Merge tag 'seccomp-v4.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp updates from Kees Cook:
"Major additions:
- sysctl and seccomp operation to discover available actions
(tyhicks)
- new per-filter configurable logging infrastructure and sysctl
(tyhicks)
- SECCOMP_RET_LOG to log allowed syscalls (tyhicks)
- SECCOMP_RET_KILL_PROCESS as the new strictest possible action
- self-tests for new behaviors"
[ This is the seccomp part of the security pull request during the merge
window that was nixed due to unrelated problems - Linus ]
* tag 'seccomp-v4.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
samples: Unrename SECCOMP_RET_KILL
selftests/seccomp: Test thread vs process killing
seccomp: Implement SECCOMP_RET_KILL_PROCESS action
seccomp: Introduce SECCOMP_RET_KILL_PROCESS
seccomp: Rename SECCOMP_RET_KILL to SECCOMP_RET_KILL_THREAD
seccomp: Action to log before allowing
seccomp: Filter flag to log all actions except SECCOMP_RET_ALLOW
seccomp: Selftest for detection of filter flag support
seccomp: Sysctl to configure actions that are allowed to be logged
seccomp: Operation for checking if an action is available
seccomp: Sysctl to display available actions
seccomp: Provide matching filter for introspection
selftests/seccomp: Refactor RET_ERRNO tests
selftests/seccomp: Add simple seccomp overhead benchmark
selftests/seccomp: Add tests for basic ptrace actions
diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt
index 789b74d..8781485 100644
--- a/Documentation/networking/filter.txt
+++ b/Documentation/networking/filter.txt
@@ -337,7 +337,7 @@
jeq #14, good /* __NR_rt_sigprocmask */
jeq #13, good /* __NR_rt_sigaction */
jeq #35, good /* __NR_nanosleep */
- bad: ret #0 /* SECCOMP_RET_KILL */
+ bad: ret #0 /* SECCOMP_RET_KILL_THREAD */
good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */
The above example code can be placed into a file (here called "foo"), and
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index ce61d1f..694968c 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -75,6 +75,7 @@
- reboot-cmd [ SPARC only ]
- rtsig-max
- rtsig-nr
+- seccomp/ ==> Documentation/userspace-api/seccomp_filter.rst
- sem
- sem_next_id [ sysv ipc ]
- sg-big-buff [ generic SCSI device (sg) ]
diff --git a/Documentation/userspace-api/seccomp_filter.rst b/Documentation/userspace-api/seccomp_filter.rst
index f71eb5e..099c412 100644
--- a/Documentation/userspace-api/seccomp_filter.rst
+++ b/Documentation/userspace-api/seccomp_filter.rst
@@ -87,11 +87,16 @@
A seccomp filter may return any of the following values. If multiple
filters exist, the return value for the evaluation of a given system
call will always use the highest precedent value. (For example,
-``SECCOMP_RET_KILL`` will always take precedence.)
+``SECCOMP_RET_KILL_PROCESS`` will always take precedence.)
In precedence order, they are:
-``SECCOMP_RET_KILL``:
+``SECCOMP_RET_KILL_PROCESS``:
+ Results in the entire process exiting immediately without executing
+ the system call. The exit status of the task (``status & 0x7f``)
+ will be ``SIGSYS``, not ``SIGKILL``.
+
+``SECCOMP_RET_KILL_THREAD``:
Results in the task exiting immediately without executing the
system call. The exit status of the task (``status & 0x7f``) will
be ``SIGSYS``, not ``SIGKILL``.
@@ -141,6 +146,15 @@
allow use of ptrace, even of other sandboxed processes, without
extreme care; ptracers can use this mechanism to escape.)
+``SECCOMP_RET_LOG``:
+ Results in the system call being executed after it is logged. This
+ should be used by application developers to learn which syscalls their
+ application needs without having to iterate through multiple test and
+ development cycles to build the list.
+
+ This action will only be logged if "log" is present in the
+ actions_logged sysctl string.
+
``SECCOMP_RET_ALLOW``:
Results in the system call being executed.
@@ -169,7 +183,41 @@
and a more generic example of a higher level macro interface for BPF
program generation.
+Sysctls
+=======
+Seccomp's sysctl files can be found in the ``/proc/sys/kernel/seccomp/``
+directory. Here's a description of each file in that directory:
+
+``actions_avail``:
+ A read-only ordered list of seccomp return values (refer to the
+ ``SECCOMP_RET_*`` macros above) in string form. The ordering, from
+ left-to-right, is the least permissive return value to the most
+ permissive return value.
+
+ The list represents the set of seccomp return values supported
+ by the kernel. A userspace program may use this list to
+ determine if the actions found in the ``seccomp.h``, when the
+ program was built, differs from the set of actions actually
+ supported in the current running kernel.
+
+``actions_logged``:
+ A read-write ordered list of seccomp return values (refer to the
+ ``SECCOMP_RET_*`` macros above) that are allowed to be logged. Writes
+ to the file do not need to be in ordered form but reads from the file
+ will be ordered in the same way as the actions_avail sysctl.
+
+ It is important to note that the value of ``actions_logged`` does not
+ prevent certain actions from being logged when the audit subsystem is
+ configured to audit a task. If the action is not found in
+ ``actions_logged`` list, the final decision on whether to audit the
+ action for that task is ultimately left up to the audit subsystem to
+ decide for all seccomp return values other than ``SECCOMP_RET_ALLOW``.
+
+ The ``allow`` string is not accepted in the ``actions_logged`` sysctl
+ as it is not possible to log ``SECCOMP_RET_ALLOW`` actions. Attempting
+ to write ``allow`` to the sysctl will result in an EINVAL being
+ returned.
Adding architecture support
===========================
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 74d4d4e..cb708eb 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -314,11 +314,7 @@
static inline void audit_seccomp(unsigned long syscall, long signr, int code)
{
- if (!audit_enabled)
- return;
-
- /* Force a record to be reported if a signal was delivered. */
- if (signr || unlikely(!audit_dummy_context()))
+ if (audit_enabled && unlikely(!audit_dummy_context()))
__audit_seccomp(syscall, signr, code);
}
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index ecc296c..c8bef43 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -3,7 +3,8 @@
#include <uapi/linux/seccomp.h>
-#define SECCOMP_FILTER_FLAG_MASK (SECCOMP_FILTER_FLAG_TSYNC)
+#define SECCOMP_FILTER_FLAG_MASK (SECCOMP_FILTER_FLAG_TSYNC | \
+ SECCOMP_FILTER_FLAG_LOG)
#ifdef CONFIG_SECCOMP
diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
index 0f238a4..f6bc1de 100644
--- a/include/uapi/linux/seccomp.h
+++ b/include/uapi/linux/seccomp.h
@@ -11,27 +11,34 @@
#define SECCOMP_MODE_FILTER 2 /* uses user-supplied filter. */
/* Valid operations for seccomp syscall. */
-#define SECCOMP_SET_MODE_STRICT 0
-#define SECCOMP_SET_MODE_FILTER 1
+#define SECCOMP_SET_MODE_STRICT 0
+#define SECCOMP_SET_MODE_FILTER 1
+#define SECCOMP_GET_ACTION_AVAIL 2
/* Valid flags for SECCOMP_SET_MODE_FILTER */
#define SECCOMP_FILTER_FLAG_TSYNC 1
+#define SECCOMP_FILTER_FLAG_LOG 2
/*
* All BPF programs must return a 32-bit value.
* The bottom 16-bits are for optional return data.
- * The upper 16-bits are ordered from least permissive values to most.
+ * The upper 16-bits are ordered from least permissive values to most,
+ * as a signed value (so 0x8000000 is negative).
*
* The ordering ensures that a min_t() over composed return values always
* selects the least permissive choice.
*/
-#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
-#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
-#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
-#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
-#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
+#define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */
+#define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
+#define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
+#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
+#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
+#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
+#define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
+#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
/* Masks for the return value sections. */
+#define SECCOMP_RET_ACTION_FULL 0xffff0000U
#define SECCOMP_RET_ACTION 0x7fff0000U
#define SECCOMP_RET_DATA 0x0000ffffU
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 98b59b5..c24579d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -17,11 +17,13 @@
#include <linux/audit.h>
#include <linux/compat.h>
#include <linux/coredump.h>
+#include <linux/kmemleak.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/seccomp.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
+#include <linux/sysctl.h>
#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
#include <asm/syscall.h>
@@ -42,6 +44,7 @@
* get/put helpers should be used when accessing an instance
* outside of a lifetime-guarded section. In general, this
* is only needed for handling filters shared across tasks.
+ * @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
* @prev: points to a previously installed, or inherited, filter
* @prog: the BPF program to evaluate
*
@@ -57,6 +60,7 @@
*/
struct seccomp_filter {
refcount_t usage;
+ bool log;
struct seccomp_filter *prev;
struct bpf_prog *prog;
};
@@ -171,10 +175,15 @@
/**
* seccomp_run_filters - evaluates all seccomp filters against @sd
* @sd: optional seccomp data to be passed to filters
+ * @match: stores struct seccomp_filter that resulted in the return value,
+ * unless filter returned SECCOMP_RET_ALLOW, in which case it will
+ * be unchanged.
*
* Returns valid seccomp BPF response codes.
*/
-static u32 seccomp_run_filters(const struct seccomp_data *sd)
+#define ACTION_ONLY(ret) ((s32)((ret) & (SECCOMP_RET_ACTION_FULL)))
+static u32 seccomp_run_filters(const struct seccomp_data *sd,
+ struct seccomp_filter **match)
{
struct seccomp_data sd_local;
u32 ret = SECCOMP_RET_ALLOW;
@@ -184,7 +193,7 @@
/* Ensure unexpected behavior doesn't result in failing open. */
if (unlikely(WARN_ON(f == NULL)))
- return SECCOMP_RET_KILL;
+ return SECCOMP_RET_KILL_PROCESS;
if (!sd) {
populate_seccomp_data(&sd_local);
@@ -198,8 +207,10 @@
for (; f; f = f->prev) {
u32 cur_ret = BPF_PROG_RUN(f->prog, sd);
- if ((cur_ret & SECCOMP_RET_ACTION) < (ret & SECCOMP_RET_ACTION))
+ if (ACTION_ONLY(cur_ret) < ACTION_ONLY(ret)) {
ret = cur_ret;
+ *match = f;
+ }
}
return ret;
}
@@ -444,6 +455,10 @@
return ret;
}
+ /* Set log flag, if present. */
+ if (flags & SECCOMP_FILTER_FLAG_LOG)
+ filter->log = true;
+
/*
* If there is an existing filter, make it the prev and don't drop its
* task reference.
@@ -514,6 +529,65 @@
}
#endif /* CONFIG_SECCOMP_FILTER */
+/* For use with seccomp_actions_logged */
+#define SECCOMP_LOG_KILL_PROCESS (1 << 0)
+#define SECCOMP_LOG_KILL_THREAD (1 << 1)
+#define SECCOMP_LOG_TRAP (1 << 2)
+#define SECCOMP_LOG_ERRNO (1 << 3)
+#define SECCOMP_LOG_TRACE (1 << 4)
+#define SECCOMP_LOG_LOG (1 << 5)
+#define SECCOMP_LOG_ALLOW (1 << 6)
+
+static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS |
+ SECCOMP_LOG_KILL_THREAD |
+ SECCOMP_LOG_TRAP |
+ SECCOMP_LOG_ERRNO |
+ SECCOMP_LOG_TRACE |
+ SECCOMP_LOG_LOG;
+
+static inline void seccomp_log(unsigned long syscall, long signr, u32 action,
+ bool requested)
+{
+ bool log = false;
+
+ switch (action) {
+ case SECCOMP_RET_ALLOW:
+ break;
+ case SECCOMP_RET_TRAP:
+ log = requested && seccomp_actions_logged & SECCOMP_LOG_TRAP;
+ break;
+ case SECCOMP_RET_ERRNO:
+ log = requested && seccomp_actions_logged & SECCOMP_LOG_ERRNO;
+ break;
+ case SECCOMP_RET_TRACE:
+ log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE;
+ break;
+ case SECCOMP_RET_LOG:
+ log = seccomp_actions_logged & SECCOMP_LOG_LOG;
+ break;
+ case SECCOMP_RET_KILL_THREAD:
+ log = seccomp_actions_logged & SECCOMP_LOG_KILL_THREAD;
+ break;
+ case SECCOMP_RET_KILL_PROCESS:
+ default:
+ log = seccomp_actions_logged & SECCOMP_LOG_KILL_PROCESS;
+ }
+
+ /*
+ * Force an audit message to be emitted when the action is RET_KILL_*,
+ * RET_LOG, or the FILTER_FLAG_LOG bit was set and the action is
+ * allowed to be logged by the admin.
+ */
+ if (log)
+ return __audit_seccomp(syscall, signr, action);
+
+ /*
+ * Let the audit subsystem decide if the action should be audited based
+ * on whether the current task itself is being audited.
+ */
+ return audit_seccomp(syscall, signr, action);
+}
+
/*
* Secure computing mode 1 allows only read/write/exit/sigreturn.
* To be fully secure this must be combined with rlimit
@@ -539,7 +613,7 @@
#ifdef SECCOMP_DEBUG
dump_stack();
#endif
- audit_seccomp(this_syscall, SIGKILL, SECCOMP_RET_KILL);
+ seccomp_log(this_syscall, SIGKILL, SECCOMP_RET_KILL_THREAD, true);
do_exit(SIGKILL);
}
@@ -566,6 +640,7 @@
const bool recheck_after_trace)
{
u32 filter_ret, action;
+ struct seccomp_filter *match = NULL;
int data;
/*
@@ -574,9 +649,9 @@
*/
rmb();
- filter_ret = seccomp_run_filters(sd);
+ filter_ret = seccomp_run_filters(sd, &match);
data = filter_ret & SECCOMP_RET_DATA;
- action = filter_ret & SECCOMP_RET_ACTION;
+ action = filter_ret & SECCOMP_RET_ACTION_FULL;
switch (action) {
case SECCOMP_RET_ERRNO:
@@ -637,14 +712,25 @@
return 0;
- case SECCOMP_RET_ALLOW:
+ case SECCOMP_RET_LOG:
+ seccomp_log(this_syscall, 0, action, true);
return 0;
- case SECCOMP_RET_KILL:
+ case SECCOMP_RET_ALLOW:
+ /*
+ * Note that the "match" filter will always be NULL for
+ * this action since SECCOMP_RET_ALLOW is the starting
+ * state in seccomp_run_filters().
+ */
+ return 0;
+
+ case SECCOMP_RET_KILL_THREAD:
+ case SECCOMP_RET_KILL_PROCESS:
default:
- audit_seccomp(this_syscall, SIGSYS, action);
+ seccomp_log(this_syscall, SIGSYS, action, true);
/* Dump core only if this is the last remaining thread. */
- if (get_nr_threads(current) == 1) {
+ if (action == SECCOMP_RET_KILL_PROCESS ||
+ get_nr_threads(current) == 1) {
siginfo_t info;
/* Show the original registers in the dump. */
@@ -653,13 +739,16 @@
seccomp_init_siginfo(&info, this_syscall, data);
do_coredump(&info);
}
- do_exit(SIGSYS);
+ if (action == SECCOMP_RET_KILL_PROCESS)
+ do_group_exit(SIGSYS);
+ else
+ do_exit(SIGSYS);
}
unreachable();
skip:
- audit_seccomp(this_syscall, 0, action);
+ seccomp_log(this_syscall, 0, action, match ? match->log : false);
return -1;
}
#else
@@ -794,6 +883,29 @@
}
#endif
+static long seccomp_get_action_avail(const char __user *uaction)
+{
+ u32 action;
+
+ if (copy_from_user(&action, uaction, sizeof(action)))
+ return -EFAULT;
+
+ switch (action) {
+ case SECCOMP_RET_KILL_PROCESS:
+ case SECCOMP_RET_KILL_THREAD:
+ case SECCOMP_RET_TRAP:
+ case SECCOMP_RET_ERRNO:
+ case SECCOMP_RET_TRACE:
+ case SECCOMP_RET_LOG:
+ case SECCOMP_RET_ALLOW:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
/* Common entry point for both prctl and syscall. */
static long do_seccomp(unsigned int op, unsigned int flags,
const char __user *uargs)
@@ -805,6 +917,11 @@
return seccomp_set_mode_strict();
case SECCOMP_SET_MODE_FILTER:
return seccomp_set_mode_filter(flags, uargs);
+ case SECCOMP_GET_ACTION_AVAIL:
+ if (flags != 0)
+ return -EINVAL;
+
+ return seccomp_get_action_avail(uargs);
default:
return -EINVAL;
}
@@ -922,3 +1039,185 @@
return ret;
}
#endif
+
+#ifdef CONFIG_SYSCTL
+
+/* Human readable action names for friendly sysctl interaction */
+#define SECCOMP_RET_KILL_PROCESS_NAME "kill_process"
+#define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
+#define SECCOMP_RET_TRAP_NAME "trap"
+#define SECCOMP_RET_ERRNO_NAME "errno"
+#define SECCOMP_RET_TRACE_NAME "trace"
+#define SECCOMP_RET_LOG_NAME "log"
+#define SECCOMP_RET_ALLOW_NAME "allow"
+
+static const char seccomp_actions_avail[] =
+ SECCOMP_RET_KILL_PROCESS_NAME " "
+ SECCOMP_RET_KILL_THREAD_NAME " "
+ SECCOMP_RET_TRAP_NAME " "
+ SECCOMP_RET_ERRNO_NAME " "
+ SECCOMP_RET_TRACE_NAME " "
+ SECCOMP_RET_LOG_NAME " "
+ SECCOMP_RET_ALLOW_NAME;
+
+struct seccomp_log_name {
+ u32 log;
+ const char *name;
+};
+
+static const struct seccomp_log_name seccomp_log_names[] = {
+ { SECCOMP_LOG_KILL_PROCESS, SECCOMP_RET_KILL_PROCESS_NAME },
+ { SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
+ { SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
+ { SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
+ { SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },
+ { SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME },
+ { SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME },
+ { }
+};
+
+static bool seccomp_names_from_actions_logged(char *names, size_t size,
+ u32 actions_logged)
+{
+ const struct seccomp_log_name *cur;
+ bool append_space = false;
+
+ for (cur = seccomp_log_names; cur->name && size; cur++) {
+ ssize_t ret;
+
+ if (!(actions_logged & cur->log))
+ continue;
+
+ if (append_space) {
+ ret = strscpy(names, " ", size);
+ if (ret < 0)
+ return false;
+
+ names += ret;
+ size -= ret;
+ } else
+ append_space = true;
+
+ ret = strscpy(names, cur->name, size);
+ if (ret < 0)
+ return false;
+
+ names += ret;
+ size -= ret;
+ }
+
+ return true;
+}
+
+static bool seccomp_action_logged_from_name(u32 *action_logged,
+ const char *name)
+{
+ const struct seccomp_log_name *cur;
+
+ for (cur = seccomp_log_names; cur->name; cur++) {
+ if (!strcmp(cur->name, name)) {
+ *action_logged = cur->log;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names)
+{
+ char *name;
+
+ *actions_logged = 0;
+ while ((name = strsep(&names, " ")) && *name) {
+ u32 action_logged = 0;
+
+ if (!seccomp_action_logged_from_name(&action_logged, name))
+ return false;
+
+ *actions_logged |= action_logged;
+ }
+
+ return true;
+}
+
+static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ char names[sizeof(seccomp_actions_avail)];
+ struct ctl_table table;
+ int ret;
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ memset(names, 0, sizeof(names));
+
+ if (!write) {
+ if (!seccomp_names_from_actions_logged(names, sizeof(names),
+ seccomp_actions_logged))
+ return -EINVAL;
+ }
+
+ table = *ro_table;
+ table.data = names;
+ table.maxlen = sizeof(names);
+ ret = proc_dostring(&table, write, buffer, lenp, ppos);
+ if (ret)
+ return ret;
+
+ if (write) {
+ u32 actions_logged;
+
+ if (!seccomp_actions_logged_from_names(&actions_logged,
+ table.data))
+ return -EINVAL;
+
+ if (actions_logged & SECCOMP_LOG_ALLOW)
+ return -EINVAL;
+
+ seccomp_actions_logged = actions_logged;
+ }
+
+ return 0;
+}
+
+static struct ctl_path seccomp_sysctl_path[] = {
+ { .procname = "kernel", },
+ { .procname = "seccomp", },
+ { }
+};
+
+static struct ctl_table seccomp_sysctl_table[] = {
+ {
+ .procname = "actions_avail",
+ .data = (void *) &seccomp_actions_avail,
+ .maxlen = sizeof(seccomp_actions_avail),
+ .mode = 0444,
+ .proc_handler = proc_dostring,
+ },
+ {
+ .procname = "actions_logged",
+ .mode = 0644,
+ .proc_handler = seccomp_actions_logged_handler,
+ },
+ { }
+};
+
+static int __init seccomp_sysctl_init(void)
+{
+ struct ctl_table_header *hdr;
+
+ hdr = register_sysctl_paths(seccomp_sysctl_path, seccomp_sysctl_table);
+ if (!hdr)
+ pr_warn("seccomp: sysctl registration failed\n");
+ else
+ kmemleak_not_leak(hdr);
+
+ return 0;
+}
+
+device_initcall(seccomp_sysctl_init)
+
+#endif /* CONFIG_SYSCTL */
diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index aeb0c80..553d870 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -1,8 +1,16 @@
-TEST_GEN_PROGS := seccomp_bpf
-CFLAGS += -Wl,-no-as-needed -Wall
-LDFLAGS += -lpthread
+all:
include ../lib.mk
-$(TEST_GEN_PROGS): seccomp_bpf.c ../kselftest_harness.h
- $(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+.PHONY: all clean
+
+BINARIES := seccomp_bpf seccomp_benchmark
+CFLAGS += -Wl,-no-as-needed -Wall
+
+seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
+ $(CC) $(CFLAGS) $(LDFLAGS) -lpthread $< -o $@
+
+TEST_PROGS += $(BINARIES)
+EXTRA_CLEAN := $(BINARIES)
+
+all: $(BINARIES)
diff --git a/tools/testing/selftests/seccomp/seccomp_benchmark.c b/tools/testing/selftests/seccomp/seccomp_benchmark.c
new file mode 100644
index 0000000..5838c86
--- /dev/null
+++ b/tools/testing/selftests/seccomp/seccomp_benchmark.c
@@ -0,0 +1,99 @@
+/*
+ * Strictly speaking, this is not a test. But it can report during test
+ * runs so relative performace can be measured.
+ */
+#define _GNU_SOURCE
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+#include <linux/filter.h>
+#include <linux/seccomp.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+unsigned long long timing(clockid_t clk_id, unsigned long long samples)
+{
+ pid_t pid, ret;
+ unsigned long long i;
+ struct timespec start, finish;
+
+ pid = getpid();
+ assert(clock_gettime(clk_id, &start) == 0);
+ for (i = 0; i < samples; i++) {
+ ret = syscall(__NR_getpid);
+ assert(pid == ret);
+ }
+ assert(clock_gettime(clk_id, &finish) == 0);
+
+ i = finish.tv_sec - start.tv_sec;
+ i *= 1000000000;
+ i += finish.tv_nsec - start.tv_nsec;
+
+ printf("%lu.%09lu - %lu.%09lu = %llu\n",
+ finish.tv_sec, finish.tv_nsec,
+ start.tv_sec, start.tv_nsec,
+ i);
+
+ return i;
+}
+
+unsigned long long calibrate(void)
+{
+ unsigned long long i;
+
+ printf("Calibrating reasonable sample size...\n");
+
+ for (i = 5; ; i++) {
+ unsigned long long samples = 1 << i;
+
+ /* Find something that takes more than 5 seconds to run. */
+ if (timing(CLOCK_REALTIME, samples) / 1000000000ULL > 5)
+ return samples;
+ }
+}
+
+int main(int argc, char *argv[])
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+ long ret;
+ unsigned long long samples;
+ unsigned long long native, filtered;
+
+ if (argc > 1)
+ samples = strtoull(argv[1], NULL, 0);
+ else
+ samples = calibrate();
+
+ printf("Benchmarking %llu samples...\n", samples);
+
+ native = timing(CLOCK_PROCESS_CPUTIME_ID, samples) / samples;
+ printf("getpid native: %llu ns\n", native);
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ assert(ret == 0);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
+ assert(ret == 0);
+
+ filtered = timing(CLOCK_PROCESS_CPUTIME_ID, samples) / samples;
+ printf("getpid RET_ALLOW: %llu ns\n", filtered);
+
+ printf("Estimated seccomp overhead per syscall: %llu ns\n",
+ filtered - native);
+
+ if (filtered == native)
+ printf("Trying running again with more samples.\n");
+
+ return 0;
+}
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 4d6f92a..67c3e27 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -68,17 +68,7 @@
#define SECCOMP_MODE_FILTER 2
#endif
-#ifndef SECCOMP_RET_KILL
-#define SECCOMP_RET_KILL 0x00000000U /* kill the task immediately */
-#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
-#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
-#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
-#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
-
-/* Masks for the return value sections. */
-#define SECCOMP_RET_ACTION 0x7fff0000U
-#define SECCOMP_RET_DATA 0x0000ffffU
-
+#ifndef SECCOMP_RET_ALLOW
struct seccomp_data {
int nr;
__u32 arch;
@@ -87,6 +77,70 @@
};
#endif
+#ifndef SECCOMP_RET_KILL_PROCESS
+#define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the process */
+#define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
+#endif
+#ifndef SECCOMP_RET_KILL
+#define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
+#define SECCOMP_RET_TRAP 0x00030000U /* disallow and force a SIGSYS */
+#define SECCOMP_RET_ERRNO 0x00050000U /* returns an errno */
+#define SECCOMP_RET_TRACE 0x7ff00000U /* pass to a tracer or disallow */
+#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */
+#endif
+#ifndef SECCOMP_RET_LOG
+#define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
+#endif
+
+#ifndef __NR_seccomp
+# if defined(__i386__)
+# define __NR_seccomp 354
+# elif defined(__x86_64__)
+# define __NR_seccomp 317
+# elif defined(__arm__)
+# define __NR_seccomp 383
+# elif defined(__aarch64__)
+# define __NR_seccomp 277
+# elif defined(__hppa__)
+# define __NR_seccomp 338
+# elif defined(__powerpc__)
+# define __NR_seccomp 358
+# elif defined(__s390__)
+# define __NR_seccomp 348
+# else
+# warning "seccomp syscall number unknown for this architecture"
+# define __NR_seccomp 0xffff
+# endif
+#endif
+
+#ifndef SECCOMP_SET_MODE_STRICT
+#define SECCOMP_SET_MODE_STRICT 0
+#endif
+
+#ifndef SECCOMP_SET_MODE_FILTER
+#define SECCOMP_SET_MODE_FILTER 1
+#endif
+
+#ifndef SECCOMP_GET_ACTION_AVAIL
+#define SECCOMP_GET_ACTION_AVAIL 2
+#endif
+
+#ifndef SECCOMP_FILTER_FLAG_TSYNC
+#define SECCOMP_FILTER_FLAG_TSYNC 1
+#endif
+
+#ifndef SECCOMP_FILTER_FLAG_LOG
+#define SECCOMP_FILTER_FLAG_LOG 2
+#endif
+
+#ifndef seccomp
+int seccomp(unsigned int op, unsigned int flags, void *args)
+{
+ errno = 0;
+ return syscall(__NR_seccomp, op, flags, args);
+}
+#endif
+
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]))
#elif __BYTE_ORDER == __BIG_ENDIAN
@@ -136,7 +190,7 @@
}
}
-/* Tests kernel support by checking for a copy_from_user() fault on * NULL. */
+/* Tests kernel support by checking for a copy_from_user() fault on NULL. */
TEST(mode_filter_support)
{
long ret;
@@ -342,6 +396,28 @@
EXPECT_EQ(EINVAL, errno);
}
+TEST(log_all)
+{
+ struct sock_filter filter[] = {
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_LOG),
+ };
+ struct sock_fprog prog = {
+ .len = (unsigned short)ARRAY_SIZE(filter),
+ .filter = filter,
+ };
+ long ret;
+ pid_t parent = getppid();
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
+ ASSERT_EQ(0, ret);
+
+ /* getppid() should succeed and be logged (no check for logging) */
+ EXPECT_EQ(parent, syscall(__NR_getppid));
+}
+
TEST_SIGNAL(unknown_ret_is_kill_inside, SIGSYS)
{
struct sock_filter filter[] = {
@@ -520,6 +596,117 @@
close(fd);
}
+/* This is a thread task to die via seccomp filter violation. */
+void *kill_thread(void *data)
+{
+ bool die = (bool)data;
+
+ if (die) {
+ prctl(PR_GET_SECCOMP, 0, 0, 0, 0);
+ return (void *)SIBLING_EXIT_FAILURE;
+ }
+
+ return (void *)SIBLING_EXIT_UNKILLED;
+}
+
+/* Prepare a thread that will kill itself or both of us. */
+void kill_thread_or_group(struct __test_metadata *_metadata, bool kill_process)
+{
+ pthread_t thread;
+ void *status;
+ /* Kill only when calling __NR_prctl. */
+ struct sock_filter filter_thread[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_THREAD),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog_thread = {
+ .len = (unsigned short)ARRAY_SIZE(filter_thread),
+ .filter = filter_thread,
+ };
+ struct sock_filter filter_process[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_PROCESS),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog prog_process = {
+ .len = (unsigned short)ARRAY_SIZE(filter_process),
+ .filter = filter_process,
+ };
+
+ ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
+ TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
+ }
+
+ ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0,
+ kill_process ? &prog_process : &prog_thread));
+
+ /*
+ * Add the KILL_THREAD rule again to make sure that the KILL_PROCESS
+ * flag cannot be downgraded by a new filter.
+ */
+ ASSERT_EQ(0, seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog_thread));
+
+ /* Start a thread that will exit immediately. */
+ ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)false));
+ ASSERT_EQ(0, pthread_join(thread, &status));
+ ASSERT_EQ(SIBLING_EXIT_UNKILLED, (unsigned long)status);
+
+ /* Start a thread that will die immediately. */
+ ASSERT_EQ(0, pthread_create(&thread, NULL, kill_thread, (void *)true));
+ ASSERT_EQ(0, pthread_join(thread, &status));
+ ASSERT_NE(SIBLING_EXIT_FAILURE, (unsigned long)status);
+
+ /*
+ * If we get here, only the spawned thread died. Let the parent know
+ * the whole process didn't die (i.e. this thread, the spawner,
+ * stayed running).
+ */
+ exit(42);
+}
+
+TEST(KILL_thread)
+{
+ int status;
+ pid_t child_pid;
+
+ child_pid = fork();
+ ASSERT_LE(0, child_pid);
+ if (child_pid == 0) {
+ kill_thread_or_group(_metadata, false);
+ _exit(38);
+ }
+
+ ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
+
+ /* If only the thread was killed, we'll see exit 42. */
+ ASSERT_TRUE(WIFEXITED(status));
+ ASSERT_EQ(42, WEXITSTATUS(status));
+}
+
+TEST(KILL_process)
+{
+ int status;
+ pid_t child_pid;
+
+ child_pid = fork();
+ ASSERT_LE(0, child_pid);
+ if (child_pid == 0) {
+ kill_thread_or_group(_metadata, true);
+ _exit(38);
+ }
+
+ ASSERT_EQ(child_pid, waitpid(child_pid, &status, 0));
+
+ /* If the entire process was killed, we'll see SIGSYS. */
+ ASSERT_TRUE(WIFSIGNALED(status));
+ ASSERT_EQ(SIGSYS, WTERMSIG(status));
+}
+
/* TODO(wad) add 64-bit versus 32-bit arg tests. */
TEST(arg_out_of_range)
{
@@ -541,26 +728,30 @@
EXPECT_EQ(EINVAL, errno);
}
+#define ERRNO_FILTER(name, errno) \
+ struct sock_filter _read_filter_##name[] = { \
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS, \
+ offsetof(struct seccomp_data, nr)), \
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1), \
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | errno), \
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), \
+ }; \
+ struct sock_fprog prog_##name = { \
+ .len = (unsigned short)ARRAY_SIZE(_read_filter_##name), \
+ .filter = _read_filter_##name, \
+ }
+
+/* Make sure basic errno values are correctly passed through a filter. */
TEST(ERRNO_valid)
{
- struct sock_filter filter[] = {
- BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
- offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | E2BIG),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
- };
- struct sock_fprog prog = {
- .len = (unsigned short)ARRAY_SIZE(filter),
- .filter = filter,
- };
+ ERRNO_FILTER(valid, E2BIG);
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_valid);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
@@ -568,26 +759,17 @@
EXPECT_EQ(E2BIG, errno);
}
+/* Make sure an errno of zero is correctly handled by the arch code. */
TEST(ERRNO_zero)
{
- struct sock_filter filter[] = {
- BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
- offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 0),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
- };
- struct sock_fprog prog = {
- .len = (unsigned short)ARRAY_SIZE(filter),
- .filter = filter,
- };
+ ERRNO_FILTER(zero, 0);
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_zero);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
@@ -595,26 +777,21 @@
EXPECT_EQ(0, read(0, NULL, 0));
}
+/*
+ * The SECCOMP_RET_DATA mask is 16 bits wide, but errno is smaller.
+ * This tests that the errno value gets capped correctly, fixed by
+ * 580c57f10768 ("seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO").
+ */
TEST(ERRNO_capped)
{
- struct sock_filter filter[] = {
- BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
- offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_read, 0, 1),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO | 4096),
- BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
- };
- struct sock_fprog prog = {
- .len = (unsigned short)ARRAY_SIZE(filter),
- .filter = filter,
- };
+ ERRNO_FILTER(capped, 4096);
long ret;
pid_t parent = getppid();
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
- ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_capped);
ASSERT_EQ(0, ret);
EXPECT_EQ(parent, syscall(__NR_getppid));
@@ -622,6 +799,37 @@
EXPECT_EQ(4095, errno);
}
+/*
+ * Filters are processed in reverse order: last applied is executed first.
+ * Since only the SECCOMP_RET_ACTION mask is tested for return values, the
+ * SECCOMP_RET_DATA mask results will follow the most recently applied
+ * matching filter return (and not the lowest or highest value).
+ */
+TEST(ERRNO_order)
+{
+ ERRNO_FILTER(first, 11);
+ ERRNO_FILTER(second, 13);
+ ERRNO_FILTER(third, 12);
+ long ret;
+ pid_t parent = getppid();
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_first);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_second);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog_third);
+ ASSERT_EQ(0, ret);
+
+ EXPECT_EQ(parent, syscall(__NR_getppid));
+ EXPECT_EQ(-1, read(0, NULL, 0));
+ EXPECT_EQ(12, errno);
+}
+
FIXTURE_DATA(TRAP) {
struct sock_fprog prog;
};
@@ -735,6 +943,7 @@
FIXTURE_DATA(precedence) {
struct sock_fprog allow;
+ struct sock_fprog log;
struct sock_fprog trace;
struct sock_fprog error;
struct sock_fprog trap;
@@ -746,6 +955,13 @@
struct sock_filter allow_insns[] = {
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
+ struct sock_filter log_insns[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_LOG),
+ };
struct sock_filter trace_insns[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
@@ -782,6 +998,7 @@
memcpy(self->_x.filter, &_x##_insns, sizeof(_x##_insns)); \
self->_x.len = (unsigned short)ARRAY_SIZE(_x##_insns)
FILTER_ALLOC(allow);
+ FILTER_ALLOC(log);
FILTER_ALLOC(trace);
FILTER_ALLOC(error);
FILTER_ALLOC(trap);
@@ -792,6 +1009,7 @@
{
#define FILTER_FREE(_x) if (self->_x.filter) free(self->_x.filter)
FILTER_FREE(allow);
+ FILTER_FREE(log);
FILTER_FREE(trace);
FILTER_FREE(error);
FILTER_FREE(trap);
@@ -809,6 +1027,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
@@ -833,6 +1053,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
@@ -864,6 +1086,8 @@
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
@@ -885,6 +1109,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
@@ -910,6 +1136,8 @@
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trap);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
@@ -931,6 +1159,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
@@ -949,6 +1179,8 @@
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->error);
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
@@ -971,6 +1203,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->trace);
ASSERT_EQ(0, ret);
/* Should work just fine. */
@@ -992,12 +1226,54 @@
ASSERT_EQ(0, ret);
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
/* Should work just fine. */
EXPECT_EQ(parent, syscall(__NR_getppid));
/* No ptracer */
EXPECT_EQ(-1, syscall(__NR_getpid));
}
+TEST_F(precedence, log_is_fifth)
+{
+ pid_t mypid, parent;
+ long ret;
+
+ mypid = getpid();
+ parent = getppid();
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
+ ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
+ /* Should work just fine. */
+ EXPECT_EQ(parent, syscall(__NR_getppid));
+ /* Should also work just fine */
+ EXPECT_EQ(mypid, syscall(__NR_getpid));
+}
+
+TEST_F(precedence, log_is_fifth_in_any_order)
+{
+ pid_t mypid, parent;
+ long ret;
+
+ mypid = getpid();
+ parent = getppid();
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
+
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->log);
+ ASSERT_EQ(0, ret);
+ ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->allow);
+ ASSERT_EQ(0, ret);
+ /* Should work just fine. */
+ EXPECT_EQ(parent, syscall(__NR_getppid));
+ /* Should also work just fine */
+ EXPECT_EQ(mypid, syscall(__NR_getpid));
+}
+
#ifndef PTRACE_O_TRACESECCOMP
#define PTRACE_O_TRACESECCOMP 0x00000080
#endif
@@ -1262,6 +1538,13 @@
# error "Do not know how to find your architecture's registers and syscalls"
#endif
+/* When the syscall return can't be changed, stub out the tests for it. */
+#ifdef SYSCALL_NUM_RET_SHARE_REG
+# define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(-1, action)
+#else
+# define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(val, action)
+#endif
+
/* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for
* architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux).
*/
@@ -1357,7 +1640,7 @@
#ifdef SYSCALL_NUM_RET_SHARE_REG
TH_LOG("Can't modify syscall return on this architecture");
#else
- regs.SYSCALL_RET = 1;
+ regs.SYSCALL_RET = EPERM;
#endif
#ifdef HAVE_GETREGS
@@ -1426,6 +1709,8 @@
if (nr == __NR_getpid)
change_syscall(_metadata, tracee, __NR_getppid);
+ if (nr == __NR_open)
+ change_syscall(_metadata, tracee, -1);
}
FIXTURE_DATA(TRACE_syscall) {
@@ -1480,6 +1765,28 @@
free(self->prog.filter);
}
+TEST_F(TRACE_syscall, ptrace_syscall_redirected)
+{
+ /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
+ teardown_trace_fixture(_metadata, self->tracer);
+ self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
+ true);
+
+ /* Tracer will redirect getpid to getppid. */
+ EXPECT_NE(self->mypid, syscall(__NR_getpid));
+}
+
+TEST_F(TRACE_syscall, ptrace_syscall_dropped)
+{
+ /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */
+ teardown_trace_fixture(_metadata, self->tracer);
+ self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL,
+ true);
+
+ /* Tracer should skip the open syscall, resulting in EPERM. */
+ EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_open));
+}
+
TEST_F(TRACE_syscall, syscall_allowed)
{
long ret;
@@ -1520,13 +1827,8 @@
ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0);
ASSERT_EQ(0, ret);
-#ifdef SYSCALL_NUM_RET_SHARE_REG
- /* gettid has been skipped */
- EXPECT_EQ(-1, syscall(__NR_gettid));
-#else
/* gettid has been skipped and an altered return value stored. */
- EXPECT_EQ(1, syscall(__NR_gettid));
-#endif
+ EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_gettid));
EXPECT_NE(self->mytid, syscall(__NR_gettid));
}
@@ -1557,6 +1859,7 @@
ASSERT_EQ(0, ret);
/* Tracer will redirect getpid to getppid, and we should see EPERM. */
+ errno = 0;
EXPECT_EQ(-1, syscall(__NR_getpid));
EXPECT_EQ(EPERM, errno);
}
@@ -1654,47 +1957,6 @@
EXPECT_NE(self->mypid, syscall(__NR_getpid));
}
-#ifndef __NR_seccomp
-# if defined(__i386__)
-# define __NR_seccomp 354
-# elif defined(__x86_64__)
-# define __NR_seccomp 317
-# elif defined(__arm__)
-# define __NR_seccomp 383
-# elif defined(__aarch64__)
-# define __NR_seccomp 277
-# elif defined(__hppa__)
-# define __NR_seccomp 338
-# elif defined(__powerpc__)
-# define __NR_seccomp 358
-# elif defined(__s390__)
-# define __NR_seccomp 348
-# else
-# warning "seccomp syscall number unknown for this architecture"
-# define __NR_seccomp 0xffff
-# endif
-#endif
-
-#ifndef SECCOMP_SET_MODE_STRICT
-#define SECCOMP_SET_MODE_STRICT 0
-#endif
-
-#ifndef SECCOMP_SET_MODE_FILTER
-#define SECCOMP_SET_MODE_FILTER 1
-#endif
-
-#ifndef SECCOMP_FILTER_FLAG_TSYNC
-#define SECCOMP_FILTER_FLAG_TSYNC 1
-#endif
-
-#ifndef seccomp
-int seccomp(unsigned int op, unsigned int flags, void *args)
-{
- errno = 0;
- return syscall(__NR_seccomp, op, flags, args);
-}
-#endif
-
TEST(seccomp_syscall)
{
struct sock_filter filter[] = {
@@ -1783,6 +2045,67 @@
}
}
+/*
+ * Test detection of known and unknown filter flags. Userspace needs to be able
+ * to check if a filter flag is supported by the current kernel and a good way
+ * of doing that is by attempting to enter filter mode, with the flag bit in
+ * question set, and a NULL pointer for the _args_ parameter. EFAULT indicates
+ * that the flag is valid and EINVAL indicates that the flag is invalid.
+ */
+TEST(detect_seccomp_filter_flags)
+{
+ unsigned int flags[] = { SECCOMP_FILTER_FLAG_TSYNC,
+ SECCOMP_FILTER_FLAG_LOG };
+ unsigned int flag, all_flags;
+ int i;
+ long ret;
+
+ /* Test detection of known-good filter flags */
+ for (i = 0, all_flags = 0; i < ARRAY_SIZE(flags); i++) {
+ flag = flags[i];
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
+ ASSERT_NE(ENOSYS, errno) {
+ TH_LOG("Kernel does not support seccomp syscall!");
+ }
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EFAULT, errno) {
+ TH_LOG("Failed to detect that a known-good filter flag (0x%X) is supported!",
+ flag);
+ }
+
+ all_flags |= flag;
+ }
+
+ /* Test detection of all known-good filter flags */
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, all_flags, NULL);
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EFAULT, errno) {
+ TH_LOG("Failed to detect that all known-good filter flags (0x%X) are supported!",
+ all_flags);
+ }
+
+ /* Test detection of an unknown filter flag */
+ flag = -1;
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EINVAL, errno) {
+ TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported!",
+ flag);
+ }
+
+ /*
+ * Test detection of an unknown filter flag that may simply need to be
+ * added to this test
+ */
+ flag = flags[ARRAY_SIZE(flags) - 1] << 1;
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, flag, NULL);
+ EXPECT_EQ(-1, ret);
+ EXPECT_EQ(EINVAL, errno) {
+ TH_LOG("Failed to detect that an unknown filter flag (0x%X) is unsupported! Does a new flag need to be added to this test?",
+ flag);
+ }
+}
+
TEST(TSYNC_first)
{
struct sock_filter filter[] = {
@@ -2421,6 +2744,99 @@
_metadata->passed = 0;
}
+TEST_SIGNAL(filter_flag_log, SIGSYS)
+{
+ struct sock_filter allow_filter[] = {
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_filter kill_filter[] = {
+ BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
+ offsetof(struct seccomp_data, nr)),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),
+ BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
+ };
+ struct sock_fprog allow_prog = {
+ .len = (unsigned short)ARRAY_SIZE(allow_filter),
+ .filter = allow_filter,
+ };
+ struct sock_fprog kill_prog = {
+ .len = (unsigned short)ARRAY_SIZE(kill_filter),
+ .filter = kill_filter,
+ };
+ long ret;
+ pid_t parent = getppid();
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret);
+
+ /* Verify that the FILTER_FLAG_LOG flag isn't accepted in strict mode */
+ ret = seccomp(SECCOMP_SET_MODE_STRICT, SECCOMP_FILTER_FLAG_LOG,
+ &allow_prog);
+ ASSERT_NE(ENOSYS, errno) {
+ TH_LOG("Kernel does not support seccomp syscall!");
+ }
+ EXPECT_NE(0, ret) {
+ TH_LOG("Kernel accepted FILTER_FLAG_LOG flag in strict mode!");
+ }
+ EXPECT_EQ(EINVAL, errno) {
+ TH_LOG("Kernel returned unexpected errno for FILTER_FLAG_LOG flag in strict mode!");
+ }
+
+ /* Verify that a simple, permissive filter can be added with no flags */
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, 0, &allow_prog);
+ EXPECT_EQ(0, ret);
+
+ /* See if the same filter can be added with the FILTER_FLAG_LOG flag */
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG,
+ &allow_prog);
+ ASSERT_NE(EINVAL, errno) {
+ TH_LOG("Kernel does not support the FILTER_FLAG_LOG flag!");
+ }
+ EXPECT_EQ(0, ret);
+
+ /* Ensure that the kill filter works with the FILTER_FLAG_LOG flag */
+ ret = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_LOG,
+ &kill_prog);
+ EXPECT_EQ(0, ret);
+
+ EXPECT_EQ(parent, syscall(__NR_getppid));
+ /* getpid() should never return. */
+ EXPECT_EQ(0, syscall(__NR_getpid));
+}
+
+TEST(get_action_avail)
+{
+ __u32 actions[] = { SECCOMP_RET_KILL_THREAD, SECCOMP_RET_TRAP,
+ SECCOMP_RET_ERRNO, SECCOMP_RET_TRACE,
+ SECCOMP_RET_LOG, SECCOMP_RET_ALLOW };
+ __u32 unknown_action = 0x10000000U;
+ int i;
+ long ret;
+
+ ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &actions[0]);
+ ASSERT_NE(ENOSYS, errno) {
+ TH_LOG("Kernel does not support seccomp syscall!");
+ }
+ ASSERT_NE(EINVAL, errno) {
+ TH_LOG("Kernel does not support SECCOMP_GET_ACTION_AVAIL operation!");
+ }
+ EXPECT_EQ(ret, 0);
+
+ for (i = 0; i < ARRAY_SIZE(actions); i++) {
+ ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &actions[i]);
+ EXPECT_EQ(ret, 0) {
+ TH_LOG("Expected action (0x%X) not available!",
+ actions[i]);
+ }
+ }
+
+ /* Check that an unknown action is handled properly (EOPNOTSUPP) */
+ ret = seccomp(SECCOMP_GET_ACTION_AVAIL, 0, &unknown_action);
+ EXPECT_EQ(ret, -1);
+ EXPECT_EQ(errno, EOPNOTSUPP);
+}
+
/*
* TODO:
* - add microbenchmarks
@@ -2429,6 +2845,8 @@
* - endianness checking when appropriate
* - 64-bit arg prodding
* - arch value testing (x86 modes especially)
+ * - verify that FILTER_FLAG_LOG filters generate log messages
+ * - verify that RET_LOG generates log messages
* - ...
*/