| Message ID | 20170908091027.9104-2-otubo@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 08, 2017 at 11:10:23AM +0200, Eduardo Otubo wrote: > This patch changes the default behavior of the seccomp filter from > whitelist to blacklist. By default now all system calls are allowed and > a small black list of definitely forbidden ones was created. > > Signed-off-by: Eduardo Otubo <otubo@redhat.com> > --- > include/sysemu/seccomp.h | 2 + > qemu-seccomp.c | 264 ++++++----------------------------------------- > vl.c | 1 - > 3 files changed, 35 insertions(+), 232 deletions(-) Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Regards, Daniel
On 08.09.2017 11:10, Eduardo Otubo wrote: > This patch changes the default behavior of the seccomp filter from > whitelist to blacklist. By default now all system calls are allowed and > a small black list of definitely forbidden ones was created. > > Signed-off-by: Eduardo Otubo <otubo@redhat.com> > --- > include/sysemu/seccomp.h | 2 + > qemu-seccomp.c | 264 ++++++----------------------------------------- > vl.c | 1 - > 3 files changed, 35 insertions(+), 232 deletions(-) > > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h > index cfc06008cb..23b9c3c789 100644 > --- a/include/sysemu/seccomp.h > +++ b/include/sysemu/seccomp.h > @@ -15,6 +15,8 @@ > #ifndef QEMU_SECCOMP_H > #define QEMU_SECCOMP_H > > +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0) > + > #include <seccomp.h> > > int seccomp_start(void); > diff --git a/qemu-seccomp.c b/qemu-seccomp.c > index df75d9c471..bc9a1f77ff 100644 > --- a/qemu-seccomp.c > +++ b/qemu-seccomp.c > @@ -28,232 +28,34 @@ > > struct QemuSeccompSyscall { > int32_t num; > - uint8_t priority; > + int type; What's this "type" field good for? I failed to spot the place in the sources where you are using it...? Anyway, some comments here right after the struct members would be useful. Thomas > + uint8_t set; > }; > > -static const struct QemuSeccompSyscall seccomp_whitelist[] = { > - { SCMP_SYS(timer_settime), 255 }, [...] > - { SCMP_SYS(memfd_create), 240 }, > -#ifdef HAVE_CACHEFLUSH > - { SCMP_SYS(cacheflush), 240 }, > -#endif > - { SCMP_SYS(sysinfo), 240 }, > +static const struct QemuSeccompSyscall blacklist[] = { > + /* default set of syscalls to blacklist */ > + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT }, > + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT }, > }; > > int seccomp_start(void) > @@ -262,19 +64,19 @@ int seccomp_start(void) > unsigned int i = 0; > scmp_filter_ctx ctx; > > - ctx = seccomp_init(SCMP_ACT_KILL); > + ctx = seccomp_init(SCMP_ACT_ALLOW); > if (ctx == NULL) { > rc = -1; > goto seccomp_return; > } > > - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) { > - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0); > - if (rc < 0) { > - goto seccomp_return; > + for (i = 0; i < ARRAY_SIZE(blacklist); i++) { > + switch (blacklist[i].set) { > + default: > + break; > } > - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num, > - seccomp_whitelist[i].priority); > + > + 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 fb1f05b937..76e0b3a946 100644 > --- a/vl.c > +++ b/vl.c > @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt) > > static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) > { > - /* FIXME: change this to true for 1.3 */ > if (qemu_opt_get_bool(opts, "enable", false)) { > #ifdef CONFIG_SECCOMP > if (seccomp_start() < 0) { >
On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote: > On 08.09.2017 11:10, Eduardo Otubo wrote: > > This patch changes the default behavior of the seccomp filter from > > whitelist to blacklist. By default now all system calls are allowed and > > a small black list of definitely forbidden ones was created. > > > > Signed-off-by: Eduardo Otubo <otubo@redhat.com> > > --- > > include/sysemu/seccomp.h | 2 + > > qemu-seccomp.c | 264 ++++++----------------------------------------- > > vl.c | 1 - > > 3 files changed, 35 insertions(+), 232 deletions(-) > > > > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h > > index cfc06008cb..23b9c3c789 100644 > > --- a/include/sysemu/seccomp.h > > +++ b/include/sysemu/seccomp.h > > @@ -15,6 +15,8 @@ > > #ifndef QEMU_SECCOMP_H > > #define QEMU_SECCOMP_H > > > > +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0) > > + > > #include <seccomp.h> > > > > int seccomp_start(void); > > diff --git a/qemu-seccomp.c b/qemu-seccomp.c > > index df75d9c471..bc9a1f77ff 100644 > > --- a/qemu-seccomp.c > > +++ b/qemu-seccomp.c > > @@ -28,232 +28,34 @@ > > > > struct QemuSeccompSyscall { > > int32_t num; > > - uint8_t priority; > > + int type; > > What's this "type" field good for? I failed to spot the place in the > sources where you are using it...? Anyway, some comments here right > after the struct members would be useful. The type is exactly the type of the system call on the blacklist array below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc. Do you think comments here worth a full v6? > > Thomas > > > + uint8_t set; > > }; > > > > -static const struct QemuSeccompSyscall seccomp_whitelist[] = { > > - { SCMP_SYS(timer_settime), 255 }, > [...] > > - { SCMP_SYS(memfd_create), 240 }, > > -#ifdef HAVE_CACHEFLUSH > > - { SCMP_SYS(cacheflush), 240 }, > > -#endif > > - { SCMP_SYS(sysinfo), 240 }, > > +static const struct QemuSeccompSyscall blacklist[] = { > > + /* default set of syscalls to blacklist */ > > + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT }, > > + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT }, > > }; > > > > int seccomp_start(void) > > @@ -262,19 +64,19 @@ int seccomp_start(void) > > unsigned int i = 0; > > scmp_filter_ctx ctx; > > > > - ctx = seccomp_init(SCMP_ACT_KILL); > > + ctx = seccomp_init(SCMP_ACT_ALLOW); > > if (ctx == NULL) { > > rc = -1; > > goto seccomp_return; > > } > > > > - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) { > > - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0); > > - if (rc < 0) { > > - goto seccomp_return; > > + for (i = 0; i < ARRAY_SIZE(blacklist); i++) { > > + switch (blacklist[i].set) { > > + default: > > + break; > > } > > - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num, > > - seccomp_whitelist[i].priority); > > + > > + 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 fb1f05b937..76e0b3a946 100644 > > --- a/vl.c > > +++ b/vl.c > > @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt) > > > > static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) > > { > > - /* FIXME: change this to true for 1.3 */ > > if (qemu_opt_get_bool(opts, "enable", false)) { > > #ifdef CONFIG_SECCOMP > > if (seccomp_start() < 0) { > > > >
On 08.09.2017 11:50, Eduardo Otubo wrote: > On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote: >> On 08.09.2017 11:10, Eduardo Otubo wrote: >>> This patch changes the default behavior of the seccomp filter from >>> whitelist to blacklist. By default now all system calls are allowed and >>> a small black list of definitely forbidden ones was created. >>> >>> Signed-off-by: Eduardo Otubo <otubo@redhat.com> >>> --- >>> include/sysemu/seccomp.h | 2 + >>> qemu-seccomp.c | 264 ++++++----------------------------------------- >>> vl.c | 1 - >>> 3 files changed, 35 insertions(+), 232 deletions(-) >>> >>> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h >>> index cfc06008cb..23b9c3c789 100644 >>> --- a/include/sysemu/seccomp.h >>> +++ b/include/sysemu/seccomp.h >>> @@ -15,6 +15,8 @@ >>> #ifndef QEMU_SECCOMP_H >>> #define QEMU_SECCOMP_H >>> >>> +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0) >>> + >>> #include <seccomp.h> >>> >>> int seccomp_start(void); >>> diff --git a/qemu-seccomp.c b/qemu-seccomp.c >>> index df75d9c471..bc9a1f77ff 100644 >>> --- a/qemu-seccomp.c >>> +++ b/qemu-seccomp.c >>> @@ -28,232 +28,34 @@ >>> >>> struct QemuSeccompSyscall { >>> int32_t num; >>> - uint8_t priority; >>> + int type; >> >> What's this "type" field good for? I failed to spot the place in the >> sources where you are using it...? Anyway, some comments here right >> after the struct members would be useful. > > The type is exactly the type of the system call on the blacklist array > below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc. Sorry, I still do not understand. If that's the case, what's the difference between the "type" field and the "set" field? Where do you use the "type" field? Thomas >>> + uint8_t set; >>> }; >>> >>> -static const struct QemuSeccompSyscall seccomp_whitelist[] = { >>> - { SCMP_SYS(timer_settime), 255 }, >> [...] >>> - { SCMP_SYS(memfd_create), 240 }, >>> -#ifdef HAVE_CACHEFLUSH >>> - { SCMP_SYS(cacheflush), 240 }, >>> -#endif >>> - { SCMP_SYS(sysinfo), 240 }, >>> +static const struct QemuSeccompSyscall blacklist[] = { >>> + /* default set of syscalls to blacklist */ >>> + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT }, >>> }; >>> >>> int seccomp_start(void) >>> @@ -262,19 +64,19 @@ int seccomp_start(void) >>> unsigned int i = 0; >>> scmp_filter_ctx ctx; >>> >>> - ctx = seccomp_init(SCMP_ACT_KILL); >>> + ctx = seccomp_init(SCMP_ACT_ALLOW); >>> if (ctx == NULL) { >>> rc = -1; >>> goto seccomp_return; >>> } >>> >>> - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) { >>> - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0); >>> - if (rc < 0) { >>> - goto seccomp_return; >>> + for (i = 0; i < ARRAY_SIZE(blacklist); i++) { >>> + switch (blacklist[i].set) { >>> + default: >>> + break; >>> } >>> - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num, >>> - seccomp_whitelist[i].priority); >>> + >>> + 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 fb1f05b937..76e0b3a946 100644 >>> --- a/vl.c >>> +++ b/vl.c >>> @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt) >>> >>> static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) >>> { >>> - /* FIXME: change this to true for 1.3 */ >>> if (qemu_opt_get_bool(opts, "enable", false)) { >>> #ifdef CONFIG_SECCOMP >>> if (seccomp_start() < 0) { >>> >> >> >
On Fri, Sep 08, 2017 at 11:52:42AM +0200, Thomas Huth wrote: > On 08.09.2017 11:50, Eduardo Otubo wrote: > > On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote: > >> On 08.09.2017 11:10, Eduardo Otubo wrote: > >>> This patch changes the default behavior of the seccomp filter from > >>> whitelist to blacklist. By default now all system calls are allowed and > >>> a small black list of definitely forbidden ones was created. > >>> > >>> Signed-off-by: Eduardo Otubo <otubo@redhat.com> > >>> --- > >>> include/sysemu/seccomp.h | 2 + > >>> qemu-seccomp.c | 264 ++++++----------------------------------------- > >>> vl.c | 1 - > >>> 3 files changed, 35 insertions(+), 232 deletions(-) > >>> > >>> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h > >>> index cfc06008cb..23b9c3c789 100644 > >>> --- a/include/sysemu/seccomp.h > >>> +++ b/include/sysemu/seccomp.h > >>> @@ -15,6 +15,8 @@ > >>> #ifndef QEMU_SECCOMP_H > >>> #define QEMU_SECCOMP_H > >>> > >>> +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0) > >>> + > >>> #include <seccomp.h> > >>> > >>> int seccomp_start(void); > >>> diff --git a/qemu-seccomp.c b/qemu-seccomp.c > >>> index df75d9c471..bc9a1f77ff 100644 > >>> --- a/qemu-seccomp.c > >>> +++ b/qemu-seccomp.c > >>> @@ -28,232 +28,34 @@ > >>> > >>> struct QemuSeccompSyscall { > >>> int32_t num; > >>> - uint8_t priority; > >>> + int type; > >> > >> What's this "type" field good for? I failed to spot the place in the > >> sources where you are using it...? Anyway, some comments here right > >> after the struct members would be useful. > > > > The type is exactly the type of the system call on the blacklist array > > below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc. > > Sorry, I still do not understand. If that's the case, what's the > difference between the "type" field and the "set" field? Where do you > use the "type" field? HARGH, sorry. Perhaps I was debugging tis for too long and didn't notice it. This was for debug purposes only. I'll remove and resend. Thanks for spotting this. > >>> + uint8_t set; > >>> }; > >>> > >>> -static const struct QemuSeccompSyscall seccomp_whitelist[] = { > >>> - { SCMP_SYS(timer_settime), 255 }, > >> [...] > >>> - { SCMP_SYS(memfd_create), 240 }, > >>> -#ifdef HAVE_CACHEFLUSH > >>> - { SCMP_SYS(cacheflush), 240 }, > >>> -#endif > >>> - { SCMP_SYS(sysinfo), 240 }, > >>> +static const struct QemuSeccompSyscall blacklist[] = { > >>> + /* default set of syscalls to blacklist */ > >>> + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT }, > >>> }; > >>> > >>> int seccomp_start(void) > >>> @@ -262,19 +64,19 @@ int seccomp_start(void) > >>> unsigned int i = 0; > >>> scmp_filter_ctx ctx; > >>> > >>> - ctx = seccomp_init(SCMP_ACT_KILL); > >>> + ctx = seccomp_init(SCMP_ACT_ALLOW); > >>> if (ctx == NULL) { > >>> rc = -1; > >>> goto seccomp_return; > >>> } > >>> > >>> - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) { > >>> - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0); > >>> - if (rc < 0) { > >>> - goto seccomp_return; > >>> + for (i = 0; i < ARRAY_SIZE(blacklist); i++) { > >>> + switch (blacklist[i].set) { > >>> + default: > >>> + break; > >>> } > >>> - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num, > >>> - seccomp_whitelist[i].priority); > >>> + > >>> + 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 fb1f05b937..76e0b3a946 100644 > >>> --- a/vl.c > >>> +++ b/vl.c > >>> @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt) > >>> > >>> static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) > >>> { > >>> - /* FIXME: change this to true for 1.3 */ > >>> if (qemu_opt_get_bool(opts, "enable", false)) { > >>> #ifdef CONFIG_SECCOMP > >>> if (seccomp_start() < 0) { > >>> > >> > >> > > >
diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h index cfc06008cb..23b9c3c789 100644 --- a/include/sysemu/seccomp.h +++ b/include/sysemu/seccomp.h @@ -15,6 +15,8 @@ #ifndef QEMU_SECCOMP_H #define QEMU_SECCOMP_H +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0) + #include <seccomp.h> int seccomp_start(void); diff --git a/qemu-seccomp.c b/qemu-seccomp.c index df75d9c471..bc9a1f77ff 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -28,232 +28,34 @@ struct QemuSeccompSyscall { int32_t num; - uint8_t priority; + int type; + uint8_t set; }; -static const struct QemuSeccompSyscall seccomp_whitelist[] = { - { SCMP_SYS(timer_settime), 255 }, - { SCMP_SYS(timer_gettime), 254 }, - { SCMP_SYS(futex), 253 }, - { SCMP_SYS(select), 252 }, - { SCMP_SYS(recvfrom), 251 }, - { SCMP_SYS(sendto), 250 }, - { SCMP_SYS(socketcall), 250 }, - { SCMP_SYS(read), 249 }, - { SCMP_SYS(io_submit), 249 }, - { SCMP_SYS(brk), 248 }, - { SCMP_SYS(clone), 247 }, - { SCMP_SYS(mmap), 247 }, - { SCMP_SYS(mprotect), 246 }, - { SCMP_SYS(execve), 245 }, - { SCMP_SYS(open), 245 }, - { SCMP_SYS(ioctl), 245 }, - { SCMP_SYS(socket), 245 }, - { SCMP_SYS(setsockopt), 245 }, - { SCMP_SYS(recvmsg), 245 }, - { SCMP_SYS(sendmsg), 245 }, - { SCMP_SYS(accept), 245 }, - { SCMP_SYS(connect), 245 }, - { SCMP_SYS(socketpair), 245 }, - { SCMP_SYS(bind), 245 }, - { SCMP_SYS(listen), 245 }, - { SCMP_SYS(semget), 245 }, - { SCMP_SYS(ipc), 245 }, - { SCMP_SYS(gettimeofday), 245 }, - { SCMP_SYS(readlink), 245 }, - { SCMP_SYS(access), 245 }, - { SCMP_SYS(prctl), 245 }, - { SCMP_SYS(signalfd), 245 }, - { SCMP_SYS(getrlimit), 245 }, - { SCMP_SYS(getrusage), 245 }, - { SCMP_SYS(set_tid_address), 245 }, - { SCMP_SYS(statfs), 245 }, - { SCMP_SYS(unlink), 245 }, - { SCMP_SYS(wait4), 245 }, - { SCMP_SYS(fcntl64), 245 }, - { SCMP_SYS(fstat64), 245 }, - { SCMP_SYS(stat64), 245 }, - { SCMP_SYS(getgid32), 245 }, - { SCMP_SYS(getegid32), 245 }, - { SCMP_SYS(getuid32), 245 }, - { SCMP_SYS(geteuid32), 245 }, - { SCMP_SYS(sigreturn), 245 }, - { SCMP_SYS(_newselect), 245 }, - { SCMP_SYS(_llseek), 245 }, - { SCMP_SYS(mmap2), 245 }, - { SCMP_SYS(sigprocmask), 245 }, - { SCMP_SYS(sched_getparam), 245 }, - { SCMP_SYS(sched_getscheduler), 245 }, - { SCMP_SYS(fstat), 245 }, - { SCMP_SYS(clock_getres), 245 }, - { SCMP_SYS(sched_get_priority_min), 245 }, - { SCMP_SYS(sched_get_priority_max), 245 }, - { SCMP_SYS(stat), 245 }, - { SCMP_SYS(uname), 245 }, - { SCMP_SYS(eventfd2), 245 }, - { SCMP_SYS(io_getevents), 245 }, - { SCMP_SYS(dup), 245 }, - { SCMP_SYS(dup2), 245 }, - { SCMP_SYS(dup3), 245 }, - { SCMP_SYS(gettid), 245 }, - { SCMP_SYS(getgid), 245 }, - { SCMP_SYS(getegid), 245 }, - { SCMP_SYS(getuid), 245 }, - { SCMP_SYS(geteuid), 245 }, - { SCMP_SYS(timer_create), 245 }, - { SCMP_SYS(times), 245 }, - { SCMP_SYS(exit), 245 }, - { SCMP_SYS(clock_gettime), 245 }, - { SCMP_SYS(time), 245 }, - { SCMP_SYS(restart_syscall), 245 }, - { SCMP_SYS(pwrite64), 245 }, - { SCMP_SYS(nanosleep), 245 }, - { SCMP_SYS(chown), 245 }, - { SCMP_SYS(openat), 245 }, - { SCMP_SYS(getdents), 245 }, - { SCMP_SYS(timer_delete), 245 }, - { SCMP_SYS(exit_group), 245 }, - { SCMP_SYS(rt_sigreturn), 245 }, - { SCMP_SYS(sync), 245 }, - { SCMP_SYS(pread64), 245 }, - { SCMP_SYS(madvise), 245 }, - { SCMP_SYS(set_robust_list), 245 }, - { SCMP_SYS(lseek), 245 }, - { SCMP_SYS(pselect6), 245 }, - { SCMP_SYS(fork), 245 }, - { SCMP_SYS(rt_sigprocmask), 245 }, - { SCMP_SYS(write), 244 }, - { SCMP_SYS(fcntl), 243 }, - { SCMP_SYS(tgkill), 242 }, - { SCMP_SYS(kill), 242 }, - { SCMP_SYS(rt_sigaction), 242 }, - { SCMP_SYS(pipe2), 242 }, - { SCMP_SYS(munmap), 242 }, - { SCMP_SYS(mremap), 242 }, - { SCMP_SYS(fdatasync), 242 }, - { SCMP_SYS(close), 242 }, - { SCMP_SYS(rt_sigpending), 242 }, - { SCMP_SYS(rt_sigtimedwait), 242 }, - { SCMP_SYS(readv), 242 }, - { SCMP_SYS(writev), 242 }, - { SCMP_SYS(preadv), 242 }, - { SCMP_SYS(pwritev), 242 }, - { SCMP_SYS(setrlimit), 242 }, - { SCMP_SYS(ftruncate), 242 }, - { SCMP_SYS(lstat), 242 }, - { SCMP_SYS(pipe), 242 }, - { SCMP_SYS(umask), 242 }, - { SCMP_SYS(chdir), 242 }, - { SCMP_SYS(setitimer), 242 }, - { SCMP_SYS(setsid), 242 }, - { SCMP_SYS(poll), 242 }, - { SCMP_SYS(epoll_create), 242 }, - { SCMP_SYS(epoll_ctl), 242 }, - { SCMP_SYS(epoll_wait), 242 }, - { SCMP_SYS(waitpid), 242 }, - { SCMP_SYS(getsockname), 242 }, - { SCMP_SYS(getpeername), 242 }, - { SCMP_SYS(accept4), 242 }, - { SCMP_SYS(timerfd_settime), 242 }, - { SCMP_SYS(newfstatat), 241 }, - { SCMP_SYS(shutdown), 241 }, - { SCMP_SYS(getsockopt), 241 }, - { SCMP_SYS(semop), 241 }, - { SCMP_SYS(semtimedop), 241 }, - { SCMP_SYS(epoll_ctl_old), 241 }, - { SCMP_SYS(epoll_wait_old), 241 }, - { SCMP_SYS(epoll_pwait), 241 }, - { SCMP_SYS(epoll_create1), 241 }, - { SCMP_SYS(ppoll), 241 }, - { SCMP_SYS(creat), 241 }, - { SCMP_SYS(link), 241 }, - { SCMP_SYS(getpid), 241 }, - { SCMP_SYS(getppid), 241 }, - { SCMP_SYS(getpgrp), 241 }, - { SCMP_SYS(getpgid), 241 }, - { SCMP_SYS(getsid), 241 }, - { SCMP_SYS(getdents64), 241 }, - { SCMP_SYS(getresuid), 241 }, - { SCMP_SYS(getresgid), 241 }, - { SCMP_SYS(getgroups), 241 }, - { SCMP_SYS(getresuid32), 241 }, - { SCMP_SYS(getresgid32), 241 }, - { SCMP_SYS(getgroups32), 241 }, - { SCMP_SYS(signal), 241 }, - { SCMP_SYS(sigaction), 241 }, - { SCMP_SYS(sigsuspend), 241 }, - { SCMP_SYS(sigpending), 241 }, - { SCMP_SYS(truncate64), 241 }, - { SCMP_SYS(ftruncate64), 241 }, - { SCMP_SYS(fchown32), 241 }, - { SCMP_SYS(chown32), 241 }, - { SCMP_SYS(lchown32), 241 }, - { SCMP_SYS(statfs64), 241 }, - { SCMP_SYS(fstatfs64), 241 }, - { SCMP_SYS(fstatat64), 241 }, - { SCMP_SYS(lstat64), 241 }, - { SCMP_SYS(sendfile64), 241 }, - { SCMP_SYS(ugetrlimit), 241 }, - { SCMP_SYS(alarm), 241 }, - { SCMP_SYS(rt_sigsuspend), 241 }, - { SCMP_SYS(rt_sigqueueinfo), 241 }, - { SCMP_SYS(rt_tgsigqueueinfo), 241 }, - { SCMP_SYS(sigaltstack), 241 }, - { SCMP_SYS(signalfd4), 241 }, - { SCMP_SYS(truncate), 241 }, - { SCMP_SYS(fchown), 241 }, - { SCMP_SYS(lchown), 241 }, - { SCMP_SYS(fchownat), 241 }, - { SCMP_SYS(fstatfs), 241 }, - { SCMP_SYS(getitimer), 241 }, - { SCMP_SYS(syncfs), 241 }, - { SCMP_SYS(fsync), 241 }, - { SCMP_SYS(fchdir), 241 }, - { SCMP_SYS(msync), 241 }, - { SCMP_SYS(sched_setparam), 241 }, - { SCMP_SYS(sched_setscheduler), 241 }, - { SCMP_SYS(sched_yield), 241 }, - { SCMP_SYS(sched_rr_get_interval), 241 }, - { SCMP_SYS(sched_setaffinity), 241 }, - { SCMP_SYS(sched_getaffinity), 241 }, - { SCMP_SYS(readahead), 241 }, - { SCMP_SYS(timer_getoverrun), 241 }, - { SCMP_SYS(unlinkat), 241 }, - { SCMP_SYS(readlinkat), 241 }, - { SCMP_SYS(faccessat), 241 }, - { SCMP_SYS(get_robust_list), 241 }, - { SCMP_SYS(splice), 241 }, - { SCMP_SYS(vmsplice), 241 }, - { SCMP_SYS(getcpu), 241 }, - { SCMP_SYS(sendmmsg), 241 }, - { SCMP_SYS(recvmmsg), 241 }, - { SCMP_SYS(prlimit64), 241 }, - { SCMP_SYS(waitid), 241 }, - { SCMP_SYS(io_cancel), 241 }, - { SCMP_SYS(io_setup), 241 }, - { SCMP_SYS(io_destroy), 241 }, - { SCMP_SYS(arch_prctl), 240 }, - { SCMP_SYS(mkdir), 240 }, - { SCMP_SYS(fchmod), 240 }, - { SCMP_SYS(shmget), 240 }, - { SCMP_SYS(shmat), 240 }, - { SCMP_SYS(shmdt), 240 }, - { SCMP_SYS(timerfd_create), 240 }, - { SCMP_SYS(shmctl), 240 }, - { SCMP_SYS(mlockall), 240 }, - { SCMP_SYS(mlock), 240 }, - { SCMP_SYS(munlock), 240 }, - { SCMP_SYS(semctl), 240 }, - { SCMP_SYS(fallocate), 240 }, - { SCMP_SYS(fadvise64), 240 }, - { SCMP_SYS(inotify_init1), 240 }, - { SCMP_SYS(inotify_add_watch), 240 }, - { SCMP_SYS(mbind), 240 }, - { SCMP_SYS(memfd_create), 240 }, -#ifdef HAVE_CACHEFLUSH - { SCMP_SYS(cacheflush), 240 }, -#endif - { SCMP_SYS(sysinfo), 240 }, +static const struct QemuSeccompSyscall blacklist[] = { + /* default set of syscalls to blacklist */ + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT }, + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT }, }; int seccomp_start(void) @@ -262,19 +64,19 @@ int seccomp_start(void) unsigned int i = 0; scmp_filter_ctx ctx; - ctx = seccomp_init(SCMP_ACT_KILL); + ctx = seccomp_init(SCMP_ACT_ALLOW); if (ctx == NULL) { rc = -1; goto seccomp_return; } - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) { - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0); - if (rc < 0) { - goto seccomp_return; + for (i = 0; i < ARRAY_SIZE(blacklist); i++) { + switch (blacklist[i].set) { + default: + break; } - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num, - seccomp_whitelist[i].priority); + + 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 fb1f05b937..76e0b3a946 100644 --- a/vl.c +++ b/vl.c @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt) static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) { - /* FIXME: change this to true for 1.3 */ if (qemu_opt_get_bool(opts, "enable", false)) { #ifdef CONFIG_SECCOMP if (seccomp_start() < 0) {
This patch changes the default behavior of the seccomp filter from whitelist to blacklist. By default now all system calls are allowed and a small black list of definitely forbidden ones was created. Signed-off-by: Eduardo Otubo <otubo@redhat.com> --- include/sysemu/seccomp.h | 2 + qemu-seccomp.c | 264 ++++++----------------------------------------- vl.c | 1 - 3 files changed, 35 insertions(+), 232 deletions(-)