linux-stable.git/include/xen/interface/io, branch v3.4.89

xen/io/ring.h: new macro to detect whether there are too many requests on the ring

2014-03-11T23:10:07+00:00

commit 8d9256906a97c24e97e016482b9be06ea2532b05 upstream.

Backends may need to protect themselves against an insane number of
produced requests stored by a frontend, in case they iterate over
requests until reaching the req_prod value. There can't be more
requests on the ring than the difference between produced requests
and produced (but possibly not yet published) responses.

This is a more strict alternative to a patch previously posted by
Konrad Rzeszutek Wilk .

Signed-off-by: Jan Beulich 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Ben Hutchings 
Cc: Yijing Wang 
Signed-off-by: Greg Kroah-Hartman

xen-netback: coalesce slots in TX path and fix regressions

2014-03-11T23:10:07+00:00

commit 2810e5b9a7731ca5fce22bfbe12c96e16ac44b6f upstream.

This patch tries to coalesce tx requests when constructing grant copy
structures. It enables netback to deal with situation when frontend's
MAX_SKB_FRAGS is larger than backend's MAX_SKB_FRAGS.

With the help of coalescing, this patch tries to address two regressions
avoid reopening the security hole in XSA-39.

Regression 1. The reduction of the number of supported ring entries (slots)
per packet (from 18 to 17). This regression has been around for some time but
remains unnoticed until XSA-39 security fix. This is fixed by coalescing
slots.

Regression 2. The XSA-39 security fix turning "too many frags" errors from
just dropping the packet to a fatal error and disabling the VIF. This is fixed
by coalescing slots (handling 18 slots when backend's MAX_SKB_FRAGS is 17)
which rules out false positive (using 18 slots is legit) and dropping packets
using 19 to `max_skb_slots` slots.

To avoid reopening security hole in XSA-39, frontend sending packet using more
than max_skb_slots is considered malicious.

The behavior of netback for packet is thus:

    1-18            slots: valid
   19-max_skb_slots slots: drop and respond with an error
   max_skb_slots+   slots: fatal error

max_skb_slots is configurable by admin, default value is 20.

Also change variable name from "frags" to "slots" in netbk_count_requests.

Please note that RX path still has dependency on MAX_SKB_FRAGS. This will be
fixed with separate patch.

Signed-off-by: Wei Liu 
Acked-by: Ian Campbell 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings 
Cc: Yijing Wang 
Signed-off-by: Greg Kroah-Hartman

xen/blkback: correctly respond to unknown, non-native requests

2013-04-05T17:04:18+00:00

commit 0e367ae46503cfe7791460c8ba8434a5d60b2bd5 upstream.

If the frontend is using a non-native protocol (e.g., a 64-bit
frontend with a 32-bit backend) and it sent an unrecognized request,
the request was not translated and the response would have the
incorrect ID.  This may cause the frontend driver to behave
incorrectly or crash.

Since the ID field in the request is always in the same place,
regardless of the request type we can get the correct ID and make a
valid response (which will report BLKIF_RSP_EOPNOTSUPP).

This bug affected 64-bit SLES 11 guests when using a 32-bit backend.
This guest does a BLKIF_OP_RESERVED_1 (BLKIF_OP_PACKET in the SLES
source) and would crash in blkif_int() as the ID in the response would
be invalid.

Signed-off-by: David Vrabel 
Signed-off-by: Konrad Rzeszutek Wilk 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-3.3/drivers' of git://git.kernel.dk/linux-block

2012-01-15T20:48:41+00:00

* 'for-3.3/drivers' of git://git.kernel.dk/linux-block:
  mtip32xx: do rebuild monitoring asynchronously
  xen-blkfront: Use kcalloc instead of kzalloc to allocate array
  mtip32xx: uninitialized variable in mtip_quiesce_io()
  mtip32xx: updates based on feedback
  xen-blkback: convert hole punching to discard request on loop devices
  xen/blkback: Move processing of BLKIF_OP_DISCARD from dispatch_rw_block_io
  xen/blk[front|back]: Enhance discard support with secure erasing support.
  xen/blk[front|back]: Squash blkif_request_rw and blkif_request_discard together
  mtip32xx: update to new ->make_request() API
  mtip32xx: add module.h include to avoid conflict with moduleh tree
  mtip32xx: mark a few more items static
  mtip32xx: ensure that all local functions are static
  mtip32xx: cleanup compat ioctl handling
  mtip32xx: fix warnings/errors on 32-bit compiles
  block: Add driver for Micron RealSSD pcie flash cards

Merge branch 'stable/for-linus-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

2012-01-10T18:09:59+00:00

* 'stable/for-linus-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (37 commits)
  xen/pciback: Expand the warning message to include domain id.
  xen/pciback: Fix "device has been assigned to X domain!" warning
  xen/pciback: Move the PCI_DEV_FLAGS_ASSIGNED ops to the "[un|]bind"
  xen/xenbus: don't reimplement kvasprintf via a fixed size buffer
  xenbus: maximum buffer size is XENSTORE_PAYLOAD_MAX
  xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX.
  Xen: consolidate and simplify struct xenbus_driver instantiation
  xen-gntalloc: introduce missing kfree
  xen/xenbus: Fix compile error - missing header for xen_initial_domain()
  xen/netback: Enable netback on HVM guests
  xen/grant-table: Support mappings required by blkback
  xenbus: Use grant-table wrapper functions
  xenbus: Support HVM backends
  xen/xenbus-frontend: Fix compile error with randconfig
  xen/xenbus-frontend: Make error message more clear
  xen/privcmd: Remove unused support for arch specific privcmp mmap
  xen: Add xenbus_backend device
  xen: Add xenbus device driver
  xen: Add privcmd device driver
  xen/gntalloc: fix reference counts on multi-page mappings
  ...

xen/xenbus: Reject replies with payload > XENSTORE_PAYLOAD_MAX.

2012-01-04T22:02:03+00:00

Haogang Chen found out that:

 There is a potential integer overflow in process_msg() that could result
 in cross-domain attack.

 	body = kmalloc(msg->hdr.len + 1, GFP_NOIO | __GFP_HIGH);

 When a malicious guest passes 0xffffffff in msg->hdr.len, the subsequent
 call to xb_read() would write to a zero-length buffer.

 The other end of this connection is always the xenstore backend daemon
 so there is no guest (malicious or otherwise) which can do this. The
 xenstore daemon is a trusted component in the system.

 However this seem like a reasonable robustness improvement so we should
 have it.

And Ian when read the API docs found that:
        The payload length (len field of the header) is limited to 4096
        (XENSTORE_PAYLOAD_MAX) in both directions.  If a client exceeds the
        limit, its xenstored connection will be immediately killed by
        xenstored, which is usually catastrophic from the client's point of
        view.  Clients (particularly domains, which cannot just reconnect)
        should avoid this.

so this patch checks against that instead.

This also avoids a potential integer overflow pointed out by Haogang Chen.

Signed-off-by: Ian Campbell 
Cc: Haogang Chen 
CC: stable@kernel.org
Signed-off-by: Konrad Rzeszutek Wilk

Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel"

2011-12-19T14:30:35+00:00

This reverts commit ddacf5ef684a655abe2bb50c4b2a5b72ae0d5e05.
As when booting the kernel under Amazon EC2 as an HVM guest it ends up
hanging during startup. Reverting this we loose the fix for kexec
booting to the crash kernels.

Fixes Canonical BZ #901305 (http://bugs.launchpad.net/bugs/901305)

Tested-by: Alessandro Salvatori 
Reported-by:  Stefan Bader 
Acked-by: Ian Campbell 
Signed-off-by: Konrad Rzeszutek Wilk

xen/blk[front|back]: Enhance discard support with secure erasing support.

2011-11-18T18:28:01+00:00

Part of the blkdev_issue_discard(xx) operation is that it can also
issue a secure discard operation that will permanantly remove the
sectors in question. We advertise that we can support that via the
'discard-secure' attribute and on the request, if the 'secure' bit
is set, we will attempt to pass in REQ_DISCARD | REQ_SECURE.

CC: Li Dongyang 
[v1: Used 'flag' instead of 'secure:1' bit]
[v2: Use 'reserved' uint8_t instead of adding a new value]
[v3: Check for nseg when mapping instead of operation]
Signed-off-by: Konrad Rzeszutek Wilk

xen/blk[front|back]: Squash blkif_request_rw and blkif_request_discard together

2011-11-18T18:27:59+00:00

In a union type structure to deal with the overlapping
attributes in a easier manner.

Suggested-by: Ian Campbell 
Signed-off-by: Konrad Rzeszutek Wilk

Merge branch 'for-3.2/drivers' of git://git.kernel.dk/linux-block

2011-11-05T00:22:14+00:00

* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits)
  virtio-blk: use ida to allocate disk index
  hpsa: add small delay when using PCI Power Management to reset for kump
  cciss: add small delay when using PCI Power Management to reset for kump
  xen/blkback: Fix two races in the handling of barrier requests.
  xen/blkback: Check for proper operation.
  xen/blkback: Fix the inhibition to map pages when discarding sector ranges.
  xen/blkback: Report VBD_WSECT (wr_sect) properly.
  xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests.
  xen-blkfront: plug device number leak in xlblk_init() error path
  xen-blkfront: If no barrier or flush is supported, use invalid operation.
  xen-blkback: use kzalloc() in favor of kmalloc()+memset()
  xen-blkback: fixed indentation and comments
  xen-blkfront: fix a deadlock while handling discard response
  xen-blkfront: Handle discard requests.
  xen-blkback: Implement discard requests ('feature-discard')
  xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
  drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()
  drivers/block/loop.c: emit uevent on auto release
  drivers/block/cpqarray.c: use pci_dev->revision
  loop: always allow userspace partitions and optionally support automatic scanning
  ...

Fic up trivial header file includsion conflict in drivers/block/loop.c