Jakub Kicinski
28e33f9d78
bpf: disallow arithmetic operations on context pointer
...
Commit f1174f77b5 ("bpf/verifier: rework value tracking")
removed the crafty selection of which pointer types are
allowed to be modified. This is OK for most pointer types
since adjust_ptr_min_max_vals() will catch operations on
immutable pointers. One exception is PTR_TO_CTX which is
now allowed to be offseted freely.
The intent of aforementioned commit was to allow context
access via modified registers. The offset passed to
->is_valid_access() verifier callback has been adjusted
by the value of the variable offset.
What is missing, however, is taking the variable offset
into account when the context register is used. Or in terms
of the code adding the offset to the value passed to the
->convert_ctx_access() callback. This leads to the following
eBPF user code:
r1 += 68
r0 = *(u32 *)(r1 + 8)
exit
being translated to this in kernel space:
0: (07) r1 += 68
1: (61) r0 = *(u32 *)(r1 +180)
2: (95) exit
Offset 8 is corresponding to 180 in the kernel, but offset
76 is valid too. Verifier will "accept" access to offset
68+8=76 but then "convert" access to offset 8 as 180.
Effective access to offset 248 is beyond the kernel context.
(This is a __sk_buff example on a debug-heavy kernel -
packet mark is 8 -> 180, 76 would be data.)
Dereferencing the modified context pointer is not as easy
as dereferencing other types, because we have to translate
the access to reading a field in kernel structures which is
usually at a different offset and often of a different size.
To allow modifying the pointer we would have to make sure
that given eBPF instruction will always access the same
field or the fields accessed are "compatible" in terms of
offset and size...
Disallow dereferencing modified context pointers and add
to selftests the test case described here.
Fixes: f1174f77b5 ("bpf/verifier: rework value tracking")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 13:21:13 +01:00
..
bpf
bpf: disallow arithmetic operations on context pointer
2017-10-18 13:21:13 +01:00
cgroup
Revert "net: defer call to cgroup_sk_alloc()"
2017-10-10 20:24:29 -07:00
configs
ANDROID: binder: add hwbinder,vndbinder to BINDER_DEVICES.
2017-08-22 18:43:23 -07:00
debug
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>
2017-03-02 08:42:34 +01:00
events
perf/aux: Only update ->aux_wakeup in non-overwrite mode
2017-09-29 10:06:45 +02:00
gcov
gcov: support GCC 7.1
2017-05-12 15:57:15 -07:00
irq
irq/generic-chip: Don't replace domain's name
2017-09-28 12:18:59 +02:00
livepatch
livepatch: Fix stacking of patches with respect to RCU
2017-06-20 10:42:19 +02:00
locking
locking/rwsem-xadd: Fix missed wakeup due to reordering of load
2017-09-29 10:10:20 +02:00
power
PM / s2idle: Invoke the ->wake() platform callback earlier
2017-09-29 01:26:13 +02:00
printk
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
2017-09-07 21:00:52 -07:00
rcu
Two updates.
2017-10-04 08:34:01 -07:00
sched
sched/debug: Ignore TASK_IDLE for SysRq-W
2017-09-29 11:02:57 +02:00
time
drivers/pps: aesthetic tweaks to PPS-related content
2017-09-08 18:26:51 -07:00
trace
Two updates.
2017-10-04 08:34:01 -07:00
.gitignore
acct.c
fs: make the buf argument to __kernel_write a void pointer
2017-09-04 19:05:15 -04:00
async.c
async: Adjust system_state checks
2017-05-23 10:01:37 +02:00
audit.c
audit: update the function comments
2017-09-05 09:46:59 -04:00
audit.h
ipc: mqueue: Replace timespec with timespec64
2017-09-03 20:21:24 -04:00
audit_fsnotify.c
Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
2017-05-03 11:05:15 -07:00
audit_tree.c
Merge branch 'fsnotify' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
2017-05-03 11:05:15 -07:00
audit_watch.c
audit/stable-4.13 PR 20170816
2017-08-16 16:48:34 -07:00
auditfilter.c
audit: kernel generated netlink traffic should have a portid of 0
2017-05-02 10:16:05 -04:00
auditsc.c
Merge branch 'work.ipc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2017-09-14 17:37:26 -07:00
backtracetest.c
bounds.c
capability.c
compat.c
semtimedop(): move compat to native
2017-07-15 20:46:47 -04:00
configs.c
context_tracking.c
cpu.c
Merge branch 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2017-10-06 08:36:41 -07:00
cpu_pm.c
PM / CPU: replace raw_notifier with atomic_notifier
2017-07-31 13:09:49 +02:00
crash_core.c
kdump: protect vmcoreinfo data under the crash memory
2017-07-12 16:26:00 -07:00
crash_dump.c
cred.c
doc: ReSTify credentials.txt
2017-05-18 10:30:19 -06:00
delayacct.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
dma.c
elfcore.c
exec_domain.c
exit.c
fix infoleak in waitid(2)
2017-09-29 13:43:15 -04:00
extable.c
extable: Enable RCU if it is not watching in kernel_text_address()
2017-09-23 16:50:20 -04:00
fork.c
android: binder: drop lru lock in isolate callback
2017-10-03 17:54:24 -07:00
freezer.c
futex.c
futex: Fix pi_state->owner serialization
2017-09-25 16:37:11 +02:00
futex_compat.c
groups.c
kernel/groups.c: use sort library function
2017-07-10 16:32:34 -07:00
hung_task.c
kernel/hung_task.c: defer showing held locks
2017-05-08 17:15:10 -07:00
irq_work.c
jump_label.c
jump_label: Provide hotplug context variants
2017-08-10 12:28:59 +02:00
kallsyms.c
kernel/kallsyms.c: replace all_var with IS_ENABLED(CONFIG_KALLSYMS_ALL)
2017-07-10 16:32:34 -07:00
kcmp.c
kernel/kcmp.c: drop branch leftover typo
2017-10-03 17:54:25 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c
kcov: support compat processes
2017-09-08 18:26:51 -07:00
kexec.c
kdump: protect vmcoreinfo data under the crash memory
2017-07-12 16:26:00 -07:00
kexec_core.c
x86/mm, kexec: Allow kexec to be used with SME
2017-07-18 11:38:04 +02:00
kexec_file.c
kexec_file: adjust declaration of kexec_purgatory
2017-07-12 16:26:02 -07:00
kexec_internal.h
kexec_file: adjust declaration of kexec_purgatory
2017-07-12 16:26:02 -07:00
kmod.c
kmod: move #ifdef CONFIG_MODULES wrapper to Makefile
2017-09-08 18:26:51 -07:00
kprobes.c
kprobes: Ensure that jprobe probepoints are at function entry
2017-07-08 11:05:35 +02:00
ksysfs.c
kexec: move vmcoreinfo out of the kernel's .bss section
2017-07-12 16:25:59 -07:00
kthread.c
kernel/kthread.c: kthread_worker: don't hog the cpu
2017-08-31 16:33:15 -07:00
latencytop.c
sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>
2017-03-02 08:42:39 +01:00
Makefile
kmod: move #ifdef CONFIG_MODULES wrapper to Makefile
2017-09-08 18:26:51 -07:00
memremap.c
memremap: add scheduling point to devm_memremap_pages
2017-10-03 17:54:25 -07:00
module-internal.h
module.c
module: fix ddebug_remove_module()
2017-07-25 15:08:32 +02:00
module_signing.c
notifier.c
kernel/notifier.c: simplify expression
2017-02-24 17:46:56 -08:00
nsproxy.c
perf: Add PERF_RECORD_NAMESPACES to include namespaces related info
2017-03-13 15:57:41 -03:00
padata.c
padata: Avoid nested calls to cpus_read_lock() in pcrypt_init_padata()
2017-05-26 10:10:37 +02:00
panic.c
locking/refcounts, x86/asm: Implement fast refcount overflow protection
2017-08-17 10:40:26 +02:00
params.c
kernel/params.c: improve STANDARD_PARAM_DEF readability
2017-10-03 17:54:26 -07:00
pid.c
pids: make task_tgid_nr_ns() safe
2017-08-21 12:47:31 -07:00
pid_namespace.c
userns,pidns: Verify the userns for new pid namespaces
2017-07-20 07:43:58 -05:00
profile.c
sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>
2017-03-02 08:42:39 +01:00
ptrace.c
signal: Remove kernel interal si_code magic
2017-07-24 14:30:28 -05:00
range.c
reboot.c
relay.c
Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2017-05-02 11:38:06 -07:00
resource.c
seccomp.c
seccomp: fix the usage of get/put_seccomp_filter() in seccomp_get_filter()
2017-09-27 22:51:12 -07:00
signal.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2017-09-11 18:34:47 -07:00
smp.c
treewide: make "nr_cpu_ids" unsigned
2017-09-08 18:26:48 -07:00
smpboot.c
watchdog/core, powerpc: Lock cpus across reconfiguration
2017-10-04 10:53:54 +02:00
smpboot.h
softirq.c
sched/core: Remove 'task' parameter and rename tsk_restore_flags() to current_restore_flags()
2017-04-11 09:06:32 +02:00
stacktrace.c
stacktrace/x86: add function for detecting reliable stack traces
2017-03-08 09:18:02 +01:00
stop_machine.c
stop_machine: Provide stop_machine_cpuslocked()
2017-05-26 10:10:36 +02:00
sys.c
prctl: Allow local CAP_SYS_ADMIN changing exe_file
2017-07-20 07:46:07 -05:00
sys_ni.c
sysctl.c
Merge branch 'core-watchdog-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2017-10-06 08:36:41 -07:00
sysctl_binary.c
fs: fix kernel_write prototype
2017-09-04 19:05:15 -04:00
task_work.c
task_work: Replace spin_unlock_wait() with lock/unlock pair
2017-07-25 10:08:58 -07:00
taskstats.c
taskstats: add e/u/stime for TGID command
2017-05-08 17:15:12 -07:00
test_kprobes.c
torture.c
torture: Fix typo suppressing CPU-hotplug statistics
2017-07-25 13:04:45 -07:00
tracepoint.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
2017-03-02 08:42:35 +01:00
tsacct.c
sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>
2017-03-02 08:42:39 +01:00
ucount.c
ucount: Remove the atomicity from ucount->count
2017-03-06 15:26:37 -06:00
uid16.c
sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>
2017-03-02 08:42:31 +01:00
umh.c
kmod: split out umh code into its own file
2017-09-08 18:26:50 -07:00
up.c
smp: Avoid using two cache lines for struct call_single_data
2017-08-29 15:14:38 +02:00
user-return-notifier.c
user.c
sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h>
2017-03-02 08:42:29 +01:00
user_namespace.c
userns,pidns: Verify the userns for new pid namespaces
2017-07-20 07:43:58 -05:00
utsname.c
sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h>
2017-03-02 08:42:38 +01:00
utsname_sysctl.c
sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
2017-03-03 01:45:36 +01:00
watchdog.c
watchdog/core: Put softlockup_threads_initialized under ifdef guard
2017-10-04 11:30:50 +02:00
watchdog_hld.c
watchdog/hardlockup/perf: Fix spelling mistake: "permanetely" -> "permanently"
2017-09-28 12:24:54 +02:00
workqueue.c
Merge branch 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2017-09-06 21:59:31 -07:00
workqueue_internal.h