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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Todd Kjos <tkjos@google.com>,
        Martijn Coenen <maco@android.com>
Subject: [PATCH 5.2 184/215] binder: Set end of SG buffer area properly.
Date:   Mon, 29 Jul 2019 21:23:00 +0200
Message-Id: <20190729190812.095573430@linuxfoundation.org>
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From: Martijn Coenen <maco@android.com>

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>

---
 drivers/android/binder.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3239,7 +3239,8 @@ static void binder_transaction(struct bi
 	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)) {