This patch adds [,resourcecontrol=deny] to `-sandbox on' option. It blacklists all process affinity and scheduler priority system calls to avoid any bigger of the process.
Signed-off-by: Eduardo Otubo <[email protected]> --- include/sysemu/seccomp.h | 1 + qemu-options.hx | 5 ++++- qemu-seccomp.c | 27 +++++++++++++++++++++++++++ vl.c | 11 +++++++++++ 4 files changed, 43 insertions(+), 1 deletion(-) diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h index f1614d6514..c7003dd197 100644 --- a/include/sysemu/seccomp.h +++ b/include/sysemu/seccomp.h @@ -18,6 +18,7 @@ #define OBSOLETE 0x0001 #define PRIVILEGED 0x0010 #define SPAWN 0x0100 +#define RESOURCECTL 0x1000 #include <seccomp.h> diff --git a/qemu-options.hx b/qemu-options.hx index 611a501684..77b437a052 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4004,11 +4004,12 @@ Old param mode (ARM only). ETEXI DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ - "-sandbox on[,obsolete=allow][,elevateprivileges=allow|deny|children][,spawn=deny]\n" \ + "-sandbox on[,obsolete=allow][,elevateprivileges=allow|deny|children][,spawn=deny][,resourcecontrol=deny]\n" \ " Enable seccomp mode 2 system call filter (default 'off').\n" \ " obsolete: Allow obsolete system calls\n" \ " elevateprivileges: allows or denies Qemu process to elevate its privileges by blacklisting all set*uid|gid system calls. 'children' will deny set*uid|gid system calls for main Qemu process but will allow forks and execves to run unprivileged", " spawn: avoids Qemu to spawn new threads or processes by blacklisting *fork and execve\n" + " resourcecontrol: disable process affinity and schedular priority\n", QEMU_ARCH_ALL) STEXI @item -sandbox @var{arg}[,obsolete=@var{string}] @@ -4022,6 +4023,8 @@ Enable Obsolete system calls Disable set*uid|gid systema calls @item spawn=@var{string} Disable *fork and execve +@item resourcecontrol=@var{string} +Disable process affinity and schedular priority @end table ETEXI diff --git a/qemu-seccomp.c b/qemu-seccomp.c index 075d87e27f..a9a35456e9 100644 --- a/qemu-seccomp.c +++ b/qemu-seccomp.c @@ -31,6 +31,19 @@ struct QemuSeccompSyscall { uint8_t priority; }; +static const struct QemuSeccompSyscall resourcecontrol_syscalls[] = { + { SCMP_SYS(getpriority), 255 }, + { SCMP_SYS(setpriority), 255 }, + { SCMP_SYS(sched_setparam), 255 }, + { SCMP_SYS(sched_getparam), 255 }, + { SCMP_SYS(sched_setscheduler), 255 }, + { SCMP_SYS(sched_getscheduler), 255 }, + { SCMP_SYS(sched_setaffinity), 255 }, + { SCMP_SYS(sched_getaffinity), 255 }, + { SCMP_SYS(sched_get_priority_max), 255 }, + { SCMP_SYS(sched_get_priority_min), 255 }, +}; + static const struct QemuSeccompSyscall spawn_syscalls[] = { { SCMP_SYS(fork), 255 }, { SCMP_SYS(vfork), 255 }, @@ -158,6 +171,20 @@ int seccomp_start(uint8_t seccomp_opts) } } + if (seccomp_opts & RESOURCECTL) { + for (i = 0; i < ARRAY_SIZE(resourcecontrol_syscalls); i++) { + rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, resourcecontrol_syscalls[i].num, 0); + if (rc < 0) { + goto seccomp_return; + } + rc = seccomp_syscall_priority(ctx, resourcecontrol_syscalls[i].num, + resourcecontrol_syscalls[i].priority); + if (rc < 0) { + goto seccomp_return; + } + } + } + rc = seccomp_load(ctx); seccomp_return: diff --git a/vl.c b/vl.c index 456a518431..8e92052603 100644 --- a/vl.c +++ b/vl.c @@ -283,6 +283,10 @@ static QemuOptsList qemu_sandbox_opts = { .name = "spawn", .type = QEMU_OPT_STRING, }, + { + .name = "resourcecontrol", + .type = QEMU_OPT_STRING, + }, { /* end of list */ } }, }; @@ -1075,6 +1079,13 @@ static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp) } } + value = qemu_opt_get(opts,"resourcecontrol"); + if (value) { + if (strcmp(value, "deny") == 0) { + seccomp_opts |= RESOURCECTL; + } + } + if (seccomp_start(seccomp_opts) < 0) { error_report("failed to install seccomp syscall filter " "in the kernel"); -- 2.13.0
