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author | Peter Maydell <peter.maydell@linaro.org> | 2024-10-04 19:28:37 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2024-10-04 19:28:37 +0100 |
commit | b5ab62b3c0050612c7f9b0b4baeb44ebab42775a (patch) | |
tree | 601a427bebe91063aa44710509155af27dd20d03 /docs | |
parent | a3fb4e93a3a7cf2be355c41cd550bef856f5ffe4 (diff) | |
parent | 7cca79fa52128054b02ecbea249aa51e1916ba72 (diff) | |
download | qemu-b5ab62b3c0050612c7f9b0b4baeb44ebab42775a.zip qemu-b5ab62b3c0050612c7f9b0b4baeb44ebab42775a.tar.gz qemu-b5ab62b3c0050612c7f9b0b4baeb44ebab42775a.tar.bz2 |
Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging
* pc: Add a description for the i8042 property
* kvm: support for nested FRED
* tests/unit: fix warning when compiling test-nested-aio-poll with LTO
* kvm: refactoring of VM creation
* target/i386: expose IBPB-BRTYPE and SBPB CPUID bits to the guest
* hw/char: clean up serial
* remove virtfs-proxy-helper
* target/i386/kvm: Report which action failed in kvm_arch_put/get_registers
* qom: improvements to object_resolve_path*()
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# gpg: issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
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* tag 'for-upstream' of https://gitlab.com/bonzini/qemu: (23 commits)
qom: update object_resolve_path*() documentation
qom: set *ambiguous on all paths
qom: rename object_resolve_path_type() "ambiguousp"
target/i386/kvm: Report which action failed in kvm_arch_put/get_registers
kvm: Allow kvm_arch_get/put_registers to accept Error**
accel/kvm: refactor dirty ring setup
minikconf: print error entirely on stderr
9p: remove 'proxy' filesystem backend driver
hw/char: Extract serial-mm
hw/char/serial.h: Extract serial-isa.h
hw: Remove unused inclusion of hw/char/serial.h
target/i386: Expose IBPB-BRTYPE and SBPB CPUID bits to the guest
kvm: refactor core virtual machine creation into its own function
kvm/i386: replace identity_base variable with a constant
kvm/i386: refactor kvm_arch_init and split it into smaller functions
kvm: replace fprintf with error_report()/printf() in kvm_init()
kvm/i386: fix return values of is_host_cpu_intel()
kvm/i386: make kvm_filter_msr() and related definitions private to kvm module
hw/i386/pc: Add a description for the i8042 property
tests/unit: remove block layer code from test-nested-aio-poll
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
# Conflicts:
# hw/arm/Kconfig
# hw/arm/pxa2xx.c
Diffstat (limited to 'docs')
-rw-r--r-- | docs/about/deprecated.rst | 22 | ||||
-rw-r--r-- | docs/about/removed-features.rst | 14 | ||||
-rw-r--r-- | docs/conf.py | 3 | ||||
-rw-r--r-- | docs/meson.build | 1 | ||||
-rw-r--r-- | docs/tools/index.rst | 1 | ||||
-rw-r--r-- | docs/tools/virtfs-proxy-helper.rst | 75 |
6 files changed, 14 insertions, 102 deletions
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 1e21fbb..48b230b 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -314,28 +314,6 @@ the addition of volatile memory support, it is now necessary to distinguish between persistent and volatile memory backends. As such, memdev is deprecated in favor of persistent-memdev. -``-fsdev proxy`` and ``-virtfs proxy`` (since 8.1) -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -The 9p ``proxy`` filesystem backend driver has been deprecated and will be -removed (along with its proxy helper daemon) in a future version of QEMU. Please -use ``-fsdev local`` or ``-virtfs local`` for using the 9p ``local`` filesystem -backend, or alternatively consider deploying virtiofsd instead. - -The 9p ``proxy`` backend was originally developed as an alternative to the 9p -``local`` backend. The idea was to enhance security by dispatching actual low -level filesystem operations from 9p server (QEMU process) over to a separate -process (the virtfs-proxy-helper binary). However this alternative never gained -momentum. The proxy backend is much slower than the local backend, hasn't seen -any development in years, and showed to be less secure, especially due to the -fact that its helper daemon must be run as root, whereas with the local backend -QEMU is typically run as unprivileged user and allows to tighten behaviour by -mapping permissions et al by using its 'mapped' security model option. - -Nowadays it would make sense to reimplement the ``proxy`` backend by using -QEMU's ``vhost`` feature, which would eliminate the high latency costs under -which the 9p ``proxy`` backend currently suffers. However as of to date nobody -has indicated plans for such kind of reimplementation unfortunately. RISC-V CPU properties which start with capital 'Z' (since 8.2) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst index 6e96cd0..c76b91a 100644 --- a/docs/about/removed-features.rst +++ b/docs/about/removed-features.rst @@ -517,6 +517,20 @@ The virtio-blk SCSI passthrough feature is a legacy VIRTIO feature. VIRTIO 1.0 and later do not support it because the virtio-scsi device was introduced for full SCSI support. Use virtio-scsi instead when SCSI passthrough is required. +``-fsdev proxy`` and ``-virtfs proxy`` (since 9.2) +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The 9p ``proxy`` filesystem backend driver was originally developed to +enhance security by dispatching low level filesystem operations from 9p +server (QEMU process) over to a separate process (the virtfs-proxy-helper +binary). However the proxy backend was much slower than the local backend, +didn't see any development in years, and showed to be less secure, +especially due to the fact that its helper daemon must be run as root. + +Use ``local``, possibly mapping permissions et al by using its 'mapped' +security model option, or switch to ``virtiofs``. The virtiofs daemon +``virtiofsd`` uses vhost to eliminate the high latency costs of the 9p +``proxy`` backend. User-mode emulator command line arguments ----------------------------------------- diff --git a/docs/conf.py b/docs/conf.py index 876f676..c11a6ea 100644 --- a/docs/conf.py +++ b/docs/conf.py @@ -275,9 +275,6 @@ man_pages = [ ('tools/qemu-trace-stap', 'qemu-trace-stap', 'QEMU SystemTap trace tool', [], 1), - ('tools/virtfs-proxy-helper', 'virtfs-proxy-helper', - 'QEMU 9p virtfs proxy filesystem helper', - ['M. Mohan Kumar'], 1), ] man_make_section_directory = False diff --git a/docs/meson.build b/docs/meson.build index 322452c..3676f81 100644 --- a/docs/meson.build +++ b/docs/meson.build @@ -54,7 +54,6 @@ if build_docs 'qemu-pr-helper.8': (have_tools ? 'man8' : ''), 'qemu-storage-daemon.1': (have_tools ? 'man1' : ''), 'qemu-trace-stap.1': (stap.found() ? 'man1' : ''), - 'virtfs-proxy-helper.1': (have_virtfs_proxy_helper ? 'man1' : ''), 'qemu.1': 'man1', 'qemu-block-drivers.7': 'man7', 'qemu-cpu-models.7': 'man7' diff --git a/docs/tools/index.rst b/docs/tools/index.rst index 33ad438..1e88ae4 100644 --- a/docs/tools/index.rst +++ b/docs/tools/index.rst @@ -15,5 +15,4 @@ command line utilities and other standalone programs. qemu-nbd qemu-pr-helper qemu-trace-stap - virtfs-proxy-helper qemu-vmsr-helper diff --git a/docs/tools/virtfs-proxy-helper.rst b/docs/tools/virtfs-proxy-helper.rst deleted file mode 100644 index bd310eb..0000000 --- a/docs/tools/virtfs-proxy-helper.rst +++ /dev/null @@ -1,75 +0,0 @@ -QEMU 9p virtfs proxy filesystem helper -====================================== - -Synopsis --------- - -**virtfs-proxy-helper** [*OPTIONS*] - -Description ------------ - -NOTE: The 9p 'proxy' backend is deprecated (since QEMU 8.1) and will be -removed, along with this daemon, in a future version of QEMU! - -Pass-through security model in QEMU 9p server needs root privilege to do -few file operations (like chown, chmod to any mode/uid:gid). There are two -issues in pass-through security model: - -- TOCTTOU vulnerability: Following symbolic links in the server could - provide access to files beyond 9p export path. - -- Running QEMU with root privilege could be a security issue. - -To overcome above issues, following approach is used: A new filesystem -type 'proxy' is introduced. Proxy FS uses chroot + socket combination -for securing the vulnerability known with following symbolic links. -Intention of adding a new filesystem type is to allow qemu to run -in non-root mode, but doing privileged operations using socket IO. - -Proxy helper (a stand alone binary part of qemu) is invoked with -root privileges. Proxy helper chroots into 9p export path and creates -a socket pair or a named socket based on the command line parameter. -QEMU and proxy helper communicate using this socket. QEMU proxy fs -driver sends filesystem request to proxy helper and receives the -response from it. - -The proxy helper is designed so that it can drop root privileges except -for the capabilities needed for doing filesystem operations. - -Options -------- - -The following options are supported: - -.. program:: virtfs-proxy-helper - -.. option:: -h - - Display help and exit - -.. option:: -p, --path PATH - - Path to export for proxy filesystem driver - -.. option:: -f, --fd SOCKET_ID - - Use given file descriptor as socket descriptor for communicating with - qemu proxy fs drier. Usually a helper like libvirt will create - socketpair and pass one of the fds as parameter to this option. - -.. option:: -s, --socket SOCKET_FILE - - Creates named socket file for communicating with qemu proxy fs driver - -.. option:: -u, --uid UID - - uid to give access to named socket file; used in combination with -g. - -.. option:: -g, --gid GID - - gid to give access to named socket file; used in combination with -u. - -.. option:: -n, --nodaemon - - Run as a normal program. By default program will run in daemon mode |