Staging: binder: Add more offset validation.

Check that datasize is not smaller than one flat_binder_object.
Check that offsets are aligned.
Check that offsets_size is aligned.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index 761f5d6..64f95ee 100644 (file)
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -1430,10 +1430,19 @@ binder_transaction(struct binder_proc *proc, struct binder_thread *thread,
                return_error = BR_FAILED_REPLY;
                goto err_copy_data_failed;
        }
+       if (!IS_ALIGNED(tr->offsets_size, sizeof(size_t))) {
+               binder_user_error("binder: %d:%d got transaction with "
+                       "invalid offsets size, %zd\n",
+                       proc->pid, thread->pid, tr->offsets_size);
+               return_error = BR_FAILED_REPLY;
+               goto err_bad_offset;
+       }
        off_end = (void *)offp + tr->offsets_size;
        for (; offp < off_end; offp++) {
                struct flat_binder_object *fp;
-               if (*offp > t->buffer->data_size - sizeof(*fp)) {
+               if (*offp > t->buffer->data_size - sizeof(*fp) ||
+                   t->buffer->data_size < sizeof(*fp) ||
+                   !IS_ALIGNED(*offp, sizeof(void *))) {
                        binder_user_error("binder: %d:%d got transaction with "
                                "invalid offset, %zd\n",
                                proc->pid, thread->pid, *offp);
@@ -1651,7 +1660,9 @@ binder_transaction_buffer_release(struct binder_proc *proc, struct binder_buffer
                off_end = (void *)offp + buffer->offsets_size;
        for (; offp < off_end; offp++) {
                struct flat_binder_object *fp;
-               if (*offp > buffer->data_size - sizeof(*fp)) {
+               if (*offp > buffer->data_size - sizeof(*fp) ||
+                   buffer->data_size < sizeof(*fp) ||
+                   !IS_ALIGNED(*offp, sizeof(void *))) {
                        printk(KERN_ERR "binder: transaction release %d bad"
                                        "offset %zd, size %zd\n", debug_id, *offp, buffer->data_size);
                        continue;