bugGNU Screen - Bugs: bug #28448, screen infloops/hangs when running...

 
 

bug #28448: screen infloops/hangs when running it with username "none"

Submitted by:  None
Submitted on:  Thu 31 Dec 2009 12:52:58 AM UTC  
 
Category: Crash/Freeze/InfloopSeverity: 3 - Normal
Priority: 5 - NormalStatus: Duplicate
Privacy: PublicAssigned to: Alexander Naumov <anaumov>
Open/Closed: ClosedRelease: None
Fixed Release: NonePlanned Release: None
Work Required: None

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Thu 04 Jun 2015 08:45:46 AM UTC, comment #2:

From acl.c:

/*

  • Add a new user. His password may be NULL or "" if none. His name must not
  • be "none", as this represents the NULL-pointer when dealing with groups.
  • He has default rights, determined by umask.

*/

Is this "none" a POSIX thing or is it a screen-specific reserved word?

I see "none" also being used in other places as keyword, too. Especially this code from process.c looks scary to me:

if (!strcmp(user->u_password, "none"))
{
if (n)
OutputMsg(0, "Password checking disabled");
free(user->u_password);
user->u_password = NullStr;
}

Does that mean that screen handles any user (or screen lock) whose password is "none" different?

Axel Beckert <abe>
Thu 04 Jun 2015 12:36:13 AM UTC, comment #1:

This bugreport is duplicate of bug #45183
(https://savannah.gnu.org/bugs/?45183)

The user's name must not be "none", as this represents the NULL-pointer when dealing with groups.

It's not a bug.

Alexander Naumov <anaumov>
Project AdministratorIn charge of this item.
Thu 31 Dec 2009 12:52:58 AM UTC, original submission:

screen will not execute succesfully when you use 'none' (without the quotes) as username. This was reproducable on Debian 4.0, Debian 5.0, OpenBSD, centOS and OSX snow leopard.

This behavior seems to be present in (all?) releases up to 4.0.3

Excerpt of a strace:

setgid32(1000) = 0
setuid32(1000) = 0
rt_sigaction(SIGHUP, {0x806be00, [], SA_RESTORER, 0xb7e539e8}, {0x806be00, [], SA_RESTORER, 0xb7e539e8}, 8) = 0
rt_sigaction(SIGHUP, {0x806be00, [], SA_RESTORER, 0xb7e539e8}, {0x806be00, [], SA_RESTORER, 0xb7e539e8}, 8) = 0
rt_sigaction(SIGUSR1, {0x806bd70, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGUSR2, {0x806b940, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGINT, {0x806bdc0, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGTSTP, {0x806b930, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGWINCH, {0x806b950, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
rt_sigaction(SIGALRM, {0x806b920, [], SA_RESTORER, 0xb7e539e8}, {SIG_DFL}, 8) = 0
alarm(15) = 0
pause() = ? ERESTARTNOHAND (To be restarted)
--- SIGALRM (Alarm clock) @ 0 (0) ---
sigreturn() = ? (mask now [])
alarm(0) = 0
kill(5636, SIG_0) = 0
rt_sigaction(SIGALRM, {0x806b920, [], SA_RESTORER, 0xb7e539e8}, {0x806b920, [], SA_RESTORER, 0xb7e539e8}, 8) = 0
alarm(15) = 0
pause() = ? ERESTARTNOHAND (To be restarted)
--- SIGALRM (Alarm clock) @ 0 (0) ---
sigreturn() = ? (mask now [])
alarm(0) = 0
kill(5636, SIG_0) = 0
rt_sigaction(SIGALRM, {0x806b920, [], SA_RESTORER, 0xb7e539e8}, {0x806b920, [], SA_RESTORER, 0xb7e539e8}, 8) = 0
alarm(15) = 0
pause() = ? ERESTARTNOHAND (To be restarted)

... and so on

Anonymous

 

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  • -unavailable- added by abe (Posted a comment)
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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Thu 04 Jun 2015 12:36:13 AM UTCanaumovStatusNone=>Duplicate
      Assigned toNone=>anaumov
      Open/ClosedOpen=>Closed

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