[v2] nss: Make nsswitch.conf more distribution friendly.
Commit Message
On 3/20/19 12:58 PM, Florian Weimer wrote:
> * Carlos O'Donell:
>
>> +# An example Name Service Switch config file. This file should be
>> +# sorted with the most-used services at the beginning.
>
> The example file itself doesn't seem to follow this.
I noticed that netmasks, automount, and bootparams are not handled by
glibc, but listed in the nsswitch.conf. Are these handled by some other
application which parses /etc/nsswitch.conf? I'm not aware of any that
do so, and so I've removed them.
We never got around to implementing the accessor functions for them,
and only added publickey. I cleaned up the docs and referenced the info
docs from the default nsswitch.conf.
>> +# ldap Use LDAP directory server
>
> Is the module really called ldap these days? I it's ldapd. ldap was
> the module that had an in-process LDAP client, which was kind of iffy.
Yes, this is the ldap module using nslcd.
rpm -qf /lib64/libnss_ldap.so
nss-pam-ldapd-0.9.9-4.fc29.x86_64
Description :
The nss-pam-ldapd daemon, nslcd, uses a directory server to look up name
service information (users, groups, etc.) on behalf of a lightweight
nsswitch module.
It's the same name (unfortunately).
v2 follows.
8< --- 8< --- 8<
The current default nsswitch.conf file provided by glibc is not very
distribution friendly. The file contains some minimal directives that no
real distribution uses. This update aims to provide a rich set of
comments which are useful for all distributions, and a broader set of
service defines which should work for all distributions.
Tested defaults on x86_64 and they work. The nsswitch.conf file more
closely matches what we have in Fedora now, and I'll adjust Fedora to
use this version with minor changes to enable Fedora-specific service
providers.
v2
- Add missing databases to manual.
- Add link to manual from default nsswitch.conf.
- Sort nsswitch.conf according to most used database first.
---
ChangeLog | 5 +++
manual/nss.texi | 20 +++++++++---
nss/nsswitch.conf | 81 +++++++++++++++++++++++++++++++++++++----------
3 files changed, 85 insertions(+), 21 deletions(-)
Comments
* Carlos O'Donell:
> On 3/20/19 12:58 PM, Florian Weimer wrote:
>> * Carlos O'Donell:
>>
>>> +# An example Name Service Switch config file. This file should be
>>> +# sorted with the most-used services at the beginning.
>>
>> The example file itself doesn't seem to follow this.
>
> I noticed that netmasks, automount, and bootparams are not handled by
> glibc, but listed in the nsswitch.conf. Are these handled by some other
> application which parses /etc/nsswitch.conf? I'm not aware of any that
> do so, and so I've removed them.
>
> We never got around to implementing the accessor functions for them,
> and only added publickey. I cleaned up the docs and referenced the info
> docs from the default nsswitch.conf.
I think we should only list what is actually implemented in glibc.
sudo uses /etc/nsswitch.conf for a custom database, too, if I recall
correctly.
This is possible because the glibc parser simply ignores unknown
entries.
> +# In order of most-used services first.
> +passwd: files
> +group: files
> +hosts: files dns
> +networks: files dns
> +initgroups: files
> +shadow: files
> +gshadow: files
> +netgroup: files
> +services: files
> +protocols: files
> +ethers: files
> +aliases: files
> +rpc: files
> +publickey: files
I fear we can discuss this to death. I would suggest alphabetic order
to avoid that.
I have no further comments on the patch.
On Mär 20 2019, Carlos O'Donell <codonell@redhat.com> wrote:
> I noticed that netmasks, automount, and bootparams are not handled by
> glibc, but listed in the nsswitch.conf. Are these handled by some other
> application which parses /etc/nsswitch.conf? I'm not aware of any that
> do so, and so I've removed them.
automount is used by autofs.
Andreas.
On 3/21/19 5:16 AM, Andreas Schwab wrote:
> On Mär 20 2019, Carlos O'Donell <codonell@redhat.com> wrote:
>
>> I noticed that netmasks, automount, and bootparams are not handled by
>> glibc, but listed in the nsswitch.conf. Are these handled by some other
>> application which parses /etc/nsswitch.conf? I'm not aware of any that
>> do so, and so I've removed them.
>
> automount is used by autofs.
OK, good to know.
Are you OK with the removal of the automount reference in the manual?
@@ -1,3 +1,8 @@
+2019-03-20 Carlos O'Donell <carlos@redhat.com>
+
+ * nss/nsswitch.conf: Expand comments, and simplify defaults.
+ * manual/nss.texi (NSS Basics): List all known databases.
+
2019-03-19 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h (HWCAP_SB): New
@@ -56,13 +56,17 @@ functions to access the databases.
@noindent
The databases available in the NSS are
+@cindex aliases
@cindex ethers
@cindex group
+@cindex gshadow
@cindex hosts
+@cindex initgroups
@cindex netgroup
@cindex networks
-@cindex protocols
@cindex passwd
+@cindex protocols
+@cindex publickey
@cindex rpc
@cindex services
@cindex shadow
@@ -75,16 +79,22 @@ Ethernet numbers,
@comment @pxref{Ethernet Numbers}.
@item group
Groups of users, @pxref{Group Database}.
+@item gshadow
+Group passphrase hashes and related information.
@item hosts
Host names and numbers, @pxref{Host Names}.
+@item initgroups
+Supplementary group access list.
@item netgroup
Network wide list of host and users, @pxref{Netgroup Database}.
@item networks
Network names and numbers, @pxref{Networks Database}.
-@item protocols
-Network protocols, @pxref{Protocols Database}.
@item passwd
User identities, @pxref{User Database}.
+@item protocols
+Network protocols, @pxref{Protocols Database}.
+@item publickey
+Public keys for Secure RPC.
@item rpc
Remote procedure call names and numbers.
@comment @pxref{RPC Database}.
@@ -96,8 +106,8 @@ User passphrase hashes and related information.
@end table
@noindent
-There will be some more added later (@code{automount}, @code{bootparams},
-@code{netmasks}, and @code{publickey}).
+More may be added later (@code{automount}, @code{bootparams},
+and @code{netmasks}).
@node NSS Configuration File, NSS Module Internals, NSS Basics, Name Service Switch
@section The NSS Configuration File
@@ -1,20 +1,69 @@
+#
# /etc/nsswitch.conf
#
-# Example configuration of GNU Name Service Switch functionality.
+# An example Name Service Switch config file. This file should be
+# sorted with the most-used services at the beginning.
#
+# Valid databases are: aliases, ethers, group, gshadow, hosts,
+# initgroups, netgroup, networks, passwd, protocols, publickey,
+# rpc, services, and shadow.
+#
+# Valid service provider entries include (in alphabetical order):
+#
+# compat Use /etc files plus *_compat pseudo-db
+# db Use the pre-processed /var/db files
+# dns Use DNS (Domain Name Service)
+# files Use the local files in /etc
+# hesiod Use Hesiod (DNS) for user lookups
+# nis Use NIS (NIS version 2), also called YP
+# nisplus Use NIS+ (NIS version 3)
+#
+# See `info libc 'NSS Basics'` for more information.
+#
+# Commonly used alternative service providers (may need installation):
+#
+# ldap Use LDAP directory server
+# myhostname Use systemd host names
+# mymachines Use systemd machine names
+# mdns*, mdns*_minimal Use Avahi mDNS/DNS-SD
+# resolve Use systemd resolved resolver
+# sss Use System Security Services Daemon (sssd)
+# systemd Use systemd for dynamic user option
+# winbind Use SAMBA winbind support
+# wins Use SAMBA wins support
+# wrapper Use wrapper module for testing
+#
+# Notes:
+#
+# 'sssd' performs its own 'files'-based caching, so it should generally
+# come before 'files'.
+#
+# WARNING: Running nscd with a secondary caching service like sssd may
+# lead to unexpected behaviour, especially with how long
+# entries are cached.
+#
+# Installation instructions:
+#
+# To use 'db', install the appropriate package(s) (provide 'makedb' and
+# libnss_db.so.*), and place the 'db' in front of 'files' for entries
+# you want to be looked up first in the databases, like this:
+#
+# passwd: db files
+# shadow: db files
+# group: db files
-passwd: db files
-group: db files
-initgroups: db [SUCCESS=continue] files
-shadow: db files
-gshadow: files
-
-hosts: files dns
-networks: files dns
-
-protocols: db files
-services: db files
-ethers: db files
-rpc: db files
-
-netgroup: db files
+# In order of most-used services first.
+passwd: files
+group: files
+hosts: files dns
+networks: files dns
+initgroups: files
+shadow: files
+gshadow: files
+netgroup: files
+services: files
+protocols: files
+ethers: files
+aliases: files
+rpc: files
+publickey: files