lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20200618153956.29558-16-m.szyprowski@samsung.com>
Date:   Thu, 18 Jun 2020 17:39:36 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     dri-devel@...ts.freedesktop.org, iommu@...ts.linux-foundation.org,
        linaro-mm-sig@...ts.linaro.org, linux-kernel@...r.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Christoph Hellwig <hch@....de>,
        Robin Murphy <robin.murphy@....com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-arm-kernel@...ts.infradead.org,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Tomi Valkeinen <tomi.valkeinen@...com>
Subject: [PATCH v6 15/36] drm: omapdrm: fix common struct sg_table related
 issues

The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function
returns the number of the created entries in the DMA address space.
However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and
dma_unmap_sg must be called with the original number of the entries
passed to the dma_map_sg().

struct sg_table is a common structure used for describing a non-contiguous
memory buffer, used commonly in the DRM and graphics subsystems. It
consists of a scatterlist with memory pages and DMA addresses (sgl entry),
as well as the number of scatterlist entries: CPU pages (orig_nents entry)
and DMA mapped pages (nents entry).

It turned out that it was a common mistake to misuse nents and orig_nents
entries, calling DMA-mapping functions with a wrong number of entries or
ignoring the number of mapped entries returned by the dma_map_sg()
function.

Fix the code to refer to proper nents or orig_nents entries. This driver
checks for a buffer contiguity in DMA address space, so it should test
sg_table->nents entry.

Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
---
 drivers/gpu/drm/omapdrm/omap_gem.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index ff0c4b0c3fd0..a7a9a0afe2b6 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -48,7 +48,7 @@ struct omap_gem_object {
 	 *   OMAP_BO_MEM_DMA_API flag set)
 	 *
 	 * - buffers imported from dmabuf (with the OMAP_BO_MEM_DMABUF flag set)
-	 *   if they are physically contiguous (when sgt->orig_nents == 1)
+	 *   if they are physically contiguous (when sgt->nents == 1)
 	 *
 	 * - buffers mapped through the TILER when dma_addr_cnt is not zero, in
 	 *   which case the DMA address points to the TILER aperture
@@ -1279,7 +1279,7 @@ struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
 	union omap_gem_size gsize;
 
 	/* Without a DMM only physically contiguous buffers can be supported. */
-	if (sgt->orig_nents != 1 && !priv->has_dmm)
+	if (sgt->nents != 1 && !priv->has_dmm)
 		return ERR_PTR(-EINVAL);
 
 	gsize.bytes = PAGE_ALIGN(size);
@@ -1293,7 +1293,7 @@ struct drm_gem_object *omap_gem_new_dmabuf(struct drm_device *dev, size_t size,
 
 	omap_obj->sgt = sgt;
 
-	if (sgt->orig_nents == 1) {
+	if (sgt->nents == 1) {
 		omap_obj->dma_addr = sg_dma_address(sgt->sgl);
 	} else {
 		/* Create pages list from sgt */
-- 
2.17.1

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ