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staging: android: binder: fix alignment issues

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The Android userspace aligns the data written to the binder buffers to
4bytes. Thus for 32bit platforms or 64bit platforms running an 32bit
Android userspace we can have a buffer looking like this:

platform    buffer(binder_cmd   pointer)      size
32/32                 32b         32b          8B
64/32                 32b         64b          12B
64/64                 32b         64b          12B

Thus the kernel needs to check that the buffer size is aligned to 4bytes
not to (void *) that will be 8bytes on 64bit machines.

The change does not affect existing 32bit ABI.

Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>
Acked-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Serban Constantinescu 2013-07-04 10:54:46 +01:00 committed by Greg Kroah-Hartman
parent fc56f2ecf0
commit ec35e852dc
1 changed files with 2 additions and 2 deletions
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4
drivers/staging/android/binder.c
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@ -1248,7 +1248,7 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
struct flat_binder_object *fp;
if (*offp > buffer->data_size - sizeof(*fp) ||
buffer->data_size < sizeof(*fp) ||
!IS_ALIGNED(*offp, sizeof(void *))) {
!IS_ALIGNED(*offp, sizeof(u32))) {
pr_err("transaction release %d bad offset %zd, size %zd\n",
debug_id, *offp, buffer->data_size);
continue;
@ -1497,7 +1497,7 @@ static void binder_transaction(struct binder_proc *proc,
struct flat_binder_object *fp;
if (*offp > t->buffer->data_size - sizeof(*fp) ||
t->buffer->data_size < sizeof(*fp) ||
!IS_ALIGNED(*offp, sizeof(void *))) {
!IS_ALIGNED(*offp, sizeof(u32))) {
binder_user_error("%d:%d got transaction with invalid offset, %zd\n",
proc->pid, thread->pid, *offp);
return_error = BR_FAILED_REPLY;