This commit contains security patches for xen 4.8. The patches
for XSA-216 applied to the kernel are omitted, as they are part of
80e0cda7ff.
XSA-216 Issue Description:
> The block interface response structure has some discontiguous fields.
> Certain backends populate the structure fields of an otherwise
> uninitialized instance of this structure on their stacks, leaking
> data through the (internal or trailing) padding field.
More: https://xenbits.xen.org/xsa/advisory-216.html
XSA-217 Issue Description:
> Domains controlling other domains are permitted to map pages owned by
> the domain being controlled. If the controlling domain unmaps such a
> page without flushing the TLB, and if soon after the domain being
> controlled transfers this page to another PV domain (via
> GNTTABOP_transfer or, indirectly, XENMEM_exchange), and that third
> domain uses the page as a page table, the controlling domain will have
> write access to a live page table until the applicable TLB entry is
> flushed or evicted. Note that the domain being controlled is
> necessarily HVM, while the controlling domain is PV.
More: https://xenbits.xen.org/xsa/advisory-217.html
XSA-218 Issue Description:
> We have discovered two bugs in the code unmapping grant references.
>
> * When a grant had been mapped twice by a backend domain, and then
> unmapped by two concurrent unmap calls, the frontend may be informed
> that the page had no further mappings when the first call completed rather
> than when the second call completed.
>
> * A race triggerable by an unprivileged guest could cause a grant
> maptrack entry for grants to be "freed" twice. The ultimate effect of
> this would be for maptrack entries for a single domain to be re-used.
More: https://xenbits.xen.org/xsa/advisory-218.html
XSA-219 Issue Description:
> When using shadow paging, writes to guest pagetables must be trapped and
> emulated, so the shadows can be suitably adjusted as well.
>
> When emulating the write, Xen maps the guests pagetable(s) to make the final
> adjustment and leave the guest's view of its state consistent.
>
> However, when mapping the frame, Xen drops the page reference before
> performing the write. This is a race window where the underlying frame can
> change ownership.
>
> One possible attack scenario is for the frame to change ownership and to be
> inserted into a PV guest's pagetables. At that point, the emulated write will
> be an unaudited modification to the PV pagetables whose value is under guest
> control.
More: https://xenbits.xen.org/xsa/advisory-219.html
XSA-220 Issue Description:
> Memory Protection Extensions (MPX) and Protection Key (PKU) are features in
> newer processors, whose state is intended to be per-thread and context
> switched along with all other XSAVE state.
>
> Xen's vCPU context switch code would save and restore the state only
> if the guest had set the relevant XSTATE enable bits. However,
> surprisingly, the use of these features is not dependent (PKU) or may
> not be dependent (MPX) on having the relevant XSTATE bits enabled.
>
> VMs which use MPX or PKU, and context switch the state manually rather
> than via XSAVE, will have the state leak between vCPUs (possibly,
> between vCPUs in different guests). This in turn corrupts state in
> the destination vCPU, and hence may lead to weakened protections
>
> Experimentally, MPX appears not to make any interaction with BND*
> state if BNDCFGS.EN is set but XCR0.BND{CSR,REGS} are clear. However,
> the SDM is not clear in this case; therefore MPX is included in this
> advisory as a precaution.
More: https://xenbits.xen.org/xsa/advisory-220.html
XSA-221 Issue Description:
> When polling event channels, in general arbitrary port numbers can be
> specified. Specifically, there is no requirement that a polled event
> channel ports has ever been created. When the code was generalised
> from an earlier implementation, introducing some intermediate
> pointers, a check should have been made that these intermediate
> pointers are non-NULL. However, that check was omitted.
More: https://xenbits.xen.org/xsa/advisory-221.html
XSA-222 Issue Description:
> Certain actions require removing pages from a guest's P2M
> (Physical-to-Machine) mapping. When large pages are in use to map
> guest pages in the 2nd-stage page tables, such a removal operation may
> incur a memory allocation (to replace a large mapping with individual
> smaller ones). If this allocation fails, these errors are ignored by
> the callers, which would then continue and (for example) free the
> referenced page for reuse. This leaves the guest with a mapping to a
> page it shouldn't have access to.
>
> The allocation involved comes from a separate pool of memory created
> when the domain is created; under normal operating conditions it never
> fails, but a malicious guest may be able to engineer situations where
> this pool is exhausted.
More: https://xenbits.xen.org/xsa/advisory-222.html
XSA-224 Issue Description:
> We have discovered a number of bugs in the code mapping and unmapping
> grant references.
>
> * If a grant is mapped with both the GNTMAP_device_map and
> GNTMAP_host_map flags, but unmapped only with host_map, the device_map
> portion remains but the page reference counts are lowered as though it
> had been removed. This bug can be leveraged cause a page's reference
> counts and type counts to fall to zero while retaining writeable
> mappings to the page.
>
> * Under some specific conditions, if a grant is mapped with both the
> GNTMAP_device_map and GNTMAP_host_map flags, the operation may not
> grab sufficient type counts. When the grant is then unmapped, the
> type count will be erroneously reduced. This bug can be leveraged
> cause a page's reference counts and type counts to fall to zero while
> retaining writeable mappings to the page.
>
> * When a grant reference is given to an MMIO region (as opposed to a
> normal guest page), if the grant is mapped with only the
> GNTMAP_device_map flag set, a mapping is created at host_addr anyway.
> This does *not* cause reference counts to change, but there will be no
> record of this mapping, so it will not be considered when reporting
> whether the grant is still in use.
More: https://xenbits.xen.org/xsa/advisory-224.html
This commit adds the xen_4_8 package to be used instead of
xen (currently at 4.5.5):
* Add packages xen_4_8, xen_4_8-slim and xen_4_8-light
* Add packages qemu_xen_4_8 and qemu_xen_4_8-light to be used
with xen_4_8-slim and xen_4_8-light respectively.
* Add systemd to buildInputs of xen (it is required by oxenstored)
* Adapt xen service to work with the new version of xen
* Use xen-init-dom0 to initlilise dom0 in xen-store
* Currently, the virtualisation.xen.stored option is ignored
if xen 4.8 is used
XSA-216 Issue Description:
> The block interface response structure has some discontiguous fields.
> Certain backends populate the structure fields of an otherwise
> uninitialized instance of this structure on their stacks, leaking
> data through the (internal or trailing) padding field.
More: https://xenbits.xen.org/xsa/advisory-216.html
XSA-217 Issue Description:
> Domains controlling other domains are permitted to map pages owned by
> the domain being controlled. If the controlling domain unmaps such a
> page without flushing the TLB, and if soon after the domain being
> controlled transfers this page to another PV domain (via
> GNTTABOP_transfer or, indirectly, XENMEM_exchange), and that third
> domain uses the page as a page table, the controlling domain will have
> write access to a live page table until the applicable TLB entry is
> flushed or evicted. Note that the domain being controlled is
> necessarily HVM, while the controlling domain is PV.
More: https://xenbits.xen.org/xsa/advisory-217.html
XSA-218 Issue Description:
> We have discovered two bugs in the code unmapping grant references.
>
> * When a grant had been mapped twice by a backend domain, and then
> unmapped by two concurrent unmap calls, the frontend may be informed
> that the page had no further mappings when the first call completed rather
> than when the second call completed.
>
> * A race triggerable by an unprivileged guest could cause a grant
> maptrack entry for grants to be "freed" twice. The ultimate effect of
> this would be for maptrack entries for a single domain to be re-used.
More: https://xenbits.xen.org/xsa/advisory-218.html
XSA-219 Issue Description:
> When using shadow paging, writes to guest pagetables must be trapped and
> emulated, so the shadows can be suitably adjusted as well.
>
> When emulating the write, Xen maps the guests pagetable(s) to make the final
> adjustment and leave the guest's view of its state consistent.
>
> However, when mapping the frame, Xen drops the page reference before
> performing the write. This is a race window where the underlying frame can
> change ownership.
>
> One possible attack scenario is for the frame to change ownership and to be
> inserted into a PV guest's pagetables. At that point, the emulated write will
> be an unaudited modification to the PV pagetables whose value is under guest
> control.
More: https://xenbits.xen.org/xsa/advisory-219.html
XSA-220 Issue Description:
> Memory Protection Extensions (MPX) and Protection Key (PKU) are features in
> newer processors, whose state is intended to be per-thread and context
> switched along with all other XSAVE state.
>
> Xen's vCPU context switch code would save and restore the state only
> if the guest had set the relevant XSTATE enable bits. However,
> surprisingly, the use of these features is not dependent (PKU) or may
> not be dependent (MPX) on having the relevant XSTATE bits enabled.
>
> VMs which use MPX or PKU, and context switch the state manually rather
> than via XSAVE, will have the state leak between vCPUs (possibly,
> between vCPUs in different guests). This in turn corrupts state in
> the destination vCPU, and hence may lead to weakened protections
>
> Experimentally, MPX appears not to make any interaction with BND*
> state if BNDCFGS.EN is set but XCR0.BND{CSR,REGS} are clear. However,
> the SDM is not clear in this case; therefore MPX is included in this
> advisory as a precaution.
More: https://xenbits.xen.org/xsa/advisory-220.html
XSA-221 Issue Description:
> When polling event channels, in general arbitrary port numbers can be
> specified. Specifically, there is no requirement that a polled event
> channel ports has ever been created. When the code was generalised
> from an earlier implementation, introducing some intermediate
> pointers, a check should have been made that these intermediate
> pointers are non-NULL. However, that check was omitted.
More: https://xenbits.xen.org/xsa/advisory-221.html
XSA-222 Issue Description:
> Certain actions require removing pages from a guest's P2M
> (Physical-to-Machine) mapping. When large pages are in use to map
> guest pages in the 2nd-stage page tables, such a removal operation may
> incur a memory allocation (to replace a large mapping with individual
> smaller ones). If this allocation fails, these errors are ignored by
> the callers, which would then continue and (for example) free the
> referenced page for reuse. This leaves the guest with a mapping to a
> page it shouldn't have access to.
>
> The allocation involved comes from a separate pool of memory created
> when the domain is created; under normal operating conditions it never
> fails, but a malicious guest may be able to engineer situations where
> this pool is exhausted.
More: https://xenbits.xen.org/xsa/advisory-222.html
XSA-224 Issue Description:
> We have discovered a number of bugs in the code mapping and unmapping
> grant references.
>
> * If a grant is mapped with both the GNTMAP_device_map and
> GNTMAP_host_map flags, but unmapped only with host_map, the device_map
> portion remains but the page reference counts are lowered as though it
> had been removed. This bug can be leveraged cause a page's reference
> counts and type counts to fall to zero while retaining writeable
> mappings to the page.
>
> * Under some specific conditions, if a grant is mapped with both the
> GNTMAP_device_map and GNTMAP_host_map flags, the operation may not
> grab sufficient type counts. When the grant is then unmapped, the
> type count will be erroneously reduced. This bug can be leveraged
> cause a page's reference counts and type counts to fall to zero while
> retaining writeable mappings to the page.
>
> * When a grant reference is given to an MMIO region (as opposed to a
> normal guest page), if the grant is mapped with only the
> GNTMAP_device_map flag set, a mapping is created at host_addr anyway.
> This does *not* cause reference counts to change, but there will be no
> record of this mapping, so it will not be considered when reporting
> whether the grant is still in use.
More: https://xenbits.xen.org/xsa/advisory-224.html
XSA-206 Issue Description:
> xenstored supports transactions, such that if writes which would
> invalidate assumptions of a transaction occur, the entire transaction
> fails. Typical response on a failed transaction is to simply retry
> the transaction until it succeeds.
>
> Unprivileged domains may issue writes to xenstore which conflict with
> transactions either of the toolstack or of backends such as the driver
> domain. Depending on the exact timing, repeated writes may cause
> transactions made by these entities to fail indefinitely.
More: https://xenbits.xen.org/xsa/advisory-206.html
XSA-211 Issue Description:
> When a graphics update command gets passed to the VGA emulator, there
> are 3 possible modes that can be used to update the display:
>
> * blank - Clears the display
> * text - Treats the display as showing text
> * graph - Treats the display as showing graphics
>
> After the display geometry gets changed (i.e., after the CIRRUS VGA
> emulation has resized the display), the VGA emulator will resize the
> console during the next update command. However, when a blank mode is
> also selected during an update, this resize doesn't happen. The resize
> will be properly handled during the next time a non-blank mode is
> selected during an update.
>
> However, other console components - such as the VNC emulation - will
> operate as though this resize had happened. When the display is
> resized to be larger than before, this can result in a heap overflow
> as console components will expect the display buffer to be larger than
> it is currently allocated.
More: https://xenbits.xen.org/xsa/advisory-211.html
XSA-212 Issue Description:
> The XSA-29 fix introduced an insufficient check on XENMEM_exchange
> input, allowing the caller to drive hypervisor memory accesses outside
> of the guest provided input/output arrays.
More: https://xenbits.xen.org/xsa/advisory-212.html
XSA-213 Issue Description:
> 64-bit PV guests typically use separate (root) page tables for their
> kernel and user modes. Hypercalls are accessible to guest kernel
> context only, which certain hypercall handlers make assumptions on.
> The IRET hypercall (replacing the identically name CPU instruction)
> is used by guest kernels to transfer control from kernel mode to user
> mode. If such an IRET hypercall is placed in the middle of a multicall
> batch, subsequent operations invoked by the same multicall batch may
> wrongly assume the guest to still be in kernel mode. If one or more of
> these subsequent operations involve operations on page tables, they may
> be using the wrong root page table, confusing internal accounting. As
> a result the guest may gain writable access to some of its page tables.
More: https://xenbits.xen.org/xsa/advisory-213.html
XSA-214 Issue Description:
> The GNTTABOP_transfer operation allows one guest to transfer a page to
> another guest. The internal processing of this, however, does not
> include zapping the previous type of the page being transferred. This
> makes it possible for a PV guest to transfer a page previously used as
> part of a segment descriptor table to another guest while retaining the
> "contains segment descriptors" property.
>
> If the destination guest is a PV one of different bitness, it may gain
> access to segment descriptors it is not normally allowed to have, like
> 64-bit code segments in a 32-bit PV guest.
>
> If the destination guest is a HVM one, that guest may freely alter the
> page contents and then hand the page back to the same or another PV
> guest.
>
> In either case, if the destination PV guest then inserts that page into
> one of its own descriptor tables, the page still having the designated
> type results in validation of its contents being skipped.
More: https://xenbits.xen.org/xsa/advisory-214.html
XSA-215 Issue Description:
> Under certain special conditions Xen reports an exception resulting
> from returning to guest mode not via ordinary exception entry points,
> but via a so call failsafe callback. This callback, unlike exception
> handlers, takes 4 extra arguments on the stack (the saved data
> selectors DS, ES, FS, and GS). Prior to placing exception or failsafe
> callback frames on the guest kernel stack, Xen checks the linear
> address range to not overlap with hypervisor space. The range spanned
> by that check was mistakenly not covering these extra 4 slots.
More: https://xenbits.xen.org/xsa/advisory-215.html
Recent commit #c10af9e744c91dff1ccc07a52a0b57d1e4d339f3 changed the
behaviour of wrapPythonPrograms, which caused pygrub to no longer
being wrapped. This commit fixes this.
OVMF{,CODE,VARS}.fd are now available in a dedicated fd output, greatly
reducing the closure in the common case where only those files are used (a
few MBs versus several hundred MBs for the full OVMF).
Note: it's unclear why `dontPatchELF` is now necessary for the build to
pass (on my end, at any rate) but it doesn't make much sense to run this
fixup anyway,
Note: my reading of xen's INSTALL suggests that --with-system-ovmf should
point directly to the OVMF binary. As such, the previous invocation was
incorrect (it pointed to the root of the OVMF tree). In any case, I have
only built xen with `--with-system-ovmf`, I have not tested it.
Fixes https://github.com/NixOS/nixpkgs/issues/25854
Closes https://github.com/NixOS/nixpkgs/pull/25855
Also:
* provides a bunch of build options
* documents build options config in longDescription
* provides a bunch of predefined packages and documents them some more
* sources' hashes stay the same
XSA-197 Issue Description:
> The compiler can emit optimizations in qemu which can lead to double
> fetch vulnerabilities. Specifically data on the rings shared
> between qemu and the hypervisor (which the guest under control can
> obtain mappings of) can be fetched twice (during which time the
> guest can alter the contents) possibly leading to arbitrary code
> execution in qemu.
More: https://xenbits.xen.org/xsa/advisory-197.html
XSA-199 Issue Description:
> The code in qemu which implements ioport read/write looks up the
> specified ioport address in a dispatch table. The argument to the
> dispatch function is a uint32_t, and is used without a range check,
> even though the table has entries for only 2^16 ioports.
>
> When qemu is used as a standalone emulator, ioport accesses are
> generated only from cpu instructions emulated by qemu, and are
> therefore necessarily 16-bit, so there is no vulnerability.
>
> When qemu is used as a device model within Xen, io requests are
> generated by the hypervisor and read by qemu from a shared ring. The
> entries in this ring use a common structure, including a 64-bit
> address field, for various accesses, including ioport addresses.
>
> Xen will write only 16-bit address ioport accesses. However,
> depending on the Xen and qemu version, the ring may be writeable by
> the guest. If so, the guest can generate out-of-range ioport
> accesses, resulting in wild pointer accesses within qemu.
More: https://xenbits.xen.org/xsa/advisory-199.html
XSA-207 Issue Description:
> Certain internal state is set up, during domain construction, in
> preparation for possible pass-through device assignment. On ARM and
> AMD V-i hardware this setup includes memory allocation. On guest
> teardown, cleanup was erroneously only performed when the guest
> actually had a pass-through device assigned.
More: https://xenbits.xen.org/xsa/advisory-207.html
XSA-209 Issue Description:
> When doing bitblt copy backwards, qemu should negate the blit width.
> This avoids an oob access before the start of video memory.
More: https://xenbits.xen.org/xsa/advisory-208.html
XSA-208 Issue Description:
> In CIRRUS_BLTMODE_MEMSYSSRC mode the bitblit copy routine
> cirrus_bitblt_cputovideo fails to check wethehr the specified memory
> region is safe.
More: https://xenbits.xen.org/xsa/advisory-209.html
The following parameters are now available:
* hardeningDisable
To disable specific hardening flags
* hardeningEnable
To enable specific hardening flags
Only the cc-wrapper supports this right now, but these may be reused by
other wrappers, builders or setup hooks.
cc-wrapper supports the following flags:
* fortify
* stackprotector
* pie (disabled by default)
* pic
* strictoverflow
* format
* relro
* bindnow
See http://nixos.org/nixpkgs/manual/#sec-package-naming
I've added an alias for multipath_tools to make sure that we don't break
existing configurations referencing the old name.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Excerpt from upstream release notes:
This release also contains the security fixes for XSA-137, XSA-138, XSA-141 to XSA-153.
XSA-139 and XSA-140 only apply to QEMU Upstream and are fixed from versions 2.3.1 and 2.4.0 of QEMU.
The qemu portion of XSA-135 has also been applied to qemu-traditional.
This seems to have been confusing people, using both xlibs and xorg, etc.
- Avoided renaming local (and different) xlibs binding in gcc*.
- Fixed cases where both xorg and xlibs were used.
Hopefully everything still works as before.
Xen required a few changes in order to be usable:
* Include xenfs module in initrd as loading it in the activation
script was failing.
* Include /etc/default/xendomains, which is needed by
xen-domains service.
* Create /var/log/xen and /var/lib/xen directories in
the xen-store service, which are needed by the xl command.
The directories could be created by any other script as long as
they are guaranteed to exist before xl is called.
* Fix a reference to /bin/ls in the xendomains script.
Previous commit reverted Xen back to 4.0.3 because xend from 4.1.* and newer
hangs for unknown reasons.
The new "xl" toolstack from 4.1.* and unstable works, yet PCI passthrough is not
supported by xl in 4.1.* and is broken in the unstable.
With this patch I was able to passthrough ATI Radeon HD 6950 without 3D
acceleration, though, to both Linux and Windows guests. Which is the best
archived result with Xen PCI passthrough on NixOS after trying out all possible
Xen versions.
Same VGA card works fine if passed through into a guest with KVM (acceleration,
GPGPU, everything works). I should have tried KVM from the start.
experiment, do this by patching a line setting sys.path into the
script, rather than using makeWrapper.
* Xen requires pythonFull because it needs https/ssl support.
svn path=/nixpkgs/trunk/; revision=23710
