[linux] 03/07: [x86] drm/vmwgfx: Make sure backup_handle is always valid (CVE-2017-9605)

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carnil pushed a commit to branch jessie-security
in repository linux.

commit 066bfdf35435eb92e95b67ac25c9574b8ed2ada4
Author: Salvatore Bonaccorso <carnil at debian.org>
Date:   Fri Jul 28 08:56:19 2017 +0200

    [x86] drm/vmwgfx: Make sure backup_handle is always valid (CVE-2017-9605)
---
 debian/changelog                                   |  1 +
 ...x-Make-sure-backup_handle-is-always-valid.patch | 48 ++++++++++++++++++++++
 debian/patches/series                              |  1 +
 3 files changed, 50 insertions(+)

diff --git a/debian/changelog b/debian/changelog
index cd07064..d8d4b1f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -10,6 +10,7 @@ linux (3.16.43-2+deb8u3) UNRELEASED; urgency=medium
     (CVE-2017-7541)
   * ipv6: avoid overflow of offset in ip6_find_1stfragopt (CVE-2017-7542)
   * [x86] mm: Tighten x86 /dev/mem with zeroing reads (CVE-2017-7889)
+  * [x86] drm/vmwgfx: Make sure backup_handle is always valid (CVE-2017-9605)
 
  -- Salvatore Bonaccorso <carnil at debian.org>  Thu, 27 Jul 2017 22:02:24 +0200
 
diff --git a/debian/patches/bugfix/x86/drm-vmwgfx-Make-sure-backup_handle-is-always-valid.patch b/debian/patches/bugfix/x86/drm-vmwgfx-Make-sure-backup_handle-is-always-valid.patch
new file mode 100644
index 0000000..3c604e7
--- /dev/null
+++ b/debian/patches/bugfix/x86/drm-vmwgfx-Make-sure-backup_handle-is-always-valid.patch
@@ -0,0 +1,48 @@
+From: Sinclair Yeh <syeh at vmware.com>
+Date: Fri, 2 Jun 2017 07:50:57 +0200
+Subject: drm/vmwgfx: Make sure backup_handle is always valid
+Origin: https://git.kernel.org/linus/07678eca2cf9c9a18584e546c2b2a0d0c9a3150c
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-9605
+
+When vmw_gb_surface_define_ioctl() is called with an existing buffer,
+we end up returning an uninitialized variable in the backup_handle.
+
+The fix is to first initialize backup_handle to 0 just to be sure, and
+second, when a user-provided buffer is found, we will use the
+req->buffer_handle as the backup_handle.
+
+Cc: <stable at vger.kernel.org>
+Reported-by: Murray McAllister <murray.mcallister at insomniasec.com>
+Signed-off-by: Sinclair Yeh <syeh at vmware.com>
+Reviewed-by: Deepak Rawat <drawat at vmware.com>
+[bwh: Backported to 3.16: There's no size check after vmw_user_dmabuf_lookup(),
+ so only check ret == 0.]
+---
+ drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+index 17c78638f34a..22f94030d995 100644
+--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
++++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+@@ -1245,7 +1245,7 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
+ 	int ret;
+ 	uint32_t size;
+ 	const struct svga3d_surface_desc *desc;
+-	uint32_t backup_handle;
++	uint32_t backup_handle = 0;
+ 
+ 	if (req->mip_levels > DRM_VMW_MAX_MIP_LEVELS)
+ 		return -EINVAL;
+@@ -1317,6 +1317,8 @@ int vmw_gb_surface_define_ioctl(struct drm_device *dev, void *data,
+ 		ret = vmw_user_dmabuf_lookup(tfile, req->buffer_handle,
+ 					     &res->backup,
+ 					     &user_srf->backup_base);
++		if (ret == 0)
++			backup_handle = req->buffer_handle;
+ 	} else if (req->drm_surface_flags &
+ 		   drm_vmw_surface_flag_create_buffer)
+ 		ret = vmw_user_dmabuf_alloc(dev_priv, tfile,
+-- 
+2.11.0
+
diff --git a/debian/patches/series b/debian/patches/series
index c8f7bd4..31b90a9 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -718,6 +718,7 @@ bugfix/all/rxrpc-Fix-several-cases-where-a-padded-len-isn-t-che.patch
 bugfix/all/brcmfmac-fix-possible-buffer-overflow-in-brcmf_cfg80.patch
 bugfix/all/ipv6-avoid-overflow-of-offset-in-ip6_find_1stfragopt.patch
 bugfix/x86/mm-Tighten-x86-dev-mem-with-zeroing-reads.patch
+bugfix/x86/drm-vmwgfx-Make-sure-backup_handle-is-always-valid.patch
 
 # Fix ABI changes
 debian/of-fix-abi-changes.patch

-- 
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