subject:"Re\: \[Qemu\-devel\] \[PATCH v3 2\/6\] seccomp\: add obsolete argument to command line"

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

2017-08-11 Thread Eduardo Otubo

On Fri, Aug 11, 2017 at 11:12:48AM +0200, Eduardo Otubo wrote:
> On Wed, Aug 02, 2017 at 01:33:56PM +0100, Daniel P. Berrange wrote:
> > On Fri, Jul 28, 2017 at 02:10:36PM +0200, Eduardo Otubo wrote:
> > > This patch introduces the argument [,obsolete=allow] to the `-sandbox on'
> > > option. It allows Qemu to run safely on old system that still relies on
> > > old system calls.
> > > 
> > > Signed-off-by: Eduardo Otubo 
> > > ---
> > >  include/sysemu/seccomp.h |  4 +++-
> > >  qemu-options.hx  |  9 +++--
> > >  qemu-seccomp.c   | 32 +++-
> > >  vl.c | 16 +++-
> > >  4 files changed, 56 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> > > index cfc06008cb..7a7bde246b 100644
> > > --- a/include/sysemu/seccomp.h
> > > +++ b/include/sysemu/seccomp.h
> > > @@ -15,7 +15,9 @@
> > >  #ifndef QEMU_SECCOMP_H
> > >  #define QEMU_SECCOMP_H
> > >  
> > > +#define OBSOLETE0x0001
> > 
> > Please namespace this - its far too generic a term to expose to other
> > source files. I'd suggest 
> > 
> >   QEMU_SECCOMP_SET_OBSOLETE
> > 
> > > -int seccomp_start(void);
> > > +int seccomp_start(uint8_t seccomp_opts);
> > 
> > This only allows for 8 sets. Perhaps its enough, but I'd suggest
> > just using a uint32_t straight away.
> > 
> > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > index 746b5fa75d..54e492f36a 100644
> > > --- a/qemu-options.hx
> > > +++ b/qemu-options.hx
> > > @@ -4004,13 +4004,18 @@ Old param mode (ARM only).
> > >  ETEXI
> > >  
> > >  DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
> > > -"-sandbox   Enable seccomp mode 2 system call filter (default 
> > > 'off').\n",
> > > +"-sandbox on[,obsolete=allow]  Enable seccomp mode 2 system call 
> > > filter (default 'off').\n" \
> > > +"obsolete: Allow obsolete system calls\n",
> > >  QEMU_ARCH_ALL)
> > >  STEXI
> > > -@item -sandbox @var{arg}
> > > +@item -sandbox @var{arg}[,obsolete=@var{string}]
> > >  @findex -sandbox
> > >  Enable Seccomp mode 2 system call filter. 'on' will enable syscall 
> > > filtering and 'off' will
> > >  disable it.  The default is 'off'.
> > > +@table @option
> > > +@item obsolete=@var{string}
> > > +Enable Obsolete system calls
> > 
> > Lets explain this a bit more.
> > 
> > E obsolete system calls that are provided by the kernel, but typically no
> > longer used by modern C library implementations. 
> > 
> > > +@end table
> > >  ETEXI
> > >  
> > >  DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
> > > diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> > > index f8877b07b5..c6a8b28260 100644
> > > --- a/qemu-seccomp.c
> > > +++ b/qemu-seccomp.c
> > > @@ -31,6 +31,20 @@ struct QemuSeccompSyscall {
> > >  uint8_t priority;
> > >  };
> > >  
> > > +static const struct QemuSeccompSyscall obsolete[] = {
> > > +{ SCMP_SYS(readdir), 255 },
> > > +{ SCMP_SYS(_sysctl), 255 },
> > > +{ SCMP_SYS(bdflush), 255 },
> > > +{ SCMP_SYS(create_module), 255 },
> > > +{ SCMP_SYS(get_kernel_syms), 255 },
> > > +{ SCMP_SYS(query_module), 255 },
> > > +{ SCMP_SYS(sgetmask), 255 },
> > > +{ SCMP_SYS(ssetmask), 255 },
> > > +{ SCMP_SYS(sysfs), 255 },
> > > +{ SCMP_SYS(uselib), 255 },
> > > +{ SCMP_SYS(ustat), 255 },
> > > +};
> > > +
> > >  static const struct QemuSeccompSyscall blacklist[] = {
> > >  { SCMP_SYS(reboot), 255 },
> > >  { SCMP_SYS(swapon), 255 },
> > > @@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] = {
> > >  { SCMP_SYS(vserver), 255 },
> > >  };
> > >  
> > > -int seccomp_start(void)
> > > +static int is_obsolete(int syscall)
> > > +{
> > > +unsigned int i = 0;
> > > +
> > > +for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
> > > +if (syscall == obsolete[i].num) {
> > > +return 1;
> > > +}
> > > +}
> > > +
> > > +return 0;
> > > +}
> > > +
> > > +int seccomp_start(uint8_t seccomp_opts)
> > >  {
> > >  int rc = 0;
> > >  unsigned int i = 0;
> > > @@ -69,6 +96,9 @@ int seccomp_start(void)
> > >  }
> > >  
> > >  for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> > > +if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) {
> > > +continue;
> > > +}
> > 
> > IMHO this is leading to a rather inefficient approach. Why not extend
> > QemuSeccompSyscall struct so that it has another field to list which
> > set it belongs to. Then you can do
> > 
> > 
> >   static const struct QemuSeccompSyscall blacklist[] = {
> > { SCMP_SYS(reboot), 255, QEMU_SECCOMP_SET_DEFAULT },
> > { SCMP_SYS(swapon), 255, QEMU_SECCOMP_SET_DEFAULT },
> >  
> > { SCMP_SYS(readdir), 255, QEMU_SECCOMP_SET_OBSOLETE },
> > { SCMP_SYS(_sysctl), 255, QEMU_SECCOMP_SET_OBSOLETE },
> > ...
> > 
> > And then to process this you can do
> > 
> >   for (i = 0; i < ARRAY_SIZE(blacklist);

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

2017-08-11 Thread Daniel P. Berrange

On Fri, Aug 11, 2017 at 11:12:48AM +0200, Eduardo Otubo wrote:
> On Wed, Aug 02, 2017 at 01:33:56PM +0100, Daniel P. Berrange wrote:
> > On Fri, Jul 28, 2017 at 02:10:36PM +0200, Eduardo Otubo wrote:
> > > This patch introduces the argument [,obsolete=allow] to the `-sandbox on'
> > > option. It allows Qemu to run safely on old system that still relies on
> > > old system calls.
> > > 
> > > Signed-off-by: Eduardo Otubo 
> > > ---
> > >  include/sysemu/seccomp.h |  4 +++-
> > >  qemu-options.hx  |  9 +++--
> > >  qemu-seccomp.c   | 32 +++-
> > >  vl.c | 16 +++-
> > >  4 files changed, 56 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> > > index cfc06008cb..7a7bde246b 100644
> > > --- a/include/sysemu/seccomp.h
> > > +++ b/include/sysemu/seccomp.h
> > > @@ -15,7 +15,9 @@
> > >  #ifndef QEMU_SECCOMP_H
> > >  #define QEMU_SECCOMP_H
> > >  
> > > +#define OBSOLETE0x0001
> > 
> > Please namespace this - its far too generic a term to expose to other
> > source files. I'd suggest 
> > 
> >   QEMU_SECCOMP_SET_OBSOLETE
> > 
> > > -int seccomp_start(void);
> > > +int seccomp_start(uint8_t seccomp_opts);
> > 
> > This only allows for 8 sets. Perhaps its enough, but I'd suggest
> > just using a uint32_t straight away.
> > 
> > > diff --git a/qemu-options.hx b/qemu-options.hx
> > > index 746b5fa75d..54e492f36a 100644
> > > --- a/qemu-options.hx
> > > +++ b/qemu-options.hx
> > > @@ -4004,13 +4004,18 @@ Old param mode (ARM only).
> > >  ETEXI
> > >  
> > >  DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
> > > -"-sandbox   Enable seccomp mode 2 system call filter (default 
> > > 'off').\n",
> > > +"-sandbox on[,obsolete=allow]  Enable seccomp mode 2 system call 
> > > filter (default 'off').\n" \
> > > +"obsolete: Allow obsolete system calls\n",
> > >  QEMU_ARCH_ALL)
> > >  STEXI
> > > -@item -sandbox @var{arg}
> > > +@item -sandbox @var{arg}[,obsolete=@var{string}]
> > >  @findex -sandbox
> > >  Enable Seccomp mode 2 system call filter. 'on' will enable syscall 
> > > filtering and 'off' will
> > >  disable it.  The default is 'off'.
> > > +@table @option
> > > +@item obsolete=@var{string}
> > > +Enable Obsolete system calls
> > 
> > Lets explain this a bit more.
> > 
> > E obsolete system calls that are provided by the kernel, but typically no
> > longer used by modern C library implementations. 
> > 
> > > +@end table
> > >  ETEXI
> > >  
> > >  DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
> > > diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> > > index f8877b07b5..c6a8b28260 100644
> > > --- a/qemu-seccomp.c
> > > +++ b/qemu-seccomp.c
> > > @@ -31,6 +31,20 @@ struct QemuSeccompSyscall {
> > >  uint8_t priority;
> > >  };
> > >  
> > > +static const struct QemuSeccompSyscall obsolete[] = {
> > > +{ SCMP_SYS(readdir), 255 },
> > > +{ SCMP_SYS(_sysctl), 255 },
> > > +{ SCMP_SYS(bdflush), 255 },
> > > +{ SCMP_SYS(create_module), 255 },
> > > +{ SCMP_SYS(get_kernel_syms), 255 },
> > > +{ SCMP_SYS(query_module), 255 },
> > > +{ SCMP_SYS(sgetmask), 255 },
> > > +{ SCMP_SYS(ssetmask), 255 },
> > > +{ SCMP_SYS(sysfs), 255 },
> > > +{ SCMP_SYS(uselib), 255 },
> > > +{ SCMP_SYS(ustat), 255 },
> > > +};
> > > +
> > >  static const struct QemuSeccompSyscall blacklist[] = {
> > >  { SCMP_SYS(reboot), 255 },
> > >  { SCMP_SYS(swapon), 255 },
> > > @@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] = {
> > >  { SCMP_SYS(vserver), 255 },
> > >  };
> > >  
> > > -int seccomp_start(void)
> > > +static int is_obsolete(int syscall)
> > > +{
> > > +unsigned int i = 0;
> > > +
> > > +for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
> > > +if (syscall == obsolete[i].num) {
> > > +return 1;
> > > +}
> > > +}
> > > +
> > > +return 0;
> > > +}
> > > +
> > > +int seccomp_start(uint8_t seccomp_opts)
> > >  {
> > >  int rc = 0;
> > >  unsigned int i = 0;
> > > @@ -69,6 +96,9 @@ int seccomp_start(void)
> > >  }
> > >  
> > >  for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> > > +if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) {
> > > +continue;
> > > +}
> > 
> > IMHO this is leading to a rather inefficient approach. Why not extend
> > QemuSeccompSyscall struct so that it has another field to list which
> > set it belongs to. Then you can do
> > 
> > 
> >   static const struct QemuSeccompSyscall blacklist[] = {
> > { SCMP_SYS(reboot), 255, QEMU_SECCOMP_SET_DEFAULT },
> > { SCMP_SYS(swapon), 255, QEMU_SECCOMP_SET_DEFAULT },
> >  
> > { SCMP_SYS(readdir), 255, QEMU_SECCOMP_SET_OBSOLETE },
> > { SCMP_SYS(_sysctl), 255, QEMU_SECCOMP_SET_OBSOLETE },
> > ...
> > 
> > And then to process this you can do
> > 
> >   for (i = 0; i < ARRAY_SIZE(blacklist);

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

2017-08-11 Thread Eduardo Otubo

On Wed, Aug 02, 2017 at 01:33:56PM +0100, Daniel P. Berrange wrote:
> On Fri, Jul 28, 2017 at 02:10:36PM +0200, Eduardo Otubo wrote:
> > This patch introduces the argument [,obsolete=allow] to the `-sandbox on'
> > option. It allows Qemu to run safely on old system that still relies on
> > old system calls.
> > 
> > Signed-off-by: Eduardo Otubo 
> > ---
> >  include/sysemu/seccomp.h |  4 +++-
> >  qemu-options.hx  |  9 +++--
> >  qemu-seccomp.c   | 32 +++-
> >  vl.c | 16 +++-
> >  4 files changed, 56 insertions(+), 5 deletions(-)
> > 
> > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> > index cfc06008cb..7a7bde246b 100644
> > --- a/include/sysemu/seccomp.h
> > +++ b/include/sysemu/seccomp.h
> > @@ -15,7 +15,9 @@
> >  #ifndef QEMU_SECCOMP_H
> >  #define QEMU_SECCOMP_H
> >  
> > +#define OBSOLETE0x0001
> 
> Please namespace this - its far too generic a term to expose to other
> source files. I'd suggest 
> 
>   QEMU_SECCOMP_SET_OBSOLETE
> 
> > -int seccomp_start(void);
> > +int seccomp_start(uint8_t seccomp_opts);
> 
> This only allows for 8 sets. Perhaps its enough, but I'd suggest
> just using a uint32_t straight away.
> 
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 746b5fa75d..54e492f36a 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -4004,13 +4004,18 @@ Old param mode (ARM only).
> >  ETEXI
> >  
> >  DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
> > -"-sandbox   Enable seccomp mode 2 system call filter (default 
> > 'off').\n",
> > +"-sandbox on[,obsolete=allow]  Enable seccomp mode 2 system call 
> > filter (default 'off').\n" \
> > +"obsolete: Allow obsolete system calls\n",
> >  QEMU_ARCH_ALL)
> >  STEXI
> > -@item -sandbox @var{arg}
> > +@item -sandbox @var{arg}[,obsolete=@var{string}]
> >  @findex -sandbox
> >  Enable Seccomp mode 2 system call filter. 'on' will enable syscall 
> > filtering and 'off' will
> >  disable it.  The default is 'off'.
> > +@table @option
> > +@item obsolete=@var{string}
> > +Enable Obsolete system calls
> 
> Lets explain this a bit more.
> 
> E obsolete system calls that are provided by the kernel, but typically no
> longer used by modern C library implementations. 
> 
> > +@end table
> >  ETEXI
> >  
> >  DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
> > diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> > index f8877b07b5..c6a8b28260 100644
> > --- a/qemu-seccomp.c
> > +++ b/qemu-seccomp.c
> > @@ -31,6 +31,20 @@ struct QemuSeccompSyscall {
> >  uint8_t priority;
> >  };
> >  
> > +static const struct QemuSeccompSyscall obsolete[] = {
> > +{ SCMP_SYS(readdir), 255 },
> > +{ SCMP_SYS(_sysctl), 255 },
> > +{ SCMP_SYS(bdflush), 255 },
> > +{ SCMP_SYS(create_module), 255 },
> > +{ SCMP_SYS(get_kernel_syms), 255 },
> > +{ SCMP_SYS(query_module), 255 },
> > +{ SCMP_SYS(sgetmask), 255 },
> > +{ SCMP_SYS(ssetmask), 255 },
> > +{ SCMP_SYS(sysfs), 255 },
> > +{ SCMP_SYS(uselib), 255 },
> > +{ SCMP_SYS(ustat), 255 },
> > +};
> > +
> >  static const struct QemuSeccompSyscall blacklist[] = {
> >  { SCMP_SYS(reboot), 255 },
> >  { SCMP_SYS(swapon), 255 },
> > @@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] = {
> >  { SCMP_SYS(vserver), 255 },
> >  };
> >  
> > -int seccomp_start(void)
> > +static int is_obsolete(int syscall)
> > +{
> > +unsigned int i = 0;
> > +
> > +for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
> > +if (syscall == obsolete[i].num) {
> > +return 1;
> > +}
> > +}
> > +
> > +return 0;
> > +}
> > +
> > +int seccomp_start(uint8_t seccomp_opts)
> >  {
> >  int rc = 0;
> >  unsigned int i = 0;
> > @@ -69,6 +96,9 @@ int seccomp_start(void)
> >  }
> >  
> >  for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> > +if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) {
> > +continue;
> > +}
> 
> IMHO this is leading to a rather inefficient approach. Why not extend
> QemuSeccompSyscall struct so that it has another field to list which
> set it belongs to. Then you can do
> 
> 
>   static const struct QemuSeccompSyscall blacklist[] = {
> { SCMP_SYS(reboot), 255, QEMU_SECCOMP_SET_DEFAULT },
> { SCMP_SYS(swapon), 255, QEMU_SECCOMP_SET_DEFAULT },
>  
> { SCMP_SYS(readdir), 255, QEMU_SECCOMP_SET_OBSOLETE },
> { SCMP_SYS(_sysctl), 255, QEMU_SECCOMP_SET_OBSOLETE },
> ...
> 
> And then to process this you can do
> 
>   for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
>   if (blacklist[i].set != QEMU_SECCOMP_SET_OBSOLETE &&
>   blacklist[i].set & seccomp_opts) {
> continue;

I agree with all the rest except with this one. This would require a
change on libseccomp itself. Not sure a change on the library would be
suited for now.

I'm working and reviewing all the

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

2017-08-02 Thread Daniel P. Berrange

On Wed, Aug 02, 2017 at 01:33:56PM +0100, Daniel P. Berrange wrote:
> On Fri, Jul 28, 2017 at 02:10:36PM +0200, Eduardo Otubo wrote:
> > This patch introduces the argument [,obsolete=allow] to the `-sandbox on'
> > option. It allows Qemu to run safely on old system that still relies on
> > old system calls.
> > 
> > Signed-off-by: Eduardo Otubo 
> > ---
> >  include/sysemu/seccomp.h |  4 +++-
> >  qemu-options.hx  |  9 +++--
> >  qemu-seccomp.c   | 32 +++-
> >  vl.c | 16 +++-
> >  4 files changed, 56 insertions(+), 5 deletions(-)


> > @@ -1032,7 +1036,17 @@ static int parse_sandbox(void *opaque, QemuOpts 
> > *opts, Error **errp)
> >  {
> >  if (qemu_opt_get_bool(opts, "enable", false)) {
> >  #ifdef CONFIG_SECCOMP
> > -if (seccomp_start() < 0) {
> > +uint8_t seccomp_opts = 0x;
> > +const char *value = NULL;
> > +
> > +value = qemu_opt_get(opts, "obsolete");
> > +if (value) {
> > +if (strcmp(value, "allow") == 0) {
> > +seccomp_opts |= OBSOLETE;
> > +}
> > +}
> 
> IIUC, the values will all be booleans, so we should just use
> 
>if (qemu_opt_get_bool(opts, "obsolete", false))
>seccomp_opts |= OBSOLETE;

Oh ignore this. I see from the next patch, we can't treat it as a boolean.

We should however explicitly look for 'value == deny', and then reject
all other values with an error message

> 
> > +
> > +if (seccomp_start(seccomp_opts) < 0) {
> >  error_report("failed to install seccomp syscall filter "
> >   "in the kernel");
> >  return -1;

Regards,
Daniel
-- 
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Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

2017-08-02 Thread Daniel P. Berrange

On Fri, Jul 28, 2017 at 02:10:36PM +0200, Eduardo Otubo wrote:
> This patch introduces the argument [,obsolete=allow] to the `-sandbox on'
> option. It allows Qemu to run safely on old system that still relies on
> old system calls.
> 
> Signed-off-by: Eduardo Otubo 
> ---
>  include/sysemu/seccomp.h |  4 +++-
>  qemu-options.hx  |  9 +++--
>  qemu-seccomp.c   | 32 +++-
>  vl.c | 16 +++-
>  4 files changed, 56 insertions(+), 5 deletions(-)
> 
> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> index cfc06008cb..7a7bde246b 100644
> --- a/include/sysemu/seccomp.h
> +++ b/include/sysemu/seccomp.h
> @@ -15,7 +15,9 @@
>  #ifndef QEMU_SECCOMP_H
>  #define QEMU_SECCOMP_H
>  
> +#define OBSOLETE0x0001

Please namespace this - its far too generic a term to expose to other
source files. I'd suggest 

  QEMU_SECCOMP_SET_OBSOLETE

> -int seccomp_start(void);
> +int seccomp_start(uint8_t seccomp_opts);

This only allows for 8 sets. Perhaps its enough, but I'd suggest
just using a uint32_t straight away.

> diff --git a/qemu-options.hx b/qemu-options.hx
> index 746b5fa75d..54e492f36a 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4004,13 +4004,18 @@ Old param mode (ARM only).
>  ETEXI
>  
>  DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \
> -"-sandbox   Enable seccomp mode 2 system call filter (default 
> 'off').\n",
> +"-sandbox on[,obsolete=allow]  Enable seccomp mode 2 system call filter 
> (default 'off').\n" \
> +"obsolete: Allow obsolete system calls\n",
>  QEMU_ARCH_ALL)
>  STEXI
> -@item -sandbox @var{arg}
> +@item -sandbox @var{arg}[,obsolete=@var{string}]
>  @findex -sandbox
>  Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering 
> and 'off' will
>  disable it.  The default is 'off'.
> +@table @option
> +@item obsolete=@var{string}
> +Enable Obsolete system calls

Lets explain this a bit more.

E obsolete system calls that are provided by the kernel, but typically no
longer used by modern C library implementations. 

> +@end table
>  ETEXI
>  
>  DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig,
> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> index f8877b07b5..c6a8b28260 100644
> --- a/qemu-seccomp.c
> +++ b/qemu-seccomp.c
> @@ -31,6 +31,20 @@ struct QemuSeccompSyscall {
>  uint8_t priority;
>  };
>  
> +static const struct QemuSeccompSyscall obsolete[] = {
> +{ SCMP_SYS(readdir), 255 },
> +{ SCMP_SYS(_sysctl), 255 },
> +{ SCMP_SYS(bdflush), 255 },
> +{ SCMP_SYS(create_module), 255 },
> +{ SCMP_SYS(get_kernel_syms), 255 },
> +{ SCMP_SYS(query_module), 255 },
> +{ SCMP_SYS(sgetmask), 255 },
> +{ SCMP_SYS(ssetmask), 255 },
> +{ SCMP_SYS(sysfs), 255 },
> +{ SCMP_SYS(uselib), 255 },
> +{ SCMP_SYS(ustat), 255 },
> +};
> +
>  static const struct QemuSeccompSyscall blacklist[] = {
>  { SCMP_SYS(reboot), 255 },
>  { SCMP_SYS(swapon), 255 },
> @@ -56,7 +70,20 @@ static const struct QemuSeccompSyscall blacklist[] = {
>  { SCMP_SYS(vserver), 255 },
>  };
>  
> -int seccomp_start(void)
> +static int is_obsolete(int syscall)
> +{
> +unsigned int i = 0;
> +
> +for (i = 0; i < ARRAY_SIZE(obsolete); i++) {
> +if (syscall == obsolete[i].num) {
> +return 1;
> +}
> +}
> +
> +return 0;
> +}
> +
> +int seccomp_start(uint8_t seccomp_opts)
>  {
>  int rc = 0;
>  unsigned int i = 0;
> @@ -69,6 +96,9 @@ int seccomp_start(void)
>  }
>  
>  for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> +if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) {
> +continue;
> +}

IMHO this is leading to a rather inefficient approach. Why not extend
QemuSeccompSyscall struct so that it has another field to list which
set it belongs to. Then you can do


  static const struct QemuSeccompSyscall blacklist[] = {
{ SCMP_SYS(reboot), 255, QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(swapon), 255, QEMU_SECCOMP_SET_DEFAULT },
 
{ SCMP_SYS(readdir), 255, QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(_sysctl), 255, QEMU_SECCOMP_SET_OBSOLETE },
...

And then to process this you can do

  for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
  if (blacklist[i].set != QEMU_SECCOMP_SET_OBSOLETE &&
  blacklist[i].set & seccomp_opts) {
  continue;
  }


>  rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
>  if (rc < 0) {
>  goto seccomp_return;
> diff --git a/vl.c b/vl.c
> index 15b98800e9..cbe09c94af 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -271,6 +271,10 @@ static QemuOptsList qemu_sandbox_opts = {
>  .name = "enable",
>  .type = QEMU_OPT_BOOL,
>  },
> +{
> +.name = "obsolete",
> +.type = QEMU_OPT_STRING,
> +},
>  { /* end of list */ }
>  },
>  };
> @@

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

Re: [Qemu-devel] [PATCH v3 2/6] seccomp: add obsolete argument to command line

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