YiFei Zhu 2d660e9770 UPSTREAM: seccomp/cache: Add "emulator" to check if filter is constant allow ... SECCOMP_CACHE will only operate on syscalls that do not access any syscall arguments or instruction pointer. To facilitate this we need a static analyser to know whether a filter will return allow regardless of syscall arguments for a given architecture number / syscall number pair. This is implemented here with a pseudo-emulator, and stored in a per-filter bitmap. In order to build this bitmap at filter attach time, each filter is emulated for every syscall (under each possible architecture), and checked for any accesses of struct seccomp_data that are not the "arch" nor "nr" (syscall) members. If only "arch" and "nr" are examined, and the program returns allow, then we can be sure that the filter must return allow independent from syscall arguments. Nearly all seccomp filters are built from these cBPF instructions: BPF_LD | BPF_W | BPF_ABS BPF_JMP | BPF_JEQ | BPF_K BPF_JMP | BPF_JGE | BPF_K BPF_JMP | BPF_JGT | BPF_K BPF_JMP | BPF_JSET | BPF_K BPF_JMP | BPF_JA BPF_RET | BPF_K BPF_ALU | BPF_AND | BPF_K Each of these instructions are emulated. Any weirdness or loading from a syscall argument will cause the emulator to bail. The emulation is also halted if it reaches a return. In that case, if it returns an SECCOMP_RET_ALLOW, the syscall is marked as good. Emulator structure and comments are from Kees [1] and Jann [2]. Emulation is done at attach time. If a filter depends on more filters, and if the dependee does not guarantee to allow the syscall, then we skip the emulation of this syscall. [1] https://lore.kernel.org/lkml/20200923232923.3142503-5-keescook@chromium.org/ [2] https://lore.kernel.org/lkml/CAG48ez1p=dR_2ikKq=xVxkoGg0fYpTBpkhJSv1w-6BG=76PAvw@mail.gmail.com/ Suggested-by: Jann Horn <jannh@google.com> Signed-off-by: YiFei Zhu <yifeifz2@illinois.edu> Reviewed-by: Jann Horn <jannh@google.com> Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/71c7be2db5ee08905f41c3be5c1ad6e2601ce88f.1602431034.git.yifeifz2@illinois.edu (cherry picked from commit 8e01b51a31) Signed-off-by: Jeff Vander Stoep <jeffv@google.com> Change-Id: I5047f7f0d6502e5de6c047743f1053fda3025a6e Bug: 176068146		2020-12-21 18:46:50 +00:00
..
bpf	bpf: Fix enum names for bpf_this_cpu_ptr() and bpf_per_cpu_ptr() helpers	2020-12-11 14:19:07 -08:00
cgroup	ANDROID: cgroup: Export functions used by modules	2020-12-14 11:22:22 +00:00
configs
debug	kdb: Fix pager search for multi-line strings	2020-10-01 14:44:08 +01:00
dma	Merge 3d5e28bff7 ("Merge branch 'stable/for-linus-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb") into android-mainline	2020-11-12 09:16:49 +01:00
entry	entry: Fix the incorrect ordering of lockdep and RCU check	2020-11-04 18:06:14 +01:00
events	Merge 9cfd9c4599 ("Merge tag 'char-misc-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc") into android-mainline	2020-11-16 08:41:35 +01:00
gcov	gcov: add support for GCC 10.1	2020-09-11 09:33:54 -07:00
irq	Merge 5.10-rc7 into android-mainline	2020-12-09 08:09:26 +01:00
kcsan	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
livepatch	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
locking	Linux 5.10-rc5	2020-11-23 08:17:16 +01:00
power	Merge 65b55d4c85 ("Merge tag 'arm-soc-fixes-v5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc") into android-mainline	2020-11-02 11:04:03 +01:00
printk	Merge c84e1efae0 ("Merge tag 'asm-generic-fixes-5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic") into android-mainline	2020-11-28 08:23:09 +01:00
rcu	Merge branch 'urgent-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu	2020-11-17 10:31:56 -08:00
sched	ANDROID: sched: Add rvh for cpu controller cgroup can attach	2020-12-21 16:37:22 +00:00
time	ANDROID: timer: Export hrtimer_expire_entry/exit tracepoints	2020-12-21 17:49:09 +00:00
trace	FROMLIST: tracing: add support for objtool mcount	2020-12-16 08:56:35 -08:00
.gitignore
acct.c	kernel: acct.c: fix some kernel-doc nits	2020-10-16 11:11:19 -07:00
async.c	treewide: Remove uninitialized_var() usage	2020-07-16 12:35:15 -07:00
audit_fsnotify.c	fsnotify: create method handle_inode_event() in fsnotify_operations	2020-07-27 23:25:50 +02:00
audit_tree.c	\n	2020-08-06 19:29:51 -07:00
audit_watch.c	fsnotify: create method handle_inode_event() in fsnotify_operations	2020-07-27 23:25:50 +02:00
audit.c	audit: Remove redundant null check	2020-08-26 09:10:39 -04:00
audit.h	audit: change unnecessary globals into statics	2020-08-17 20:26:58 -04:00
auditfilter.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
auditsc.c	audit/stable-5.9 PR 20200803	2020-08-04 14:20:26 -07:00
backtracetest.c	treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()	2020-07-30 11:15:58 -07:00
bounds.c
capability.c	LSM: Signal to SafeSetID when setting group IDs	2020-10-13 09:17:34 -07:00
compat.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
configs.c
context_tracking.c	context_tracking: Ensure that the critical path cannot be instrumented	2020-06-11 15:14:36 +02:00
cpu_pm.c	notifier: Fix broken error handling pattern	2020-09-01 09:58:03 +02:00
cpu.c	Merge 5.10-rc7 into android-mainline	2020-12-09 08:09:26 +01:00
crash_core.c	kdump: append kernel build-id string to VMCOREINFO	2020-08-12 10:58:01 -07:00
crash_dump.c	crash_dump: Remove no longer used saved_max_pfn	2020-04-15 11:21:54 +02:00
cred.c	exec: Teach prepare_exec_creds how exec treats uids & gids	2020-05-20 14:44:21 -05:00
delayacct.c
dma.c
exec_domain.c
exit.c	don't dump the threads that had been already exiting when zapped.	2020-10-28 16:39:49 -04:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-19 11:58:16 -08:00
fork.c	ANDROID: Sched: Export scheduler symbols needed by vendor modules	2020-12-03 16:50:04 +00:00
freezer.c
futex.c	Merge 9cfd9c4599 ("Merge tag 'char-misc-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc") into android-mainline	2020-11-16 08:41:35 +01:00
gen_kheaders.sh	kbuild: add variables for compression tools	2020-06-06 23:42:01 +09:00
groups.c	LSM: Signal to SafeSetID when setting group IDs	2020-10-13 09:17:34 -07:00
hung_task.c	kernel/hung_task.c: make type annotations consistent	2020-11-02 12:14:19 -08:00
iomem.c
irq_work.c	ANDROID: Sched: Export scheduler symbols needed by vendor modules	2020-12-03 16:50:04 +00:00
jump_label.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
kallsyms.c	treewide: Convert macro and uses of __section(foo) to __section("foo")	2020-10-25 14:51:49 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: make some symbols static	2020-08-12 10:58:02 -07:00
kexec_core.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
kexec_elf.c
kexec_file.c	kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED	2020-10-16 11:11:18 -07:00
kexec_internal.h
kexec.c	LSM: Introduce kernel_post_load_data() hook	2020-10-05 13:37:03 +02:00
kheaders.c
kmod.c	kmod: remove redundant "be an" in the comment	2020-08-12 10:58:01 -07:00
kprobes.c	kprobes: Tell lockdep about kprobe nesting	2020-11-04 09:46:06 -05:00
ksysfs.c
kthread.c	ANDROID: Sched: Export scheduler symbols needed by vendor modules	2020-12-03 16:50:04 +00:00
latencytop.c	sysctl: pass kernel pointers to ->proc_handler	2020-04-27 02:07:40 -04:00
Makefile	elfcore: fix building with clang	2020-12-11 14:02:14 -08:00
module_signature.c
module_signing.c
module-internal.h
module.c	Modules updates for v5.10	2020-10-22 13:08:57 -07:00
notifier.c	notifier: Fix broken error handling pattern	2020-09-01 09:58:03 +02:00
nsproxy.c	nsproxy: support CLONE_NEWTIME with setns()	2020-07-08 11:14:22 +02:00
padata.c	padata: fix possible padata_works_lock deadlock	2020-09-04 17:51:55 +10:00
panic.c	panic: don't dump stack twice on warn	2020-11-14 11:26:04 -08:00
params.c	params: Replace zero-length array with flexible-array member	2020-10-29 17:22:59 -05:00
pid_namespace.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
pid.c	Merge 922a763ae1 ("Merge tag 'zonefs-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs") into android-mainline	2020-10-26 10:08:43 +01:00
profile.c
ptrace.c	ptrace: Set PF_SUPERPRIV when checking capability	2020-11-17 12:53:22 -08:00
range.c	kernel.h: split out min()/max() et al. helpers	2020-10-16 11:11:19 -07:00
reboot.c	Merge e28c0d7c92 ("Merge branch 'akpm' (patches from Andrew)") into android-mainline	2020-11-15 14:37:09 +01:00
regset.c	regset: kill ->get()	2020-07-27 14:31:12 -04:00
relay.c	kernel/relay.c: drop unneeded initialization	2020-10-16 11:11:22 -07:00
resource.c	kernel/resource: make iomem_resource implicit in release_mem_region_adjustable()	2020-10-16 11:11:18 -07:00
rseq.c
scftorture.c	scftorture: Add cond_resched() to test loop	2020-08-24 18:38:38 -07:00
scs.c	mm: memcontrol: account kernel stack per node	2020-08-07 11:33:25 -07:00
seccomp.c	UPSTREAM: seccomp/cache: Add "emulator" to check if filter is constant allow	2020-12-21 18:46:50 +00:00
signal.c	Merge 4ef8451b33 ("Merge tag 'perf-tools-for-v5.10-2020-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux") into android-mainline	2020-11-06 08:00:53 +01:00
smp.c	Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2020-10-18 14:34:50 -07:00
smpboot.c
smpboot.h
softirq.c	ANDROID: softirq: Export irq_handler_exit tracepoint	2020-12-21 17:48:06 +00:00
stackleak.c	stackleak: let stack_erasing_sysctl take a kernel pointer buffer	2020-09-19 13:13:39 -07:00
stacktrace.c	stacktrace: Remove reliable argument from arch_stack_walk() callback	2020-09-18 14:24:16 +01:00
static_call.c	static_call: Fix return type of static_call_init	2020-10-02 21:18:25 +02:00
stop_machine.c	ANDROID: stop_machine: stop_one_cpu_async	2020-12-08 19:07:21 +00:00
sys_ni.c	mm/madvise: introduce process_madvise() syscall: an external memory hinting API	2020-10-18 09:27:10 -07:00
sys.c	Linux 5.10-rc1	2020-10-29 06:32:38 +01:00
sysctl-test.c
sysctl.c	Linux 5.9-rc6	2020-09-21 12:13:45 +02:00
task_work.c	task_work: cleanup notification modes	2020-10-17 15:05:30 -06:00
taskstats.c	taskstats: move specifying netlink policy back to ops	2020-10-02 19:11:12 -07:00
test_kprobes.c
torture.c	torture: Dump ftrace at shutdown only if requested	2020-06-29 12:01:45 -07:00
tracepoint.c	tracepoint: Replace zero-length array with flexible-array member	2020-10-29 17:22:59 -05:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c	usermodehelper: reset umask to default before executing user process	2020-10-06 10:31:52 -07:00
up.c
user_namespace.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
user-return-notifier.c
user.c	user.c: make uidhash_table static	2020-06-04 19:06:24 -07:00
usermode_driver.c	umd: Stop using split_argv	2020-07-07 11:58:59 -05:00
utsname_sysctl.c	sysctl: pass kernel pointers to ->proc_handler	2020-04-27 02:07:40 -04:00
utsname.c	nsproxy: add struct nsset	2020-05-09 13:57:12 +02:00
watch_queue.c	watch_queue: Limit the number of watches a user can hold	2020-08-17 09:39:18 -07:00
watchdog_hld.c
watchdog.c	kernel/watchdog: fix watchdog_allowed_mask not used warning	2020-11-14 11:26:03 -08:00
workqueue_internal.h
workqueue.c	ANDROID: workqueue: Export workqueue_execute_start/end tracepoints	2020-12-21 17:48:38 +00:00