Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-26 Thread Miklos Szeredi
On Tue, Jan 26, 2021 at 11:18 AM Stefan Hajnoczi wrote: > > On Mon, Jan 25, 2021 at 05:12:23PM +0100, Miklos Szeredi wrote: > > On Thu, Jan 21, 2021 at 3:44 PM Stefan Hajnoczi wrote: > > > > > This patch adds the missing checks to virtiofsd. This is a short-term > > > solution because it does not

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-26 Thread Stefan Hajnoczi
On Mon, Jan 25, 2021 at 05:12:23PM +0100, Miklos Szeredi wrote: > On Thu, Jan 21, 2021 at 3:44 PM Stefan Hajnoczi wrote: > > > This patch adds the missing checks to virtiofsd. This is a short-term > > solution because it does not prevent a compromised virtiofsd process > > from opening device nod

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-26 Thread Stefan Hajnoczi
On Fri, Jan 22, 2021 at 10:40:54AM -0500, Vivek Goyal wrote: > On Thu, Jan 21, 2021 at 02:44:29PM +, Stefan Hajnoczi wrote: > > A well-behaved FUSE client does not attempt to open special files with > > FUSE_OPEN because they are handled on the client side (e.g. device nodes > > are handled by

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-25 Thread Miklos Szeredi
On Thu, Jan 21, 2021 at 3:44 PM Stefan Hajnoczi wrote: > This patch adds the missing checks to virtiofsd. This is a short-term > solution because it does not prevent a compromised virtiofsd process > from opening device nodes on the host. I think the proper solution is adding support to the host

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-25 Thread Stefan Hajnoczi
On Thu, Jan 21, 2021 at 02:48:03PM +, Daniel P. Berrangé wrote: > On Thu, Jan 21, 2021 at 02:44:29PM +, Stefan Hajnoczi wrote: > > A well-behaved FUSE client does not attempt to open special files with > > FUSE_OPEN because they are handled on the client side (e.g. device nodes > > are hand

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-22 Thread Vivek Goyal
On Thu, Jan 21, 2021 at 02:48:03PM +, Daniel P. Berrangé wrote: > On Thu, Jan 21, 2021 at 02:44:29PM +, Stefan Hajnoczi wrote: > > A well-behaved FUSE client does not attempt to open special files with > > FUSE_OPEN because they are handled on the client side (e.g. device nodes > > are hand

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-22 Thread Vivek Goyal
On Thu, Jan 21, 2021 at 02:44:29PM +, Stefan Hajnoczi wrote: > A well-behaved FUSE client does not attempt to open special files with > FUSE_OPEN because they are handled on the client side (e.g. device nodes > are handled by client-side device drivers). > > The check to prevent virtiofsd from

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread Dr. David Alan Gilbert
* Stefan Hajnoczi (stefa...@redhat.com) wrote: > A well-behaved FUSE client does not attempt to open special files with > FUSE_OPEN because they are handled on the client side (e.g. device nodes > are handled by client-side device drivers). > > The check to prevent virtiofsd from opening special f

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread Laszlo Ersek
On 01/21/21 16:52, Alex Xu wrote: > Excerpts from Laszlo Ersek's message of January 21, 2021 10:32 am: >> Assuming a benign / trusted guest, is there going to be an override for >> this? >> >> Asked differently -- if we don't want to set up a separate block device >> on the host, to contain the fil

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread alex--- via
Excerpts from Laszlo Ersek's message of January 21, 2021 10:32 am: > Assuming a benign / trusted guest, is there going to be an override for > this? > > Asked differently -- if we don't want to set up a separate block device > on the host, to contain the filesystem that is mounted as the shared >

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread Laszlo Ersek
On 01/21/21 15:44, Stefan Hajnoczi wrote: > A well-behaved FUSE client does not attempt to open special files with > FUSE_OPEN because they are handled on the client side (e.g. device nodes > are handled by client-side device drivers). > > The check to prevent virtiofsd from opening special files

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread alex--- via
Excerpts from Stefan Hajnoczi's message of January 21, 2021 9:44 am: > A well-behaved FUSE client does not attempt to open special files with > FUSE_OPEN because they are handled on the client side (e.g. device nodes > are handled by client-side device drivers). > > The check to prevent virtiofsd

Re: [PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread Daniel P . Berrangé
On Thu, Jan 21, 2021 at 02:44:29PM +, Stefan Hajnoczi wrote: > A well-behaved FUSE client does not attempt to open special files with > FUSE_OPEN because they are handled on the client side (e.g. device nodes > are handled by client-side device drivers). > > The check to prevent virtiofsd from

[PATCH] virtiofsd: prevent opening of special files (CVE-2020-35517)

2021-01-21 Thread Stefan Hajnoczi
A well-behaved FUSE client does not attempt to open special files with FUSE_OPEN because they are handled on the client side (e.g. device nodes are handled by client-side device drivers). The check to prevent virtiofsd from opening special files is missing in a few cases, most notably FUSE_OPEN. A