys_chroot, cap_sys_ptrace
> | 	cap_sys_pacct, cap_sys_admin, cap_sys_boot, cap_sys_nice
> | 	cap_sys_resource, cap_sys_time,
> | 	cap_sys_tty_config, cap_mknod
> |         cap_lease, cap_audit_write, cap_audit_controlMemory fault

Ah, this actually makes sense.  The setfcaps usage() statement does

	for (i=0; _cap_names[i]; i++) {
		printf...

so it expects _cap_names to end with a terminating NULL, but that
doesn't seem to be the case in cap_names.h in libcap.

KaiGai, perhaps setfcaps should do something like

diff setfcaps.c.orig setfcaps.c
25c25
<     for (i=0; _cap_names[i]; i++)
---
>     for (i=0; i<__CAP_BITS; i++)

thanks,
-serge