binder: Set end of SG buffer area properly.

commit a56587065094fd96eb4c2b5ad65571daad32156d upstream.

In case the target node requests a security context, the
extra_buffers_size is increased with the size of the security context.
But, that size is not available for use by regular scatter-gather
buffers; make sure the ending of that buffer is marked correctly.

Acked-by: Todd Kjos <tkjos@google.com>
Fixes: ec74136ded79 ("binder: create node flag to request sender's security context")
Signed-off-by: Martijn Coenen <maco@android.com>
Cc: stable@vger.kernel.org # 5.1+
Link: https://lore.kernel.org/r/20190709110923.220736-1-maco@android.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 38a59a630cd4cb98badec27818949d75a206813e..5bde08603fbc2156f773702b3bfae000365bdd6a 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3239,7 +3239,8 @@ static void binder_transaction(struct binder_proc *proc,
        buffer_offset = off_start_offset;
        off_end_offset = off_start_offset + tr->offsets_size;
        sg_buf_offset = ALIGN(off_end_offset, sizeof(void *));
-       sg_buf_end_offset = sg_buf_offset + extra_buffers_size;
+       sg_buf_end_offset = sg_buf_offset + extra_buffers_size -
+               ALIGN(secctx_sz, sizeof(u64));
        off_min = 0;
        for (buffer_offset = off_start_offset; buffer_offset < off_end_offset;
             buffer_offset += sizeof(binder_size_t)) {