NetBSD Problem Report #47951

From riz@slash.lan  Fri Jun 21 18:28:59 2013
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Date: Fri, 21 Jun 2013 11:26:28 -0700 (PDT)
From: riz@NetBSD.org
Reply-To: riz@NetBSD.org
To: gnats-bugs@NetBSD.org
Subject: modstat(8) can't display load address
X-Send-Pr-Version: 3.95

>Number:         47951
>Category:       bin
>Synopsis:       modstat(8) has no option to display load address
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jun 21 18:30:00 +0000 2013
>Closed-Date:    Mon Oct 07 03:38:35 +0000 2013
>Last-Modified:  Mon Oct 07 03:38:35 +0000 2013
>Originator:     Jeff Rizzo
>Release:        NetBSD 6.99.21
>Organization:

>Environment:


System: NetBSD slash.lan 6.99.21 NetBSD 6.99.21 (DTRACE) #23: Sun Jun 16 22:36:30 PDT 2013 riz@slash.lan:/usr/src/sys/arch/amd64/compile/DTRACE amd64
Architecture: x86_64
Machine: amd64
>Description:
	The modstat(8) command should be able to display the address
	at which a kernel module is loaded.
>How-To-Repeat:
	Want to find the load address for a module.  Note that modstat(8)
	can't do it, even though it has all the information.
>Fix:
	This is a SMOP, as in sbin/modstat/main.c, the information
	is already retrieved from the kernel (ms->ms_addr) - it just
	needs to be displayed.  It's probably not needed by default,
	but maybe an option flag?

	I started in on some actual code for this,  and realized I
	don't have time to make it look nice enough, but it should
	be easy enough for someone with a few minutes at hand.

>Release-Note:

>Audit-Trail:
From: riz@NetBSD.org
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: bin/47951: modstat(8) can't display load address
Date: Fri, 21 Jun 2013 12:15:13 -0700

 OK, I cooked up a patch that is untested on anything except amd64
 at this point.

 Index: main.c
 ===================================================================
 RCS file: /cvsroot/src/sbin/modstat/main.c,v
 retrieving revision 1.15
 diff -u -r1.15 main.c
 --- main.c	7 Aug 2012 01:19:05 -0000	1.15
 +++ main.c	21 Jun 2013 19:13:25 -0000
 @@ -175,9 +175,9 @@
  		if (maxnamelen < namelen)
  			maxnamelen = namelen;
  	}
 -	printf("%-*s %-10s %-10s %-5s %-8s %s\n",
 -	    (int)maxnamelen, "NAME", "CLASS", "SOURCE", "REFS", "SIZE",
 -	    "REQUIRES");
 +	printf("%-*s %-10s %-10s %-5s %-16s %-8s %s \n",
 +	    (int)maxnamelen, "NAME", "CLASS", "SOURCE", "REFS", "ADDRESS",
 +	    "SIZE", "REQUIRES");
  	for (ms = iov.iov_base; len != 0; ms++, len--) {
  		const char *class;
  		const char *source;
 @@ -204,9 +204,9 @@
  		else
  			source = "UNKNOWN";

 -		printf("%-*s %-10s %-10s %-5d %-8s %s\n",
 +		printf("%-*s %-10s %-10s %-5d %-16" PRIx64 " %-8s %s\n",
  		    (int)maxnamelen, ms->ms_name, class, source, ms->ms_refcnt,
 -		    sbuf, ms->ms_required);
 +		    ms->ms_addr, sbuf, ms->ms_required);
  	}

  	exit(EXIT_SUCCESS);
 Index: modstat.8
 ===================================================================
 RCS file: /cvsroot/src/sbin/modstat/modstat.8,v
 retrieving revision 1.11
 diff -u -r1.11 modstat.8
 --- modstat.8	12 Aug 2012 17:20:19 -0000	1.11
 +++ modstat.8	21 Jun 2013 19:13:25 -0000
 @@ -32,7 +32,7 @@
  .\"
  .\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
  .\"
 -.Dd August 6, 2012
 +.Dd June 21, 2013
  .Dt MODSTAT 8
  .Os
  .Sh NAME
 @@ -92,6 +92,9 @@
  .It Li REFS
  Number of references held on the module.
  Disabled builtin modules will show a count of \-1 here.
 +.It Li ADDRESS
 +The kernel address at which the module is loaded.
 +Builtin modules will show 0 here.
  .It Li REQUIRES
  Additional modules that must be present.
  .El

From: matthew green <mrg@eterna.com.au>
To: gnats-bugs@NetBSD.org
Cc: gnats-admin@netbsd.org, netbsd-bugs@netbsd.org
Subject: re: bin/47951: modstat(8) can't display load address
Date: Sat, 22 Jun 2013 10:03:34 +1000

 please be aware of releasing ALSR-based info to non priviledged
 users...


 .mrg.

From: Jeff Rizzo <riz@NetBSD.org>
To: gnats-bugs@NetBSD.org
Cc: 
Subject: Re: bin/47951: modstat(8) can't display load address
Date: Fri, 21 Jun 2013 17:13:05 -0700

 On 6/21/13 5:05 PM, matthew green wrote:
 > The following reply was made to PR bin/47951; it has been noted by GNATS.
 >
 > From: matthew green <mrg@eterna.com.au>
 > To: gnats-bugs@NetBSD.org
 > Cc: gnats-admin@netbsd.org, netbsd-bugs@netbsd.org
 > Subject: re: bin/47951: modstat(8) can't display load address
 > Date: Sat, 22 Jun 2013 10:03:34 +1000
 >
 >   please be aware of releasing ALSR-based info to non priviledged
 >   users...
 >   
 >   
 >   .mrg.
 >   

 This is a non-setuid program, and I'm only printing information which is 
 already retrieved by the syscall...


From: matthew green <mrg@eterna.com.au>
To: gnats-bugs@NetBSD.org
Cc: gnats-admin@netbsd.org, netbsd-bugs@netbsd.org, riz@NetBSD.org
Subject: re: bin/47951: modstat(8) can't display load address
Date: Sat, 22 Jun 2013 10:19:15 +1000

 >  >   please be aware of releasing ALSR-based info to non priviledged
 >  >   users...
 >  
 >  This is a non-setuid program, and I'm only printing information which is 
 >  already retrieved by the syscall...

 yeah - i noticed that from the followup patch.

 alsr is hard :)

From: matthew green <mrg@eterna.com.au>
To: John Nemeth <jnemeth@cue.bc.ca>
Cc: gnats-admin@netbsd.org, netbsd-bugs@netbsd.org, riz@netbsd.org,
    gnats-bugs@netbsd.org
Subject: re: bin/47951: modstat(8) can't display load address
Date: Sat, 22 Jun 2013 11:12:01 +1000

 > } >  >   please be aware of releasing ALSR-based info to non priviledged
 > } >  >   users...
 > } >  
 > } >  This is a non-setuid program, and I'm only printing information which is 
 > } >  already retrieved by the syscall...
 > } 
 > } yeah - i noticed that from the followup patch.
 > } 
 > } alsr is hard :)
 > 
 >      Not to mention, they are kernel addresses, not userland
 > addresses, so ASLR isn't applicable.

 ah right, we haven't fixed our kernels to be properly
 relocatable yet.. pity.


 .mrg.

From: John Nemeth <jnemeth@cue.bc.ca>
To: matthew green <mrg@eterna.com.au>, gnats-bugs@NetBSD.org
Cc: gnats-admin@NetBSD.org, netbsd-bugs@NetBSD.org, riz@NetBSD.org
Subject: re: bin/47951: modstat(8) can't display load address
Date: Fri, 21 Jun 2013 17:38:19 -0700

 On Jun 22, 10:19am, matthew green wrote:
 } 
 } >  >   please be aware of releasing ALSR-based info to non priviledged
 } >  >   users...
 } >  
 } >  This is a non-setuid program, and I'm only printing information which is 
 } >  already retrieved by the syscall...
 } 
 } yeah - i noticed that from the followup patch.
 } 
 } alsr is hard :)

      Not to mention, they are kernel addresses, not userland
 addresses, so ASLR isn't applicable.

 }-- End of excerpt from matthew green

From: "Jeff Rizzo" <riz@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/47951 CVS commit: src/sbin/modstat
Date: Wed, 26 Jun 2013 17:55:38 +0000

 Module Name:	src
 Committed By:	riz
 Date:		Wed Jun 26 17:55:38 UTC 2013

 Modified Files:
 	src/sbin/modstat: main.c modstat.8

 Log Message:
 Display the load address of modules. PR bin/47951.


 To generate a diff of this commit:
 cvs rdiff -u -r1.15 -r1.16 src/sbin/modstat/main.c
 cvs rdiff -u -r1.11 -r1.12 src/sbin/modstat/modstat.8

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: open->closed
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Mon, 07 Oct 2013 03:38:35 +0000
State-Changed-Why:
submitter fixed it a week later


>Unformatted:

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