Malicious code can attempt to free buffers using the BC_FREE_BUFFER
ioctl to binder. There are protections against a user freeing a buffer
while in use by the kernel, however there was a window where
BC_FREE_BUFFER could be used to free a recently allocated buffer that
was not completely initialized. This resulted in a use-after-free
detected by KASAN with a malicious test program.
This window is closed by setting the buffer's allow_user_free attribute
to 0 when the buffer is allocated or when the user has previously freed
it instead of waiting for the caller to set it. The problem was that
when the struct buffer was recycled, allow_user_free was stale and set
to 1 allowing a free to go through.
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Arve Hjønnevåg <arve@android.com>
Cc: stable <stable@vger.kernel.org> # 4.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes the following sparse warning:
drivers/android/binder.c:3312:1: warning:
symbol 'binder_free_buf' was not declared. Should it be static?
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This allows the context manager to retrieve information about nodes
that it holds a reference to, such as the current number of
references to those nodes.
Such information can for example be used to determine whether the
servicemanager is the only process holding a reference to a node.
This information can then be passed on to the process holding the
node, which can in turn decide whether it wants to shut down to
reduce resource usage.
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Binder uses internal fs interfaces to allocate and install fds:
__alloc_fd
__fd_install
__close_fd
get_files_struct
put_files_struct
These were used to support the passing of fds between processes
as part of a transaction. The actual allocation and installation
of the fds in the target process was handled by the sending
process so the standard functions, alloc_fd() and fd_install()
which assume task==current couldn't be used.
This patch refactors this mechanism so that the fds are
allocated and installed by the target process allowing the
standard functions to be used.
The sender now creates a list of fd fixups that contains the
struct *file and the address to fixup with the new fd once
it is allocated. This list is processed by the target process
when the transaction is dequeued.
A new error case is introduced by this change. If an async
transaction with file descriptors cannot allocate new
fds in the target (probably due to out of file descriptors),
the transaction is discarded with a log message. In the old
implementation this would have been detected in the sender
context and failed prior to sending.
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a process dies, failed reply is sent to the sender of any transaction
queued on a dead thread's todo list. The sender asserts that the
received failed reply corresponds to the head of the transaction stack.
This assert can fail if the dead thread is allowed to send outgoing
transactions when there is already a transaction on its todo list,
because this new transaction can end up on the transaction stack of the
original sender. The following steps illustrate how this assertion can
fail.
1. Thread1 sends txn19 to Thread2
(T1->transaction_stack=txn19, T2->todo+=txn19)
2. Without processing todo list, Thread2 sends txn20 to Thread1
(T1->todo+=txn20, T2->transaction_stack=txn20)
3. T1 processes txn20 on its todo list
(T1->transaction_stack=txn20->txn19, T1->todo=<empty>)
4. T2 dies, T2->todo cleanup attempts to send failed reply for txn19, but
T1->transaction_stack points to txn20 -- assertion failes
Step 2. is the incorrect behavior. When there is a transaction on a
thread's todo list, this thread should not be able to send any outgoing
synchronous transactions. Only the head of the todo list needs to be
checked because only threads that are waiting for proc work can directly
receive work from another thread, and no work is allowed to be queued
on such a thread without waking up the thread. This patch also enforces
that a thread is not waiting for proc work when a work is directly
enqueued to its todo list.
Acked-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Sherry Yang <sherryy@android.com>
Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If asm/cacheflush.h is included first, the following build warnings are
seen with sparc32 builds.
In file included from arch/sparc/include/asm/cacheflush.h:11:0,
from drivers/android/binder.c:54:
arch/sparc/include/asm/cacheflush_32.h:40:37: warning:
'struct page' declared inside parameter list will not be visible
outside of this definition or declaration
Moving the asm/ include after linux/ includes solves the problem.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use new return type vm_fault_t for fault handler in
struct vm_operations_struct. For now, this is just
documenting that the function returns a VM_FAULT
value rather than an errno. Once all instances are
converted, vm_fault_t will become a distinct type.
Reference id -> 1c8f422059 ("mm: change return type
to vm_fault_t")
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder_update_page_range needs down_write of mmap_sem because
vm_insert_page need to change vma->vm_flags to VM_MIXEDMAP unless
it is set. However, when I profile binder working, it seems
every binder buffers should be mapped in advance by binder_mmap.
It means we could set VM_MIXEDMAP in binder_mmap time which is
already hold a mmap_sem as down_write so binder_update_page_range
doesn't need to hold a mmap_sem as down_write.
Please use proper API down_read. It would help mmap_sem contention
problem as well as fixing down_write abuse.
Ganesh Mahendran tested app launching and binder throughput test
and he said he couldn't find any problem and I did binder latency
test per Greg KH request(Thanks Martijn to teach me how I can do)
I cannot find any problem, too.
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Todd Kjos <tkjos@google.com>
Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When to execute binder_stat_br the e->cmd has been modifying as BR_OK
instead of the original return error cmd, in fact we want to know the
original return error, such as BR_DEAD_REPLY or BR_FAILED_REPLY, etc.
instead of always BR_OK, in order to avoid the value of the e->cmd is
always BR_OK, so we need assign the value of the e->cmd to cmd before
e->cmd = BR_OK.
Signed-off-by: songjinshi <songjinshi@xiaomi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
New devices launching with Android P need to use the 64-bit
binder interface, even on 32-bit SoCs [0].
This change removes the Kconfig option to select the 32-bit
binder interface. We don't think this will affect existing
userspace for the following reasons:
1) The latest Android common tree is 4.14, so we don't
believe any Android devices are on kernels >4.14.
2) Android devices launch on an LTS release and stick with
it, so we wouldn't expect devices running on <= 4.14 now
to upgrade to 4.17 or later. But even if they did, they'd
rebuild the world (kernel + userspace) anyway.
3) Other userspaces like 'anbox' are already using the
64-bit interface.
Note that this change doesn't remove the 32-bit UAPI
itself; the reason for that is that Android userspace
always uses the latest UAPI headers from upstream, and
userspace retains 32-bit support for devices that are
upgrading. This will be removed as well in 2-3 years,
at which point we can remove the code from the UAPI
as well.
Finally, this change introduces build errors on archs where
64-bit get_user/put_user is not supported, so make binder
unavailable on m68k (which wouldn't want it anyway).
[0]: https://android-review.googlesource.com/c/platform/build/+/595193
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It doesn't make any difference to runtime but I've switched these two
checks to make my static checker happy.
The problem is that "buffer->data_size" is user controlled and if it's
less than "sizeo(*hdr)" then that means "offset" can be more than
"buffer->data_size". It's just cleaner to check it in the other order.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This can't happen with normal nodes (because you can't get a ref
to a node you own), but it could happen with the context manager;
to make the behavior consistent with regular nodes, reject
transactions into the context manager by the process owning it.
Reported-by: syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com
Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The format specifier "%p" can leak kernel addresses. Use
"%pK" instead. There were 4 remaining cases in binder.c.
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
binder_send_failed_reply() is called when a synchronous
transaction fails. It reports an error to the thread that
is waiting for the completion. Given that the transaction
is synchronous, there should never be more than 1 error
response to that thread -- this was being asserted with
a WARN().
However, when exercising the driver with syzbot tests, cases
were observed where multiple "synchronous" requests were
sent without waiting for responses, so it is possible that
multiple errors would be reported to the thread. This testing
was conducted with panic_on_warn set which forced the crash.
This is easily reproduced by sending back-to-back
"synchronous" transactions without checking for any
response (eg, set read_size to 0):
bwr.write_buffer = (uintptr_t)&bc1;
bwr.write_size = sizeof(bc1);
bwr.read_buffer = (uintptr_t)&br;
bwr.read_size = 0;
ioctl(fd, BINDER_WRITE_READ, &bwr);
sleep(1);
bwr2.write_buffer = (uintptr_t)&bc2;
bwr2.write_size = sizeof(bc2);
bwr2.read_buffer = (uintptr_t)&br;
bwr2.read_size = 0;
ioctl(fd, BINDER_WRITE_READ, &bwr2);
sleep(1);
The first transaction is sent to the servicemanager and the reply
fails because no VMA is set up by this client. After
binder_send_failed_reply() is called, the BINDER_WORK_RETURN_ERROR
is sitting on the thread's todo list since the read_size was 0 and
the client is not waiting for a response.
The 2nd transaction is sent and the BINDER_WORK_RETURN_ERROR has not
been consumed, so the thread's reply_error.cmd is still set (normally
cleared when the BINDER_WORK_RETURN_ERROR is handled). Therefore
when the servicemanager attempts to reply to the 2nd failed
transaction, the error is already set and it triggers this warning.
This is a user error since it is not waiting for the synchronous
transaction to complete. If it ever does check, it will see an
error.
Changed the WARN() to a pr_warn().
Signed-off-by: Todd Kjos <tkjos@android.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the kzalloc() in binder_get_thread() fails, binder_poll()
dereferences the resulting NULL pointer.
Fix it by returning POLLERR if the memory allocation failed.
This bug was found by syzkaller using fault injection.
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:
for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done
with de-mangling cleanups yet to come.
NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.
The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull char/misc driver updates from Greg KH:
"Here is the big pull request for char/misc drivers for 4.16-rc1.
There's a lot of stuff in here. Three new driver subsystems were added
for various types of hardware busses:
- siox
- slimbus
- soundwire
as well as a new vboxguest subsystem for the VirtualBox hypervisor
drivers.
There's also big updates from the FPGA subsystem, lots of Android
binder fixes, the usual handful of hyper-v updates, and lots of other
smaller driver updates.
All of these have been in linux-next for a long time, with no reported
issues"
* tag 'char-misc-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (155 commits)
char: lp: use true or false for boolean values
android: binder: use VM_ALLOC to get vm area
android: binder: Use true and false for boolean values
lkdtm: fix handle_irq_event symbol for INT_HW_IRQ_EN
EISA: Delete error message for a failed memory allocation in eisa_probe()
EISA: Whitespace cleanup
misc: remove AVR32 dependencies
virt: vbox: Add error mapping for VERR_INVALID_NAME and VERR_NO_MORE_FILES
soundwire: Fix a signedness bug
uio_hv_generic: fix new type mismatch warnings
uio_hv_generic: fix type mismatch warnings
auxdisplay: img-ascii-lcd: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE
uio_hv_generic: add rescind support
uio_hv_generic: check that host supports monitor page
uio_hv_generic: create send and receive buffers
uio: document uio_hv_generic regions
doc: fix documentation about uio_hv_generic
vmbus: add monitor_id and subchannel_id to sysfs per channel
vmbus: fix ABI documentation
uio_hv_generic: use ISR callback method
...
Pull poll annotations from Al Viro:
"This introduces a __bitwise type for POLL### bitmap, and propagates
the annotations through the tree. Most of that stuff is as simple as
'make ->poll() instances return __poll_t and do the same to local
variables used to hold the future return value'.
Some of the obvious brainos found in process are fixed (e.g. POLLIN
misspelled as POLL_IN). At that point the amount of sparse warnings is
low and most of them are for genuine bugs - e.g. ->poll() instance
deciding to return -EINVAL instead of a bitmap. I hadn't touched those
in this series - it's large enough as it is.
Another problem it has caught was eventpoll() ABI mess; select.c and
eventpoll.c assumed that corresponding POLL### and EPOLL### were
equal. That's true for some, but not all of them - EPOLL### are
arch-independent, but POLL### are not.
The last commit in this series separates userland POLL### values from
the (now arch-independent) kernel-side ones, converting between them
in the few places where they are copied to/from userland. AFAICS, this
is the least disruptive fix preserving poll(2) ABI and making epoll()
work on all architectures.
As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
it will trigger only on what would've triggered EPOLLWRBAND on other
architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
at all on sparc. With this patch they should work consistently on all
architectures"
* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
make kernel-side POLL... arch-independent
eventpoll: no need to mask the result of epi_item_poll() again
eventpoll: constify struct epoll_event pointers
debugging printk in sg_poll() uses %x to print POLL... bitmap
annotate poll(2) guts
9p: untangle ->poll() mess
->si_band gets POLL... bitmap stored into a user-visible long field
ring_buffer_poll_wait() return value used as return value of ->poll()
the rest of drivers/*: annotate ->poll() instances
media: annotate ->poll() instances
fs: annotate ->poll() instances
ipc, kernel, mm: annotate ->poll() instances
net: annotate ->poll() instances
apparmor: annotate ->poll() instances
tomoyo: annotate ->poll() instances
sound: annotate ->poll() instances
acpi: annotate ->poll() instances
crypto: annotate ->poll() instances
block: annotate ->poll() instances
x86: annotate ->poll() instances
...
checkpatch warns against the use of symbolic permissions,
this patch migrates all symbolic permissions in the binder
driver to octal permissions.
Test: debugfs nodes created by binder have the same unix
permissions prior to and after this patch was applied.
Signed-off-by: Harsh Shandilya <harsh@prjkt.io>
Cc: "Arve Hjønnevåg" <arve@android.com>
Cc: Todd Kjos <tkjos@android.com>
Cc: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Todd Kjos
Wei Yongjun
Martijn Coenen
Rasmus Villemoes
Sherry Yang
Guenter Roeck
Souptick Joarder
Minchan Kim
宋金时
Martijn Coenen
Greg Kroah-Hartman
Dan Carpenter
Eric Biggers
Linus Torvalds
Gustavo A. R. Silva
Harsh Shandilya