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From: Dan Carpenter <dan.carpenter@oracle.com>
To: kernel-janitors@vger.kernel.org
Subject: [PATCH] ANDROID: binder: re-order some conditions
Date: Thu, 29 Mar 2018 09:14:40 +0000	[thread overview]
Message-ID: <20180329091440.GC17927@mwanda> (raw)

It doesn't make any difference to runtime but I've switched these two
checks to make my static checker happy.

The problem is that "buffer->data_size" is user controlled and if it's
less than "sizeo(*hdr)" then that means "offset" can be more than
"buffer->data_size".  It's just cleaner to check it in the other order.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 764b63a5aade..00322b146469 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2058,8 +2058,8 @@ static size_t binder_validate_object(struct binder_buffer *buffer, u64 offset)
 	struct binder_object_header *hdr;
 	size_t object_size = 0;
 
-	if (offset > buffer->data_size - sizeof(*hdr) ||
-	    buffer->data_size < sizeof(*hdr) ||
+	if (buffer->data_size < sizeof(*hdr) ||
+	    offset > buffer->data_size - sizeof(*hdr) ||
 	    !IS_ALIGNED(offset, sizeof(u32)))
 		return 0;
 

             reply	other threads:[~2018-03-29  9:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-29  9:14 Dan Carpenter [this message]
2018-03-29 12:19 ` [PATCH] ANDROID: binder: re-order some conditions Martijn Coenen

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