kern/126368: Running ktrace/kdump in jail leads to stale jails

alexus alexus at gmail.com
Fri Aug 15 00:44:45 UTC 2008


where can I get latest patch? that I can apply to 7.0-RELEASE-p3 ?


2008/8/9 Mateusz Guzik <mjguzik at gmail.com>:
> On Fri, Aug 08, 2008 at 06:43:38PM +0000, Bjoern A. Zeeb wrote:
>> >The following reply was made to PR kern/126368; it has been noted by GNATS.
>> >
>> >From: "Mateusz Guzik" <mjguzik at gmail.com>
>> >To: bug-followup at freebsd.org
>> >Cc:
>> >Subject: Re: kern/126368: Running ktrace/kdump in jail leads to stale jails
>> >Date: Fri, 8 Aug 2008 19:30:22 +0200
>> >
>> >Err, I made a mistake. crfree() will be called in case of failure
>> >(loop starting at line 959), so the following patch should be ok:
>> >
>> >--- sys/kern/kern_ktrace.c.orig      2008-08-08 16:37:45.000000000 +0200
>> >+++ sys/kern/kern_ktrace.c   2008-08-08 19:25:16.000000000 +0200
>> >@@ -933,12 +933,14 @@
>> >             error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred);
>> >     VOP_UNLOCK(vp, 0, td);
>> >     vn_finished_write(mp);
>> >     vrele(vp);
>> >     VFS_UNLOCK_GIANT(vfslocked);
>> >-    if (!error)
>> >+    if (!error) {
>> >+            crfree(cred);
>> >             return;
>> >+    }
>>
>> that sounds more plausible w/o seeing the surrounding code. I had
>> wondered already earlier today when I was pointed at.
>>
>> I'll look into this.
>>
>
> Sorry for the noise -- the first patch was right. ;)
>
> ktr_writerequest() is called multiple times and it _always_ calls
> crhold(), so crfree() must be called before it returns (even in case of
> failure).
>
> Also, in this function one can find:
>
> [..]
> crhold(cred)
> [..]
> if (vp == NULL) {
>        KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL"));
>        return;
> }
>
> `Normal' kernel might leak credentials in this case, so I believe crfree() should be added there too.
>
> Thanks, and again, sorry for the noise.
> --
> Mateusz Guzik
>
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