remarkable-linux/kernel
Alexei Starovoitov 725f9dcd58 bpf: fix two bugs in verification logic when accessing 'ctx' pointer
1.
first bug is a silly mistake. It broke tracing examples and prevented
simple bpf programs from loading.

In the following code:
if (insn->imm == 0 && BPF_SIZE(insn->code) == BPF_W) {
} else if (...) {
  // this part should have been executed when
  // insn->code == BPF_W and insn->imm != 0
}

Obviously it's not doing that. So simple instructions like:
r2 = *(u64 *)(r1 + 8)
will be rejected. Note the comments in the code around these branches
were and still valid and indicate the true intent.

Replace it with:
if (BPF_SIZE(insn->code) != BPF_W)
  continue;

if (insn->imm == 0) {
} else if (...) {
  // now this code will be executed when
  // insn->code == BPF_W and insn->imm != 0
}

2.
second bug is more subtle.
If malicious code is using the same dest register as source register,
the checks designed to prevent the same instruction to be used with different
pointer types will fail to trigger, since we were assigning src_reg_type
when it was already overwritten by check_mem_access().
The fix is trivial. Just move line:
src_reg_type = regs[insn->src_reg].type;
before check_mem_access().
Add new 'access skb fields bad4' test to check this case.

Fixes: 9bac3d6d54 ("bpf: allow extended BPF programs access skb fields")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-16 14:08:49 -04:00
..
bpf bpf: fix two bugs in verification logic when accessing 'ctx' pointer 2015-04-16 14:08:49 -04:00
configs
debug debug: prevent entering debug mode on panic/exception. 2015-02-19 12:39:03 -06:00
events Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2015-04-15 09:00:47 -07:00
gcov kbuild,gcov: simplify kernel/gcov/Makefile more 2015-01-09 17:25:44 +01:00
irq irqchip core change for v4.1 (round 3) 2015-04-11 11:17:28 +02:00
livepatch Merge branch 'for-4.1/core-noarch' into for-linus 2015-04-13 23:57:20 +02:00
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 10:27:28 -07:00
power Merge back earlier suspend/hibernate material for v4.1. 2015-04-10 12:01:59 +02:00
printk Merge branch 'iocb' into for-next 2015-04-11 22:24:41 -04:00
rcu Merge branches 'doc.2015.02.26a', 'earlycb.2015.03.03a', 'fixes.2015.03.03a', 'gpexp.2015.02.26a', 'hotplug.2015.03.20a', 'sysidle.2015.02.26b' and 'tiny.2015.02.26a' into HEAD 2015-03-20 08:31:01 -07:00
sched Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 13:58:48 -07:00
time timers/PM: Drop unnecessary braces from tick_freeze() 2015-04-03 15:15:52 +02:00
trace Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 14:37:47 -07:00
.gitignore
acct.c new fs_pin killing logics 2015-01-25 23:17:28 -05:00
async.c
audit.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-12-30 10:45:47 -08:00
audit.h audit: replace getname()/putname() hacks with reference counters 2015-01-23 00:23:58 -05:00
audit_tree.c
audit_watch.c
auditfilter.c Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit 2015-02-11 20:07:47 -08:00
auditsc.c Merge branch 'getname2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-02-17 15:27:47 -08:00
backtracetest.c
bounds.c
capability.c
cgroup.c cgroup: Use kvfree in pidlist_free() 2015-03-03 08:47:25 -05:00
cgroup_freezer.c
compat.c all arches, signal: move restart_block to struct task_struct 2015-02-12 18:54:12 -08:00
configs.c
context_tracking.c context_tracking: Export context_tracking_user_enter/exit 2015-03-09 15:43:00 +01:00
cpu.c Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 13:36:04 -07:00
cpu_pm.c
cpuset.c kernel, cpuset: remove exception for __GFP_THISNODE 2015-04-14 16:49:03 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c oom, PM: make OOM detection in the freezer path raceless 2015-02-11 17:06:03 -08:00
extable.c
fork.c mm: do not use mm->nr_pmds on !MMU configurations 2015-02-12 18:54:10 -08:00
freezer.c
futex.c Linux 34.0-rc1 2015-02-24 08:41:07 +01:00
futex_compat.c
groups.c
hung_task.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/mcs: Better differentiate between MCS variants 2015-01-14 15:07:32 +01:00
Kconfig.preempt
kexec.c kexec: simplify conditional 2015-02-17 14:34:51 -08:00
kmod.c
kprobes.c kprobes: makes kprobes/enabled works correctly for optimized kprobes. 2015-02-13 21:21:42 -08:00
ksysfs.c
kthread.c
latencytop.c
Makefile Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2015-02-11 20:25:11 -08:00
module-internal.h
module.c Some clean ups and small fixes, but the biggest change is the addition 2015-04-14 10:49:03 -07:00
module_signing.c
notifier.c rcu: Make SRCU optional by using CONFIG_SRCU 2015-01-06 11:04:29 -08:00
nsproxy.c
padata.c padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:38 -08:00
panic.c livepatch: kernel: add TAINT_LIVEPATCH 2014-12-22 15:40:48 +01:00
params.c param: fix uninitialized read with CONFIG_DEBUG_LOCK_ALLOC 2015-01-20 11:38:31 +10:30
pid.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-12-16 15:53:03 -08:00
pid_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-12-16 15:53:03 -08:00
profile.c profile: use %*pb[l] to print bitmaps including cpumasks and nodemasks 2015-02-13 21:21:38 -08:00
ptrace.c ptrace: remove linux/compat.h inclusion under CONFIG_COMPAT 2015-02-17 14:34:51 -08:00
range.c kernel: avoid overflow in cmp_range 2015-01-17 10:02:23 +13:00
reboot.c
relay.c
resource.c resources: Move struct resource_list_entry from ACPI into resource core 2015-02-05 15:09:25 +01:00
seccomp.c seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO 2015-02-17 14:34:55 -08:00
signal.c signal: use current->state helpers 2015-02-17 14:34:51 -08:00
smp.c
smpboot.c smpboot: Add common code for notification from dying CPU 2015-03-11 13:20:25 -07:00
smpboot.h
softirq.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-02-09 15:24:03 -08:00
stacktrace.c
stop_machine.c
sys.c kernel/sys.c: fix UNAME26 for 4.0 2015-02-28 09:57:51 -08:00
sys_ni.c
sysctl.c Merge branch 'akpm' (patches from Andrew) 2015-04-14 16:49:17 -07:00
sysctl_binary.c
system_certificates.S
system_keyring.c
task_work.c
taskstats.c netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2014-12-17 12:31:40 -08:00
user_namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2014-12-17 12:31:40 -08:00
utsname.c
utsname_sysctl.c
watchdog.c Merge branch 'akpm' (patches from Andrew) 2015-04-14 16:49:17 -07:00
workqueue.c workqueue: Reorder sysfs code 2015-04-06 11:16:04 -04:00
workqueue_internal.h