[PATCH] seccomp: fix killing of whole process instead of thread

[PATCH] seccomp: fix killing of whole process instead of thread

[Daniel P. Berrangé]

Back in 2018 we introduced support for killing the whole QEMU process
instead of just one thread, when a seccomp rule is violated:

  commit bda08a5764d470f101fa38635d30b41179a313e1
  Author: Marc-André Lureau <marcandre.lureau@redhat.com>
  Date:   Wed Aug 22 19:02:48 2018 +0200

    seccomp: prefer SCMP_ACT_KILL_PROCESS if available

Fast forward a year and we introduced a patch to avoid killing the
process for resource control syscalls tickled by Mesa.

  commit 9a1565a03b79d80b236bc7cc2dbce52a2ef3a1b8
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Wed Mar 13 09:49:03 2019 +0000

    seccomp: don't kill process for resource control syscalls

Unfortunately a logic bug effectively reverted the first commit
mentioned so that we go back to only killing the thread, not the whole
process.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 qemu-seccomp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qemu-seccomp.c b/qemu-seccomp.c
index e0a1829b3d..8325ecb766 100644
--- a/qemu-seccomp.c
+++ b/qemu-seccomp.c
@@ -136,8 +136,9 @@ static uint32_t qemu_seccomp_get_action(int set)
 
             if (qemu_seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &action) == 0) {
                 kill_process = 1;
+            } else {
+                kill_process = 0;
             }
-            kill_process = 0;
         }
         if (kill_process == 1) {
             return SCMP_ACT_KILL_PROCESS;
-- 
2.26.2

Re: [PATCH] seccomp: fix killing of whole process instead of thread

[Stefan Hajnoczi]

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On Fri, Sep 11, 2020 at 03:18:32PM +0100, Daniel P. Berrangé wrote:
> Back in 2018 we introduced support for killing the whole QEMU process
> instead of just one thread, when a seccomp rule is violated:
> 
>   commit bda08a5764d470f101fa38635d30b41179a313e1
>   Author: Marc-André Lureau <marcandre.lureau@redhat.com>
>   Date:   Wed Aug 22 19:02:48 2018 +0200
> 
>     seccomp: prefer SCMP_ACT_KILL_PROCESS if available
> 
> Fast forward a year and we introduced a patch to avoid killing the
> process for resource control syscalls tickled by Mesa.
> 
>   commit 9a1565a03b79d80b236bc7cc2dbce52a2ef3a1b8
>   Author: Daniel P. Berrangé <berrange@redhat.com>
>   Date:   Wed Mar 13 09:49:03 2019 +0000
> 
>     seccomp: don't kill process for resource control syscalls
> 
> Unfortunately a logic bug effectively reverted the first commit
> mentioned so that we go back to only killing the thread, not the whole
> process.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  qemu-seccomp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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Re: [PATCH] seccomp: fix killing of whole process instead of thread

[Eduardo Otubo]

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On 11/09/2020 - 15:18:32, Daniel P. Berrange wrote:
> Back in 2018 we introduced support for killing the whole QEMU process
> instead of just one thread, when a seccomp rule is violated:
> 
>   commit bda08a5764d470f101fa38635d30b41179a313e1
>   Author: Marc-André Lureau <marcandre.lureau@redhat.com>
>   Date:   Wed Aug 22 19:02:48 2018 +0200
> 
>     seccomp: prefer SCMP_ACT_KILL_PROCESS if available
> 
> Fast forward a year and we introduced a patch to avoid killing the
> process for resource control syscalls tickled by Mesa.
> 
>   commit 9a1565a03b79d80b236bc7cc2dbce52a2ef3a1b8
>   Author: Daniel P. Berrangé <berrange@redhat.com>
>   Date:   Wed Mar 13 09:49:03 2019 +0000
> 
>     seccomp: don't kill process for resource control syscalls
> 
> Unfortunately a logic bug effectively reverted the first commit
> mentioned so that we go back to only killing the thread, not the whole
> process.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  qemu-seccomp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> index e0a1829b3d..8325ecb766 100644
> --- a/qemu-seccomp.c
> +++ b/qemu-seccomp.c
> @@ -136,8 +136,9 @@ static uint32_t qemu_seccomp_get_action(int set)
>  
>              if (qemu_seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &action) == 0) {
>                  kill_process = 1;
> +            } else {
> +                kill_process = 0;
>              }
> -            kill_process = 0;
>          }
>          if (kill_process == 1) {
>              return SCMP_ACT_KILL_PROCESS;
> -- 
> 2.26.2
> 

Acked-by: Eduardo Otubo <otubo@redhat.com>

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