<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/include/uapi/asm-generic, branch v5.13</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>quota: finish disable quotactl_path syscall</title>
<updated>2021-06-15T09:22:45+00:00</updated>
<author>
<name>Marcin Juszkiewicz</name>
<email>marcin@juszkiewicz.com.pl</email>
</author>
<published>2021-06-14T15:37:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8b1462b67f23da548f27b779a36b8ea75f5ef249'/>
<id>8b1462b67f23da548f27b779a36b8ea75f5ef249</id>
<content type='text'>
In commit 5b9fedb31e47 ("quota: Disable quotactl_path syscall") Jan Kara
disabled quotactl_path syscall on several architectures.

This commit disables it on all architectures using unified list of
system calls:

- arm64
- arc
- csky
- h8300
- hexagon
- nds32
- nios2
- openrisc
- riscv (32/64)

CC: Jan Kara &lt;jack@suse.cz&gt;
CC: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
CC: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Link: https://lore.kernel.org/lkml/20210512153621.n5u43jsytbik4yze@wittgenstein
Link: https://lore.kernel.org/r/20210614153712.313707-1-marcin@juszkiewicz.com.pl
Fixes: 5b9fedb31e47 ("quota: Disable quotactl_path syscall")
Acked-by: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Signed-off-by: Marcin Juszkiewicz &lt;marcin@juszkiewicz.com.pl&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In commit 5b9fedb31e47 ("quota: Disable quotactl_path syscall") Jan Kara
disabled quotactl_path syscall on several architectures.

This commit disables it on all architectures using unified list of
system calls:

- arm64
- arc
- csky
- h8300
- hexagon
- nds32
- nios2
- openrisc
- riscv (32/64)

CC: Jan Kara &lt;jack@suse.cz&gt;
CC: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
CC: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Link: https://lore.kernel.org/lkml/20210512153621.n5u43jsytbik4yze@wittgenstein
Link: https://lore.kernel.org/r/20210614153712.313707-1-marcin@juszkiewicz.com.pl
Fixes: 5b9fedb31e47 ("quota: Disable quotactl_path syscall")
Acked-by: Christian Brauner &lt;christian.brauner@ubuntu.com&gt;
Signed-off-by: Marcin Juszkiewicz &lt;marcin@juszkiewicz.com.pl&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace</title>
<updated>2021-05-21T16:12:52+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-05-21T16:12:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a0e31f3a38e77612ed8967aaad28db6d3ee674b5'/>
<id>a0e31f3a38e77612ed8967aaad28db6d3ee674b5</id>
<content type='text'>
Pull siginfo fix from Eric Biederman:
 "During the merge window an issue with si_perf and the siginfo ABI came
  up. The alpha and sparc siginfo structure layout had changed with the
  addition of SIGTRAP TRAP_PERF and the new field si_perf.

  The reason only alpha and sparc were affected is that they are the
  only architectures that use si_trapno.

  Looking deeper it was discovered that si_trapno is used for only a few
  select signals on alpha and sparc, and that none of the other
  _sigfault fields past si_addr are used at all. Which means technically
  no regression on alpha and sparc.

  While the alignment concerns might be dismissed the abuse of si_errno
  by SIGTRAP TRAP_PERF does have the potential to cause regressions in
  existing userspace.

  While we still have time before userspace starts using and depending
  on the new definition siginfo for SIGTRAP TRAP_PERF this set of
  changes cleans up siginfo_t.

   - The si_trapno field is demoted from magic alpha and sparc status
     and made an ordinary union member of the _sigfault member of
     siginfo_t. Without moving it of course.

   - si_perf is replaced with si_perf_data and si_perf_type ending the
     abuse of si_errno.

   - Unnecessary additions to signalfd_siginfo are removed"

* 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo
  signal: Deliver all of the siginfo perf data in _perf
  signal: Factor force_sig_perf out of perf_sigtrap
  signal: Implement SIL_FAULT_TRAPNO
  siginfo: Move si_trapno inside the union inside _si_fault
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull siginfo fix from Eric Biederman:
 "During the merge window an issue with si_perf and the siginfo ABI came
  up. The alpha and sparc siginfo structure layout had changed with the
  addition of SIGTRAP TRAP_PERF and the new field si_perf.

  The reason only alpha and sparc were affected is that they are the
  only architectures that use si_trapno.

  Looking deeper it was discovered that si_trapno is used for only a few
  select signals on alpha and sparc, and that none of the other
  _sigfault fields past si_addr are used at all. Which means technically
  no regression on alpha and sparc.

  While the alignment concerns might be dismissed the abuse of si_errno
  by SIGTRAP TRAP_PERF does have the potential to cause regressions in
  existing userspace.

  While we still have time before userspace starts using and depending
  on the new definition siginfo for SIGTRAP TRAP_PERF this set of
  changes cleans up siginfo_t.

   - The si_trapno field is demoted from magic alpha and sparc status
     and made an ordinary union member of the _sigfault member of
     siginfo_t. Without moving it of course.

   - si_perf is replaced with si_perf_data and si_perf_type ending the
     abuse of si_errno.

   - Unnecessary additions to signalfd_siginfo are removed"

* 'for-v5.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo
  signal: Deliver all of the siginfo perf data in _perf
  signal: Factor force_sig_perf out of perf_sigtrap
  signal: Implement SIL_FAULT_TRAPNO
  siginfo: Move si_trapno inside the union inside _si_fault
</pre>
</div>
</content>
</entry>
<entry>
<title>signal: Deliver all of the siginfo perf data in _perf</title>
<updated>2021-05-18T21:20:54+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2021-05-02T22:28:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0683b53197b55343a166f1507086823030809a19'/>
<id>0683b53197b55343a166f1507086823030809a19</id>
<content type='text'>
Don't abuse si_errno and deliver all of the perf data in _perf member
of siginfo_t.

Note: The data field in the perf data structures in a u64 to allow a
pointer to be encoded without needed to implement a 32bit and 64bit
version of the same structure.  There already exists a 32bit and 64bit
versions siginfo_t, and the 32bit version can not include a 64bit
member as it only has 32bit alignment.  So unsigned long is used in
siginfo_t instead of a u64 as unsigned long can encode a pointer on
all architectures linux supports.

v1: https://lkml.kernel.org/r/m11rarqqx2.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210503203814.25487-10-ebiederm@xmission.com
v3: https://lkml.kernel.org/r/20210505141101.11519-11-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-4-ebiederm@xmission.com
Reviewed-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Don't abuse si_errno and deliver all of the perf data in _perf member
of siginfo_t.

Note: The data field in the perf data structures in a u64 to allow a
pointer to be encoded without needed to implement a 32bit and 64bit
version of the same structure.  There already exists a 32bit and 64bit
versions siginfo_t, and the 32bit version can not include a 64bit
member as it only has 32bit alignment.  So unsigned long is used in
siginfo_t instead of a u64 as unsigned long can encode a pointer on
all architectures linux supports.

v1: https://lkml.kernel.org/r/m11rarqqx2.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210503203814.25487-10-ebiederm@xmission.com
v3: https://lkml.kernel.org/r/20210505141101.11519-11-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-4-ebiederm@xmission.com
Reviewed-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>siginfo: Move si_trapno inside the union inside _si_fault</title>
<updated>2021-05-18T21:17:03+00:00</updated>
<author>
<name>Eric W. Biederman</name>
<email>ebiederm@xmission.com</email>
</author>
<published>2021-04-30T22:06:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=add0b32ef9146a8559a60aed54c37692a5f9d34f'/>
<id>add0b32ef9146a8559a60aed54c37692a5f9d34f</id>
<content type='text'>
It turns out that linux uses si_trapno very sparingly, and as such it
can be considered extra information for a very narrow selection of
signals, rather than information that is present with every fault
reported in siginfo.

As such move si_trapno inside the union inside of _si_fault.  This
results in no change in placement, and makes it eaiser
to extend _si_fault in the future as this reduces the number of
special cases.  In particular with si_trapno included in the union it
is no longer a concern that the union must be pointer aligned on most
architectures because the union follows immediately after si_addr
which is a pointer.

This change results in a difference in siginfo field placement on
sparc and alpha for the fields si_addr_lsb, si_lower, si_upper,
si_pkey, and si_perf.  These architectures do not implement the
signals that would use si_addr_lsb, si_lower, si_upper, si_pkey, and
si_perf.  Further these architecture have not yet implemented the
userspace that would use si_perf.

The point of this change is in fact to correct these placement issues
before sparc or alpha grow userspace that cares.  This change was
discussed[1] and the agreement is that this change is currently safe.

[1]: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@mail.gmail.com
Acked-by: Marco Elver &lt;elver@google.com&gt;
v1: https://lkml.kernel.org/r/m1tunns7yf.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-5-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It turns out that linux uses si_trapno very sparingly, and as such it
can be considered extra information for a very narrow selection of
signals, rather than information that is present with every fault
reported in siginfo.

As such move si_trapno inside the union inside of _si_fault.  This
results in no change in placement, and makes it eaiser
to extend _si_fault in the future as this reduces the number of
special cases.  In particular with si_trapno included in the union it
is no longer a concern that the union must be pointer aligned on most
architectures because the union follows immediately after si_addr
which is a pointer.

This change results in a difference in siginfo field placement on
sparc and alpha for the fields si_addr_lsb, si_lower, si_upper,
si_pkey, and si_perf.  These architectures do not implement the
signals that would use si_addr_lsb, si_lower, si_upper, si_pkey, and
si_perf.  Further these architecture have not yet implemented the
userspace that would use si_perf.

The point of this change is in fact to correct these placement issues
before sparc or alpha grow userspace that cares.  This change was
discussed[1] and the agreement is that this change is currently safe.

[1]: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@mail.gmail.com
Acked-by: Marco Elver &lt;elver@google.com&gt;
v1: https://lkml.kernel.org/r/m1tunns7yf.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-5-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" &lt;ebiederm@xmission.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security</title>
<updated>2021-05-02T01:50:44+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-05-02T01:50:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=17ae69aba89dbfa2139b7f8024b757ab3cc42f59'/>
<id>17ae69aba89dbfa2139b7f8024b757ab3cc42f59</id>
<content type='text'>
Pull Landlock LSM from James Morris:
 "Add Landlock, a new LSM from Mickaël Salaün.

  Briefly, Landlock provides for unprivileged application sandboxing.

  From Mickaël's cover letter:
    "The goal of Landlock is to enable to restrict ambient rights (e.g.
     global filesystem access) for a set of processes. Because Landlock
     is a stackable LSM [1], it makes possible to create safe security
     sandboxes as new security layers in addition to the existing
     system-wide access-controls. This kind of sandbox is expected to
     help mitigate the security impact of bugs or unexpected/malicious
     behaviors in user-space applications. Landlock empowers any
     process, including unprivileged ones, to securely restrict
     themselves.

     Landlock is inspired by seccomp-bpf but instead of filtering
     syscalls and their raw arguments, a Landlock rule can restrict the
     use of kernel objects like file hierarchies, according to the
     kernel semantic. Landlock also takes inspiration from other OS
     sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
     Pledge/Unveil.

     In this current form, Landlock misses some access-control features.
     This enables to minimize this patch series and ease review. This
     series still addresses multiple use cases, especially with the
     combined use of seccomp-bpf: applications with built-in sandboxing,
     init systems, security sandbox tools and security-oriented APIs [2]"

  The cover letter and v34 posting is here:

      https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/

  See also:

      https://landlock.io/

  This code has had extensive design discussion and review over several
  years"

Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]

* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  landlock: Enable user space to infer supported features
  landlock: Add user and kernel documentation
  samples/landlock: Add a sandbox manager example
  selftests/landlock: Add user space tests
  landlock: Add syscall implementations
  arch: Wire up Landlock syscalls
  fs,security: Add sb_delete hook
  landlock: Support filesystem access-control
  LSM: Infrastructure management of the superblock
  landlock: Add ptrace restrictions
  landlock: Set up the security framework and manage credentials
  landlock: Add ruleset and domain management
  landlock: Add object management
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull Landlock LSM from James Morris:
 "Add Landlock, a new LSM from Mickaël Salaün.

  Briefly, Landlock provides for unprivileged application sandboxing.

  From Mickaël's cover letter:
    "The goal of Landlock is to enable to restrict ambient rights (e.g.
     global filesystem access) for a set of processes. Because Landlock
     is a stackable LSM [1], it makes possible to create safe security
     sandboxes as new security layers in addition to the existing
     system-wide access-controls. This kind of sandbox is expected to
     help mitigate the security impact of bugs or unexpected/malicious
     behaviors in user-space applications. Landlock empowers any
     process, including unprivileged ones, to securely restrict
     themselves.

     Landlock is inspired by seccomp-bpf but instead of filtering
     syscalls and their raw arguments, a Landlock rule can restrict the
     use of kernel objects like file hierarchies, according to the
     kernel semantic. Landlock also takes inspiration from other OS
     sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
     Pledge/Unveil.

     In this current form, Landlock misses some access-control features.
     This enables to minimize this patch series and ease review. This
     series still addresses multiple use cases, especially with the
     combined use of seccomp-bpf: applications with built-in sandboxing,
     init systems, security sandbox tools and security-oriented APIs [2]"

  The cover letter and v34 posting is here:

      https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/

  See also:

      https://landlock.io/

  This code has had extensive design discussion and review over several
  years"

Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]

* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  landlock: Enable user space to infer supported features
  landlock: Add user and kernel documentation
  samples/landlock: Add a sandbox manager example
  selftests/landlock: Add user space tests
  landlock: Add syscall implementations
  arch: Wire up Landlock syscalls
  fs,security: Add sb_delete hook
  landlock: Support filesystem access-control
  LSM: Infrastructure management of the superblock
  landlock: Add ptrace restrictions
  landlock: Set up the security framework and manage credentials
  landlock: Add ruleset and domain management
  landlock: Add object management
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for_v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs</title>
<updated>2021-04-29T17:51:29+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-04-29T17:51:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=767fcbc80f63d7f08ff6c0858fe33583e6fdd327'/>
<id>767fcbc80f63d7f08ff6c0858fe33583e6fdd327</id>
<content type='text'>
Pull quota, ext2, reiserfs updates from Jan Kara:

 - support for path (instead of device) based quotactl syscall
   (quotactl_path(2))

 - ext2 conversion to kmap_local()

 - other minor cleanups &amp; fixes

* tag 'for_v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fs/reiserfs/journal.c: delete useless variables
  fs/ext2: Replace kmap() with kmap_local_page()
  ext2: Match up ext2_put_page() with ext2_dotdot() and ext2_find_entry()
  fs/ext2/: fix misspellings using codespell tool
  quota: report warning limits for realtime space quotas
  quota: wire up quotactl_path
  quota: Add mountpath based quota support
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull quota, ext2, reiserfs updates from Jan Kara:

 - support for path (instead of device) based quotactl syscall
   (quotactl_path(2))

 - ext2 conversion to kmap_local()

 - other minor cleanups &amp; fixes

* tag 'for_v5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fs/reiserfs/journal.c: delete useless variables
  fs/ext2: Replace kmap() with kmap_local_page()
  ext2: Match up ext2_put_page() with ext2_dotdot() and ext2_find_entry()
  fs/ext2/: fix misspellings using codespell tool
  quota: report warning limits for realtime space quotas
  quota: wire up quotactl_path
  quota: Add mountpath based quota support
</pre>
</div>
</content>
</entry>
<entry>
<title>signal, perf: Fix siginfo_t by avoiding u64 on 32-bit architectures</title>
<updated>2021-04-23T07:03:16+00:00</updated>
<author>
<name>Marco Elver</name>
<email>elver@google.com</email>
</author>
<published>2021-04-22T19:18:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3ddb3fd8cdb0a6c11b7c8d91ba42d84c4ea3cc43'/>
<id>3ddb3fd8cdb0a6c11b7c8d91ba42d84c4ea3cc43</id>
<content type='text'>
The alignment of a structure is that of its largest member. On
architectures like 32-bit Arm (but not e.g. 32-bit x86) 64-bit integers
will require 64-bit alignment and not its natural word size.

This means that there is no portable way to add 64-bit integers to
siginfo_t on 32-bit architectures without breaking the ABI, because
siginfo_t does not yet (and therefore likely never will) contain 64-bit
fields on 32-bit architectures. Adding a 64-bit integer could change the
alignment of the union after the 3 initial int si_signo, si_errno,
si_code, thus introducing 4 bytes of padding shifting the entire union,
which would break the ABI.

One alternative would be to use the __packed attribute, however, it is
non-standard C. Given siginfo_t has definitions outside the Linux kernel
in various standard libraries that can be compiled with any number of
different compilers (not just those we rely on), using non-standard
attributes on siginfo_t should be avoided to ensure portability.

In the case of the si_perf field, word size is sufficient since there is
no exact requirement on size, given the data it contains is user-defined
via perf_event_attr::sig_data. On 32-bit architectures, any excess bits
of perf_event_attr::sig_data will therefore be truncated when copying
into si_perf.

Since si_perf is intended to disambiguate events (e.g. encoding relevant
information if there are more events of the same type), 32 bits should
provide enough entropy to do so on 32-bit architectures.

For 64-bit architectures, no change is intended.

Fixes: fb6cc127e0b6 ("signal: Introduce TRAP_PERF si_code and si_perf to siginfo")
Reported-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reported-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Link: https://lkml.kernel.org/r/20210422191823.79012-1-elver@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The alignment of a structure is that of its largest member. On
architectures like 32-bit Arm (but not e.g. 32-bit x86) 64-bit integers
will require 64-bit alignment and not its natural word size.

This means that there is no portable way to add 64-bit integers to
siginfo_t on 32-bit architectures without breaking the ABI, because
siginfo_t does not yet (and therefore likely never will) contain 64-bit
fields on 32-bit architectures. Adding a 64-bit integer could change the
alignment of the union after the 3 initial int si_signo, si_errno,
si_code, thus introducing 4 bytes of padding shifting the entire union,
which would break the ABI.

One alternative would be to use the __packed attribute, however, it is
non-standard C. Given siginfo_t has definitions outside the Linux kernel
in various standard libraries that can be compiled with any number of
different compilers (not just those we rely on), using non-standard
attributes on siginfo_t should be avoided to ensure portability.

In the case of the si_perf field, word size is sufficient since there is
no exact requirement on size, given the data it contains is user-defined
via perf_event_attr::sig_data. On 32-bit architectures, any excess bits
of perf_event_attr::sig_data will therefore be truncated when copying
into si_perf.

Since si_perf is intended to disambiguate events (e.g. encoding relevant
information if there are more events of the same type), 32 bits should
provide enough entropy to do so on 32-bit architectures.

For 64-bit architectures, no change is intended.

Fixes: fb6cc127e0b6 ("signal: Introduce TRAP_PERF si_code and si_perf to siginfo")
Reported-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Reported-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Marek Szyprowski &lt;m.szyprowski@samsung.com&gt;
Tested-by: Jon Hunter &lt;jonathanh@nvidia.com&gt;
Link: https://lkml.kernel.org/r/20210422191823.79012-1-elver@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>arch: Wire up Landlock syscalls</title>
<updated>2021-04-22T19:22:11+00:00</updated>
<author>
<name>Mickaël Salaün</name>
<email>mic@linux.microsoft.com</email>
</author>
<published>2021-04-22T15:41:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a49f4f81cb48925e8d7cbd9e59068f516e984144'/>
<id>a49f4f81cb48925e8d7cbd9e59068f516e984144</id>
<content type='text'>
Wire up the following system calls for all architectures:
* landlock_create_ruleset(2)
* landlock_add_rule(2)
* landlock_restrict_self(2)

Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Serge E. Hallyn &lt;serge@hallyn.com&gt;
Signed-off-by: Mickaël Salaün &lt;mic@linux.microsoft.com&gt;
Link: https://lore.kernel.org/r/20210422154123.13086-10-mic@digikod.net
Signed-off-by: James Morris &lt;jamorris@linux.microsoft.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Wire up the following system calls for all architectures:
* landlock_create_ruleset(2)
* landlock_add_rule(2)
* landlock_restrict_self(2)

Cc: Arnd Bergmann &lt;arnd@arndb.de&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Kees Cook &lt;keescook@chromium.org&gt;
Cc: Serge E. Hallyn &lt;serge@hallyn.com&gt;
Signed-off-by: Mickaël Salaün &lt;mic@linux.microsoft.com&gt;
Link: https://lore.kernel.org/r/20210422154123.13086-10-mic@digikod.net
Signed-off-by: James Morris &lt;jamorris@linux.microsoft.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>signal: Introduce TRAP_PERF si_code and si_perf to siginfo</title>
<updated>2021-04-16T14:32:41+00:00</updated>
<author>
<name>Marco Elver</name>
<email>elver@google.com</email>
</author>
<published>2021-04-08T10:36:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fb6cc127e0b6e629252cdd0f77d5a1f49db95b92'/>
<id>fb6cc127e0b6e629252cdd0f77d5a1f49db95b92</id>
<content type='text'>
Introduces the TRAP_PERF si_code, and associated siginfo_t field
si_perf. These will be used by the perf event subsystem to send signals
(if requested) to the task where an event occurred.

Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt; # m68k
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt; # asm-generic
Link: https://lkml.kernel.org/r/20210408103605.1676875-6-elver@google.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduces the TRAP_PERF si_code, and associated siginfo_t field
si_perf. These will be used by the perf event subsystem to send signals
(if requested) to the task where an event occurred.

Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt; # m68k
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt; # asm-generic
Link: https://lkml.kernel.org/r/20210408103605.1676875-6-elver@google.com
</pre>
</div>
</content>
</entry>
<entry>
<title>quota: wire up quotactl_path</title>
<updated>2021-03-17T14:51:17+00:00</updated>
<author>
<name>Sascha Hauer</name>
<email>s.hauer@pengutronix.de</email>
</author>
<published>2021-03-04T12:35:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fa8b90070a80bb1a3042b4b25af4b3ee2c4c27e1'/>
<id>fa8b90070a80bb1a3042b4b25af4b3ee2c4c27e1</id>
<content type='text'>
Wire up the quotactl_path syscall added in the previous patch.

Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Wire up the quotactl_path syscall added in the previous patch.

Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer &lt;s.hauer@pengutronix.de&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
</pre>
</div>
</content>
</entry>
</feed>
