The binder_buffer allocator currently only allocates
space for the data and offsets buffers of a Parcel.
This change allows for requesting an additional chunk
of data in the buffer, which can for example be used
to hold additional meta-data about the transaction
(eg a security context).
Signed-off-by: Martijn Coenen <m...@android.com>
---
drivers/android/binder.c | 41 ++++++++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 13 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f2a0ae6..18a3254 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -302,6 +302,7 @@ struct binder_buffer {
struct binder_node *target_node;
size_t data_size;
size_t offsets_size;
+ size_t extra_buffers_size;
uint8_t data[0];
};
@@ -669,7 +670,9 @@ static int binder_update_page_range(struct binder_proc
*proc, int allocate,
static struct binder_buffer *binder_alloc_buf(struct binder_proc *proc,
size_t data_size,
- size_t offsets_size, int is_async)
+ size_t offsets_size,
+ size_t extra_buffers_size,
+ int is_async)
{
struct rb_node *n = proc->free_buffers.rb_node;
struct binder_buffer *buffer;
@@ -677,7 +680,7 @@ static struct binder_buffer *binder_alloc_buf(struct
binder_proc *proc,
struct rb_node *best_fit = NULL;
void *has_page_addr;
void *end_page_addr;
- size_t size;
+ size_t size, data_offsets_size;
if (proc->vma == NULL) {
pr_err("%d: binder_alloc_buf, no vma\n",
@@ -685,15 +688,20 @@ static struct binder_buffer *binder_alloc_buf(struct
binder_proc *proc,
return NULL;
}
- size = ALIGN(data_size, sizeof(void *)) +
+ data_offsets_size = ALIGN(data_size, sizeof(void *)) +
ALIGN(offsets_size, sizeof(void *));
- if (size < data_size || size < offsets_size) {
+ if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
binder_user_error("%d: got transaction with invalid size
%zd-%zd\n",
proc->pid, data_size, offsets_size);
return NULL;
}
-
+ size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
+ if (size < data_offsets_size || size < extra_buffers_size) {
+ binder_user_error("%d: got transaction with invalid
extra_buffers_size %zd\n",
+ proc->pid, extra_buffers_size);
+ return NULL;
+ }
if (is_async &&
proc->free_async_space < size + sizeof(struct binder_buffer)) {
binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
@@ -762,6 +770,7 @@ static struct binder_buffer *binder_alloc_buf(struct
binder_proc *proc,
proc->pid, size, buffer);
buffer->data_size = data_size;
buffer->offsets_size = offsets_size;
+ buffer->extra_buffers_size = extra_buffers_size;
buffer->async_transaction = is_async;
if (is_async) {
proc->free_async_space -= size + sizeof(struct binder_buffer);
@@ -836,7 +845,8 @@ static void binder_free_buf(struct binder_proc *proc,
buffer_size = binder_buffer_size(proc, buffer);
size = ALIGN(buffer->data_size, sizeof(void *)) +
- ALIGN(buffer->offsets_size, sizeof(void *));
+ ALIGN(buffer->offsets_size, sizeof(void *)) +
+ ALIGN(buffer->extra_buffers_size, sizeof(void *));
binder_debug(BINDER_DEBUG_BUFFER_ALLOC,
"%d: binder_free_buf %p size %zd buffer_size %zd\n",
@@ -1554,7 +1564,8 @@ static int binder_translate_fd(int fd,
static void binder_transaction(struct binder_proc *proc,
struct binder_thread *thread,
- struct binder_transaction_data *tr, int reply)
+ struct binder_transaction_data *tr, int reply,
+ binder_size_t extra_buffers_size)
{
int ret;
struct binder_transaction *t;
@@ -1698,20 +1709,22 @@ static void binder_transaction(struct binder_proc *proc,
if (reply)
binder_debug(BINDER_DEBUG_TRANSACTION,
- "%d:%d BC_REPLY %d -> %d:%d, data %016llx-%016llx
size %lld-%lld\n",
+ "%d:%d BC_REPLY %d -> %d:%d, data %016llx-%016llx
size %lld-%lld-%lld\n",
proc->pid, thread->pid, t->debug_id,
target_proc->pid, target_thread->pid,
(u64)tr->data.ptr.buffer,
(u64)tr->data.ptr.offsets,
- (u64)tr->data_size, (u64)tr->offsets_size);
+ (u64)tr->data_size, (u64)tr->offsets_size,
+ (u64)extra_buffers_size);
else
binder_debug(BINDER_DEBUG_TRANSACTION,
- "%d:%d BC_TRANSACTION %d -> %d - node %d, data
%016llx-%016llx size %lld-%lld\n",
+ "%d:%d BC_TRANSACTION %d -> %d - node %d, data
%016llx-%016llx size %lld-%lld-%lld\n",
proc->pid, thread->pid, t->debug_id,
target_proc->pid, target_node->debug_id,
(u64)tr->data.ptr.buffer,
(u64)tr->data.ptr.offsets,
- (u64)tr->data_size, (u64)tr->offsets_size);
+ (u64)tr->data_size, (u64)tr->offsets_size,
+ (u64)extra_buffers_size);
if (!reply && !(tr->flags & TF_ONE_WAY))
t->from = thread;
@@ -1727,7 +1740,8 @@ static void binder_transaction(struct binder_proc *proc,
trace_binder_transaction(reply, t, target_node);
t->buffer = binder_alloc_buf(target_proc, tr->data_size,
- tr->offsets_size, !reply && (t->flags & TF_ONE_WAY));
+ tr->offsets_size, extra_buffers_size,
+ !reply && (t->flags & TF_ONE_WAY));
if (t->buffer == NULL) {
return_error = BR_FAILED_REPLY;
goto err_binder_alloc_buf_failed;
@@ -2077,7 +2091,8 @@ static int binder_thread_write(struct binder_proc *proc,
if (copy_from_user(&tr, ptr, sizeof(tr)))
return -EFAULT;
ptr += sizeof(tr);
- binder_transaction(proc, thread, &tr, cmd == BC_REPLY);
+ binder_transaction(proc, thread, &tr,
+ cmd == BC_REPLY, 0);
break;
}
--
2.8.0.rc3.226.g39d4020
