From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58926) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dsWPH-00051q-51 for qemu-devel@nongnu.org; Thu, 14 Sep 2017 11:50:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dsWPE-0000qo-P9 for qemu-devel@nongnu.org; Thu, 14 Sep 2017 11:50:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41996) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dsWPE-0000q9-Ft for qemu-devel@nongnu.org; Thu, 14 Sep 2017 11:50:20 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5762F7E420 for ; Thu, 14 Sep 2017 15:50:19 +0000 (UTC) Date: Thu, 14 Sep 2017 16:50:12 +0100 From: "Daniel P. Berrange" Message-ID: <20170914155012.GD11763@redhat.com> Reply-To: "Daniel P. Berrange" References: <20170908114407.25906-1-otubo@redhat.com> <20170908114407.25906-3-otubo@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170908114407.25906-3-otubo@redhat.com> Subject: Re: [Qemu-devel] [PATCHv6 2/5] seccomp: add obsolete argument to command line List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Otubo Cc: qemu-devel@nongnu.org, thuth@redhat.com On Fri, Sep 08, 2017 at 01:44:04PM +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 | 3 ++- > qemu-options.hx | 12 ++++++++++-- > qemu-seccomp.c | 19 ++++++++++++++++++- > vl.c | 23 ++++++++++++++++++++++- > 4 files changed, 52 insertions(+), 5 deletions(-) > > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h > index 23b9c3c789..215138a372 100644 > --- a/include/sysemu/seccomp.h > +++ b/include/sysemu/seccomp.h > @@ -16,8 +16,9 @@ > #define QEMU_SECCOMP_H > > #define QEMU_SECCOMP_SET_DEFAULT (1 << 0) > +#define QEMU_SECCOMP_SET_OBSOLETE (1 << 1) > > #include > > -int seccomp_start(void); > +int seccomp_start(uint32_t seccomp_opts); > #endif > diff --git a/qemu-options.hx b/qemu-options.hx > index 9f6e2adfff..72150c6b84 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -4017,13 +4017,21 @@ 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|deny]\n" \ > + " Enable seccomp mode 2 system call filter (default 'off').\n" \ > + " use 'obsolete' to allow obsolete system calls that are provided\n" \ > + " by the kernel, but typically no longer used by modern\n" \ > + " C library implementations.\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 > +@end table > ETEXI > > DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, > diff --git a/qemu-seccomp.c b/qemu-seccomp.c > index f66613fc71..8a5fbd2ff1 100644 > --- a/qemu-seccomp.c > +++ b/qemu-seccomp.c > @@ -55,9 +55,22 @@ static const struct QemuSeccompSyscall blacklist[] = { > { SCMP_SYS(tuxcall), QEMU_SECCOMP_SET_DEFAULT }, > { SCMP_SYS(ulimit), QEMU_SECCOMP_SET_DEFAULT }, > { SCMP_SYS(vserver), QEMU_SECCOMP_SET_DEFAULT }, > + /* obsolete */ > + { SCMP_SYS(readdir), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(_sysctl), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(bdflush), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(create_module), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(get_kernel_syms), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(query_module), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(sgetmask), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(ssetmask), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(sysfs), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(uselib), QEMU_SECCOMP_SET_OBSOLETE }, > + { SCMP_SYS(ustat), QEMU_SECCOMP_SET_OBSOLETE }, > }; > > -int seccomp_start(void) > + > +int seccomp_start(uint32_t seccomp_opts) > { > int rc = 0; > unsigned int i = 0; > @@ -70,6 +83,10 @@ int seccomp_start(void) > } > > for (i = 0; i < ARRAY_SIZE(blacklist); i++) { > + if (!(seccomp_opts & blacklist[i].set)) { > + 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 76e0b3a946..62b71dd529 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 */ } > }, > }; > @@ -1034,7 +1038,24 @@ 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) { > + uint32_t seccomp_opts = QEMU_SECCOMP_SET_DEFAULT > + | QEMU_SECCOMP_SET_OBSOLETE; > + const char *value = NULL; > + > + value = qemu_opt_get(opts, "obsolete"); > + if (value) { > + if (g_str_equal(value, "allow")) { > + seccomp_opts &= ~QEMU_SECCOMP_SET_OBSOLETE; > + } else if (g_str_equal(value, "deny")) { > + /* this is the default option, this if is here > + * to provide a little bit of consistency for > + * the command line */ > + } else { > + error_report("invalid argument for obsolete"); Needs a 'return -1;' > + } > + } > + > + if (seccomp_start(seccomp_opts) < 0) { > error_report("failed to install seccomp syscall filter " > "in the kernel"); > return -1; If that bug is fixed Reviewed-by: Daniel P. Berrange Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|