From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33824) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cnl8j-0007Dk-D4 for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:01:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cnl8g-0005LV-9E for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:01:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50122) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cnl8g-0005KN-0f for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:01:18 -0400 References: <20170314113209.12025-1-eduardo.otubo@profitbricks.com> <20170314113209.12025-3-eduardo.otubo@profitbricks.com> From: Thomas Huth Message-ID: Date: Tue, 14 Mar 2017 13:01:11 +0100 MIME-Version: 1.0 In-Reply-To: <20170314113209.12025-3-eduardo.otubo@profitbricks.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 2/5] seccomp: add obsolete argument to command line List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Otubo , qemu-devel@nongnu.org On 14.03.2017 12:32, 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 | 47 ++++++++++++++++++++++++++++++++++++++++++++++- > vl.c | 16 +++++++++++++++- > 4 files changed, 71 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 OBSOLETE 0x0001 > + > #include > > -int seccomp_start(void); > +int seccomp_start(uint8_t seccomp_opts); > #endif > diff --git a/qemu-options.hx b/qemu-options.hx > index 8dd8ee34a6..1403d0c85f 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3732,13 +3732,18 @@ 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", > 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 > +@end table > ETEXI > > DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, > diff --git a/qemu-seccomp.c b/qemu-seccomp.c > index f8877b07b5..5ef36890da 100644 > --- a/qemu-seccomp.c > +++ b/qemu-seccomp.c > @@ -31,6 +31,35 @@ struct QemuSeccompSyscall { > uint8_t priority; > }; > > +static const struct QemuSeccompSyscall obsolete[] = { > + { SCMP_SYS(readdir), 255 }, > + { SCMP_SYS(_sysctl), 255 }, > + { SCMP_SYS(afs_syscall), 255 }, > + { SCMP_SYS(bdflush), 255 }, > + { SCMP_SYS(break), 255 }, > + { SCMP_SYS(create_module), 255 }, > + { SCMP_SYS(ftime), 255 }, > + { SCMP_SYS(get_kernel_syms), 255 }, > + { SCMP_SYS(getpmsg), 255 }, > + { SCMP_SYS(gtty), 255 }, > + { SCMP_SYS(lock), 255 }, > + { SCMP_SYS(mpx), 255 }, > + { SCMP_SYS(prof), 255 }, > + { SCMP_SYS(profil), 255 }, > + { SCMP_SYS(putpmsg), 255 }, > + { SCMP_SYS(query_module), 255 }, > + { SCMP_SYS(security), 255 }, > + { SCMP_SYS(sgetmask), 255 }, > + { SCMP_SYS(ssetmask), 255 }, > + { SCMP_SYS(stty), 255 }, > + { SCMP_SYS(sysfs), 255 }, > + { SCMP_SYS(tuxcall), 255 }, > + { SCMP_SYS(ulimit), 255 }, > + { SCMP_SYS(uselib), 255 }, > + { SCMP_SYS(ustat), 255 }, > + { SCMP_SYS(vserver), 255 }, > +}; > + > static const struct QemuSeccompSyscall blacklist[] = { > { SCMP_SYS(reboot), 255 }, > { SCMP_SYS(swapon), 255 }, > @@ -56,7 +85,20 @@ 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 +111,9 @@ int seccomp_start(void) > } > > for (i = 0; i < ARRAY_SIZE(blacklist); i++) { > + if ((seccomp_opts & OBSOLETE) && is_obsolete(blacklist[i].num)) { > + 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 1a95500ac7..7b08b3383b 100644 > --- a/vl.c > +++ b/vl.c > @@ -269,6 +269,10 @@ static QemuOptsList qemu_sandbox_opts = { > .name = "enable", > .type = QEMU_OPT_BOOL, > }, > + { > + .name = "obsolete", > + .type = QEMU_OPT_STRING, > + }, Since this is basically a boolean switch, could you maybe rather use "QEMU_OPT_BOOL" here, too (and also in the following patches)? I think it is also easier for the users to memorize "obsolete=on" instead of yet-another-parameter-syntax like "obsolete=allow". Thomas