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  1. Feb 02, 2020
    • Lukas Bulwahn's avatar
      MAINTAINERS: correct entries for ISDN/mISDN section · dff6bc1b
      Lukas Bulwahn authored 
      
Commit 6d979850 ("isdn: move capi drivers to staging") cleaned up the
isdn drivers and split the MAINTAINERS section for ISDN, but missed to add
the terminal slash for the two directories mISDN and hardware. Hence, all
files in those directories were not part of the new ISDN/mISDN SUBSYSTEM,
but were considered to be part of "THE REST".

Rectify the situation, and while at it, also complete the section with two
further build files that belong to that subsystem.

This was identified with a small script that finds all files belonging to
"THE REST" according to the current MAINTAINERS file, and I investigated
upon its output.

Fixes: 6d979850 ("isdn: move capi drivers to staging")
Signed-off-by: default avatarLukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      dff6bc1b
  3. Feb 01, 2020
    • Sven Eckelmann's avatar
      MAINTAINERS: Orphan HSR network protocol · e8d5bb4d
      Sven Eckelmann authored 
      
The current maintainer Arvid Brodin <arvid.brodin@alten.se> hasn't
contributed to the kernel since 2015-02-27. His company mail address is
also bouncing and the company confirmed (2020-01-31) that no Arvid Brodin
is working for them:

> Vi har dessvärre ingen  Arvid Brodin som arbetar på ALTEN.

A MIA person cannot be the maintainer. It is better to mark is as orphaned
until some other person can jump in and take over the responsibility for
HSR.

Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      e8d5bb4d
  5. Jan 29, 2020
  7. Jan 28, 2020
  9. Jan 27, 2020
  11. Jan 26, 2020
  13. Jan 25, 2020
  15. Jan 24, 2020
  17. Jan 23, 2020
  19. Jan 22, 2020
  21. Jan 20, 2020
  23. Jan 18, 2020
    • Aleksa Sarai's avatar
      open: introduce openat2(2) syscall · fddb5d43
      Aleksa Sarai authored 
      /* Background. */
For a very long time, extending openat(2) with new features has been
incredibly frustrating. This stems from the fact that openat(2) is
possibly the most famous counter-example to the mantra "don't silently
accept garbage from userspace" -- it doesn't check whether unknown flags
are present[1].

This means that (generally) the addition of new flags to openat(2) has
been fraught with backwards-compatibility issues (O_TMPFILE has to be
defined as __O_TMPFILE|O_DIRECTORY|[O_RDWR or O_WRONLY] to ensure old
kernels gave errors, since it's insecure to silently ignore the
flag[2]). All new security-related flags therefore have a tough road to
being added to openat(2).

Userspace also has a hard time figuring out whether a particular flag is
supported on a particular kernel. While it is now possible with
contemporary kernels (thanks to [3]), older kernels will expose unknown
flag bits through fcntl(F_GETFL). Giving a clear -EINVAL during
openat(2) time matches modern syscall designs and is far more
fool-proof.

In addition, the newly-added path resolution restriction LOOKUP flags
(which we would like to expose to user-space) don't feel related to the
pre-existing O_* flag set -- they affect all components of path lookup.
We'd therefore like to add a new flag argument.

Adding a new syscall allows us to finally fix the flag-ignoring problem,
and we can make it extensible enough so that we will hopefully never
need an openat3(2).

/* Syscall Prototype. */
  /*
   * open_how is an extensible structure (similar in interface to
   * clone3(2) or sched_setattr(2)). The size parameter must be set to
   * sizeof(struct open_how), to allow for future extensions. All future
   * extensions will be appended to open_how, with their zero value
   * acting as a no-op default.
   */
  struct open_how { /* ... */ };

  int openat2(int dfd, const char *pathname,
              struct open_how *how, size_t size);

/* Description. */
The initial version of 'struct open_how' contains the following fields:

  flags
    Used to specify openat(2)-style flags. However, any unknown flag
    bits or otherwise incorrect flag combinations (like O_PATH|O_RDWR)
    will result in -EINVAL. In addition, this field is 64-bits wide to
    allow for more O_ flags than currently permitted with openat(2).

  mode
    The file mode for O_CREAT or O_TMPFILE.

    Must be set to zero if flags does not contain O_CREAT or O_TMPFILE.

  resolve
    Restrict path resolution (in contrast to O_* flags they affect all
    path components). The current set of flags are as follows (at the
    moment, all of the RESOLVE_ flags are implemented as just passing
    the corresponding LOOKUP_ flag).

    RESOLVE_NO_XDEV       => LOOKUP_NO_XDEV
    RESOLVE_NO_SYMLINKS   => LOOKUP_NO_SYMLINKS
    RESOLVE_NO_MAGICLINKS => LOOKUP_NO_MAGICLINKS
    RESOLVE_BENEATH       => LOOKUP_BENEATH
    RESOLVE_IN_ROOT       => LOOKUP_IN_ROOT

open_how does not contain an embedded size field, because it is of
little benefit (userspace can figure out the kernel open_how size at
runtime fairly easily without it). It also only contains u64s (even
though ->mode arguably should be a u16) to avoid having padding fields
which are never used in the future.

Note that as a result of the new how->flags handling, O_PATH|O_TMPFILE
is no longer permitted for openat(2). As far as I can tell, this has
always been a bug and appears to not be used by userspace (and I've not
seen any problems on my machines by disallowing it). If it turns out
this breaks something, we can special-case it and only permit it for
openat(2) but not openat2(2).

After input from Florian Weimer, the new open_how and flag definitions
are inside a separate header from uapi/linux/fcntl.h, to avoid problems
that glibc has with importing that header.

/* Testing. */
In a follow-up patch there are over 200 selftests which ensure that this
syscall has the correct semantics and will correctly handle several
attack scenarios.

In addition, I've written a userspace library[4] which provides
convenient wrappers around openat2(RESOLVE_IN_ROOT) (this is necessary
because no other syscalls support RESOLVE_IN_ROOT, and thus lots of care
must be taken when using RESOLVE_IN_ROOT'd file descriptors with other
syscalls). During the development of this patch, I've run numerous
verification tests using libpathrs (showing that the API is reasonably
usable by userspace).

/* Future Work. */
Additional RESOLVE_ flags have been suggested during the review period.
These can be easily implemented separately (such as blocking auto-mount
during resolution).

Furthermore, there are some other proposed changes to the openat(2)
interface (the most obvious example is magic-link hardening[5]) which
would be a good opportunity to add a way for userspace to restrict how
O_PATH file descriptors can be re-opened.

Another possible avenue of future work would be some kind of
CHECK_FIELDS[6] flag which causes the kernel to indicate to userspace
which openat2(2) flags and fields are supported by the current kernel
(to avoid userspace having to go through several guesses to figure it
out).

[1]: https://lwn.net/Articles/588444/
[2]: https://lore.kernel.org/lkml/CA+55aFyyxJL1LyXZeBsf2ypriraj5ut1XkNDsunRBqgVjZU_6Q@mail.gmail.com
[3]: commit 629e014b ("fs: completely ignore unknown open flags")
[4]: https://sourceware.org/bugzilla/show_bug.cgi?id=17523
[5]: https://lore.kernel.org/lkml/20190930183316.10190-2-cyphar@cyphar.com/
[6]: https://youtu.be/ggD-eb3yPVs



Suggested-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: default avatarAleksa Sarai <cyphar@cyphar.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      fddb5d43
    • Lukas Bulwahn's avatar
      MAINTAINERS: Mark simple firmware interface (SFI) obsolete · b2aa0917
      Lukas Bulwahn authored 
      
Len Brown has not been active in this part since around 2010 and
confirmed that he is not maintaining this part of the kernel sources
anymore and the git log suggests that nobody is actively maintaining it.

The referenced git tree does not exist. Instead, I found an sfi branch
in Len's kernel git repository, but that has not been updated since 2014;
so that is not worth to be mentioned in MAINTAINERS now anymore either.

Len Brown expects no further systems to be shipped with SFI, so we can
mark it obsolete and schedule it for deletion.

This change was motivated after I found that I could not send any mails
to the sfi-devel mailing list, and that the mailing list does not exist
anymore.

Signed-off-by: default avatarLukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200118082545.23464-1-lukas.bulwahn@gmail.com
      b2aa0917
  25. Jan 16, 2020
  27. Jan 15, 2020
  29. Jan 14, 2020
  31. Jan 13, 2020
    • Srinivas Pandruvada's avatar
      MAINTAINERS: Update for the intel uncore frequency control · d81d18fd
      Srinivas Pandruvada authored 
      
Add an entry for drivers/platform/x86/intel-uncore-frequency.c.

Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
      d81d18fd
    • Sean Christopherson's avatar
      x86/vmx: Introduce VMX_FEATURES_* · 15934878
      Sean Christopherson authored 
      
Add a VMX-specific variant of X86_FEATURE_* flags, which will eventually
supplant the synthetic VMX flags defined in cpufeatures word 8.  Use the
Intel-defined layouts for the major VMX execution controls so that their
word entries can be directly populated from their respective MSRs, and
so that the VMX_FEATURE_* flags can be used to define the existing bit
definitions in asm/vmx.h, i.e. force developers to define a VMX_FEATURE
flag when adding support for a new hardware feature.

The majority of Intel's (and compatible CPU's) VMX capabilities are
enumerated via MSRs and not CPUID, i.e. querying /proc/cpuinfo doesn't
naturally provide any insight into the virtualization capabilities of
VMX enabled CPUs.  Commit

  e38e05a8 ("x86: extended "flags" to show virtualization HW feature
		 in /proc/cpuinfo")

attempted to address the issue by synthesizing select VMX features into
a Linux-defined word in cpufeatures.

Lack of reporting of VMX capabilities via /proc/cpuinfo is problematic
because there is no sane way for a user to query the capabilities of
their platform, e.g. when trying to find a platform to test a feature or
debug an issue that has a hardware dependency.  Lack of reporting is
especially problematic when the user isn't familiar with VMX, e.g. the
format of the MSRs is non-standard, existence of some MSRs is reported
by bits in other MSRs, several "features" from KVM's point of view are
enumerated as 3+ distinct features by hardware, etc...

The synthetic cpufeatures approach has several flaws:

  - The set of synthesized VMX flags has become extremely stale with
    respect to the full set of VMX features, e.g. only one new flag
    (EPT A/D) has been added in the the decade since the introduction of
    the synthetic VMX features.  Failure to keep the VMX flags up to
    date is likely due to the lack of a mechanism that forces developers
    to consider whether or not a new feature is worth reporting.

  - The synthetic flags may incorrectly be misinterpreted as affecting
    kernel behavior, i.e. KVM, the kernel's sole consumer of VMX,
    completely ignores the synthetic flags.

  - New CPU vendors that support VMX have duplicated the hideous code
    that propagates VMX features from MSRs to cpufeatures.  Bringing the
    synthetic VMX flags up to date would exacerbate the copy+paste
    trainwreck.

Define separate VMX_FEATURE flags to set the stage for enumerating VMX
capabilities outside of the cpu_has() framework, and for adding
functional usage of VMX_FEATURE_* to help ensure the features reported
via /proc/cpuinfo is up to date with respect to kernel recognition of
VMX capabilities.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-10-sean.j.christopherson@intel.com
      15934878
  33. Jan 11, 2020
    • Jakub Kicinski's avatar
      MAINTAINERS: update my email address · c9f53049
      Jakub Kicinski authored 
      
My Netronome email address may become inactive soon.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c9f53049
    • Jacob Keller's avatar
      devlink: convert driver-specific files to reStructuredText · 6c39e015
      Jacob Keller authored 
      
Several drivers document what parameters they support in
a devlink-params-*.txt file. This file is supposed to contain both the
list of generic parameters implemented by the driver, as well as a list
of driver-specific parameters and their descriptions.

It would also be good if the driver documentation included other
driver-specific implementations, such as info versions, devlink
regions, and so forth.

Convert all of these documentation files to reStructuredText, and rename
them to just the driver name. Future changes will include other
driver-specific implementations. Each file will contain a table for the
generic parameters implemented, as well as a separate table for the
driver-specific parameters.

Future sections such as for devlink info versions will be added to these
files. This avoids creating additional devlink-<feature>-<driver> files
for each devlink feature, reducing clutter in the documentation folder.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Michael Chan <michael.chan@broadcom.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Ido Schimmel <idosch@mellanox.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6c39e015
    • Jacob Keller's avatar
      devlink: move devlink documentation to subfolder · f4bdd710
      Jacob Keller authored 
      
Combine the documentation for devlink into a subfolder, and provide an
index.rst file that can be used to generally describe devlink.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f4bdd710
  35. Jan 10, 2020