Add a per-transaction flag to indicate that the buffer
must be cleared when the transaction is complete to
prevent copies of sensitive data from being preserved
in memory.
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20201120233743.3617529-1-tkjos@google.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bug: 171501513
Change-Id: Ic9338c85cbe3b11ab6f2bda55dce9964bb48447a
(cherry picked from commit 0f966cba95c78029f491b433ea95ff38f414a761)
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
The most common cause of the binder transaction buffer filling up is a
client rapidly firing oneway transactions into a process, before it has
a chance to handle them. Yet the root cause of this is often hard to
debug, because either the system or the app will stop, and by that time
binder debug information we dump in bugreports is no longer relevant.
This change warns as soon as a process dips below 80% of its oneway
space (less than 100kB available in the configuration), when any one
process is responsible for either more than 50 transactions, or more
than 50% of the oneway space.
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Martijn Coenen <maco@google.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20200821122544.1277051-1-maco@android.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 261e7818f06ec51e488e007f787ccd7e77272918
git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git/
char-misc-next)
Bug: 147795659
Change-Id: Idc2b03ddc779880ca4716fdae47a70df43211f25
Now that alloc->buffer points to the userspace vm_area
rename buffer->data to buffer->user_data and rename
local pointers that hold user addresses. Also use the
"__user" tag to annotate all user pointers so sparse
can flag cases where user pointer vaues are copied to
kernel pointers. Refactor code to use offsets instead
of user pointers.
(cherry pick from commit bde4a19fc04f5f46298c86b1acb7a4af1d5f138d)
Bug: 67668716
Change-Id: I9d04b844c5994d1f6214da795799e6b373bc9816
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Avoid vm_area when copying to or from binder buffers.
Instead, new copy functions are added that copy from
kernel space to binder buffer space. These use
kmap_atomic() and kunmap_atomic() to create temporary
mappings and then memcpy() is used to copy within
that page.
Also, kmap_atomic() / kunmap_atomic() use the appropriate
cache flushing to support VIVT cache architectures.
Allow binder to build if CPU_CACHE_VIVT is defined.
Several uses of the new functions are added here. More
to follow in subsequent patches.
(cherry picked from commit 8ced0c6231ead26eca8cb416dcb7cc1c2cdd41d8)
Bug: 67668716
Change-Id: I6a93d2396d0a80c352a1d563fc7fb523a753e38c
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The binder driver uses a vm_area to map the per-process
binder buffer space. For 32-bit android devices, this is
now taking too much vmalloc space. This patch removes
the use of vm_area when copying the transaction data
from the sender to the buffer space. Instead of using
copy_from_user() for multi-page copies, it now uses
binder_alloc_copy_user_to_buffer() which uses kmap()
and kunmap() to map each page, and uses copy_from_user()
for copying to that page.
(cherry picked from 1a7c3d9bb7a926e88d5f57643e75ad1abfc55013)
Bug: 67668716
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: I59ff83455984fce4626476e30601ed8b99858a92
commit 7bada55ab50697861eee6bb7d60b41e68a961a9c upstream
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.
Bug: 116855682
Change-Id: I0b38089f6fdb1adbf7e1102747e4119c9a05b191
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>
Show the high watermark of the index into the alloc->pages
array, to facilitate sizing the buffer on a per-process
basis.
Change-Id: I2b40cd16628e0ee45216c51dc9b3c5b0c862032e
Signed-off-by: Martijn Coenen <maco@android.com>
(from https://patchwork.kernel.org/patch/9954125/)
Use binder_alloc struct's mm_struct rather than getting
a reference to the mm struct through get_task_mm to
avoid a potential deadlock between lru lock, task lock and
dentry lock, since a thread can be holding the task lock
and the dentry lock while trying to acquire the lru lock.
Test: ran binderLibTest, throughputtest, interfacetest and
mempressure w/lockdep
Bug: 63926541
Change-Id: Icc661404eb7a4a2ecc5234b1bf8f0104665f9b45
Acked-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Sherry Yang <sherryy@android.com>
(from https://patchwork.kernel.org/patch/9928611/)
Add the number of active, lru, and free pages for
each binder process in binder stats
Bug: 63926541
Change-Id: I12618e4eb8ecc08f4f05fe4cba454a88830897f9
Signed-off-by: Sherry Yang <sherryy@android.com>
(from https://patchwork.kernel.org/patch/9928615/)
Hold on to the pages allocated and mapped for transaction
buffers until the system is under memory pressure. When
that happens, use linux shrinker to free pages. Without
using shrinker, patch "android: binder: Move buffer out
of area shared with user space" will cause a significant
slow down for small transactions that fit into the first
page because free list buffer header used to be inlined
with buffer data.
In addition to prevent the performance regression for
small transactions, this patch improves the performance
for transactions that take up more than one page.
Modify alloc selftest to work with the shrinker change.
Test: Run memory intensive applications (Chrome and Camera)
to trigger shrinker callbacks. Binder frees memory as expected.
Test: Run binderThroughputTest with high memory pressure
option enabled.
Bug: 63926541
Change-Id: I3abfc43b405e7e0a6228da37e0689a4b944f0e00
Signed-off-by: Sherry Yang <sherryy@android.com>
(from https://patchwork.kernel.org/patch/9928607/)
Binder driver allocates buffer meta data in a region that is mapped
in user space. These meta data contain pointers in the kernel.
This patch allocates buffer meta data on the kernel heap that is
not mapped in user space, and uses a pointer to refer to the data mapped.
Also move alloc->buffers initialization from mmap to init since it's
now used even when mmap failed or was not called.
Bug: 36007193
Change-Id: Id5136048bdb7b796f59de066de7ea7df410498f5
Signed-off-by: Sherry Yang <sherryy@android.com>
(from https://patchwork.kernel.org/patch/9928609/)
binder_alloc_selftest tests that alloc_new_buf handles page allocation and
deallocation properly when allocate and free buffers. The test allocates 5
buffers of various sizes to cover all possible page alignment cases, and
frees the buffers using a list of exhaustive freeing order.
Test: boot the device with ANDROID_BINDER_IPC_SELFTEST config option
enabled. Allocator selftest passes.
Bug: 36007193
Change-Id: I2fe396232b7dfe4bbc50bdba99ca0de9be63cc37
Signed-off-by: Sherry Yang <sherryy@android.com>
(from https://patchwork.kernel.org/patch/9817815/)
Adds protection against malicious user code freeing
the same buffer at the same time which could cause
a crash. Cannot happen under normal use.
Change-Id: I9461229401aaa7f3b5b2477960f79d4d1bd17fee
Signed-off-by: Todd Kjos <tkjos@google.com>
