Date: Mon, 3 Feb 1997 02:24:55 +1100 From: davidn@unique.usn.blaze.net.au (David Nugent) To: freebsd-current@freebsd.org, freebsd-bugs@freebsd.org Subject: sys/param.h: MAXLOGNAME Message-ID: <19970203022455.AC08025@usn.blaze.net.au>
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After some testing with a username with exactly 16 characters
in length, I hit a problem:
Feb 3 01:54:27 labs login: setlogin 'abcdef0123456789': Invalid argument
Feb 3 01:54:27 labs login: setusercontext() failed - exiting
The error is generated by this code in sys/kern/kern_prot.c:
int
setlogin(p, uap, retval)
struct proc *p;
struct setlogin_args *uap;
int *retval;
{
int error;
if ((error = suser(p->p_ucred, &p->p_acflag)))
return (error);
error = copyinstr((caddr_t) uap->namebuf,
(caddr_t) p->p_pgrp->pg_session->s_login,
sizeof (p->p_pgrp->pg_session->s_login) - 1, (u_int *)0);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
if (error == ENAMETOOLONG)
error = EINVAL;
return (error);
}
and inspecting src/sys/sys/proc.h shows:
struct session {
int s_count; /* Ref cnt; pgrps in session. */
struct proc *s_leader; /* Session leader. */
struct vnode *s_ttyvp; /* Vnode of controlling terminal. */
struct tty *s_ttyp; /* Controlling terminal. */
char s_login[MAXLOGNAME]; /* Setlogin() name. */
^^^^^^^^^^
};
.. which means that in reality, MAXLOGNAME-1 is the maximum
number of characters in a username, which is currently 15,
not 16 as everything else assumes.
The fix for -current is obvious, although it seems that
MAXLOGNAME should be at least as large as a valid user
name. MAXLOGNAME in 2.2 was 12, so it won't be affected.
Regards,
David Nugent - Unique Computing Pty Ltd - Melbourne, Australia
Voice +61-3-9791-9547 Data/BBS +61-3-9792-3507 3:632/348@fidonet
davidn@freebsd.org davidn@blaze.net.au http://www.blaze.net.au/~davidn/
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