linux-stable.git/drivers/android/binder.c, branch v5.4.280

binder: fix max_thread type inconsistency

2024-06-16T11:28:48+00:00

commit 42316941335644a98335f209daafa4c122f28983 upstream.

The type defined for the BINDER_SET_MAX_THREADS ioctl was changed from
size_t to __u32 in order to avoid incompatibility issues between 32 and
64-bit kernels. However, the internal types used to copy from user and
store the value were never updated. Use u32 to fix the inconsistency.

Fixes: a9350fc859ae ("staging: android: binder: fix BINDER_SET_MAX_THREADS declaration")
Reported-by: Arve Hjønnevåg 
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20240421173750.3117808-1-cmllamas@google.com
[cmllamas: resolve minor conflicts due to missing commit 421518a2740f]
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman

binder: check offset alignment in binder_get_object()

2024-05-02T14:18:31+00:00

commit aaef73821a3b0194a01bd23ca77774f704a04d40 upstream.

Commit 6d98eb95b450 ("binder: avoid potential data leakage when copying
txn") introduced changes to how binder objects are copied. In doing so,
it unintentionally removed an offset alignment check done through calls
to binder_alloc_copy_from_buffer() -> check_buffer().

These calls were replaced in binder_get_object() with copy_from_user(),
so now an explicit offset alignment check is needed here. This avoids
later complications when unwinding the objects gets harder.

It is worth noting this check existed prior to commit 7a67a39320df
("binder: add function to copy binder object from buffer"), likely
removed due to redundancy at the time.

Fixes: 6d98eb95b450 ("binder: avoid potential data leakage when copying txn")
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas 
Acked-by: Todd Kjos 
Link: https://lore.kernel.org/r/20240330190115.1877819-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman

binder: signal epoll threads of self-work

2024-02-23T07:25:11+00:00

commit 97830f3c3088638ff90b20dfba2eb4d487bf14d7 upstream.

In (e)poll mode, threads often depend on I/O events to determine when
data is ready for consumption. Within binder, a thread may initiate a
command via BINDER_WRITE_READ without a read buffer and then make use
of epoll_wait() or similar to consume any responses afterwards.

It is then crucial that epoll threads are signaled via wakeup when they
queue their own work. Otherwise, they risk waiting indefinitely for an
event leaving their work unhandled. What is worse, subsequent commands
won't trigger a wakeup either as the thread has pending work.

Fixes: 457b9a6f09f0 ("Staging: android: add binder driver")
Cc: Arve Hjønnevåg 
Cc: Martijn Coenen 
Cc: Alice Ryhl 
Cc: Steven Moreland 
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Carlos Llamas 
Link: https://lore.kernel.org/r/20240131215347.1808751-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

binder: use EPOLLERR from eventpoll.h

2024-01-25T22:34:21+00:00

commit 6ac061db9c58ca5b9270b1b3940d2464fb3ff183 upstream.

Use EPOLLERR instead of POLLERR to make sure it is cast to the correct
__poll_t type. This fixes the following sparse issue:

  drivers/android/binder.c:5030:24: warning: incorrect type in return expression (different base types)
  drivers/android/binder.c:5030:24:    expected restricted __poll_t
  drivers/android/binder.c:5030:24:    got int

Fixes: f88982679f54 ("binder: check for binder_thread allocation failure in binder_poll()")
Cc: stable@vger.kernel.org
Cc: Eric Biggers 
Reviewed-by: Alice Ryhl 
Signed-off-by: Carlos Llamas 
Link: https://lore.kernel.org/r/20231201172212.1813387-2-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman

binder: fix memory leak in binder_init()

2023-08-16T16:19:23+00:00

commit adb9743d6a08778b78d62d16b4230346d3508986 upstream.

In binder_init(), the destruction of binder_alloc_shrinker_init() is not
performed in the wrong path, which will cause memory leaks. So this commit
introduces binder_alloc_shrinker_exit() and calls it in the wrong path to
fix that.

Signed-off-by: Qi Zheng 
Acked-by: Carlos Llamas 
Fixes: f2517eb76f1f ("android: binder: Add global lru shrinker to binder")
Cc: stable 
Link: https://lore.kernel.org/r/20230625154937.64316-1-qi.zheng@linux.dev
Signed-off-by: Greg Kroah-Hartman

binder: fix UAF caused by faulty buffer cleanup

2023-06-05T06:17:33+00:00

commit bdc1c5fac982845a58d28690cdb56db8c88a530d upstream.

In binder_transaction_buffer_release() the 'failed_at' offset indicates
the number of objects to clean up. However, this function was changed by
commit 44d8047f1d87 ("binder: use standard functions to allocate fds"),
to release all the objects in the buffer when 'failed_at' is zero.

This introduced an issue when a transaction buffer is released without
any objects having been processed so far. In this case, 'failed_at' is
indeed zero yet it is misinterpreted as releasing the entire buffer.

This leads to use-after-free errors where nodes are incorrectly freed
and subsequently accessed. Such is the case in the following KASAN
report:

  ==================================================================
  BUG: KASAN: slab-use-after-free in binder_thread_read+0xc40/0x1f30
  Read of size 8 at addr ffff4faf037cfc58 by task poc/474

  CPU: 6 PID: 474 Comm: poc Not tainted 6.3.0-12570-g7df047b3f0aa #5
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   dump_backtrace+0x94/0xec
   show_stack+0x18/0x24
   dump_stack_lvl+0x48/0x60
   print_report+0xf8/0x5b8
   kasan_report+0xb8/0xfc
   __asan_load8+0x9c/0xb8
   binder_thread_read+0xc40/0x1f30
   binder_ioctl+0xd9c/0x1768
   __arm64_sys_ioctl+0xd4/0x118
   invoke_syscall+0x60/0x188
  [...]

  Allocated by task 474:
   kasan_save_stack+0x3c/0x64
   kasan_set_track+0x2c/0x40
   kasan_save_alloc_info+0x24/0x34
   __kasan_kmalloc+0xb8/0xbc
   kmalloc_trace+0x48/0x5c
   binder_new_node+0x3c/0x3a4
   binder_transaction+0x2b58/0x36f0
   binder_thread_write+0x8e0/0x1b78
   binder_ioctl+0x14a0/0x1768
   __arm64_sys_ioctl+0xd4/0x118
   invoke_syscall+0x60/0x188
  [...]

  Freed by task 475:
   kasan_save_stack+0x3c/0x64
   kasan_set_track+0x2c/0x40
   kasan_save_free_info+0x38/0x5c
   __kasan_slab_free+0xe8/0x154
   __kmem_cache_free+0x128/0x2bc
   kfree+0x58/0x70
   binder_dec_node_tmpref+0x178/0x1fc
   binder_transaction_buffer_release+0x430/0x628
   binder_transaction+0x1954/0x36f0
   binder_thread_write+0x8e0/0x1b78
   binder_ioctl+0x14a0/0x1768
   __arm64_sys_ioctl+0xd4/0x118
   invoke_syscall+0x60/0x188
  [...]
  ==================================================================

In order to avoid these issues, let's always calculate the intended
'failed_at' offset beforehand. This is renamed and wrapped in a helper
function to make it clear and convenient.

Fixes: 32e9f56a96d8 ("binder: don't detect sender/target during buffer cleanup")
Reported-by: Zi Fan Tan 
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas 
Acked-by: Todd Kjos 
Link: https://lore.kernel.org/r/20230505203020.4101154-1-cmllamas@google.com
[cmllamas: resolve trivial conflict due to missing commit 9864bb4801331]
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman

binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0

2022-12-08T10:23:01+00:00

commit ef38de9217a04c9077629a24652689d8fdb4c6c6 upstream.

Some android userspace is sending BINDER_TYPE_FDA objects with
num_fds=0. Like the previous patch, this is reproducible when
playing a video.

Before commit 09184ae9b575 BINDER_TYPE_FDA objects with num_fds=0
were 'correctly handled', as in no fixup was performed.

After commit 09184ae9b575 we aggregate fixup and skip regions in
binder_ptr_fixup structs and distinguish between the two by using
the skip_size field: if it's 0, then it's a fixup, otherwise skip.
When processing BINDER_TYPE_FDA objects with num_fds=0 we add a
skip region of skip_size=0, and this causes issues because now
binder_do_deferred_txn_copies will think this was a fixup region.

To address that, return early from binder_translate_fd_array to
avoid adding an empty skip region.

Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos 
Cc: stable 
Signed-off-by: Alessandro Astone 
Link: https://lore.kernel.org/r/20220415120015.52684-1-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman

binder: Address corner cases in deferred copy and fixup

2022-12-08T10:23:01+00:00

commit 2d1746e3fda0c3612143d7c06f8e1d1830c13e23 upstream.

When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().

This is reproducible in android when playing a video.
We receive a transaction that looks like this:
    obj[0] BINDER_TYPE_PTR, parent
    obj[1] BINDER_TYPE_PTR, child
    obj[2] BINDER_TYPE_PTR, child
    obj[3] BINDER_TYPE_FDA, child

Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos 
Cc: stable 
Signed-off-by: Alessandro Astone 
Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman

binder: fix pointer cast warning

2022-12-08T10:23:01+00:00

commit 9a0a930fe2535a76ad70d3f43caeccf0d86a3009 upstream.

binder_uintptr_t is not the same as uintptr_t, so converting it into a
pointer requires a second cast:

drivers/android/binder.c: In function 'binder_translate_fd_array':
drivers/android/binder.c:2511:28: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
 2511 |         sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
      |                            ^

Fixes: 656e01f3ab54 ("binder: read pre-translated fds from sender buffer")
Acked-by: Todd Kjos 
Acked-by: Randy Dunlap  # build-tested
Acked-by: Christian Brauner 
Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20211207122448.1185769-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman

binder: defer copies of pre-patched txn data

2022-12-08T10:23:01+00:00

commit 09184ae9b5756cc469db6fd1d1cfdcffbf627c2d upstream.

BINDER_TYPE_PTR objects point to memory areas in the
source process to be copied into the target buffer
as part of a transaction. This implements a scatter-
gather model where non-contiguous memory in a source
process is "gathered" into a contiguous region in
the target buffer.

The data can include pointers that must be fixed up
to correctly point to the copied data. To avoid making
source process pointers visible to the target process,
this patch defers the copy until the fixups are known
and then copies and fixeups are done together.

There is a special case of BINDER_TYPE_FDA which applies
the fixup later in the target process context. In this
case the user data is skipped (so no untranslated fds
become visible to the target).

Reviewed-by: Martijn Coenen 
Signed-off-by: Todd Kjos 
Link: https://lore.kernel.org/r/20211130185152.437403-5-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman 
[cmllamas: fix trivial merge conflict]
Signed-off-by: Carlos Llamas 
Signed-off-by: Greg Kroah-Hartman