linux-kernel - [PATCH v2 1/5] xen/gntdev: Fix dmabuf import with non-zero sgt offset

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200813062113.11030-2-andr2000@gmail.com>
Date:   Thu, 13 Aug 2020 09:21:09 +0300
From:   Oleksandr Andrushchenko <andr2000@...il.com>
To:     xen-devel@...ts.xenproject.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, boris.ostrovsky@...cle.com,
        jgross@...e.com, airlied@...ux.ie, daniel@...ll.ch
Cc:     sstabellini@...nel.org, dan.carpenter@...cle.com,
        intel-gfx@...ts.freedesktop.org,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>,
        stable@...r.kernel.org
Subject: [PATCH v2 1/5] xen/gntdev: Fix dmabuf import with non-zero sgt offset

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>

It is possible that the scatter-gather table during dmabuf import has
non-zero offset of the data, but user-space doesn't expect that.
Fix this by failing the import, so user-space doesn't access wrong data.

Fixes: bf8dc55b1358 ("xen/gntdev: Implement dma-buf import functionality")

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
Acked-by: Juergen Gross <jgross@...e.com>
Cc: <stable@...r.kernel.org>
---
 drivers/xen/gntdev-dmabuf.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index 75d3bb948bf3..b1b6eebafd5d 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -613,6 +613,14 @@ dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
 		goto fail_detach;
 	}
 
+	/* Check that we have zero offset. */
+	if (sgt->sgl->offset) {
+		ret = ERR_PTR(-EINVAL);
+		pr_debug("DMA buffer has %d bytes offset, user-space expects 0\n",
+			 sgt->sgl->offset);
+		goto fail_unmap;
+	}
+
 	/* Check number of pages that imported buffer has. */
 	if (attach->dmabuf->size != gntdev_dmabuf->nr_pages << PAGE_SHIFT) {
 		ret = ERR_PTR(-EINVAL);
-- 
2.17.1