BACKPORT: binder: Set end of SG buffer area properly.

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.

Bug: 136210786
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>
(cherry picked from commit a56587065094fd96eb4c2b5ad65571daad32156d)
Change-Id: Ib4d3a99e7a881992c1313169f902cfad02a508a6

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 235c4e11e01fe69438d3e90e8c7ec5d65f179737..1fe5f0c6f392bb79971d89fb7865ab321067f743 100644 (file)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3230,7 +3230,8 @@ static void binder_transaction(struct binder_proc *proc,
        }
        off_end = (void *)off_start + tr->offsets_size;
        sg_bufp = (u8 *)(PTR_ALIGN(off_end, sizeof(void *)));
-       sg_buf_end = sg_bufp + extra_buffers_size;
+       sg_buf_end = sg_bufp + extra_buffers_size -
+               ALIGN(secctx_sz, sizeof(u64));
        off_min = 0;
        for (; offp < off_end; offp++) {
                struct binder_object_header *hdr;