Re: [Pkg-shadow-devel] Bug#483645: Bug with UID=4294967296 on Alpha-Arch. (lenny/sid)
Hello, Nicolas,
31.05.08, 17:55, "Nicolas François" <nicolas.francois@centraliens.net>:
> reassign 483645 glibc
>
> On Fri, May 30, 2008 at 06:43:07PM +0400, xrgtn@yandex.ru wrote:
> > 30.05.08, 13:28, "Nicolas François" <nicolas.francois@centraliens.net>:
> > > On Fri, May 30, 2008 at 09:10:29AM +0200, oliver.morais@akhwien.at wrote:
> > > > Creating an user-account and changing the UID via vipw to "4294967296"
> > > > (Which is 2^32) results in an overflow and the user gets the UID=0,
> > > > an UID of "4294967297" leads to an UID=1 and so on.
> >
> > Maybe this is a platform limit (passwd.pw_uid is of uid_t type).
> > For example, on 64-bit HP Tru64 I see the next:
>
> It looks like a glibc bug to me.
I don't know all the details that you refer to,
just wanted to add another 2c: I've checked
sizeof(uid_t) on SPARC Solaris 9 (SunOS 5.9
Generic_122300-05 sun4u sparc SUNW,Sun-Fire)
and HP-UX 11 (B.11.11 U 9000/800).
On both of these (64bit) systems size of the uid_t
is 4 (32 bit), same as on Tru64 UNIX. I think that
uid_t size is 4 on almost every UNIX platform
(this can be checked for at build time using
autoconf).
> At least, INT_FIELD should check for ERANGE after calling strtoul
> (in nss/nss_files/files-parse.c)
> On i386, all UIDs >= 4294967296 are silently converted to 4294967295.
> (when IMHO, an error should be returned by getpwnam)
> Also, the glibc should check if the UID returned by strtoul fits in the
> range of allowed UIDs.
I can't comment on glibc behaviour, but
regarding the vipw/pwck/grpck, it could check
that uid/gid are within the valid range.
E.g. useradd/groupadd do check uid/gid against
ranges (actually, whether it is a valid number
or not at first):
root@xrgtn-w4000:~# groupadd -g 4294967296 g32
groupadd: invalid numeric argument '4294967296'
root@xrgtn-w4000:~# useradd -u 4294967296 u32
useradd: invalid numeric argument '4294967296'
But if I add uid 4294967296 manually (
root@xrgtn-w4000:~# echo 'u32:x:4294967296:100::/root:/bin/bash' >> /etc/passwd
root@xrgtn-w4000:~# echo 'u32::14000:0:99999:7:::' >> /etc/shadow
), pwck does not complain. ;)
After this, I can "su" to the 4294967296 user,
but it looks like glibc cuts his uid to smth.
like UID_MAX (this is for _i386_):
root@xrgtn-w4000:~# su - u32
u32@xrgtn-w4000:~$ id
uid=4294967295(u32) gid=100(users) groups=100(users)
I think that Debian/GNU on Alpha must exhibit the same
behaviour.
--
With best regards,
xrgtn (+380501102966/ICQ:381730053/xrgtn@jabber.kiev.ua)
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