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
The rsync binary was previously built without iconv support which is needed
for utf-8 conversions on darwin. Fixes#26864.
Additionally rsync used to be built with bundled versions of zlib and popt
that were outdated. This decreases the size of the rsync binary by ~82KB.
The following errors occur when you start Chromium prior to this commit:
[2534:2534:0625/202928.673160:ERROR:gl_implementation.cc(246)] Failed to
load .../libexec/chromium/swiftshader/libGLESv2.so:
../libexec/chromium/swiftshader/libGLESv2.so: cannot open shared object
file: No such file or directory
[2534:2534:0625/202928.674434:ERROR:gpu_child_thread.cc(174)] Exiting
GPU process due to errors during initialization
While in theory we do not strictly need libGLESv2.so, in practice this
means that the GPU process isn't starting up at all which in turn leads
to crawling rendering performance on some sites.
So let's install all shared libraries in swiftshader.
I've tested this with the chromium.stable NixOS VM test and also locally
on my machine and the errors as well as the performance issues are gone.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Due to licensing costs, Vivaldi bundles a version of ffmpeg compiled
without support for the common H.264 codec. However, it is possible to
supply a custom libffmpeg.so with additional codecs. This derivation
uses the Chromium source to compile a compatible libffmpeg.so.
This approach is recommended by a Vivaldi developer, see
https://gist.github.com/ruario/bec42d156d30affef655
