Commit Graph
10586 Commits
Author SHA1 Message Date
Ian Jackson 1c0ac70ad5 libxl: Fix bootloader-related virtual memory leak on pv build failure
The bootloader may call libxl__file_reference_map(), which mmap's the
pv_kernel and pv_ramdisk into process memory.  This was only unmapped,
however, on the success path of libxl__build_pv().  If there were a
failure anywhere between libxl_bootloader.c:parse_bootloader_result()
and the end of libxl__build_pv(), the calls to
libxl__file_reference_unmap() would be skipped, leaking the mapped
virtual memory.

Ideally this would be fixed by adding the unmap calls to the
destruction path for libxl__domain_build_state.  Unfortunately the
lifetime of the libxl__domain_build_state is opaque, and it doesn't
have a proper destruction path.  But, the only thing in it that isn't
from the gc are these bootloader references, and they are only ever
set for one libxl__domain_build_state, the one which is
libxl__domain_create_state.build_state.

So we can clean up in the exit path from libxl__domain_create_*, which
always comes through domcreate_complete.

Remove the now-redundant unmaps in libxl__build_pv's success path.

This is XSA-160.

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Tested-by: George Dunlap <george.dunlap@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 62dc4c1a96)
2015-12-08 15:32:13 +00:00
Ian Jackson e875e0e5fc libxl: adjust PoD target by memory fudge, too
PoD guests need to balloon at least as far as required by PoD, or risk
crashing.  Currently they don't necessarily know what the right value
is, because our memory accounting is (at the very least) confusing.

Apply the memory limit fudge factor to the in-hypervisor PoD memory
target, too.  This will increase the size of the guest's PoD cache by
the fudge factor LIBXL_MAXMEM_CONSTANT (currently 1Mby).  This ensures
that even with a slightly-off balloon driver, the guest will be
stable even under memory pressure.

There are two call sites of xc_domain_set_pod_target that need fixing:

The one in libxl_set_memory_target is straightforward.

The one in xc_hvm_build_x86.c:setup_guest is more awkward.  Simply
setting the PoD target differently does not work because the various
amounts of memory during domain construction no longer match up.
Instead, we adjust the guest memory target in xenstore (but only for
PoD guests).

This introduces a 1Mby discrepancy between the balloon target of a PoD
guest at boot, and the target set by an apparently-equivalent `xl
mem-set' (or similar) later.  This approach is low-risk for a security
fix but we need to fix this up properly in xen.git#staging and
probably also in stable trees.

This is XSA-153.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit 56fb5fd623)
(cherry picked from commit 423d2cd814)

Conflicts:
	tools/libxl/libxl_dom.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 73b70e3c5d)
2015-10-29 15:14:34 +00:00
Ian Jackson 85ca813ec2 tools/console: Fix build after "xenconsole tolerate tty errors"
2ddcdd96 "tools/console: xenconsole tolerate tty errors" contains a
compile error introduced during conflict resolution of the backport
from 4.4 to 4.3:

 client/main.c: In function 'get_pty_fd':
 client/main.c:124:10: error: passing argument 1 of 'warn' makes pointer from integer without a cast [-Werror]
 In file included from client/main.c:35:0:
 /usr/include/err.h:35:13: note: expected 'const char *' but argument is of type 'int'

Fix this.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
2015-10-21 15:10:22 +01:00
Ian Campbell 634a5d52d6 tools: libxl: allow permissive qemu-upstream pci passthrough.
Since XSA-131 qemu-xen now restricts access to PCI cfg by default. In
order to allow local configuration of the existing libxl_device_pci
"permissive" flag needs to be plumbed through via the new QMP property
added by the XSA-131 patches.

Versions of QEMU prior to XSA-131 did not support this permissive
property, so we only pass it if it is true. Older versions only
supported permissive mode.

qemu-xen-traditional already supports the permissive mode setting via
xenstore.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 015a373351)
2015-10-20 17:57:28 +01:00
Ian Jackson 2ddcdd96a0 tools/console: xenconsole tolerate tty errors
Since 28d386fc43 (XSA-57), libxl writes an empty value for the
console tty node, with read-only permission for the guest, when
setting up pv console "frontends".  (The actual tty value is later set
by xenconsoled.)   Writing an empty node is not strictly necessary to
stop the frontend from writing dangerous values here, but it is a good
belt-and-braces approach.

Unfortunately this confuses xenconsole.  It reads the empty value, and
tries to open it as the tty.  xenconsole then exits.

Fix this by having xenconsole treat an empty value the same way as no
value at all.

Also, make the error opening the tty be nonfatal: we just print a
warning, but do not exit.  I think this is helpful in theoretical
situations where xenconsole is racing with libxl and/or xenconsoled.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>

---
v2: Combine two conditions and move the free
(cherry picked from commit 39ba2989b1)
(cherry picked from commit 7b161be2e5)

Conflicts:
	tools/console/client/main.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-10-20 17:53:54 +01:00
Stefano Stabellini 998424e33d libxl: handle read-only drives with qemu-xen
The current libxl code doesn't deal with read-only drives at all.

Upstream QEMU and qemu-xen only support read-only cdrom drives: make
sure to specify "readonly=on" for cdrom drives and return error in case
the user requested a non-cdrom read-only drive.

This is XSA-142, discovered by Lin Liu
(https://bugzilla.redhat.com/show_bug.cgi?id=1257893).

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Backport to Xen 4.5 and earlier, apropos of report and review from
Michael Young.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-09-22 16:56:35 +01:00
Anthony PERARD 6d81366482 libxl: Increase device model startup timeout to 1min.
On a busy host, QEMU may take more than 10s to load and start.

This is likely due to a bug in Linux where the I/O subsystem sometime
produce high latency under load and result in QEMU taking a long time to
load every single dynamic libraries.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 9acfbe14d7)

Conflicts:
	tools/libxl/libxl_internal.h
(cherry picked from commit bbbd29a25d)
(cherry picked from commit fe66a76a2d)
2015-09-18 16:29:55 +01:00
Wei Liu f97021eb92 xl: correct handling of extra_config in main_cpupoolcreate
Don't dereference extra_config if it's NULL. Don't leak extra_config in
the end.

Also fixed a typo in error string while I was there.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 705c9e1242)
(cherry picked from commit ffb4e6387f)
(cherry picked from commit 213e243819)
2015-09-11 11:56:56 +01:00
Matthew Daley 8d394a4355 libxl: fix leak of config_data in main_cpupoolcreate
Coverity-ID: 1087193
Signed-off-by: Matthew Daley <mattjd@gmail.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 7737ecb20c)
2015-09-11 11:56:51 +01:00
Ian Jackson 3bcb2c062a libxl: poll: Avoid fd deregistration race POLLNVAL crash
It can happen that an fd is deregistered, and closed, and then a new
fd opened, and reregistered, all while another thread is in poll().

If this happens poll might report POLLNVAL, but the event loop would
think that the fd was supposed to have been valid, and then fail an
assertion:
  libxl_event.c:1183: afterpoll_check_fd: Assertion `poller->fds_changed || !(fds[slot].revents & 0x020)' failed.

We can't simply ignore POLLNVAL because if we have bugs which cause
messed-up fds, it is a serious problem which we really need to detect.

Instead, add extra tracking to spot when this possibility arises, and
abort on POLLNVAL if we are sure that it is unexpected.

Reported-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Jim Fehlig <jfehlig@suse.com>
(cherry picked from commit 681ce16816)

(cherry picked from commit 7f7642f778)

And, adjusted for semantic conflict over CTX vs ctx.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

(cherry picked from commit 3646b134c1)
Conflicts:
	tools/libxl/libxl_event.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-08-12 12:54:29 +01:00
Ian Jackson f66f746df7 libxl: make libxl__poller_put tolerate p==NULL
This is less fragile, and more in keeping with the usual style of
initialising everything to 0 and freeing things unconditionally.

Correspondingly, remove the tests at the call sites.

Apropos of c1f3f174.  No overall functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 6ed09e3772)
2015-08-12 12:50:06 +01:00
Ian Jackson 856f59437b libxl: poll: Use poller_get and poller_put for poller_app
This makes the code more regular.  We are going to want to do some
more work in poller_get and poller_put, which work also wants to be
done for poller_app.

Two very minor functional changes:

 * We call malloc an extra time since poller_app is now a pointer

 * ERROR_FAIL on poller_get failing for poller_app is generated in
   libxl_ctx_init rather than passed through by libxl_poller_init
   from libxl__pipe_nonblock.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Jim Fehlig <jfehlig@suse.com>
(cherry picked from commit aae3765206)

(cherry picked from commit 9f6f513eec)
Conflicts:
	tools/libxl/libxl.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 0348c450fe)
2015-08-12 12:43:27 +01:00
Ian Jackson dd80ee80c9 libxl: poll: Make libxl__poller_get have only one success return path
In preparation for doing some more work on successful exit.

No functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Tested-by: Jim Fehlig <jfehlig@suse.com>
(cherry picked from commit 6fc946bc55)

(cherry picked from commit 8c409135e6)
Conflicts:
	tools/libxl/libxl_event.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 900c7970de)
2015-08-12 12:39:36 +01:00
Matthew Daley e9a0fc5998 libxl: don't leak memory in libxl__poller_get failure case
Coverity-ID: 1055894
Signed-off-by: Matthew Daley <mattjd@gmail.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 1edd6d8da3)
2015-08-12 12:39:10 +01:00
Ian Jackson 32f82fa8d9 libxl: event handling: ao_inprogress does waits while reports outstanding
libxl__ao_inprogress needs to check (like
libxl__ao_complete_check_progress_reports) that there are no
oustanding progress callbacks.

Otherwise it might happen that we would destroy the ao while another
thread has an outstanding callback its egc report queue.  The other
thread would then, in its egc_run_callbacks, touch the destroyed ao.

Instead, when this happens in libxl__ao_inprogress, simply run round
the event loop again.  The thread which eventually makes the callback
will spot our poller in the ao, and notify the poller, waking us up.

This fixes an assertion failure race seen with libvirt:
  libvirtd: libxl_event.c:1792: libxl__ao_complete_check_progress_reports: Assertion `ao->in_initiator' failed.
or (after "Add an assert to egc_run_callbacks")
  libvirtd: libxl_event.c:1338: egc_run_callbacks: Assertion `aop->ao->magic == 0xA0FACE00ul' failed.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit f1335f0d7b)
(cherry picked from commit dfed6d96fd)
2015-08-12 12:25:32 +01:00
Ian Jackson 546960ca05 libxl: event handling: Break out ao_work_outstanding
Break out the test in libxl__ao_complete_check_progress_reports, into
ao_work_outstanding, which reports false if either (i) the ao is still
ongoing or (ii) there is a progress report (perhaps on a different
thread's callback queue) which has yet to be reported to the
application.

No functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 93699882d9)
(cherry picked from commit ba683105b5)
2015-08-12 12:25:13 +01:00
Konrad Rzeszutek Wilk 116bbc6062 libxl: In libxl_set_vcpuonline check for maximum number of VCPUs against the cpumap.
There is no sense in trying to online (or offline) CPUs when the size of
cpumap is greater than the maximum number of VCPUs the guest can go to.

As such fail the operation if the count of CPUs to online is greater
than what the guest started with. For the offline case we do not
check (as the bits are unset in the cpumap) and let it go through.

We coalesce some of the underlying libxl_set_vcpuonline code
together which was duplicated in QMP and XenStore codepaths.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

(cherry picked from commit d83bf9d224)
Conflicts:
	tools/libxl/libxl.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

(cherry picked from commit 0d8cbcad03)
Conflicts:
	tools/libxl/libxl.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>

(cherry picked from commit ca0f468192)
Conflicts:
	tools/libxl/libxl.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-08-12 12:15:20 +01:00
Andrew Cooper c776b6429b tools/libxc: Fix build of 32bit toolstacks on CentOS 5.x following XSA-125
gcc 4.1 of CentOS 5.x era does not like the typecheck in min() between
uint64_t and unsigned long.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>

(cherry picked from commit 6c1cb3dba4)
Conflicts:
	tools/libxc/xc_domain.c
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
2015-08-12 12:04:09 +01:00
Andrew Cooper 9d6754dc2d tools/xenconsoled: Increase file descriptor limit
XenServer's VM density testing uncovered a regression when moving from
sysvinit to systemd where the file descriptor limit dropped from 4096 to
1024. (XenServer had previously inserted a ulimit statement into its
initscripts.)

One solution is to use LimitNOFILE=4096 in xenconsoled.service to match the
lost ulimit, but that is only a stopgap solution.

As Xenconsoled genuinely needs a large number of file descriptors if a large
number of domains are running, attempt to increase the limit.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit 588df84c0d)
(cherry picked from commit 9d5b2b0102)
(cherry picked from commit a490f8df8c)
2015-08-12 11:58:40 +01:00
Andrew Cooper 04f8006b66 ocaml/xenctrl: Fix stub_xc_readconsolering()
The Ocaml stub to retrieve the hypervisor console ring had a few problems.

 * A single 32k buffer would truncate a large console ring.
 * The buffer was static and not under the protection of the Ocaml GC lock so
   could be clobbered by concurrent accesses.
 * Embedded NUL characters would cause caml_copy_string() (which is strlen()
   based) to truncate the buffer.

The function is rewritten from scratch, using the same algorithm as the python
stubs, but uses the protection of the Ocaml GC lock to maintain a static
running total of the ring size, to avoid redundant realloc()ing in future
calls.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Dave Scott <dave.scott@eu.citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: David Scott <dave.scott@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 1a010ca99e)
(cherry picked from commit cfc4c43be1)
(cherry picked from commit c669c24424)
2015-08-12 11:58:33 +01:00
Andrew Cooper dea3fd1e94 ocaml/xenctrl: Make failwith_xc() thread safe
The static error_str[] buffer is not thread-safe, and 1024 bytes is
unreasonably large.  Reduce to 256 bytes (which is still much larger than any
current use), and move it to being a stack variable.

Also, propagate the Noreturn attribute from caml_raise_with_string().

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Dave Scott <Dave.Scott@eu.citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Acked-by: David Scott <dave.scott@citrix.com>
(cherry picked from commit c8945d5161)
(cherry picked from commit 032673c883)
(cherry picked from commit 9702e084d0)
2015-08-12 11:57:40 +01:00
Andrew Cooper 8d0ca8a5e1 ocaml/xenctrl: Check return values from hypercalls
rather than blindly continuing and possibly using negative values.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Dave Scott <dave.scott@eu.citrix.com>
Acked-by: David Scott <dave.scott@citrix.com>
(cherry picked from commit 3380f5b627)
(cherry picked from commit c91ed889ea)
(cherry picked from commit 10a95535b0)
2015-08-12 11:57:18 +01:00
Ian Jackson 0332b3f24b libxl: In domain death search, start search at first domid we want
From: Ian Jackson <Ian.Jackson@eu.citrix.com>

When domain_death_xswatch_callback needed a further call to
xc_domain_getinfolist it would restart it with the last domain it
found rather than the first one it wants.

If it only wants one it will also only ask for one domain.  The result
would then be that it gets the previous domain again (ie, the previous
one to the one it wants), which still doesn't reveal the answer to the
question, and it would therefore loop again.

It's completely unclear to me why I thought it was a good idea to
start the xc_domain_getinfolist with the last domain previously found
rather than the first one left un-confirmed.  The code has been that
way since it was introduced.

Instead, start each xc_domain_getinfolist at the next domain whose
status we need to check.

We also need to move the test for !evg into the loop, we now need evg
to compute the arguments to getinfolist.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reported-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Tested-by: Jim Fehlig <jfehlig@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 4783c99aab)
(cherry picked from commit 0b19348f3c)
(cherry picked from commit 13623d5d8e)
2015-08-12 11:52:25 +01:00
Ian Jackson d7ab3a1c1c xl: Sane handling of extra config file arguments
Various xl sub-commands take additional parameters containing = as
additional config fragments.

The handling of these config fragments has a number of bugs:

 1. Use of a static 1024-byte buffer.  (If truncation would occur,
    with semi-trusted input, a security risk arises due to quotes
    being lost.)

 2. Mishandling of the return value from snprintf, so that if
    truncation occurs, the to-write pointer is updated with the
    wanted-to-write length, resulting in stack corruption.  (This is
    XSA-137.)

 3. Clone-and-hack of the code for constructing the appended
    config file.

These are fixed here, by introducing a new function
`string_realloc_append' and using it everywhere.  The `extra_info'
buffers are replaced by pointers, which start off NULL and are
explicitly freed on all return paths.

The separate variable which will become dom_info.extra_config is
abolished (which involves moving the clearing of dom_info).

Additional bugs I observe, not fixed here:

 4. The functions which now call string_realloc_append use ad-hoc
    error returns, with multiple calls to `return'.  This currently
    necessitates multiple new calls to `free'.

 5. Many of the paths in xl call exit(-rc) where rc is a libxl status
    code.  This is a ridiculous exit status `convention'.

 6. The loops for handling extra config data are clone-and-hacks.

 7. Once the extra config buffer is accumulated, it must be combined
    with the appropriate main config file.  The code to do this
    combining is clone-and-hacked too.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Tested-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian,campbell@citrix.com>
(cherry picked from commit dd84604f35)
(cherry picked from commit 6040b3aeb3)
(cherry picked from commit 214fd40a20)
2015-07-29 16:40:08 +01:00
Konrad Rzeszutek Wilk 18856366dc Limit XEN_DOMCTL_memory_mapping hypercall to only process up to 64 GFNs (or less)
Said hypercall for large BARs can take quite a while. As such
we can require that the hypercall MUST break up the request
in smaller values.

Another approach is to add preemption to it - whether we do the
preemption using hypercall_create_continuation or returning
EAGAIN to userspace (and have it re-invocate the call) - either
way the issue we cannot easily solve is that in 'map_mmio_regions'
if we encounter an error we MUST call 'unmap_mmio_regions' for the
whole BAR region.

Since the preemption would re-use input fields such as nr_mfns,
first_gfn, first_mfn - we would lose the original values -
and only undo what was done in the current round (i.e. ignoring
anything that was done prior to earlier preemptions).

Unless we re-used the return value as 'EAGAIN|nr_mfns_done<<10' but
that puts a limit (since the return value is a long) on the amount
of nr_mfns that can provided.

This patch sidesteps this problem by:
 - Setting an hard limit of nr_mfns having to be 64 or less.
 - Toolstack adjusts correspondingly to the nr_mfn limit.
 - If the there is an error when adding the toolstack will call the
   remove operation to remove the whole region.

The need to break this hypercall down is for large BARs can take
more than the guest (initial domain usually) time-slice. This has
the negative result in that the guest is locked out for a long
duration and is unable to act on any pending events.

We also augment the code to return zero if nr_mfns instead
of trying to the hypercall.

This is XSA-125 / CVE-2015-2752.

Suggested-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
2015-04-01 10:15:21 +01:00
Ian Campbell 1cf1e6024b tools: libxl: Explicitly disable graphics backends on qemu cmdline
By default qemu will try to create some sort of backend for the
emulated VGA device, either SDL or VNC.

However when the user specifies sdl=0 and vnc=0 in their configuration
libxl was not explicitly disabling either backend, which could lead to
one unexpectedly running.

If either sdl=1 or vnc=1 is configured then both before and after this
change only the backends which are explicitly enabled are configured,
i.e. this issue only occurs when all backends are supposed to have
been disabled.

This affects qemu-xen and qemu-xen-traditional differently.

If qemu-xen was compiled with SDL support then this would result in an
SDL window being opened if $DISPLAY is valid, or a failure to start
the guest if not. Passing "-display none" to qemu before any further
-sdl options disables this default behaviour and ensures that SDL is
only started if the libxl configuration demands it.

If qemu-xen was compiled without SDL support then qemu would instead
start a VNC server listening on ::1 (IPv6 localhost) or 127.0.0.1
(IPv4 localhost) with IPv6 preferred if available. Explicitly pass
"-vnc none" when vnc is not enabled in the libxl configuration to
remove this possibility.

qemu-xen-traditional would never start a vnc backend unless asked.
However by default it will start an SDL backend, the way to disable
this is to pass a -vnc option. In other words passing "-vnc none" will
disable both vnc and sdl by default. sdl can then be reenabled if
configured by subsequent use of the -sdl option.

Tested with both qemu-xen and qemu-xen-traditional built with SDL
support and:
	xl cr # defaults
	xl cr sdl=0 vnc=0
	xl cr sdl=1 vnc=0
	xl cr sdl=0 vnc=1
	xl cr sdl=0 vnc=0 vga=\"none\"
	xl cr sdl=0 vnc=0 nographic=1
with both valid and invalid $DISPLAY.

This is XSA-119 / CVE-2015-2152.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 91b0ae9db3)
(cherry picked from commit 6616c4d6fe)
(cherry picked from commit 84ca072f37)
2015-03-12 13:47:55 +00:00
Vadim A. Misbakh-Soloviov 08d6f790eb flask: avoid installing policy file as '/boot'
Signed-off-by: Vadim A. Misbakh-Soloviov <mva@mva.name>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
(cherry picked from commit 8bff3edead)
2015-03-09 09:31:23 +00:00
Boris Ostrovsky eb3594ca13 pygrub: Fix regression from c/s d1b93ea, attempt 2
c/s d1b93ea causes substantial functional regressions in pygrub's ability to
parse bootloader configuration files.

c/s d1b93ea itself changed an an interface which previously used exclusively
integers, to using strings in the case of a grub configuration with explicit
default set, along with changing the code calling the interface to require a
string.  The default value for "default" remained as an integer.

As a result, any Extlinux or Lilo configuration (which drives this interface
exclusively with integers), or Grub configuration which doesn't explicitly
declare a default will die with an AttributeError when attempting to call
"self.cf.default.isdigit()" where "default" is an integer.

Sadly, this AttributeError gets swallowed by the blanket ignore in the loop
which searches partitions for valid bootloader configurations, causing the
issue to be reported as "Unable to find partition containing kernel"

We should explicitly check type of "default" in image_index() and process it
appropriately.

Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 3b27981170)
(cherry picked from commit bc0ce24c8f)
2015-02-27 15:18:56 +00:00
Simon Rowe 8d04f3746e pygrub: fix non-interactive parsing of grub1 config files
Changes to handle non-numeric default attributes for grub2 caused run_grub()
to attempt to index into the images list using a string. Pull out the code
that handles submenus into a new function and use that to ensure sel is
numeric.

Reported-by: David Scott <dave.scott@citrix.com>
Signed-off-by: Simon Rowe <simon.rowe@eu.citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-and-tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 4ee393f9d6)
(cherry picked from commit 7962c936a4)
2015-02-27 15:18:56 +00:00
Boris Ostrovsky 29a5fcbdc1 tools/pygrub: Make pygrub understand default entry in string format
Currently pygrub can only correctly parse grub2's default attribute when it is
specified as a number. If it is set to ${saved_entry} or ${next_entry} then
the first image (i.e. entry number 0) is selected. If any other value is
specified (typically this would be the string in menuentry) pygrub will crash.

This patch will allow pygrub to interpret default attribute if it is specified
as a string (note that in case of submenus only the leaf string will be
considered).

Also issue a warning if default is set to ${saved_entry} or ${next_entry}.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit d1b93ea261)
(cherry picked from commit 3f9d2e1863)
2015-02-27 15:18:56 +00:00
Andrew Cooper a4d28628b3 tools/pygrub: Fix extlinux when /boot is a separate partition from /
Grub and Grub2 already cope with this.

Reported-by: Joseph Hom <jhom@softlayer.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 0c12e5b742)

Conflicts:
	tools/pygrub/src/pygrub

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 9c6425b06a)
2015-02-27 15:18:56 +00:00
Julien Grall 027f025680 libxl: Don't ignore error when we fail to give access to ioport/irq/iomem
If we fail to give the access, the domain will unlikely work correctly.
So we should bail out at the first error.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>

(Based on commit 7070eec417)
(cherry picked from commit 17664f0ba0)
2015-01-19 17:47:30 +00:00
Charles Arnold d07266e83f tools/hotplug: set mtu from bridge for tap interface
With changeset 22885 support was added for setting the MTU in the vif-bridge
script for when a vif interface was set to 'online'.  The was not done for the
'add' operation.  The 'add' operation was added to the script for when tap
devices were specified (c/s 21944). With the setting of the MTU for the
'online' case was there a reason for omitting the 'add'?

This patch sets the MTU for both 'online' and 'add' in the vif-bridge script.

Backport for Xen version 4.3.

[ Removed spurious addition of blank line.
  Backport of f3f5f1927f (as it is in staging-4.4).  -iwj ]

Signed-off-by: Charles Arnold <carnold@suse.com>
2015-01-12 17:05:46 +00:00
Ian Campbell 59ec057efa tools: libxl: do not leak diskpath during local disk attach
libxl__device_disk_local_initiate_attach is assigning dls->diskpath with a
strdup of the device path. This is then passed to the callback, e.g.
parse_bootloader_result but bootloader_cleanup will not free it.

Since the callback is within the scope of the (e)gc and therefore doesn't need
to be malloc'd, a gc'd alloc will do. All other assignments to this field use
the gc.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=767295

Reported-by: Gedalya <gedalya@gedalya.net>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 379b351889)
2015-01-12 15:41:18 +00:00
Ian Campbell 9503b44a90 tools: libxl: do not overrun input buffer in libxl__parse_mac
Valgrind reports:
==7971== Invalid read of size 1
==7971==    at 0x40877BE: libxl__parse_mac (libxl_internal.c:288)
==7971==    by 0x405C5F8: libxl__device_nic_from_xs_be (libxl.c:3405)
==7971==    by 0x4065542: libxl__append_nic_list_of_type (libxl.c:3484)
==7971==    by 0x4065542: libxl_device_nic_list (libxl.c:3504)
==7971==    by 0x406F561: libxl_retrieve_domain_configuration (libxl.c:6661)
==7971==    by 0x805671C: reload_domain_config (xl_cmdimpl.c:2037)
==7971==    by 0x8057F30: handle_domain_death (xl_cmdimpl.c:2116)
==7971==    by 0x8057F30: create_domain (xl_cmdimpl.c:2580)
==7971==    by 0x805B4B2: main_create (xl_cmdimpl.c:4652)
==7971==    by 0x804EAB2: main (xl.c:378)

This is because on the final iteration the tok += 3 skips over the terminating
NUL to the next byte, and then *tok reads it. Fix this by using endptr as the
iterator.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Don Slutz <dslutz@verizon.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 5a430eca0b)
2015-01-12 15:41:03 +00:00
Luis R. Rodriguez 5b3620f871 libxc: check return values on mmap() and madvise() on xc_alloc_hypercall_buffer()
On a Thinkpad T4440p with OpenSUSE tumbleweed with v3.15-rc4
and today's latest xen tip from the git tree strace -f reveals
we end up on a never ending wait shortly after

write(20, "backend/console/5\0", 18 <unfinished ...>

This is right before we just wait on the qemu process which we
had mmap'd for. Without this you'll end up getting stuck on a
loop if mmap() worked but madvise() did not. While at it I noticed
even the mmap() error fail was not being checked, fix that too.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit e86539a388)
2015-01-12 15:40:03 +00:00
Andrew Cooper fccb5892c8 fix listing of vcpus when domains lacking any vcpus exist
On a system which looks like this:

[root@st04 ~]# xl list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0   752     4     r-----   46699.3
(null)                                       1     0     0     --p---       0.0
(null)                                       2     0     0     --p---       0.0
(null)                                       3     0     0     --p---       0.0
badger                                      25     0     1     --p---       0.0

`xl vcpu-list` failes as so:

[root@st04 ~]# xl vcpu-list
Name                                ID  VCPU   CPU State   Time(s) CPU Affinity
Domain-0                             0     0    0   -b-   12171.0  all
Domain-0                             0     1    1   -b-   11779.6  all
Domain-0                             0     2    2   -b-   11599.0  all
Domain-0                             0     3    3   r--   11007.0  all
libxl: critical: libxl__calloc: libxl: FATAL ERROR: memory allocation failure (libxl__calloc, 4294935299 x 40)
: Cannot allocate memory
libxl: FATAL ERROR: memory allocation failure (libxl__calloc, 4294935299 x 40)

The root cause of this is in Xen.  getdomaininfo() has no way of expressing
"this domain has no vcpus".  Previously, info->max_vcpu_id would be returned
uninitialised in such a case.

Unfortunately, setting it to 0 as a default is not appropriate.  A max_vcpu_id
of 0 and nr_online_cpus of 0 is the valid state for a single vcpu domain which
is in the process of being destroyed.

As all components are required to add 1 to max_vcpu_id to get the number of
vcpus, an id of ~0U is not valid to be used.  Explicitly define this as an
invalid max vcpu value, and use it to express "no vcpus" in getdomaininfo()

In libxl, the issue is seen as libxl_list_vcpu() attempts to use the
uninitialised domaininfo.max_vcpu_id for memory allocation.

Check domaininfo.max_vcpu_id against the new sentinel value
XEN_INVALID_MAX_VCPU_ID, and return early.  This means that it is now valid
for libxl_list_vcpu() to return NULL for a domain which lacks any vcpus.

As part of this change, remove the pointless call to libxl_get_max_cpus(),
whose returned value is unconditionally clobbered in the for() loop.

Reported-by: Euan Harris <euan.harris@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Don Slutz <dslutz@verizon.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>

tools/libxl: Fix libxl_list_vcpu() following c/s 93e52d52

My reasoning regarding nr_cpus_out was wrong, as I had confused nr_cpus_out
with nr_vcpus_out.

Dario pointed this out, but the patch (having gained appropriate acks) got
committed before I could post a correction.

Noticed-by: Dario Faggioli <dario.faggioli@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
master commit: 93e52d5242
master date: 2014-10-23 10:19:53 +0200
master commit: c90a755f26
master date: 2014-10-23 12:29:00 +0100
2014-11-13 09:52:09 +01:00
Jan Beulich 5f18214843 x86_emulate: properly do IP updates and other side effects on success
The two MMX/SSE/AVX code blocks failed to update IP properly, and these
as well as get_reg_refix(), which "manually" updated IP so far, failed
to do the TF and RF processing needed at the end of successfully
emulated instructions.

Fix the test utility at once to check IP is properly getting updated,
and while at it macroize the respective code quite a bit, hopefully
making it easier to add further tests when the need arises.

Reported-by: Andrei LUTAS <vlutas@bitdefender.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
Reviewed-by: Andrew Cooper <andrew.cooper@citrix.com>
master commit: 3af450fd2d
master date: 2014-08-08 09:34:03 +0200
2014-08-22 14:10:09 +02:00
Dario Faggioli c591613f8c blktap2: Fix two 'maybe uninitialized' variables
for which gcc 4.9.0 complains about, like this:

block-qcow.c: In function `get_cluster_offset':
block-qcow.c:431:3: error: `tmp_ptr' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
   memcpy(tmp_ptr, l1_ptr, 4096);
   ^
block-qcow.c:606:7: error: `tmp_ptr2' may be used uninitialized in this
function [-Werror=maybe-uninitialized]
   if (write(s->fd, tmp_ptr2, 4096) != 4096) {
       ^
cc1: all warnings being treated as errors
/home/dario/Sources/xen/xen/xen.git/tools/blktap2/drivers/../../../tools/Rules.mk:89:
 recipe for target 'block-qcow.o' failed
make[5]: *** [block-qcow.o] Error 1

The proper behavior is to return upon allocation failure.
About what to return, 0 seems the best option, looking
at both the function and the call sites.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 345e44a85d)
(cherry picked from commit 5e39eb05aa)
2014-07-02 15:38:24 +01:00
Andrew Cooper 50454d3a04 tools/libxl: Don't read off the end of tinfo[]
It is very common for BIOSes to advertise more cpus than are actually present
on the system, and mark some of them as offline.  This is what Xen does to
allow for later CPU hotplug, and what BIOSes common to multiple different
systems do to to save fully rewriting the MADT in memory.

An excerpt from `xl info` might look like:

...
nr_cpus                : 2
max_cpu_id             : 3
...

Which shows 4 CPUs in the MADT, but only 2 online (as this particular box is
the dual-core rather than the quad-core SKU of its particular brand)

Because of the way Xen exposes this information, a libxl_cputopology array is
bounded by 'nr_cpus', while cpu bitmaps are bounded by 'max_cpu_id + 1'.

The current libxl code has two places which erroneously assume that a
libxl_cputopology array is as long as the number of bits found in a cpu
bitmap, and valgrind complains:

==14961== Invalid read of size 4
==14961==    at 0x407AB7F: libxl__get_numa_candidate (libxl_numa.c:230)
==14961==    by 0x407030B: libxl__build_pre (libxl_dom.c:167)
==14961==    by 0x406246F: libxl__domain_build (libxl_create.c:371)
...
==14961==  Address 0x4324788 is 8 bytes after a block of size 24 alloc'd
==14961==    at 0x402669D: calloc (in/usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==14961==    by 0x4075BB9: libxl__zalloc (libxl_internal.c:83)
==14961==    by 0x4052F87: libxl_get_cpu_topology (libxl.c:4408)
==14961==    by 0x407A899: libxl__get_numa_candidate (libxl_numa.c:342)
...

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit 81b0305048)
(cherry picked from commit 3aaa40fd58)
2014-05-22 16:51:31 +01:00
Andrew Cooper 11b2541f45 tools/pygrub: Fix error handling if no valid partitions are found
If no partitions at all are found, pygrub never creates the name 'fs',
resulting in a NameError indicating the lack of fs, rather than a
RuntimeError explaining that no partitions were found.

Set fs to None right at the start, and use the pythonic idiom "if fs is None:"
to protect against otherwise valid values for fs which compare equal to
0/False.

Reported-by: Sven Köhler <sven.koehler@gmail.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit d75215805c)
(cherry picked from commit 5ee75ef147)
2014-05-22 16:50:05 +01:00
Wei Liu a14bb4db51 libxl_json: remove extra "break"
... otherwise JSON array elements are not freed and memory is leaked.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
(cherry picked from commit 3eb54a2fdb)
(cherry picked from commit d6eff6fcc0)
2014-05-22 16:48:28 +01:00
Joby Poriyath 4481b30d5e xen/pygrub: grub2/grub.cfg from RHEL 7 has new commands in menuentry
menuentry in grub2/grub.cfg uses linux16 and initrd16 commands
instead of linux and initrd. Due to this RHEL 7 (beta) guest failed to
boot after the installation.

In addition to this, RHEL 7 menu entries have two different single-quote
delimited strings on the same line, and the greedy grouping for menuentry
parsing gets both strings, and the options inbetween.

Signed-off-by: Joby Poriyath <joby.poriyath@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: george.dunlap@citrix.com
(cherry picked from commit dd03048708)
(cherry picked from commit 607d9c98e8)
2014-04-04 16:13:06 +01:00
Ian Jackson de474025e7 libxl: Fix carefd lock leak in save callout
If libxl_pipe fails we leave the carefd locked, which translates to
the atfork lock remaining held.  This would probably cause the process
to deadlock shortly afterwards.

Of course libxl_pipe is very unlikely to fail unless things are
already going very badly.  This bug has not been observed anywhere as
far as we are aware.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>
(cherry picked from commit 7eb73add5d)
(cherry picked from commit 4bb3a17449)
2014-04-04 16:02:45 +01:00
Ian Jackson d0c5e6a5e5 libxl: Hold the atfork lock while closing carefd
This avoids the process being forked while a carefd is recorded in the
list but the actual fd has been closed.  If that happened, a
subsequent libxl_postfork_child_noexec would attempt to close the fd
again.  If we are lucky that results in a harmless warning; but if we
are unlucky the fd number has been reused and we close an unrelated
fd.

This race has not been observed anywhere as far as we are aware.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>
(cherry picked from commit 2a0c3a62ea)
(cherry picked from commit 86c00cb6e2)
2014-04-04 16:02:40 +01:00
Stefan Bader 449062ac36 libxl: Auto-assign NIC devids in initiate_domain_create
This will change initiate_domain_create to walk through NIC definitions
and automatically assign devids to those which have not assigned one.
The devids are needed later in domcreate_launch_dm (for HVM domains
using emulated NICs). The command string for starting the device-model
has those ids as part of its arguments.
Assignment of devids in the hotplug case is handled by libxl_device_nic_add
but that would be called too late in the startup case.
I also moved the call to libxl__device_nic_setdefault here as this seems
to be the only path leading there and avoids doing the loop a third time.
The two loops are trying to handle a case where the caller sets some devids
(not sure that should be valid) but leaves some unset.

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 2d03be65d5)
2014-03-14 14:23:48 +00:00
Andrew Cooper 50082c5090 tools/libxc: Correct read_exact() error messages
The errors have been incorrectly identifying their function since c/s
861aef6e15 which did a lot of error handling
cleanup.

Use __func__ to ensure the name remains correct in the future.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit 1671cdeac7)
2014-03-14 14:23:26 +00:00
Andrew Cooper 2778b572ab libxc: Fix out-of-memory error handling in xc_cpupool_getinfo()
Avoid freeing info then returning it to the caller.

This is XSA-88.

Coverity-ID: 1056192
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit d883c179a7)
2014-02-12 16:54:18 +00:00
Marek Marczykowski-Górecki d7c6be6183 libvchan: Fix handling of invalid ring buffer indices
The remote (hostile) process can set ring buffer indices to any value
at any time. If that happens, it is possible to get "buffer space"
(either for writing data, or ready for reading) negative or greater
than buffer size.  This will end up with buffer overflow in the second
memcpy inside of do_send/do_recv.

Fix this by introducing new available bytes accessor functions
raw_get_data_ready and raw_get_buffer_space which are robust against
mad ring states, and only return sanitised values.

Proof sketch of correctness:

Now {rd,wr}_{cons,prod} are only ever used in the raw available bytes
functions, and in do_send and do_recv.

The raw available bytes functions do unsigned arithmetic on the
returned values.  If the result is "negative" or too big it will be
>ring_size (since we used unsigned arithmetic).  Otherwise the result
is a positive in-range value representing a reasonable ring state, in
which case we can safely convert it to int (as the rest of the code
expects).

do_send and do_recv immediately mask the ring index value with the
ring size.  The result is always going to be plausible.  If the ring
state has become mad, the worst case is that our behaviour is
inconsistent with the peer's ring pointer.  I.e. we read or write to
arguably-incorrect parts of the ring - but always parts of the ring.
And of course if a peer misoperates the ring they can achieve this
effect anyway.

So the security problem is fixed.

This is XSA-86.

(The patch is essentially Ian Jackson's work, although parts of the
commit message are by Marek.)

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
master commit: 2efcb0193b
master date: 2014-02-06 16:44:41 +0100
2014-02-06 17:27:10 +01:00
Andrew Cooper 6d7b67c670 tools/xc_restore: Initialise console and store mfns
If the console or store mfn chunks are not present in the migration stream,
stack junk gets reported for the mfns.

XenServer had a very hard to track down VM corruption issue caused by exactly
this issue.  Xenconsoled would connect to a junk mfn and incremented the ring
pointer if the junk happend to look like a valid gfn.

Coverity ID: 1056093 1056094

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 592b614f34)
2014-01-09 12:36:23 +00:00