Date: Tue, 26 Apr 2016 11:44:36 -0700 From: Conrad Meyer <cem@FreeBSD.org> To: NGie Cooper <yaneurabeya@gmail.com> Cc: =?UTF-8?Q?Ulrich_Sp=C3=B6rlein?= <uspoerlein@gmail.com>, Jamie Gritton <jamie@freebsd.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r298585 - in head: sys/kern usr.sbin/jail Message-ID: <CAG6CVpU2BwQtCcavz0Vj0f=o44q4LD0LiCLc_WPsPTWH5jVFQQ@mail.gmail.com> In-Reply-To: <CA043211-34D4-4562-86A1-F737F8ED1550@gmail.com> References: <201604251706.u3PH6okj031018@repo.freebsd.org> <CAJ9axoQq6ZY1ys5FVzDFv%2Bpu1JZVaF=eQQ1UNwo9YC_-QKewPg@mail.gmail.com> <CA043211-34D4-4562-86A1-F737F8ED1550@gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Right. False positive. Coverity doesn't grok sbuf memory management fully= . On Tue, Apr 26, 2016 at 11:22 AM, NGie Cooper <yaneurabeya@gmail.com> wrote= : > > > On Apr 26, 2016, at 11:03, Ulrich Sp=C3=B6rlein <uspoerlein@gmail.com> = wrote: > > > > 2016-04-25 10:06 GMT-07:00 Jamie Gritton <jamie@freebsd.org>: > >> Author: jamie > >> Date: Mon Apr 25 17:06:50 2016 > >> New Revision: 298585 > >> URL: https://svnweb.freebsd.org/changeset/base/298585 > >> > >> Log: > >> Encapsulate SYSV IPC objects in jails. Define per-module parameters > >> sysvmsg, sysvsem, and sysvshm, with the following bahavior: > >> > >> inherit: allow full access to the IPC primitives. This is the same a= s > >> the current setup with allow.sysvipc is on. Jails and the base syste= m > >> can see (and moduly) each other's objects, which is generally > considered > >> a bad thing (though may be useful in some circumstances). > >> > >> disable: all no access, same as the current setup with allow.sysvipc > off. > >> > >> new: A jail may see use the IPC objects that it has created. It also > >> gets its own IPC key namespace, so different jails may have their own > >> objects using the same key value. The parent jail (or base system) c= an > >> see the jail's IPC objects, but not its keys. > >> > >> PR: 48471 > >> Submitted by: based on work by kikuchan98@gmail.com > >> MFC after: 5 days > >> > >> Modified: > >> head/sys/kern/sysv_msg.c > >> head/sys/kern/sysv_sem.c > >> head/sys/kern/sysv_shm.c > >> head/usr.sbin/jail/jail.8 > > > > Looks like some bad sbuf_deletes, see the recent Coverity report (are > > you folks getting these emails?) > > > > *** CID 1354974: Memory - corruptions (BAD_FREE) > > /sys/kern/sysv_shm.c: 1043 in sysctl_shmsegs() > > 1037 shmseg->u.shm_perm.key =3D IPC_PRIVATE; > > 1038 } > > 1039 > > 1040 sbuf_bcat(&sb, shmseg, sizeof(*shmseg)); > > 1041 } > > 1042 error =3D sbuf_finish(&sb); > >>>> CID 1354974: Memory - corruptions (BAD_FREE) > >>>> "sbuf_delete" frees address of "sb". > > 1043 sbuf_delete(&sb); > > 1044 > > 1045 done: > > 1046 SYSVSHM_UNLOCK(); > > 1047 return (error); > > 1048 } > > > > ** CID 1354975: Memory - corruptions (BAD_FREE) > > > > and one in sysv_msg.c > > cem and I hashed this out recently with ntb on phrabricator. The issue is > that our sbuf implementation is "clever" and has different code paths for > stack vs heap allocation -- this pattern is ok per stack allocation, but > not heap allocation... Coverity only knows about how to instrument the > latter. > > Thanks, > -Ngie >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAG6CVpU2BwQtCcavz0Vj0f=o44q4LD0LiCLc_WPsPTWH5jVFQQ>