linux_dsm_epyc7002/kernel
Daniel Borkmann 25af1ec4c5 bpf: Add lockdown check for probe_write_user helper
commit 51e1bb9eeaf7868db56e58f47848e364ab4c4129 upstream.

Back then, commit 96ae522795 ("bpf: Add bpf_probe_write_user BPF helper
to be called in tracers") added the bpf_probe_write_user() helper in order
to allow to override user space memory. Its original goal was to have a
facility to "debug, divert, and manipulate execution of semi-cooperative
processes" under CAP_SYS_ADMIN. Write to kernel was explicitly disallowed
since it would otherwise tamper with its integrity.

One use case was shown in cf9b1199de ("samples/bpf: Add test/example of
using bpf_probe_write_user bpf helper") where the program DNATs traffic
at the time of connect(2) syscall, meaning, it rewrites the arguments to
a syscall while they're still in userspace, and before the syscall has a
chance to copy the argument into kernel space. These days we have better
mechanisms in BPF for achieving the same (e.g. for load-balancers), but
without having to write to userspace memory.

Of course the bpf_probe_write_user() helper can also be used to abuse
many other things for both good or bad purpose. Outside of BPF, there is
a similar mechanism for ptrace(2) such as PTRACE_PEEK{TEXT,DATA} and
PTRACE_POKE{TEXT,DATA}, but would likely require some more effort.
Commit 96ae522795 explicitly dedicated the helper for experimentation
purpose only. Thus, move the helper's availability behind a newly added
LOCKDOWN_BPF_WRITE_USER lockdown knob so that the helper is disabled under
the "integrity" mode. More fine-grained control can be implemented also
from LSM side with this change.

Fixes: 96ae522795 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-05 18:53:10 +02:00
..
bpf bpf: Fix pointer arithmetic mask tightening under state pruning 2024-07-05 18:06:10 +02:00
cgroup cgroup1: fix leaked context root causing sporadic NULL deref in LTP 2021-07-31 08:16:11 +02:00
configs
debug kgdb: fix to kill breakpoints on initmem after boot 2021-03-04 11:38:46 +01:00
dma dma-mapping: handle vmalloc addresses in dma_common_{mmap,get_sgtable} 2021-07-28 14:35:38 +02:00
entry x86/entry: Move nmi entry/exit into common code 2021-03-17 17:06:36 +01:00
events init: add dsm gpl source 2024-07-05 18:00:04 +02:00
gcov gcov: re-fix clang-11+ support 2021-04-14 08:41:58 +02:00
irq genirq/matrix: Prevent allocation counter corruption 2021-05-11 14:47:17 +02:00
kcsan kcsan: Fix debugfs initcall return type 2021-05-26 12:06:54 +02:00
livepatch kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
locking init: add dsm gpl source 2024-07-05 18:00:04 +02:00
power PM: EM: postpone creating the debugfs dir till fs_initcall 2021-03-30 14:32:04 +02:00
printk init: add dsm gpl source 2024-07-05 18:00:04 +02:00
rcu rcu-tasks: Don't delete holdouts within trc_wait_for_one_reader() 2021-07-31 08:16:11 +02:00
sched sched/rt: Fix double enqueue caused by rt_effective_prio 2024-07-05 18:52:32 +02:00
time timers: Move clearing of base::timer_running under base:: Lock 2024-07-05 18:52:30 +02:00
trace bpf: Add lockdown check for probe_write_user helper 2024-07-05 18:53:10 +02:00
.gitignore kbuild: update config_data.gz only when the content of .config is changed 2021-05-11 14:47:37 +02:00
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: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
audit_tree.c fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
audit_watch.c fsnotify: generalize handle_inode_event() 2020-12-30 11:54:18 +01:00
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 init: add dsm gpl source 2024-07-05 18:00:04 +02:00
crash_core.c crash_core, vmcoreinfo: append 'SECTION_SIZE_BITS' to vmcoreinfo 2021-06-23 14:42:52 +02:00
crash_dump.c
cred.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
delayacct.c
dma.c
exec_domain.c
exit.c kernel/io_uring: cancel io_uring before task works 2021-01-30 13:55:18 +01:00
extable.c
fail_function.c fail_function: Remove a redundant mutex unlock 2020-11-19 11:58:16 -08:00
fork.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
freezer.c Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing" 2021-04-07 15:00:14 +02:00
futex.c mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:29 -04:00
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 init: add dsm gpl source 2024-07-05 18:00:04 +02:00
iomem.c
irq_work.c
jump_label.c jump_label: Fix jump_label_text_reserved() vs __init 2021-07-20 16:05:58 +02:00
kallsyms.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kcmp.c exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:46:24 +01:00
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: kexec: remove the lock operation of system_transition_mutex 2021-02-03 23:28:37 +01:00
kexec_elf.c
kexec_file.c kernel: kexec_file: fix error return code of kexec_calculate_store_digests() 2021-05-19 10:13:09 +02:00
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: Fix to delay the kprobes jump optimization 2021-03-04 11:38:35 +01:00
ksysfs.c
kthread.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
latencytop.c
Makefile init: add dsm gpl source 2024-07-05 18:00:04 +02:00
module_signature.c module: harden ELF info handling 2021-03-25 09:04:11 +01:00
module_signing.c module: harden ELF info handling 2021-03-25 09:04:11 +01:00
module-internal.h
module.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
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 init: add dsm gpl source 2024-07-05 18:00:04 +02:00
profile.c
ptrace.c ptrace: make ptrace() fail if the tracee changed its pid unexpectedly 2021-05-26 12:06:49 +02:00
range.c kernel.h: split out min()/max() et al. helpers 2020-10-16 11:11:19 -07:00
reboot.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
regset.c regset: kill ->get() 2020-07-27 14:31:12 -04:00
relay.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
resource.c kernel/resource: make walk_mem_res() find all busy IORESOURCE_MEM resources 2021-05-19 10:13:09 +02:00
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 seccomp: Refactor notification handler to prepare for new semantics 2021-06-03 09:00:31 +02:00
signal.c ptrace: fix task_join_group_stop() for the case when current is traced 2020-11-02 12:14:19 -08:00
smp.c smp: Fix smp_call_function_single_async prototype 2021-05-14 09:50:46 +02:00
smpboot.c sched/core: Initialize the idle task with preemption disabled 2021-07-14 16:55:50 +02:00
smpboot.h
softirq.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
stackleak.c stackleak: let stack_erasing_sysctl take a kernel pointer buffer 2020-09-19 13:13:39 -07:00
stacktrace.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
static_call.c static_call: Fix static_call_text_reserved() vs __init 2021-07-20 16:05:58 +02:00
stop_machine.c stop_machine, rcu: Mark functions as notrace 2020-10-26 12:12:27 +01:00
syno_bootargs.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
syno-module-internal.h init: add dsm gpl source 2024-07-05 18:00:04 +02:00
sys_ni.c mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
sys.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
sysctl-test.c
sysctl.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
task_work.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
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: Fix static call function vs data state mismatch 2024-07-05 18:52:28 +02:00
tsacct.c
ucount.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
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 smp: Fix smp_call_function_single_async prototype 2021-05-14 09:50:46 +02:00
user_namespace.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
user-return-notifier.c
user.c user.c: make uidhash_table static 2020-06-04 19:06:24 -07:00
usermode_driver.c bpf: Fix umd memory leak in copy_process() 2021-03-30 14:32:03 +02:00
utsname_sysctl.c
utsname.c
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 init: add dsm gpl source 2024-07-05 18:00:04 +02:00
watchdog.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
workqueue_internal.h init: add dsm gpl source 2024-07-05 18:00:04 +02:00
workqueue.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00
workstat.c init: add dsm gpl source 2024-07-05 18:00:04 +02:00