[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 1/5] seccomp: allow action to be customized per syscall
|
From: |
Daniel P . Berrangé |
|
Subject: |
[PATCH 1/5] seccomp: allow action to be customized per syscall |
|
Date: |
Mon, 2 Aug 2021 14:02:59 +0100 |
We're currently tailoring whether to use kill process or return EPERM
based on the syscall set. This is not flexible enough for future
requirements where we also need to be able to return a variety of
actions on a per-syscall granularity.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
softmmu/qemu-seccomp.c | 172 +++++++++++++++++++++++++----------------
1 file changed, 106 insertions(+), 66 deletions(-)
diff --git a/softmmu/qemu-seccomp.c b/softmmu/qemu-seccomp.c
index f50026778c..9f6df8d033 100644
--- a/softmmu/qemu-seccomp.c
+++ b/softmmu/qemu-seccomp.c
@@ -38,6 +38,7 @@ struct QemuSeccompSyscall {
uint8_t set;
uint8_t narg;
const struct scmp_arg_cmp *arg_cmp;
+ uint32_t action;
};
const struct scmp_arg_cmp sched_setscheduler_arg[] = {
@@ -47,61 +48,111 @@ const struct scmp_arg_cmp sched_setscheduler_arg[] = {
static const struct QemuSeccompSyscall denylist[] = {
/* default set of syscalls that should get blocked */
- { SCMP_SYS(reboot), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(swapon), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(swapoff), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(syslog), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(mount), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(umount), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(kexec_load), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(afs_syscall), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(break), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(ftime), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(getpmsg), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(gtty), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(lock), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(mpx), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(prof), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(profil), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(putpmsg), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(security), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(stty), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(tuxcall), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(ulimit), QEMU_SECCOMP_SET_DEFAULT },
- { SCMP_SYS(vserver), QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(reboot), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(swapon), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(swapoff), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(syslog), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(mount), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(umount), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(kexec_load), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(afs_syscall), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(break), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(ftime), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(getpmsg), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(gtty), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(lock), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(mpx), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(prof), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(profil), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(putpmsg), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(security), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(stty), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(tuxcall), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(ulimit), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(vserver), QEMU_SECCOMP_SET_DEFAULT,
+ 0, NULL, SCMP_ACT_TRAP },
/* 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 },
+ { SCMP_SYS(readdir), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(_sysctl), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(bdflush), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(create_module), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(get_kernel_syms), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(query_module), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(sgetmask), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(ssetmask), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(sysfs), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(uselib), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(ustat), QEMU_SECCOMP_SET_OBSOLETE,
+ 0, NULL, SCMP_ACT_TRAP },
/* privileged */
- { SCMP_SYS(setuid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setgid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setpgid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setsid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setreuid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setregid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setresuid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setresgid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setfsuid), QEMU_SECCOMP_SET_PRIVILEGED },
- { SCMP_SYS(setfsgid), QEMU_SECCOMP_SET_PRIVILEGED },
+ { SCMP_SYS(setuid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setgid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setpgid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setsid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setreuid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setregid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setresuid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setresgid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setfsuid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(setfsgid), QEMU_SECCOMP_SET_PRIVILEGED,
+ 0, NULL, SCMP_ACT_TRAP },
/* spawn */
- { SCMP_SYS(fork), QEMU_SECCOMP_SET_SPAWN },
- { SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN },
- { SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN },
+ { SCMP_SYS(fork), QEMU_SECCOMP_SET_SPAWN,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN,
+ 0, NULL, SCMP_ACT_TRAP },
+ { SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN,
+ 0, NULL, SCMP_ACT_TRAP },
/* resource control */
- { SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
+ { SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL,
+ 0, NULL, SCMP_ACT_ERRNO(EPERM) },
+ { SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL,
+ 0, NULL, SCMP_ACT_ERRNO(EPERM) },
{ SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
- ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
- { SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
+ ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg,
+ SCMP_ACT_ERRNO(EPERM) },
+ { SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL,
+ 0, NULL, SCMP_ACT_ERRNO(EPERM) },
};
static inline __attribute__((unused)) int
@@ -115,15 +166,11 @@ qemu_seccomp(unsigned int operation, unsigned int flags,
void *args)
#endif
}
-static uint32_t qemu_seccomp_get_action(int set)
+static uint32_t qemu_seccomp_update_action(uint32_t action)
{
- switch (set) {
- case QEMU_SECCOMP_SET_DEFAULT:
- case QEMU_SECCOMP_SET_OBSOLETE:
- case QEMU_SECCOMP_SET_PRIVILEGED:
- case QEMU_SECCOMP_SET_SPAWN: {
#if defined(SECCOMP_GET_ACTION_AVAIL) && defined(SCMP_ACT_KILL_PROCESS) && \
defined(SECCOMP_RET_KILL_PROCESS)
+ if (action == SCMP_ACT_TRAP) {
static int kill_process = -1;
if (kill_process == -1) {
uint32_t action = SECCOMP_RET_KILL_PROCESS;
@@ -137,16 +184,9 @@ static uint32_t qemu_seccomp_get_action(int set)
if (kill_process == 1) {
return SCMP_ACT_KILL_PROCESS;
}
-#endif
- return SCMP_ACT_TRAP;
- }
-
- case QEMU_SECCOMP_SET_RESOURCECTL:
- return SCMP_ACT_ERRNO(EPERM);
-
- default:
- g_assert_not_reached();
}
+#endif
+ return action;
}
@@ -175,7 +215,7 @@ static int seccomp_start(uint32_t seccomp_opts, Error
**errp)
continue;
}
- action = qemu_seccomp_get_action(denylist[i].set);
+ action = qemu_seccomp_update_action(denylist[i].action);
rc = seccomp_rule_add_array(ctx, action, denylist[i].num,
denylist[i].narg, denylist[i].arg_cmp);
if (rc < 0) {
--
2.31.1
- [PATCH 0/5] seccomp: fix hole in blocking forks, Daniel P . Berrangé, 2021/08/02
- [PATCH 1/5] seccomp: allow action to be customized per syscall,
Daniel P . Berrangé <=
- [PATCH 4/5] seccomp: block use of clone3 syscall, Daniel P . Berrangé, 2021/08/02
- [PATCH 5/5] seccomp: block setns, unshare and execveat syscalls, Daniel P . Berrangé, 2021/08/02
- [PATCH 2/5] seccomp: add unit test for seccomp filtering, Daniel P . Berrangé, 2021/08/02
- [PATCH 3/5] seccomp: fix blocking of process spawning, Daniel P . Berrangé, 2021/08/02
- Re: [PATCH 0/5] seccomp: fix hole in blocking forks, Eduardo Terrell Ferrari Otubo, 2021/08/04