Re: svn commit: r318262 - head/usr.sbin/mountd
Oh, and if the commit doesn't get reverted, I do plan on committing a
change to the exports.5 man page. I just held off on that until the dust
settles.
I had expected more discussion on freebsd-current@ w.r.t. this, but after
several days of no messages, I went ahead with what the two responders
seemed to support.
rick
From: Bruce Evans <b...@optusnet.com.au>
Sent: Saturday, May 13, 2017 11:35:00 PM
To: Rick Macklem
Cc: src-committ...@freebsd.org; svn-src-all@freebsd.org;
svn-src-h...@freebsd.org
Subject: Re: svn commit: r318262 - head/usr.sbin/mountd
On Sun, 14 May 2017, Rick Macklem wrote:
> Log:
> Change the default uid/gid values for nobody/nogroup to 65534/65533.
>
> The default values found in /etc/passwd and /etc/group are 65534, 65533.
> In mountd.c, the defaults were -2, which was 65534 back when uid_t was
> 16bits.
> Without this patch, a file created by root on an NFS exported volume without
> the "-root=" export option will end up owned by uid 4**32 - 2.
> When discussed on freebsd-current@, it seemed that users preferred the
> values being changed to 65534/65533.
I got used to 4294967294. The large number makes it easy to see files
created by root on another system. I mostly use nfs without maproot, and
create such files often using tmp directories to transfer files.
> I have not added code to acquire these values from the databases, since
> the mountd daemon might get "stuck" during startup waiting for a
> non-responsive
> password database server.
>
> Discussed on:freebsd-current
>
> Modified:
> head/usr.sbin/mountd/mountd.c
exports(5) is not modified, so still documents -2:-2 but not the actual
value of 4294967294:4294967294. It seems dangerous to change the documented
default.
What happens if the server only supports 16-bit (or 15-bit, or 8-bit) uids?
> Modified: head/usr.sbin/mountd/mountd.c
> ==
> --- head/usr.sbin/mountd/mountd.c Sun May 14 00:23:27 2017
> (r318261)
> +++ head/usr.sbin/mountd/mountd.c Sun May 14 00:38:41 2017
> (r318262)
> @@ -230,9 +230,9 @@ static char **exnames;
> static char **hosts = NULL;
> static struct xucred def_anon = {
> XUCRED_VERSION,
> - (uid_t)-2,
> + (uid_t)65534,
> 1,
> - { (gid_t)-2 },
> + { (gid_t)65533 },
> NULL
> };
> static int force_v2 = 0;
The casts are now bogus. They might have been needed to avoid warnings
about possible sign extension bugs...
> @@ -2893,8 +2893,8 @@ parsecred(char *namelist, struct xucred
> /*
>* Set up the unprivileged user.
>*/
> - cr->cr_uid = -2;
> - cr->cr_groups[0] = -2;
> + cr->cr_uid = 65534;
> + cr->cr_groups[0] = 65533;
> cr->cr_ngroups = 1;
> /*
>* Get the user's password table entry.
But there were no casts here, and the warnings should be the same.
Bruce
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Re: svn commit: r318262 - head/usr.sbin/mountd
On Sun, 14 May 2017, Rick Macklem wrote:
Log:
Change the default uid/gid values for nobody/nogroup to 65534/65533.
The default values found in /etc/passwd and /etc/group are 65534, 65533.
In mountd.c, the defaults were -2, which was 65534 back when uid_t was 16bits.
Without this patch, a file created by root on an NFS exported volume without
the "-root=" export option will end up owned by uid 4**32 - 2.
When discussed on freebsd-current@, it seemed that users preferred the
values being changed to 65534/65533.
I got used to 4294967294. The large number makes it easy to see files
created by root on another system. I mostly use nfs without maproot, and
create such files often using tmp directories to transfer files.
I have not added code to acquire these values from the databases, since
the mountd daemon might get "stuck" during startup waiting for a non-responsive
password database server.
Discussed on: freebsd-current
Modified:
head/usr.sbin/mountd/mountd.c
exports(5) is not modified, so still documents -2:-2 but not the actual
value of 4294967294:4294967294. It seems dangerous to change the documented
default.
What happens if the server only supports 16-bit (or 15-bit, or 8-bit) uids?
Modified: head/usr.sbin/mountd/mountd.c
==
--- head/usr.sbin/mountd/mountd.c Sun May 14 00:23:27 2017
(r318261)
+++ head/usr.sbin/mountd/mountd.c Sun May 14 00:38:41 2017
(r318262)
@@ -230,9 +230,9 @@ static char **exnames;
static char **hosts = NULL;
static struct xucred def_anon = {
XUCRED_VERSION,
- (uid_t)-2,
+ (uid_t)65534,
1,
- { (gid_t)-2 },
+ { (gid_t)65533 },
NULL
};
static int force_v2 = 0;
The casts are now bogus. They might have been needed to avoid warnings
about possible sign extension bugs...
@@ -2893,8 +2893,8 @@ parsecred(char *namelist, struct xucred
/*
* Set up the unprivileged user.
*/
- cr->cr_uid = -2;
- cr->cr_groups[0] = -2;
+ cr->cr_uid = 65534;
+ cr->cr_groups[0] = 65533;
cr->cr_ngroups = 1;
/*
* Get the user's password table entry.
But there were no casts here, and the warnings should be the same.
Bruce
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svn commit: r318262 - head/usr.sbin/mountd
Author: rmacklem
Date: Sun May 14 00:38:41 2017
New Revision: 318262
URL: https://svnweb.freebsd.org/changeset/base/318262
Log:
Change the default uid/gid values for nobody/nogroup to 65534/65533.
The default values found in /etc/passwd and /etc/group are 65534, 65533.
In mountd.c, the defaults were -2, which was 65534 back when uid_t was 16bits.
Without this patch, a file created by root on an NFS exported volume without
the "-root=" export option will end up owned by uid 4**32 - 2.
When discussed on freebsd-current@, it seemed that users preferred the
values being changed to 65534/65533.
I have not added code to acquire these values from the databases, since
the mountd daemon might get "stuck" during startup waiting for a
non-responsive
password database server.
Discussed on: freebsd-current
Modified:
head/usr.sbin/mountd/mountd.c
Modified: head/usr.sbin/mountd/mountd.c
==
--- head/usr.sbin/mountd/mountd.c Sun May 14 00:23:27 2017
(r318261)
+++ head/usr.sbin/mountd/mountd.c Sun May 14 00:38:41 2017
(r318262)
@@ -230,9 +230,9 @@ static char **exnames;
static char **hosts = NULL;
static struct xucred def_anon = {
XUCRED_VERSION,
- (uid_t)-2,
+ (uid_t)65534,
1,
- { (gid_t)-2 },
+ { (gid_t)65533 },
NULL
};
static int force_v2 = 0;
@@ -2893,8 +2893,8 @@ parsecred(char *namelist, struct xucred
/*
* Set up the unprivileged user.
*/
- cr->cr_uid = -2;
- cr->cr_groups[0] = -2;
+ cr->cr_uid = 65534;
+ cr->cr_groups[0] = 65533;
cr->cr_ngroups = 1;
/*
* Get the user's password table entry.
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