On Mon, 2007-12-17 at 12:40 -0800, Reed, Tim (US SSA) wrote: > Lets try this again....Patch Try #3 This looks ok to me, although it doesn't apply cleanly on the trunk, and the coding style still needs fixing (but I suppose make indent will fix it up). Does anyone else have any comments on this? Does it meet Ted's need too? I tried running a program that detached the tty and then invoked the patched newrole with a command, and as expected, if configured to use pam modules that required authentication, it just failed at that point with an authentication failed error, and otherwise, it proceeded without problem. > -----Original Message----- > From: owner-selinux@xxxxxxxxxxxxx [mailto:owner-selinux@xxxxxxxxxxxxx] > On Behalf Of Stephen Smalley > Sent: Monday, December 17, 2007 11:10 AM > To: Reed, Tim (US SSA) > Cc: Xavier Toth; SE Linux > Subject: RE: newrole in the background > > On Mon, 2007-12-17 at 08:01 -0800, Reed, Tim (US SSA) wrote: > > When newrole goes and grabs the ttyname, if it cannot get one should > it > > still log something to the screen or not? > > > > Currently it says "Error! Could not retrieve tty information". I was > > thinking of changing Error to Warning. > > Yes, that's fine. > > > > What is the recommendation here? > > Also do you have the coding standards posted somewhere? > > We just loosely follow kernel coding style, > http://lxr.linux.no/linux/Documentation/CodingStyle > and make indent can be used as a hammer (but not a very good one). > > > > > -----Original Message----- > > From: Stephen Smalley [mailto:sds@xxxxxxxxxxxxx] > > Sent: Thursday, December 13, 2007 12:40 PM > > To: Reed, Tim (US SSA) > > Cc: Xavier Toth; SE Linux > > Subject: RE: newrole in the background > > > > On Thu, 2007-12-13 at 09:06 -0800, Reed, Tim (US SSA) wrote: > > > New patch...I have added checks around the calls that deal with the > > tty. > > > So if ttyn is an empty string (something had a heartache with it > being > > > NULL) then it skips the processing. It does appear to work but more > > > testing is needed. Please review and comment. > > > > Patch is reversed, and doesn't seem to be complete (test for a NULL > > ttyname still remains and is fatal in main). > > > > ttyn should really be NULL if not defined - just fix the code. > Cleaner > > and faster to test for NULL than for empty string. Looks like > > authenticate_via_pam() needs a check. > > > > You can simplify the logic a fair amount, e.g. on entry to > relabel_tty() > > and restore_tty_label(), just do a if (!ttyn) return 0; > > > > Coding style doesn't match. > > > > > Now say if someone ran `newrole -l SystemHigh -- -c "su - foo"` in > the > > > background of a script, you would not be able to give su input as it > > is > > > in the background and has no tty. su in this case exits gracefully > I > > > guess you could say. > > > > > > My point is that if you have an application that needs to run from > > > newrole, in the background AND requires user input, you will not be > > able > > > to give the application input while it is in the background and have > > it > > > work successfully. > > > > You can't do that anyway, by definition. > > > > > Example: > > > foo.sh > > > --------------- > > > #!/bin/bash > > > > > > ./bar.sh & > > > --------------- > > > bar.sh > > > --------------- > > > #!/bin/bash > > > > > > su - root -c /bin/date > > > --------------- > > > > > > su exits because there is no tty for input. So is chasing down > having > > > newrole run in a pseudo tty in the background and accept input worth > > the > > > time? > > > > It doesn't help - there is no input to accept. > > > > We just need to make sure that the pam modules and chkpwd don't block > > forever or seg fault when handed a NULL PAM_TTY. > > -- Stephen Smalley National Security Agency -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
