[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCHv6 2/5] seccomp: add obsolete argument to command
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCHv6 2/5] seccomp: add obsolete argument to command line |
Date: |
Thu, 14 Sep 2017 16:50:12 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
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 <address@hidden>
> ---
> 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 <seccomp.h>
>
> -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 <arg> 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
> address@hidden -sandbox @var{arg}
> address@hidden -sandbox @var{arg}[,address@hidden
> @findex -sandbox
> Enable Seccomp mode 2 system call filter. 'on' will enable syscall filtering
> and 'off' will
> disable it. The default is 'off'.
> address@hidden @option
> address@hidden address@hidden
> +Enable Obsolete system calls
> address@hidden 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 <address@hidden>
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 :|
- [Qemu-devel] [PATCHv6 0/6] seccomp: feature refactoring, Eduardo Otubo, 2017/09/08
- [Qemu-devel] [PATCHv6 1/5] seccomp: changing from whitelist to blacklist, Eduardo Otubo, 2017/09/08
- [Qemu-devel] [PATCHv6 2/5] seccomp: add obsolete argument to command line, Eduardo Otubo, 2017/09/08
- [Qemu-devel] [PATCHv6 3/5] seccomp: add elevateprivileges argument to command line, Eduardo Otubo, 2017/09/08
- [Qemu-devel] [PATCHv6 4/5] seccomp: add spawn argument to command line, Eduardo Otubo, 2017/09/08
- [Qemu-devel] [PATCHv6 5/5] seccomp: add resourcecontrol argument to command line, Eduardo Otubo, 2017/09/08
- Re: [Qemu-devel] [PATCHv6 0/6] seccomp: feature refactoring, Eduardo Otubo, 2017/09/14