Revision tags: v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9, v6.6.8, v6.6.7, v6.6.6, v6.6.5, v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3, v6.5.2, v6.1.51, v6.5.1, v6.1.50, v6.5, v6.1.49, v6.1.48, v6.1.46, v6.1.45, v6.1.44, v6.1.43, v6.1.42, v6.1.41, v6.1.40, v6.1.39, v6.1.38, v6.1.37, v6.1.36, v6.4, v6.1.35, v6.1.34, v6.1.33, v6.1.32, v6.1.31, v6.1.30 |
|
#
73648e6f |
| 17-May-2023 |
Arnd Bergmann <arnd@arndb.de> |
init: move cifs_root_data() prototype into linux/mount.h
cifs_root_data() is defined in cifs and called from early init code, but lacks a global prototype:
fs/cifs/cifsroot.c:83:12: error: no previ
init: move cifs_root_data() prototype into linux/mount.h
cifs_root_data() is defined in cifs and called from early init code, but lacks a global prototype:
fs/cifs/cifsroot.c:83:12: error: no previous prototype for 'cifs_root_data'
Move the declaration from do_mounts.c into an appropriate header.
Link: https://lkml.kernel.org/r/20230517131102.934196-13-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Eric Paris <eparis@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
show more ...
|
#
cf056a43 |
| 31-May-2023 |
Christoph Hellwig <hch@lst.de> |
init: improve the name_to_dev_t interface
name_to_dev_t has a very misleading name, that doesn't make clear it should only be used by the early init code, and also has a bad calling convention that
init: improve the name_to_dev_t interface
name_to_dev_t has a very misleading name, that doesn't make clear it should only be used by the early init code, and also has a bad calling convention that doesn't allow returning different kinds of errors. Rename it to early_lookup_bdev to make the use case clear, and return an errno, where -EINVAL means the string could not be parsed, and -ENODEV means it the string was valid, but there was no device found for it.
Also stub out the whole call for !CONFIG_BLOCK as all the non-block root cases are always covered in the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230531125535.676098-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
show more ...
|
Revision tags: v6.1.29, v6.1.28, v6.1.27, v6.1.26, v6.3, v6.1.25, v6.1.24, v6.1.23, v6.1.22, v6.1.21, v6.1.20, v6.1.19, v6.1.18, v6.1.17, v6.1.16, v6.1.15, v6.1.14, v6.1.13, v6.2, v6.1.12, v6.1.11, v6.1.10, v6.1.9 |
|
#
da27f796 |
| 27-Jan-2023 |
Rik van Riel <riel@surriel.com> |
ipc,namespace: batch free ipc_namespace structures
Instead of waiting for an RCU grace period between each ipc_namespace structure that is being freed, wait an RCU grace period for every batch of ip
ipc,namespace: batch free ipc_namespace structures
Instead of waiting for an RCU grace period between each ipc_namespace structure that is being freed, wait an RCU grace period for every batch of ipc_namespace structures.
Thanks to Al Viro for the suggestion of the helper function.
This speeds up the run time of the test case that allocates ipc_namespaces in a loop from 6 minutes, to a little over 1 second:
real 0m1.192s user 0m0.038s sys 0m1.152s
Signed-off-by: Rik van Riel <riel@surriel.com> Reported-by: Chris Mason <clm@meta.com> Tested-by: Giuseppe Scrivano <gscrivan@redhat.com> Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
Revision tags: v6.1.8, v6.1.7, v6.1.6 |
|
#
3707d84c |
| 13-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: move mnt_idmap
Now that we converted everything to just rely on struct mnt_idmap move it all into a separate file. This ensure that no code can poke around in struct mnt_idmap without any dedica
fs: move mnt_idmap
Now that we converted everything to just rely on struct mnt_idmap move it all into a separate file. This ensure that no code can poke around in struct mnt_idmap without any dedicated helpers and makes it easier to extend it in the future. Filesystems will now not be able to conflate mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. We are now also able to extend struct mnt_idmap as we see fit.
Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
show more ...
|
#
e67fe633 |
| 13-Jan-2023 |
Christian Brauner <brauner@kernel.org> |
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
Convert to struct mnt_idmap. Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in 256c8aed2b42
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
Convert to struct mnt_idmap. Remove legacy file_mnt_user_ns() and mnt_user_ns().
Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap.
Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs.
Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap.
Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
show more ...
|
Revision tags: v6.1.5, v6.0.19, v6.0.18, v6.1.4, v6.1.3, v6.0.17, v6.1.2, v6.0.16, v6.1.1, v6.0.15, v6.0.14, v6.0.13, v6.1, v6.0.12, v6.0.11, v6.0.10, v5.15.80, v6.0.9, v5.15.79, v6.0.8, v5.15.78, v6.0.7, v5.15.77, v5.15.76, v6.0.6, v6.0.5 |
|
#
256c8aed |
| 26-Oct-2022 |
Christian Brauner <brauner@kernel.org> |
fs: introduce dedicated idmap type for mounts
Last cycle we've already made the interaction with idmapped mounts more robust and type safe by introducing the vfs{g,u}id_t type. This cycle we conclud
fs: introduce dedicated idmap type for mounts
Last cycle we've already made the interaction with idmapped mounts more robust and type safe by introducing the vfs{g,u}id_t type. This cycle we concluded the conversion and removed the legacy helpers.
Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate filesystem and mount namespaces and what different roles they have to play. Especially for filesystem developers without much experience in this area this is an easy source for bugs.
Instead of passing the plain namespace we introduce a dedicated type struct mnt_idmap and replace the pointer with a pointer to a struct mnt_idmap. There are no semantic or size changes for the mount struct caused by this.
We then start converting all places aware of idmapped mounts to rely on struct mnt_idmap. Once the conversion is done all helpers down to the really low-level make_vfs{g,u}id() and from_vfs{g,u}id() will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two, removing and thus eliminating the possibility of any bugs. Fwiw, I fixed some issues in that area a while ago in ntfs3 and ksmbd in the past. Afterwards, only low-level code can ultimately use the associated namespace for any permission checks. Even most of the vfs can be ultimately completely oblivious about this and filesystems will never interact with it directly in any form in the future.
A struct mnt_idmap currently encompasses a simple refcount and a pointer to the relevant namespace the mount is idmapped to. If a mount isn't idmapped then it will point to a static nop_mnt_idmap. If it is an idmapped mount it will point to a new struct mnt_idmap. As usual there are no allocations or anything happening for non-idmapped mounts. Everthing is carefully written to be a nop for non-idmapped mounts as has always been the case.
If an idmapped mount or mount tree is created a new struct mnt_idmap is allocated and a reference taken on the relevant namespace. For each mount in a mount tree that gets idmapped or a mount that inherits the idmap when it is cloned the reference count on the associated struct mnt_idmap is bumped. Just a reminder that we only allow a mount to change it's idmapping a single time and only if it hasn't already been attached to the filesystems and has no active writers.
The actual changes are fairly straightforward. This will have huge benefits for maintenance and security in the long run even if it causes some churn. I'm aware that there's some cost for all of you. And I'll commit to doing this work and make this as painless as I can.
Note that this also makes it possible to extend struct mount_idmap in the future. For example, it would be possible to place the namespace pointer in an anonymous union together with an idmapping struct. This would allow us to expose an api to userspace that would let it specify idmappings directly instead of having to go through the detour of setting up namespaces at all.
This just adds the infrastructure and doesn't do any conversions.
Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
show more ...
|
Revision tags: v5.15.75, v6.0.4, v6.0.3, v6.0.2, v5.15.74, v5.15.73, v6.0.1, v5.15.72, v6.0, v5.15.71, v5.15.70, v5.15.69, v5.15.68, v5.15.67, v5.15.66, v5.15.65, v5.15.64, v5.15.63, v5.15.62, v5.15.61, v5.15.60, v5.15.59, v5.19, v5.15.58, v5.15.57, v5.15.56, v5.15.55, v5.15.54, v5.15.53, v5.15.52, v5.15.51, v5.15.50, v5.15.49, v5.15.48, v5.15.47, v5.15.46, v5.15.45, v5.15.44, v5.15.43, v5.15.42, v5.18, v5.15.41, v5.15.40, v5.15.39, v5.15.38, v5.15.37, v5.15.36, v5.15.35, v5.15.34, v5.15.33, v5.15.32, v5.15.31, v5.17, v5.15.30, v5.15.29, v5.15.28, v5.15.27 |
|
#
70f8d9c5 |
| 02-Mar-2022 |
Al Viro <viro@zeniv.linux.org.uk> |
move mount-related externs from fs.h to mount.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
Revision tags: v5.15.26 |
|
#
59df85d5 |
| 01-Mar-2022 |
Al Viro <viro@zeniv.linux.org.uk> |
linux/mount.h: trim includes
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
Revision tags: v5.15.25, v5.15.24, v5.15.23, v5.15.22, v5.15.21, v5.15.20, v5.15.19, v5.15.18, v5.15.17 |
|
#
ab171b95 |
| 22-Jan-2022 |
Luis Chamberlain <mcgrof@kernel.org> |
fs: move namespace sysctls and declare fs base directory
This moves the namespace sysctls to its own file as part of the kernel/sysctl.c spring cleaning
Since we have now removed all sysctls for "f
fs: move namespace sysctls and declare fs base directory
This moves the namespace sysctls to its own file as part of the kernel/sysctl.c spring cleaning
Since we have now removed all sysctls for "fs", we now have to declare it on the filesystem code, we do that using the new helper, which reduces boiler plate code.
We rename init_fs_shared_sysctls() to init_fs_sysctls() to reflect that now fs/sysctls.c is taking on the burden of being the first to register the base directory as well.
Lastly, since init code will load in the order in which we link it we have to move the sysctl code to be linked in early, so that its early init routine runs prior to other fs code. This way, other filesystem code can register their own sysctls using the helpers after this:
* register_sysctl_init() * register_sysctl()
Link: https://lkml.kernel.org/r/20211129211943.640266-3-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Antti Palosaari <crope@iki.fi> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Stephen Kitt <steve@sk2.org> Cc: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
show more ...
|
Revision tags: v5.4.173, v5.15.16, v5.15.15, v5.16, v5.15.10, v5.15.9, v5.15.8, v5.15.7, v5.15.6, v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60, v5.10.53, v5.10.52, v5.10.51, v5.10.50, v5.10.49, v5.13, v5.10.46, v5.10.43, v5.10.42, v5.10.41, v5.10.40, v5.10.39, v5.4.119, v5.10.36, v5.10.35, v5.10.34, v5.4.116, v5.10.33, v5.12, v5.10.32, v5.10.31, v5.10.30, v5.10.27, v5.10.26, v5.10.25, v5.10.24, v5.10.23, v5.10.22, v5.10.21, v5.10.20, v5.10.19, v5.4.101, v5.10.18, v5.10.17, v5.11, v5.10.16, v5.10.15, v5.10.14 |
|
#
9caccd41 |
| 21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
fs: introduce MOUNT_ATTR_IDMAP
Introduce a new mount bind mount property to allow idmapping mounts. The MOUNT_ATTR_IDMAP flag can be set via the new mount_setattr() syscall together with a file desc
fs: introduce MOUNT_ATTR_IDMAP
Introduce a new mount bind mount property to allow idmapping mounts. The MOUNT_ATTR_IDMAP flag can be set via the new mount_setattr() syscall together with a file descriptor referring to a user namespace.
The user namespace referenced by the namespace file descriptor will be attached to the bind mount. All interactions with the filesystem going through that mount will be mapped according to the mapping specified in the user namespace attached to it.
Using user namespaces to mark mounts means we can reuse all the existing infrastructure in the kernel that already exists to handle idmappings and can also use this for permission checking to allow unprivileged user to create idmapped mounts in the future.
Idmapping a mount is decoupled from the caller's user and mount namespace. This means idmapped mounts can be created in the initial user namespace which is an important use-case for systemd-homed, portable usb-sticks between systems, sharing data between the initial user namespace and unprivileged containers, and other use-cases that have been brought up. For example, assume a home directory where all files are owned by uid and gid 1000 and the home directory is brought to a new laptop where the user has id 12345. The system administrator can simply create a mount of this home directory with a mapping of 1000:12345:1 and other mappings to indicate the ids should be kept. (With this it is e.g. also possible to create idmapped mounts on the host with an identity mapping 1:1:100000 where the root user is not mapped. A user with root access that e.g. has been pivot rooted into such a mount on the host will be not be able to execute, read, write, or create files as root.)
Given that mapping a mount is decoupled from the caller's user namespace a sufficiently privileged process such as a container manager can set up an idmapped mount for the container and the container can simply pivot root to it. There's no need for the container to do anything. The mount will appear correctly mapped independent of the user namespace the container uses. This means we don't need to mark a mount as idmappable.
In order to create an idmapped mount the caller must currently be privileged in the user namespace of the superblock the mount belongs to. Once a mount has been idmapped we don't allow it to change its mapping. This keeps permission checking and life-cycle management simple. Users wanting to change the idmapped can always create a new detached mount with a different idmapping.
Link: https://lore.kernel.org/r/20210121131959.646623-36-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Mauricio Vásquez Bernal <mauricio@kinvolk.io> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
show more ...
|
#
a6435940 |
| 21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
mount: attach mappings to mounts
In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects wh
mount: attach mappings to mounts
In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before.
Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. Later patches enforce that once a mount has been idmapped it can't be remapped. This keeps permission checking and life-cycle management simple. Users wanting to change the idmapped can always create a new detached mount with a different idmapping.
Add a new mnt_userns member to vfsmount and two simple helpers to retrieve the mnt_userns from vfsmounts and files.
The idea to attach user namespaces to vfsmounts has been floated around in various forms at Linux Plumbers in ~2018 with the original idea tracing back to a discussion in 2017 at a conference in St. Petersburg between Christoph, Tycho, and myself.
Link: https://lore.kernel.org/r/20210121131959.646623-2-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
show more ...
|
Revision tags: v5.10, v5.8.17, v5.8.16, v5.8.15, v5.9, v5.8.14, v5.8.13, v5.8.12, v5.8.11 |
|
#
14e43bf4 |
| 22-Sep-2020 |
Eric Biggers <ebiggers@google.com> |
vfs: don't unnecessarily clone write access for writable fds
There's no need for mnt_want_write_file() to increment mnt_writers when the file is already open for writing, provided that mnt_drop_writ
vfs: don't unnecessarily clone write access for writable fds
There's no need for mnt_want_write_file() to increment mnt_writers when the file is already open for writing, provided that mnt_drop_write_file() is changed to conditionally decrement it.
We seem to have ended up in the current situation because mnt_want_write_file() used to be paired with mnt_drop_write(), due to mnt_drop_write_file() not having been added yet. So originally mnt_want_write_file() had to always increment mnt_writers.
But later mnt_drop_write_file() was added, and all callers of mnt_want_write_file() were paired with it. This makes the compatibility between mnt_want_write_file() and mnt_drop_write() no longer necessary.
Therefore, make __mnt_want_write_file() and __mnt_drop_write_file() skip incrementing mnt_writers on files already open for writing. This removes the only caller of mnt_clone_write(), so remove that too.
Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
Revision tags: v5.8.10, v5.8.9, v5.8.8, v5.8.7, v5.8.6, v5.4.62 |
|
#
dab741e0 |
| 27-Aug-2020 |
Mattias Nissler <mnissler@chromium.org> |
Add a "nosymfollow" mount option.
For mounts that have the new "nosymfollow" option, don't follow symlinks when resolving paths. The new option is similar in spirit to the existing "nodev", "noexec"
Add a "nosymfollow" mount option.
For mounts that have the new "nosymfollow" option, don't follow symlinks when resolving paths. The new option is similar in spirit to the existing "nodev", "noexec", and "nosuid" options, as well as to the LOOKUP_NO_SYMLINKS resolve flag in the openat2(2) syscall. Various BSD variants have been supporting the "nosymfollow" mount option for a long time with equivalent implementations.
Note that symlinks may still be created on file systems mounted with the "nosymfollow" option present. readlink() remains functional, so user space code that is aware of symlinks can still choose to follow them explicitly.
Setting the "nosymfollow" mount option helps prevent privileged writers from modifying files unintentionally in case there is an unexpected link along the accessed path. The "nosymfollow" option is thus useful as a defensive measure for systems that need to deal with untrusted file systems in privileged contexts.
More information on the history and motivation for this patch can be found here:
https://sites.google.com/a/chromium.org/dev/chromium-os/chromiumos-design-docs/hardening-against-malicious-stateful-data#TOC-Restricting-symlink-traversal
Signed-off-by: Mattias Nissler <mnissler@chromium.org> Signed-off-by: Ross Zwisler <zwisler@google.com> Reviewed-by: Aleksa Sarai <cyphar@cyphar.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
Revision tags: v5.8.5, v5.8.4, v5.4.61, v5.8.3, v5.4.60, v5.8.2, v5.4.59, v5.8.1, v5.4.58, v5.4.57, v5.4.56, v5.8, v5.7.12, v5.4.55, v5.7.11, v5.4.54, v5.7.10, v5.4.53, v5.4.52, v5.7.9, v5.7.8, v5.4.51, v5.4.50, v5.7.7, v5.4.49, v5.7.6, v5.7.5, v5.4.48, v5.7.4, v5.7.3, v5.4.47, v5.4.46, v5.7.2, v5.4.45, v5.7.1 |
|
#
df820f8d |
| 04-Jun-2020 |
Miklos Szeredi <mszeredi@redhat.com> |
ovl: make private mounts longterm
Overlayfs is using clone_private_mount() to create internal mounts for underlying layers. These are used for operations requiring a path, such as dentry_open().
S
ovl: make private mounts longterm
Overlayfs is using clone_private_mount() to create internal mounts for underlying layers. These are used for operations requiring a path, such as dentry_open().
Since these private mounts are not in any namespace they are treated as short term, "detached" mounts and mntput() involves taking the global mount_lock, which can result in serious cacheline pingpong.
Make these private mounts longterm instead, which trade the penalty on mntput() for a slightly longer shutdown time due to an added RCU grace period when putting these mounts.
Introduce a new helper kern_unmount_many() that can take care of multiple longterm mounts with a single RCU grace period.
Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
show more ...
|
Revision tags: v5.4.44, v5.7, v5.4.43, v5.4.42 |
|
#
9f6c61f9 |
| 14-May-2020 |
Miklos Szeredi <mszeredi@redhat.com> |
proc/mounts: add cursor
If mounts are deleted after a read(2) call on /proc/self/mounts (or its kin), the subsequent read(2) could miss a mount that comes after the deleted one in the list. This is
proc/mounts: add cursor
If mounts are deleted after a read(2) call on /proc/self/mounts (or its kin), the subsequent read(2) could miss a mount that comes after the deleted one in the list. This is because the file position is interpreted as the number mount entries from the start of the list.
E.g. first read gets entries #0 to #9; the seq file index will be 10. Then entry #5 is deleted, resulting in #10 becoming #9 and #11 becoming #10, etc... The next read will continue from entry #10, and #9 is missed.
Solve this by adding a cursor entry for each open instance. Taking the global namespace_sem for write seems excessive, since we are only dealing with a per-namespace list. Instead add a per-namespace spinlock and use that together with namespace_sem taken for read to protect against concurrent modification of the mount list. This may reduce parallelism of is_local_mountpoint(), but it's hardly a big contention point. We could also use RCU freeing of cursors to make traversal not need additional locks, if that turns out to be neceesary.
Only move the cursor once for each read (cursor is not added on open) to minimize cacheline invalidation. When EOF is reached, the cursor is taken off the list, in order to prevent an excessive number of cursors due to inactive open file descriptors.
Reported-by: Karel Zak <kzak@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
show more ...
|
Revision tags: v5.4.41, v5.4.40, v5.4.39, v5.4.38, v5.4.37, v5.4.36, v5.4.35, v5.4.34, v5.4.33, v5.4.32, v5.4.31, v5.4.30, v5.4.29, v5.6, v5.4.28, v5.4.27, v5.4.26, v5.4.25, v5.4.24, v5.4.23, v5.4.22, v5.4.21, v5.4.20, v5.4.19, v5.4.18, v5.4.17, v5.4.16, v5.5, v5.4.15, v5.4.14, v5.4.13, v5.4.12, v5.4.11, v5.4.10, v5.4.9, v5.4.8, v5.4.7, v5.4.6, v5.4.5, v5.4.4, v5.4.3, v5.3.15, v5.4.2, v5.4.1, v5.3.14, v5.4, v5.3.13, v5.3.12, v5.3.11, v5.3.10, v5.3.9, v5.3.8, v5.3.7, v5.3.6, v5.3.5, v5.3.4, v5.3.3, v5.3.2, v5.3.1, v5.3, v5.2.14, v5.3-rc8, v5.2.13, v5.2.12, v5.2.11, v5.2.10, v5.2.9, v5.2.8, v5.2.7, v5.2.6, v5.2.5, v5.2.4, v5.2.3, v5.2.2, v5.2.1, v5.2, v5.1.16, v5.1.15, v5.1.14, v5.1.13, v5.1.12, v5.1.11, v5.1.10, v5.1.9, v5.1.8, v5.1.7, v5.1.6, v5.1.5, v5.1.4, v5.1.3, v5.1.2, v5.1.1, v5.0.14, v5.1, v5.0.13, v5.0.12, v5.0.11, v5.0.10, v5.0.9, v5.0.8, v5.0.7 |
|
#
9419a319 |
| 04-Apr-2019 |
Al Viro <viro@zeniv.linux.org.uk> |
acct_on(): don't mess with freeze protection
What happens there is that we are replacing file->path.mnt of a file we'd just opened with a clone and we need the write count contribution to be transfe
acct_on(): don't mess with freeze protection
What happens there is that we are replacing file->path.mnt of a file we'd just opened with a clone and we need the write count contribution to be transferred from original mount to new one. That's it. We do *NOT* want any kind of freeze protection for the duration of switchover.
IOW, we should just use __mnt_{want,drop}_write() for that switchover; no need to bother with mnt_{want,drop}_write() there.
Tested-by: Amir Goldstein <amir73il@gmail.com> Reported-by: syzbot+2a73a6ea9507b7112141@syzkaller.appspotmail.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
Revision tags: v5.0.6, v5.0.5, v5.0.4, v5.0.3, v4.19.29, v5.0.2, v4.19.28, v5.0.1, v4.19.27, v5.0, v4.19.26, v4.19.25, v4.19.24, v4.19.23, v4.19.22, v4.19.21, v4.19.20, v4.19.19, v4.19.18, v4.19.17, v4.19.16, v4.19.15, v4.19.14, v4.19.13, v4.19.12, v4.19.11, v4.19.10, v4.19.9, v4.19.8, v4.19.7, v4.19.6, v4.19.5, v4.19.4, v4.18.20, v4.19.3, v4.18.19, v4.19.2, v4.18.18, v4.18.17, v4.19.1 |
|
#
8f291889 |
| 04-Nov-2018 |
Al Viro <viro@zeniv.linux.org.uk> |
new helpers: vfs_create_mount(), fc_mount()
Create a new helper, vfs_create_mount(), that creates a detached vfsmount object from an fs_context that has a superblock attached to it.
Almost all uses
new helpers: vfs_create_mount(), fc_mount()
Create a new helper, vfs_create_mount(), that creates a detached vfsmount object from an fs_context that has a superblock attached to it.
Almost all uses will be paired with immediately preceding vfs_get_tree(); add a helper for such combination.
Switch vfs_kern_mount() to use this.
NOTE: mild behaviour change; passing NULL as 'device name' to something like procfs will change /proc/*/mountstats - "device none" instead on "no device". That is consistent with /proc/mounts et.al.
[do'h - EXPORT_SYMBOL_GPL slipped in by mistake; removed] [AV -- remove confused comment from vfs_create_mount()] [AV -- removed the second argument]
Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
#
43f5e655 |
| 01-Nov-2018 |
David Howells <dhowells@redhat.com> |
vfs: Separate changing mount flags full remount
Separate just the changing of mount flags (MS_REMOUNT|MS_BIND) from full remount because the mount data will get parsed with the new fs_context stuff
vfs: Separate changing mount flags full remount
Separate just the changing of mount flags (MS_REMOUNT|MS_BIND) from full remount because the mount data will get parsed with the new fs_context stuff prior to doing a remount - and this causes the syscall to fail under some circumstances.
To quote Eric's explanation:
[...] mount(..., MS_REMOUNT|MS_BIND, ...) now validates the mount options string, which breaks systemd unit files with ProtectControlGroups=yes (e.g. systemd-networkd.service) when systemd does the following to change a cgroup (v1) mount to read-only:
mount(NULL, "/run/systemd/unit-root/sys/fs/cgroup/systemd", NULL, MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_REMOUNT|MS_BIND, NULL)
... when the kernel has CONFIG_CGROUPS=y but no cgroup subsystems enabled, since in that case the error "cgroup1: Need name or subsystem set" is hit when the mount options string is empty.
Probably it doesn't make sense to validate the mount options string at all in the MS_REMOUNT|MS_BIND case, though maybe you had something else in mind.
This is also worthwhile doing because we will need to add a mount_setattr() syscall to take over the remount-bind function.
Reported-by: Eric Biggers <ebiggers@google.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: David Howells <dhowells@redhat.com>
show more ...
|
Revision tags: v4.19, v4.18.16, v4.18.15, v4.18.14, v4.18.13, v4.18.12, v4.18.11, v4.18.10, v4.18.9, v4.18.7, v4.18.6, v4.18.5, v4.17.18, v4.18.4, v4.18.3, v4.17.17, v4.18.2, v4.17.16, v4.17.15, v4.18.1, v4.18, v4.17.14, v4.17.13, v4.17.12, v4.17.11, v4.17.10, v4.17.9, v4.17.8, v4.17.7, v4.17.6, v4.17.5, v4.17.4, v4.17.3, v4.17.2, v4.17.1, v4.17, v4.16, v4.15, v4.13.16, v4.14 |
|
#
b2441318 |
| 01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine
License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license identifiers to apply.
- when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary:
SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became the concluded license(s).
- when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time.
In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related.
Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
show more ...
|
Revision tags: v4.13.5, v4.13, v4.12, v4.10.17, v4.10.16, v4.10.15, v4.10.14, v4.10.13, v4.10.12, v4.10.11, v4.10.10, v4.10.9, v4.10.8, v4.10.7, v4.10.6, v4.10.5, v4.10.4, v4.10.3, v4.10.2, v4.10.1, v4.10, v4.9, openbmc-4.4-20161121-1, v4.4.33, v4.4.32, v4.4.31, v4.4.30, v4.4.29 |
|
#
3859a271 |
| 28-Oct-2016 |
Kees Cook <keescook@chromium.org> |
randstruct: Mark various structs for randomization
This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or con
randstruct: Mark various structs for randomization
This marks many critical kernel structures for randomization. These are structures that have been targeted in the past in security exploits, or contain functions pointers, pointers to function pointer tables, lists, workqueues, ref-counters, credentials, permissions, or are otherwise sensitive. This initial list was extracted from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code.
Left out of this list is task_struct, which requires special handling and will be covered in a subsequent patch.
Signed-off-by: Kees Cook <keescook@chromium.org>
show more ...
|
#
93faccbb |
| 31-Jan-2017 |
Eric W. Biederman <ebiederm@xmission.com> |
fs: Better permission checking for submounts
To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the
fs: Better permission checking for submounts
To support unprivileged users mounting filesystems two permission checks have to be performed: a test to see if the user allowed to create a mount in the mount namespace, and a test to see if the user is allowed to access the specified filesystem.
The automount case is special in that mounting the original filesystem grants permission to mount the sub-filesystems, to any user who happens to stumble across the their mountpoint and satisfies the ordinary filesystem permission checks.
Attempting to handle the automount case by using override_creds almost works. It preserves the idea that permission to mount the original filesystem is permission to mount the sub-filesystem. Unfortunately using override_creds messes up the filesystems ordinary permission checks.
Solve this by being explicit that a mount is a submount by introducing vfs_submount, and using it where appropriate.
vfs_submount uses a new mount internal mount flags MS_SUBMOUNT, to let sget and friends know that a mount is a submount so they can take appropriate action.
sget and sget_userns are modified to not perform any permission checks on submounts.
follow_automount is modified to stop using override_creds as that has proven problemantic.
do_mount is modified to always remove the new MS_SUBMOUNT flag so that we know userspace will never by able to specify it.
autofs4 is modified to stop using current_real_cred that was put in there to handle the previous version of submount permission checking.
cifs is modified to pass the mountpoint all of the way down to vfs_submount.
debugfs is modified to pass the mountpoint all of the way down to trace_automount by adding a new parameter. To make this change easier a new typedef debugfs_automount_t is introduced to capture the type of the debugfs automount function.
Cc: stable@vger.kernel.org Fixes: 069d5ac9ae0d ("autofs: Fix automounts by using current_real_cred()->uid") Fixes: aeaa4a79ff6a ("fs: Call d_automount with the filesystems creds") Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
show more ...
|
#
ca71cf71 |
| 20-Nov-2016 |
Al Viro <viro@zeniv.linux.org.uk> |
namespace.c: constify struct path passed to a bunch of primitives
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
#
c6609c0a |
| 23-Nov-2016 |
Ian Kent <ikent@redhat.com> |
vfs: add path_is_mountpoint() helper
d_mountpoint() can only be used reliably to establish if a dentry is not mounted in any namespace. It isn't aware of the possibility there may be multiple mounts
vfs: add path_is_mountpoint() helper
d_mountpoint() can only be used reliably to establish if a dentry is not mounted in any namespace. It isn't aware of the possibility there may be multiple mounts using a given dentry that may be in a different namespace.
Add helper functions, path_is_mountpoint(), that checks if a struct path is a mountpoint for this case.
Link: http://lkml.kernel.org/r/20161011053358.27645.9729.stgit@pluto.themaw.net Signed-off-by: Ian Kent <raven@themaw.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Omar Sandoval <osandov@osandov.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
show more ...
|
Revision tags: v4.4.28, v4.4.27, v4.7.10, openbmc-4.4-20161021-1, v4.7.9, v4.4.26, v4.7.8, v4.4.25, v4.4.24, v4.7.7, v4.8, v4.4.23, v4.7.6 |
|
#
d2921684 |
| 28-Sep-2016 |
Eric W. Biederman <ebiederm@xmission.com> |
mnt: Add a per mount namespace limit on the number of mounts
CAI Qian <caiqian@redhat.com> pointed out that the semantics of shared subtrees make it possible to create an exponentially increasing nu
mnt: Add a per mount namespace limit on the number of mounts
CAI Qian <caiqian@redhat.com> pointed out that the semantics of shared subtrees make it possible to create an exponentially increasing number of mounts in a mount namespace.
mkdir /tmp/1 /tmp/2 mount --make-rshared / for i in $(seq 1 20) ; do mount --bind /tmp/1 /tmp/2 ; done
Will create create 2^20 or 1048576 mounts, which is a practical problem as some people have managed to hit this by accident.
As such CVE-2016-6213 was assigned.
Ian Kent <raven@themaw.net> described the situation for autofs users as follows:
> The number of mounts for direct mount maps is usually not very large because of > the way they are implemented, large direct mount maps can have performance > problems. There can be anywhere from a few (likely case a few hundred) to less > than 10000, plus mounts that have been triggered and not yet expired. > > Indirect mounts have one autofs mount at the root plus the number of mounts that > have been triggered and not yet expired. > > The number of autofs indirect map entries can range from a few to the common > case of several thousand and in rare cases up to between 30000 and 50000. I've > not heard of people with maps larger than 50000 entries. > > The larger the number of map entries the greater the possibility for a large > number of active mounts so it's not hard to expect cases of a 1000 or somewhat > more active mounts.
So I am setting the default number of mounts allowed per mount namespace at 100,000. This is more than enough for any use case I know of, but small enough to quickly stop an exponential increase in mounts. Which should be perfect to catch misconfigurations and malfunctioning programs.
For anyone who needs a higher limit this can be changed by writing to the new /proc/sys/fs/mount-max sysctl.
Tested-by: CAI Qian <caiqian@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
show more ...
|
Revision tags: v4.7.5, v4.4.22, v4.4.21, v4.7.4, v4.7.3, v4.4.20, v4.7.2, v4.4.19, openbmc-4.4-20160819-1, v4.7.1, v4.4.18, v4.4.17, openbmc-4.4-20160804-1, v4.4.16, v4.7, openbmc-4.4-20160722-1, openbmc-20160722-1, openbmc-20160713-1, v4.4.15, v4.6.4, v4.6.3, v4.4.14 |
|
#
380cf5ba |
| 23-Jun-2016 |
Andy Lutomirski <luto@amacapital.net> |
fs: Treat foreign mounts as nosuid
If a process gets access to a mount from a different user namespace, that process should not be able to take advantage of setuid files or selinux entrypoints from
fs: Treat foreign mounts as nosuid
If a process gets access to a mount from a different user namespace, that process should not be able to take advantage of setuid files or selinux entrypoints from that filesystem. Prevent this by treating mounts from other mount namespaces and those not owned by current_user_ns() or an ancestor as nosuid.
This will make it safer to allow more complex filesystems to be mounted in non-root user namespaces.
This does not remove the need for MNT_LOCK_NOSUID. The setuid, setgid, and file capability bits can no longer be abused if code in a user namespace were to clear nosuid on an untrusted filesystem, but this patch, by itself, is insufficient to protect the system from abuse of files that, when execed, would increase MAC privilege.
As a more concrete explanation, any task that can manipulate a vfsmount associated with a given user namespace already has capabilities in that namespace and all of its descendents. If they can cause a malicious setuid, setgid, or file-caps executable to appear in that mount, then that executable will only allow them to elevate privileges in exactly the set of namespaces in which they are already privileges.
On the other hand, if they can cause a malicious executable to appear with a dangerous MAC label, running it could change the caller's security context in a way that should not have been possible, even inside the namespace in which the task is confined.
As a hardening measure, this would have made CVE-2014-5207 much more difficult to exploit.
Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: James Morris <james.l.morris@oracle.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
show more ...
|