ANDROID: binder: support for file-descriptor arrays.
This patch introduces a new binder_fd_array object,
that allows us to support one or more file descriptors
embedded in a buffer that is scatter-gathered.
Change-Id: I647a53cf0d905c7be0dfd9333806982def68dd74
Signed-off-by: Martijn Coenen <maco@google.com>
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 6cf8747..6d3f4ee 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -155,6 +155,9 @@
#define to_binder_buffer_object(hdr) \
container_of(hdr, struct binder_buffer_object, hdr)
+#define to_binder_fd_array_object(hdr) \
+ container_of(hdr, struct binder_fd_array_object, hdr)
+
enum binder_stat_types {
BINDER_STAT_PROC,
BINDER_STAT_THREAD,
@@ -1311,6 +1314,9 @@
case BINDER_TYPE_PTR:
object_size = sizeof(struct binder_buffer_object);
break;
+ case BINDER_TYPE_FDA:
+ object_size = sizeof(struct binder_fd_array_object);
+ break;
default:
return 0;
}
@@ -1504,6 +1510,47 @@
* transaction buffer gets freed
*/
break;
+ case BINDER_TYPE_FDA: {
+ struct binder_fd_array_object *fda;
+ struct binder_buffer_object *parent;
+ uintptr_t parent_buffer;
+ u32 *fd_array;
+ size_t fd_index;
+ binder_size_t fd_buf_size;
+
+ fda = to_binder_fd_array_object(hdr);
+ parent = binder_validate_ptr(buffer, fda->parent,
+ off_start,
+ offp - off_start);
+ if (!parent) {
+ pr_err("transaction release %d bad parent offset",
+ debug_id);
+ continue;
+ }
+ /*
+ * Since the parent was already fixed up, convert it
+ * back to kernel address space to access it
+ */
+ parent_buffer = parent->buffer -
+ proc->user_buffer_offset;
+
+ fd_buf_size = sizeof(u32) * fda->num_fds;
+ if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
+ pr_err("transaction release %d invalid number of fds (%lld)\n",
+ debug_id, (u64)fda->num_fds);
+ continue;
+ }
+ if (fd_buf_size > parent->length ||
+ fda->parent_offset > parent->length - fd_buf_size) {
+ /* No space for all file descriptors here. */
+ pr_err("transaction release %d not enough space for %lld fds in buffer\n",
+ debug_id, (u64)fda->num_fds);
+ continue;
+ }
+ fd_array = (u32 *)(parent_buffer + fda->parent_offset);
+ for (fd_index = 0; fd_index < fda->num_fds; fd_index++)
+ task_close_fd(proc, fd_array[fd_index]);
+ } break;
default:
pr_err("transaction release %d bad object type %x\n",
debug_id, hdr->type);
@@ -1673,6 +1720,63 @@
return ret;
}
+static int binder_translate_fd_array(struct binder_fd_array_object *fda,
+ struct binder_buffer_object *parent,
+ struct binder_transaction *t,
+ struct binder_thread *thread,
+ struct binder_transaction *in_reply_to)
+{
+ binder_size_t fdi, fd_buf_size, num_installed_fds;
+ int target_fd;
+ uintptr_t parent_buffer;
+ u32 *fd_array;
+ struct binder_proc *proc = thread->proc;
+ struct binder_proc *target_proc = t->to_proc;
+
+ fd_buf_size = sizeof(u32) * fda->num_fds;
+ if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
+ binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",
+ proc->pid, thread->pid, (u64)fda->num_fds);
+ return -EINVAL;
+ }
+ if (fd_buf_size > parent->length ||
+ fda->parent_offset > parent->length - fd_buf_size) {
+ /* No space for all file descriptors here. */
+ binder_user_error("%d:%d not enough space to store %lld fds in buffer\n",
+ proc->pid, thread->pid, (u64)fda->num_fds);
+ return -EINVAL;
+ }
+ /*
+ * Since the parent was already fixed up, convert it
+ * back to the kernel address space to access it
+ */
+ parent_buffer = parent->buffer - target_proc->user_buffer_offset;
+ fd_array = (u32 *)(parent_buffer + fda->parent_offset);
+ if (!IS_ALIGNED((unsigned long)fd_array, sizeof(u32))) {
+ binder_user_error("%d:%d parent offset not aligned correctly.\n",
+ proc->pid, thread->pid);
+ return -EINVAL;
+ }
+ for (fdi = 0; fdi < fda->num_fds; fdi++) {
+ target_fd = binder_translate_fd(fd_array[fdi], t, thread,
+ in_reply_to);
+ if (target_fd < 0)
+ goto err_translate_fd_failed;
+ fd_array[fdi] = target_fd;
+ }
+ return 0;
+
+err_translate_fd_failed:
+ /*
+ * Failed to allocate fd or security error, free fds
+ * installed so far.
+ */
+ num_installed_fds = fdi;
+ for (fdi = 0; fdi < num_installed_fds; fdi++)
+ task_close_fd(target_proc, fd_array[fdi]);
+ return target_fd;
+}
+
static int binder_fixup_parent(struct binder_transaction *t,
struct binder_thread *thread,
struct binder_buffer_object *bp,
@@ -2001,6 +2105,38 @@
fp->pad_binder = 0;
fp->fd = target_fd;
} break;
+ case BINDER_TYPE_FDA: {
+ struct binder_fd_array_object *fda =
+ to_binder_fd_array_object(hdr);
+ struct binder_buffer_object *parent =
+ binder_validate_ptr(t->buffer, fda->parent,
+ off_start,
+ offp - off_start);
+ if (!parent) {
+ binder_user_error("%d:%d got transaction with invalid parent offset or type\n",
+ proc->pid, thread->pid);
+ return_error = BR_FAILED_REPLY;
+ goto err_bad_parent;
+ }
+ if (!binder_validate_fixup(t->buffer, off_start,
+ parent, fda->parent_offset,
+ last_fixup_obj,
+ last_fixup_min_off)) {
+ binder_user_error("%d:%d got transaction with out-of-order buffer fixup\n",
+ proc->pid, thread->pid);
+ return_error = BR_FAILED_REPLY;
+ goto err_bad_parent;
+ }
+ ret = binder_translate_fd_array(fda, parent, t, thread,
+ in_reply_to);
+ if (ret < 0) {
+ return_error = BR_FAILED_REPLY;
+ goto err_translate_failed;
+ }
+ last_fixup_obj = parent;
+ last_fixup_min_off =
+ fda->parent_offset + sizeof(u32) * fda->num_fds;
+ } break;
case BINDER_TYPE_PTR: {
struct binder_buffer_object *bp =
to_binder_buffer_object(hdr);
@@ -2071,6 +2207,7 @@
err_translate_failed:
err_bad_object_type:
err_bad_offset:
+err_bad_parent:
err_copy_data_failed:
trace_binder_transaction_failed_buffer_release(t->buffer);
binder_transaction_buffer_release(target_proc, t->buffer, offp);