From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38654) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cnlSr-0004FY-JC for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:22:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cnlSn-00050F-2U for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:22:09 -0400 Received: from mail-wm0-x231.google.com ([2a00:1450:400c:c09::231]:38346) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cnlSm-000505-Mx for qemu-devel@nongnu.org; Tue, 14 Mar 2017 08:22:04 -0400 Received: by mail-wm0-x231.google.com with SMTP id t189so62416924wmt.1 for ; Tue, 14 Mar 2017 05:22:04 -0700 (PDT) Date: Tue, 14 Mar 2017 13:22:00 +0100 From: Eduardo Otubo Message-ID: <20170314122200.GA21475@vader> References: <20170314113209.12025-1-eduardo.otubo@profitbricks.com> <20170314113209.12025-3-eduardo.otubo@profitbricks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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: Thomas Huth Cc: qemu-devel@nongnu.org, berrange@redhat.com On Tue, Mar 14, 2017 at 01=01=11PM +0100, Thomas Huth wrote: > 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". > Yes, that's definitely in my mind. I just wanted to make the first draft the same way Daniel designed and evolve from there. -- Eduardo Otubo ProfitBricks GmbH