From 9d0fdecbad130f01b602e35e87c6d3fad5821d6e Mon Sep 17 00:00:00 2001 From: Yi Min Zhao Date: Thu, 31 May 2018 11:29:37 +0800 Subject: [PATCH] sandbox: disable -sandbox if CONFIG_SECCOMP undefined MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If CONFIG_SECCOMP is undefined, the option 'elevatedprivileges' remains compiled. This would make libvirt set the corresponding capability and then trigger failure during guest startup. This patch moves the code regarding seccomp command line options to qemu-seccomp.c file and wraps qemu_opts_foreach finding sandbox option with CONFIG_SECCOMP. Because parse_sandbox() is moved into qemu-seccomp.c file, change seccomp_start() to static function. Signed-off-by: Yi Min Zhao Reviewed-by: Ján Tomko Tested-by: Ján Tomko Acked-by: Eduardo Otubo --- include/sysemu/seccomp.h | 3 +- qemu-seccomp.c | 121 ++++++++++++++++++++++++++++++++++++++++++++- vl.c | 124 +++-------------------------------------------- 3 files changed, 130 insertions(+), 118 deletions(-) diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h index 9b092aa23f..fe859894f6 100644 --- a/include/sysemu/seccomp.h +++ b/include/sysemu/seccomp.h @@ -21,5 +21,6 @@ #define QEMU_SECCOMP_SET_SPAWN (1 << 3) #define QEMU_SECCOMP_SET_RESOURCECTL (1 << 4) -int seccomp_start(uint32_t seccomp_opts); +int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp); + #endif diff --git a/qemu-seccomp.c b/qemu-seccomp.c index b770a77d33..148e4c6f24 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -13,6 +13,11 @@ * GNU GPL, version 2 or (at your option) any later version. */ #include "qemu/osdep.h" +#include "qemu/config-file.h" +#include "qemu/option.h" +#include "qemu/module.h" +#include "qemu/error-report.h" +#include #include #include "sysemu/seccomp.h" @@ -96,7 +101,7 @@ static const struct QemuSeccompSyscall blacklist[] = { }; -int seccomp_start(uint32_t seccomp_opts) +static int seccomp_start(uint32_t seccomp_opts) { int rc = 0; unsigned int i = 0; @@ -125,3 +130,117 @@ int seccomp_start(uint32_t seccomp_opts) seccomp_release(ctx); return rc; } + +#ifdef CONFIG_SECCOMP +int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) +{ + if (qemu_opt_get_bool(opts, "enable", false)) { + 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"); + return -1; + } + } + + value = qemu_opt_get(opts, "elevateprivileges"); + if (value) { + if (g_str_equal(value, "deny")) { + seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED; + } else if (g_str_equal(value, "children")) { + seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED; + + /* calling prctl directly because we're + * not sure if host has CAP_SYS_ADMIN set*/ + if (prctl(PR_SET_NO_NEW_PRIVS, 1)) { + error_report("failed to set no_new_privs " + "aborting"); + return -1; + } + } else if (g_str_equal(value, "allow")) { + /* default value */ + } else { + error_report("invalid argument for elevateprivileges"); + return -1; + } + } + + value = qemu_opt_get(opts, "spawn"); + if (value) { + if (g_str_equal(value, "deny")) { + seccomp_opts |= QEMU_SECCOMP_SET_SPAWN; + } else if (g_str_equal(value, "allow")) { + /* default value */ + } else { + error_report("invalid argument for spawn"); + return -1; + } + } + + value = qemu_opt_get(opts, "resourcecontrol"); + if (value) { + if (g_str_equal(value, "deny")) { + seccomp_opts |= QEMU_SECCOMP_SET_RESOURCECTL; + } else if (g_str_equal(value, "allow")) { + /* default value */ + } else { + error_report("invalid argument for resourcecontrol"); + return -1; + } + } + + if (seccomp_start(seccomp_opts) < 0) { + error_report("failed to install seccomp syscall filter " + "in the kernel"); + return -1; + } + } + + return 0; +} + +static QemuOptsList qemu_sandbox_opts = { + .name = "sandbox", + .implied_opt_name = "enable", + .head = QTAILQ_HEAD_INITIALIZER(qemu_sandbox_opts.head), + .desc = { + { + .name = "enable", + .type = QEMU_OPT_BOOL, + }, + { + .name = "obsolete", + .type = QEMU_OPT_STRING, + }, + { + .name = "elevateprivileges", + .type = QEMU_OPT_STRING, + }, + { + .name = "spawn", + .type = QEMU_OPT_STRING, + }, + { + .name = "resourcecontrol", + .type = QEMU_OPT_STRING, + }, + { /* end of list */ } + }, +}; + +static void seccomp_register(void) +{ + qemu_add_opts(&qemu_sandbox_opts); +} +opts_init(seccomp_register); +#endif diff --git a/vl.c b/vl.c index c4fe25560c..70f090c823 100644 --- a/vl.c +++ b/vl.c @@ -28,11 +28,7 @@ #include "qemu/cutils.h" #include "qemu/help_option.h" #include "qemu/uuid.h" - -#ifdef CONFIG_SECCOMP -#include #include "sysemu/seccomp.h" -#endif #ifdef CONFIG_SDL #if defined(__APPLE__) || defined(main) @@ -259,35 +255,6 @@ static QemuOptsList qemu_rtc_opts = { }, }; -static QemuOptsList qemu_sandbox_opts = { - .name = "sandbox", - .implied_opt_name = "enable", - .head = QTAILQ_HEAD_INITIALIZER(qemu_sandbox_opts.head), - .desc = { - { - .name = "enable", - .type = QEMU_OPT_BOOL, - }, - { - .name = "obsolete", - .type = QEMU_OPT_STRING, - }, - { - .name = "elevateprivileges", - .type = QEMU_OPT_STRING, - }, - { - .name = "spawn", - .type = QEMU_OPT_STRING, - }, - { - .name = "resourcecontrol", - .type = QEMU_OPT_STRING, - }, - { /* end of list */ } - }, -}; - static QemuOptsList qemu_option_rom_opts = { .name = "option-rom", .implied_opt_name = "romfile", @@ -1050,88 +1017,6 @@ static int bt_parse(const char *opt) return 1; } -static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) -{ - if (qemu_opt_get_bool(opts, "enable", false)) { -#ifdef CONFIG_SECCOMP - 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"); - return -1; - } - } - - value = qemu_opt_get(opts, "elevateprivileges"); - if (value) { - if (g_str_equal(value, "deny")) { - seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED; - } else if (g_str_equal(value, "children")) { - seccomp_opts |= QEMU_SECCOMP_SET_PRIVILEGED; - - /* calling prctl directly because we're - * not sure if host has CAP_SYS_ADMIN set*/ - if (prctl(PR_SET_NO_NEW_PRIVS, 1)) { - error_report("failed to set no_new_privs " - "aborting"); - return -1; - } - } else if (g_str_equal(value, "allow")) { - /* default value */ - } else { - error_report("invalid argument for elevateprivileges"); - return -1; - } - } - - value = qemu_opt_get(opts, "spawn"); - if (value) { - if (g_str_equal(value, "deny")) { - seccomp_opts |= QEMU_SECCOMP_SET_SPAWN; - } else if (g_str_equal(value, "allow")) { - /* default value */ - } else { - error_report("invalid argument for spawn"); - return -1; - } - } - - value = qemu_opt_get(opts, "resourcecontrol"); - if (value) { - if (g_str_equal(value, "deny")) { - seccomp_opts |= QEMU_SECCOMP_SET_RESOURCECTL; - } else if (g_str_equal(value, "allow")) { - /* default value */ - } else { - error_report("invalid argument for resourcecontrol"); - return -1; - } - } - - if (seccomp_start(seccomp_opts) < 0) { - error_report("failed to install seccomp syscall filter " - "in the kernel"); - return -1; - } -#else - error_report("seccomp support is disabled"); - return -1; -#endif - } - - return 0; -} - static int parse_name(void *opaque, QemuOpts *opts, Error **errp) { const char *proc_name; @@ -3079,7 +2964,6 @@ int main(int argc, char **argv, char **envp) qemu_add_opts(&qemu_mem_opts); qemu_add_opts(&qemu_smp_opts); qemu_add_opts(&qemu_boot_opts); - qemu_add_opts(&qemu_sandbox_opts); qemu_add_opts(&qemu_add_fd_opts); qemu_add_opts(&qemu_object_opts); qemu_add_opts(&qemu_tpmdev_opts); @@ -3980,11 +3864,17 @@ int main(int argc, char **argv, char **envp) qtest_log = optarg; break; case QEMU_OPTION_sandbox: +#ifdef CONFIG_SECCOMP opts = qemu_opts_parse_noisily(qemu_find_opts("sandbox"), optarg, true); if (!opts) { exit(1); } +#else + error_report("-sandbox support is not enabled " + "in this QEMU binary"); + exit(1); +#endif break; case QEMU_OPTION_add_fd: #ifndef _WIN32 @@ -4077,10 +3967,12 @@ int main(int argc, char **argv, char **envp) exit(1); } +#ifdef CONFIG_SECCOMP if (qemu_opts_foreach(qemu_find_opts("sandbox"), parse_sandbox, NULL, NULL)) { exit(1); } +#endif if (qemu_opts_foreach(qemu_find_opts("name"), parse_name, NULL, NULL)) { -- 2.11.0