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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Alex Deucher <alexander.deucher@amd.com>
Cc: "Sasha Levin" <sasha.levin@oracle.com>,
	"Christian König" <christian.koenig@amd.com>,
	dri-devel@lists.freedesktop.org
Subject: [patch] drm/radeon: integer underflow in radeon_cp_dispatch_texture()
Date: Tue, 23 Dec 2014 12:56:49 +0300	[thread overview]
Message-ID: <20141223095649.GA21469@mwanda> (raw)

The test:

	if (size > RADEON_MAX_TEXTURE_SIZE) {

"size" is an integer and it's controled by the user so it can be
negative and the test can underflow.  Later we use "size" in:

	dwords = size / 4;
	...
	RADEON_COPY_MT(buffer, data, (int)(dwords * sizeof(u32)));

It causes memory corruption to copy a negative size buffer.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Static checkers complain about the integer overflows here, and there are
many real overflows but they appear harmless.

diff --git a/drivers/gpu/drm/radeon/radeon_state.c b/drivers/gpu/drm/radeon/radeon_state.c
index 535403e..15aee72 100644
--- a/drivers/gpu/drm/radeon/radeon_state.c
+++ b/drivers/gpu/drm/radeon/radeon_state.c
@@ -1703,7 +1703,7 @@ static int radeon_cp_dispatch_texture(struct drm_device * dev,
 	u32 format;
 	u32 *buffer;
 	const u8 __user *data;
-	int size, dwords, tex_width, blit_width, spitch;
+	unsigned int size, dwords, tex_width, blit_width, spitch;
 	u32 height;
 	int i;
 	u32 texpitch, microtile;
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             reply	other threads:[~2014-12-23  9:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-23  9:56 Dan Carpenter [this message]
2014-12-29  9:42 ` [patch] drm/radeon: integer underflow in radeon_cp_dispatch_texture() Christian König
2015-01-05 17:10 ` Alex Deucher

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