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>
