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* [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
@ 2022-04-27 10:01 Stefan Hajnoczi
  2022-04-30  3:44 ` Raphael Norwitz
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2022-04-27 10:01 UTC (permalink / raw)
  To: qemu-devel; +Cc: Raphael Norwitz, Stefan Hajnoczi, Michael S. Tsirkin

Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
Program conventions for vhost-user-scsi") introduced fd-passing support
as part of implementing the vhost-user backend program conventions.

When fd passing is used the UNIX domain socket path is NULL and we must
not call unlink(2).

Fixes: Coverity CID 1488353
Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
index b2c0f98253..08335d4b2b 100644
--- a/contrib/vhost-user-scsi/vhost-user-scsi.c
+++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
@@ -433,7 +433,9 @@ out:
     if (vdev_scsi) {
         g_main_loop_unref(vdev_scsi->loop);
         g_free(vdev_scsi);
-        unlink(opt_socket_path);
+        if (opt_socket_path) {
+            unlink(opt_socket_path);
+        }
     }
     if (csock >= 0) {
         close(csock);
-- 
2.35.1



^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
  2022-04-27 10:01 [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing Stefan Hajnoczi
@ 2022-04-30  3:44 ` Raphael Norwitz
  2022-05-09 12:18 ` Philippe Mathieu-Daudé via
  2022-05-12 15:57 ` Peter Maydell
  2 siblings, 0 replies; 6+ messages in thread
From: Raphael Norwitz @ 2022-04-30  3:44 UTC (permalink / raw)
  To: Stefan Hajnoczi; +Cc: Raphael Norwitz, qemu-devel, Michael S. Tsirkin

On Wed, Apr 27, 2022 at 11:01:16AM +0100, Stefan Hajnoczi wrote:
> Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
> Program conventions for vhost-user-scsi") introduced fd-passing support
> as part of implementing the vhost-user backend program conventions.
> 
> When fd passing is used the UNIX domain socket path is NULL and we must
> not call unlink(2).
> 
> Fixes: Coverity CID 1488353
> Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>

> ---
>  contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
> index b2c0f98253..08335d4b2b 100644
> --- a/contrib/vhost-user-scsi/vhost-user-scsi.c
> +++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
> @@ -433,7 +433,9 @@ out:
>      if (vdev_scsi) {
>          g_main_loop_unref(vdev_scsi->loop);
>          g_free(vdev_scsi);
> -        unlink(opt_socket_path);
> +        if (opt_socket_path) {
> +            unlink(opt_socket_path);
> +        }
>      }
>      if (csock >= 0) {
>          close(csock);
> -- 
> 2.35.1
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
  2022-04-27 10:01 [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing Stefan Hajnoczi
  2022-04-30  3:44 ` Raphael Norwitz
@ 2022-05-09 12:18 ` Philippe Mathieu-Daudé via
  2022-05-12 15:57 ` Peter Maydell
  2 siblings, 0 replies; 6+ messages in thread
From: Philippe Mathieu-Daudé via @ 2022-05-09 12:18 UTC (permalink / raw)
  To: Stefan Hajnoczi, qemu-devel; +Cc: Raphael Norwitz, Michael S. Tsirkin

On 27/4/22 12:01, Stefan Hajnoczi wrote:
> Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
> Program conventions for vhost-user-scsi") introduced fd-passing support
> as part of implementing the vhost-user backend program conventions.
> 
> When fd passing is used the UNIX domain socket path is NULL and we must
> not call unlink(2).
> 
> Fixes: Coverity CID 1488353
> Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
  2022-04-27 10:01 [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing Stefan Hajnoczi
  2022-04-30  3:44 ` Raphael Norwitz
  2022-05-09 12:18 ` Philippe Mathieu-Daudé via
@ 2022-05-12 15:57 ` Peter Maydell
  2022-05-13 11:16   ` Michael S. Tsirkin
  2022-05-16 15:57   ` Stefan Hajnoczi
  2 siblings, 2 replies; 6+ messages in thread
From: Peter Maydell @ 2022-05-12 15:57 UTC (permalink / raw)
  To: Stefan Hajnoczi; +Cc: qemu-devel, Raphael Norwitz, Michael S. Tsirkin

On Wed, 27 Apr 2022 at 11:04, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
> Program conventions for vhost-user-scsi") introduced fd-passing support
> as part of implementing the vhost-user backend program conventions.
>
> When fd passing is used the UNIX domain socket path is NULL and we must
> not call unlink(2).
>
> Fixes: Coverity CID 1488353
> Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
> index b2c0f98253..08335d4b2b 100644
> --- a/contrib/vhost-user-scsi/vhost-user-scsi.c
> +++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
> @@ -433,7 +433,9 @@ out:
>      if (vdev_scsi) {
>          g_main_loop_unref(vdev_scsi->loop);
>          g_free(vdev_scsi);
> -        unlink(opt_socket_path);
> +        if (opt_socket_path) {
> +            unlink(opt_socket_path);
> +        }
>      }

Shouldn't this check-and-unlink be one level up, outside the
"if (vdev_scsi)" ? There are error exit paths which get us to
the 'out:' label where we have called unix_sock_new() but
not yet done the g_new0() of vdev_scsi(). The only thing
that needs to be guarded by "if (vdev_scsi)" is the
g_main_loop_unref() (the g_free of vdev_scsi itself could
be inside or outside, since g_free(NULL) is a nop).

thanks
-- PMM


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
  2022-05-12 15:57 ` Peter Maydell
@ 2022-05-13 11:16   ` Michael S. Tsirkin
  2022-05-16 15:57   ` Stefan Hajnoczi
  1 sibling, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2022-05-13 11:16 UTC (permalink / raw)
  To: Peter Maydell; +Cc: Stefan Hajnoczi, qemu-devel, Raphael Norwitz

On Thu, May 12, 2022 at 04:57:13PM +0100, Peter Maydell wrote:
> On Wed, 27 Apr 2022 at 11:04, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
> > Program conventions for vhost-user-scsi") introduced fd-passing support
> > as part of implementing the vhost-user backend program conventions.
> >
> > When fd passing is used the UNIX domain socket path is NULL and we must
> > not call unlink(2).
> >
> > Fixes: Coverity CID 1488353
> > Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
> > index b2c0f98253..08335d4b2b 100644
> > --- a/contrib/vhost-user-scsi/vhost-user-scsi.c
> > +++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
> > @@ -433,7 +433,9 @@ out:
> >      if (vdev_scsi) {
> >          g_main_loop_unref(vdev_scsi->loop);
> >          g_free(vdev_scsi);
> > -        unlink(opt_socket_path);
> > +        if (opt_socket_path) {
> > +            unlink(opt_socket_path);
> > +        }
> >      }
> 
> Shouldn't this check-and-unlink be one level up, outside the
> "if (vdev_scsi)" ? There are error exit paths which get us to
> the 'out:' label where we have called unix_sock_new() but
> not yet done the g_new0() of vdev_scsi(). The only thing
> that needs to be guarded by "if (vdev_scsi)" is the
> g_main_loop_unref() (the g_free of vdev_scsi itself could
> be inside or outside, since g_free(NULL) is a nop).
> 
> thanks
> -- PMM

Stefan, want to respond?

-- 
MST



^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing
  2022-05-12 15:57 ` Peter Maydell
  2022-05-13 11:16   ` Michael S. Tsirkin
@ 2022-05-16 15:57   ` Stefan Hajnoczi
  1 sibling, 0 replies; 6+ messages in thread
From: Stefan Hajnoczi @ 2022-05-16 15:57 UTC (permalink / raw)
  To: Peter Maydell; +Cc: qemu-devel, Raphael Norwitz, Michael S. Tsirkin

[-- Attachment #1: Type: text/plain, Size: 1900 bytes --]

On Thu, May 12, 2022 at 04:57:13PM +0100, Peter Maydell wrote:
> On Wed, 27 Apr 2022 at 11:04, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > Commit 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend
> > Program conventions for vhost-user-scsi") introduced fd-passing support
> > as part of implementing the vhost-user backend program conventions.
> >
> > When fd passing is used the UNIX domain socket path is NULL and we must
> > not call unlink(2).
> >
> > Fixes: Coverity CID 1488353
> > Fixes: 747421e949fc1eb3ba66b5fcccdb7ba051918241 ("Implements Backend Program conventions for vhost-user-scsi")
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> > ---
> >  contrib/vhost-user-scsi/vhost-user-scsi.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/contrib/vhost-user-scsi/vhost-user-scsi.c b/contrib/vhost-user-scsi/vhost-user-scsi.c
> > index b2c0f98253..08335d4b2b 100644
> > --- a/contrib/vhost-user-scsi/vhost-user-scsi.c
> > +++ b/contrib/vhost-user-scsi/vhost-user-scsi.c
> > @@ -433,7 +433,9 @@ out:
> >      if (vdev_scsi) {
> >          g_main_loop_unref(vdev_scsi->loop);
> >          g_free(vdev_scsi);
> > -        unlink(opt_socket_path);
> > +        if (opt_socket_path) {
> > +            unlink(opt_socket_path);
> > +        }
> >      }
> 
> Shouldn't this check-and-unlink be one level up, outside the
> "if (vdev_scsi)" ? There are error exit paths which get us to
> the 'out:' label where we have called unix_sock_new() but
> not yet done the g_new0() of vdev_scsi(). The only thing
> that needs to be guarded by "if (vdev_scsi)" is the
> g_main_loop_unref() (the g_free of vdev_scsi itself could
> be inside or outside, since g_free(NULL) is a nop).

Sorry, I was offline last week due to illness. Now I'm back and agree
with what you found. I have sent a v2.

Stefan

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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-05-16 16:21 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-27 10:01 [PATCH] vhost-user-scsi: avoid unlink(NULL) with fd passing Stefan Hajnoczi
2022-04-30  3:44 ` Raphael Norwitz
2022-05-09 12:18 ` Philippe Mathieu-Daudé via
2022-05-12 15:57 ` Peter Maydell
2022-05-13 11:16   ` Michael S. Tsirkin
2022-05-16 15:57   ` Stefan Hajnoczi

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