<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/security, branch v6.15-rc4</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>Merge tag 'landlock-6.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux</title>
<updated>2025-04-24T19:59:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-24T19:59:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=30e268185e59c3d5a1233416a2135cfda5630644'/>
<id>30e268185e59c3d5a1233416a2135cfda5630644</id>
<content type='text'>
Pull landlock fixes from Mickaël Salaün:
 "Fix some Landlock audit issues, add related tests, and updates
  documentation"

* tag 'landlock-6.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
  landlock: Update log documentation
  landlock: Fix documentation for landlock_restrict_self(2)
  landlock: Fix documentation for landlock_create_ruleset(2)
  selftests/landlock: Add PID tests for audit records
  selftests/landlock: Factor out audit fixture in audit_test
  landlock: Log the TGID of the domain creator
  landlock: Remove incorrect warning
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull landlock fixes from Mickaël Salaün:
 "Fix some Landlock audit issues, add related tests, and updates
  documentation"

* tag 'landlock-6.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
  landlock: Update log documentation
  landlock: Fix documentation for landlock_restrict_self(2)
  landlock: Fix documentation for landlock_create_ruleset(2)
  selftests/landlock: Add PID tests for audit records
  selftests/landlock: Factor out audit fixture in audit_test
  landlock: Log the TGID of the domain creator
  landlock: Remove incorrect warning
</pre>
</div>
</content>
</entry>
<entry>
<title>ima: process_measurement() needlessly takes inode_lock() on MAY_READ</title>
<updated>2025-04-22T14:39:32+00:00</updated>
<author>
<name>Frederick Lawler</name>
<email>fred@cloudflare.com</email>
</author>
<published>2025-03-27T16:09:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=30d68cb0c37ebe2dc63aa1d46a28b9163e61caa2'/>
<id>30d68cb0c37ebe2dc63aa1d46a28b9163e61caa2</id>
<content type='text'>
On IMA policy update, if a measure rule exists in the policy,
IMA_MEASURE is set for ima_policy_flags which makes the violation_check
variable always true. Coupled with a no-action on MAY_READ for a
FILE_CHECK call, we're always taking the inode_lock().

This becomes a performance problem for extremely heavy read-only workloads.
Therefore, prevent this only in the case there's no action to be taken.

Signed-off-by: Frederick Lawler &lt;fred@cloudflare.com&gt;
Acked-by: Roberto Sassu &lt;roberto.sassu@huawei.com&gt;
Signed-off-by: Mimi Zohar &lt;zohar@linux.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On IMA policy update, if a measure rule exists in the policy,
IMA_MEASURE is set for ima_policy_flags which makes the violation_check
variable always true. Coupled with a no-action on MAY_READ for a
FILE_CHECK call, we're always taking the inode_lock().

This becomes a performance problem for extremely heavy read-only workloads.
Therefore, prevent this only in the case there's no action to be taken.

Signed-off-by: Frederick Lawler &lt;fred@cloudflare.com&gt;
Acked-by: Roberto Sassu &lt;roberto.sassu@huawei.com&gt;
Signed-off-by: Mimi Zohar &lt;zohar@linux.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>landlock: Fix documentation for landlock_restrict_self(2)</title>
<updated>2025-04-17T09:09:10+00:00</updated>
<author>
<name>Mickaël Salaün</name>
<email>mic@digikod.net</email>
</author>
<published>2025-04-16T15:47:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=25b1fc1cdc8931cf26e8d169f65ad07dfd653ca2'/>
<id>25b1fc1cdc8931cf26e8d169f65ad07dfd653ca2</id>
<content type='text'>
Fix, deduplicate, and improve rendering of landlock_restrict_self(2)'s
flags documentation.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack &lt;gnoack@google.com&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Link: https://lore.kernel.org/r/20250416154716.1799902-2-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix, deduplicate, and improve rendering of landlock_restrict_self(2)'s
flags documentation.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack &lt;gnoack@google.com&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Link: https://lore.kernel.org/r/20250416154716.1799902-2-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>landlock: Fix documentation for landlock_create_ruleset(2)</title>
<updated>2025-04-17T09:09:07+00:00</updated>
<author>
<name>Mickaël Salaün</name>
<email>mic@digikod.net</email>
</author>
<published>2025-04-16T15:47:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=50492f942c281af4a48f8028f8409d7b8f2655d9'/>
<id>50492f942c281af4a48f8028f8409d7b8f2655d9</id>
<content type='text'>
Move and fix the flags documentation, and improve formatting.

It makes more sense and it eases maintenance to document syscall flags
in landlock.h, where they are defined.  This is already the case for
landlock_restrict_self(2)'s flags.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack &lt;gnoack@google.com&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Link: https://lore.kernel.org/r/20250416154716.1799902-1-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move and fix the flags documentation, and improve formatting.

It makes more sense and it eases maintenance to document syscall flags
in landlock.h, where they are defined.  This is already the case for
landlock_restrict_self(2)'s flags.

The flags are now rendered like the syscall's parameters and
description.

Cc: Günther Noack &lt;gnoack@google.com&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Link: https://lore.kernel.org/r/20250416154716.1799902-1-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>hardening: Disable GCC randstruct for COMPILE_TEST</title>
<updated>2025-04-15T20:50:17+00:00</updated>
<author>
<name>Kees Cook</name>
<email>kees@kernel.org</email>
</author>
<published>2025-04-09T15:11:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f5c68a4e84f9feca3be578199ec648b676db2030'/>
<id>f5c68a4e84f9feca3be578199ec648b676db2030</id>
<content type='text'>
There is a GCC crash bug in the randstruct for latest GCC versions that
is being tickled by landlock[1]. Temporarily disable GCC randstruct for
COMPILE_TEST builds to unbreak CI systems for the coming -rc2. This can
be restored once the bug is fixed.

Suggested-by: Mark Brown &lt;broonie@kernel.org&gt;
Link: https://lore.kernel.org/all/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/ [1]
Acked-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Link: https://lore.kernel.org/r/20250409151154.work.872-kees@kernel.org
Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is a GCC crash bug in the randstruct for latest GCC versions that
is being tickled by landlock[1]. Temporarily disable GCC randstruct for
COMPILE_TEST builds to unbreak CI systems for the coming -rc2. This can
be restored once the bug is fixed.

Suggested-by: Mark Brown &lt;broonie@kernel.org&gt;
Link: https://lore.kernel.org/all/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/ [1]
Acked-by: Mark Brown &lt;broonie@kernel.org&gt;
Acked-by: Arnd Bergmann &lt;arnd@arndb.de&gt;
Link: https://lore.kernel.org/r/20250409151154.work.872-kees@kernel.org
Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>landlock: Log the TGID of the domain creator</title>
<updated>2025-04-11T10:53:17+00:00</updated>
<author>
<name>Mickaël Salaün</name>
<email>mic@digikod.net</email>
</author>
<published>2025-04-10T17:17:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4767af82a08ffaa5e55fe71febfa8cdef201b620'/>
<id>4767af82a08ffaa5e55fe71febfa8cdef201b620</id>
<content type='text'>
As for other Audit's "pid" fields, Landlock should use the task's TGID
instead of its TID.  Fix this issue by keeping a reference to the TGID
of the domain creator.

Existing tests already check for the PID but only with the thread group
leader, so always the TGID.  A following patch adds dedicated tests for
non-leader thread.

Remove the current_real_cred() check which does not make sense because
we only reference a struct pid, whereas a previous version did reference
a struct cred instead.

Cc: Christian Brauner &lt;brauner@kernel.org&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Reviewed-by: Günther Noack &lt;gnoack3000@gmail.com&gt;
Link: https://lore.kernel.org/r/20250410171725.1265860-1-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As for other Audit's "pid" fields, Landlock should use the task's TGID
instead of its TID.  Fix this issue by keeping a reference to the TGID
of the domain creator.

Existing tests already check for the PID but only with the thread group
leader, so always the TGID.  A following patch adds dedicated tests for
non-leader thread.

Remove the current_real_cred() check which does not make sense because
we only reference a struct pid, whereas a previous version did reference
a struct cred instead.

Cc: Christian Brauner &lt;brauner@kernel.org&gt;
Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Reviewed-by: Günther Noack &lt;gnoack3000@gmail.com&gt;
Link: https://lore.kernel.org/r/20250410171725.1265860-1-mic@digikod.net
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>landlock: Remove incorrect warning</title>
<updated>2025-04-08T17:18:20+00:00</updated>
<author>
<name>Mickaël Salaün</name>
<email>mic@digikod.net</email>
</author>
<published>2025-03-31T10:47:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fe81536af3978f26a1383e4da7f135b973eb4209'/>
<id>fe81536af3978f26a1383e4da7f135b973eb4209</id>
<content type='text'>
landlock_put_hierarchy() can be called when an error occurs in
landlock_merge_ruleset() due to insufficient memory.  In this case, the
domain's audit details might not have been allocated yet, which would
cause landlock_free_hierarchy_details() to print a warning (but still
safely handle this case).

We could keep the WARN_ON_ONCE(!hierarchy) but it's not worth it for
this kind of function, so let's remove it entirely.

Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Reported-by: syzbot+8bca99e91de7e060e4ea@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20250331104709.897062-1-mic@digikod.net
Reviewed-by: Günther Noack &lt;gnoack@google.com&gt;
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
landlock_put_hierarchy() can be called when an error occurs in
landlock_merge_ruleset() due to insufficient memory.  In this case, the
domain's audit details might not have been allocated yet, which would
cause landlock_free_hierarchy_details() to print a warning (but still
safely handle this case).

We could keep the WARN_ON_ONCE(!hierarchy) but it's not worth it for
this kind of function, so let's remove it entirely.

Cc: Paul Moore &lt;paul@paul-moore.com&gt;
Reported-by: syzbot+8bca99e91de7e060e4ea@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20250331104709.897062-1-mic@digikod.net
Reviewed-by: Günther Noack &lt;gnoack@google.com&gt;
Signed-off-by: Mickaël Salaün &lt;mic@digikod.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mseal sysmap: kernel config and header change</title>
<updated>2025-04-01T22:17:14+00:00</updated>
<author>
<name>Jeff Xu</name>
<email>jeffxu@chromium.org</email>
</author>
<published>2025-03-05T02:17:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=5796d3967c0956734bd1249f76989ca80da0225b'/>
<id>5796d3967c0956734bd1249f76989ca80da0225b</id>
<content type='text'>
Patch series "mseal system mappings", v9.

As discussed during mseal() upstream process [1], mseal() protects the
VMAs of a given virtual memory range against modifications, such as the
read/write (RW) and no-execute (NX) bits.  For complete descriptions of
memory sealing, please see mseal.rst [2].

The mseal() is useful to mitigate memory corruption issues where a
corrupted pointer is passed to a memory management system.  For example,
such an attacker primitive can break control-flow integrity guarantees
since read-only memory that is supposed to be trusted can become writable
or .text pages can get remapped.

The system mappings are readonly only, memory sealing can protect them
from ever changing to writable or unmmap/remapped as different attributes.

System mappings such as vdso, vvar, vvar_vclock, vectors (arm
compat-mode), sigpage (arm compat-mode), are created by the kernel during
program initialization, and could be sealed after creation.

Unlike the aforementioned mappings, the uprobe mapping is not established
during program startup.  However, its lifetime is the same as the
process's lifetime [3].  It could be sealed from creation.

The vsyscall on x86-64 uses a special address (0xffffffffff600000), which
is outside the mm managed range.  This means mprotect, munmap, and mremap
won't work on the vsyscall.  Since sealing doesn't enhance the vsyscall's
security, it is skipped in this patch.  If we ever seal the vsyscall, it
is probably only for decorative purpose, i.e.  showing the 'sl' flag in
the /proc/pid/smaps.  For this patch, it is ignored.

It is important to note that the CHECKPOINT_RESTORE feature (CRIU) may
alter the system mappings during restore operations.  UML(User Mode Linux)
and gVisor, rr are also known to change the vdso/vvar mappings. 
Consequently, this feature cannot be universally enabled across all
systems.  As such, CONFIG_MSEAL_SYSTEM_MAPPINGS is disabled by default.

To support mseal of system mappings, architectures must define
CONFIG_ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS and update their special
mappings calls to pass mseal flag.  Additionally, architectures must
confirm they do not unmap/remap system mappings during the process
lifetime.  The existence of this flag for an architecture implies that it
does not require the remapping of thest system mappings during process
lifetime, so sealing these mappings is safe from a kernel perspective.

This version covers x86-64 and arm64 archiecture as minimum viable feature.

While no specific CPU hardware features are required for enable this
feature on an archiecture, memory sealing requires a 64-bit kernel.  Other
architectures can choose whether or not to adopt this feature.  Currently,
I'm not aware of any instances in the kernel code that actively
munmap/mremap a system mapping without a request from userspace.  The PPC
does call munmap when _install_special_mapping fails for vdso; however,
it's uncertain if this will ever fail for PPC - this needs to be
investigated by PPC in the future [4].  The UML kernel can add this
support when KUnit tests require it [5].

In this version, we've improved the handling of system mapping sealing
from previous versions, instead of modifying the _install_special_mapping
function itself, which would affect all architectures, we now call
_install_special_mapping with a sealing flag only within the specific
architecture that requires it.  This targeted approach offers two key
advantages: 1) It limits the code change's impact to the necessary
architectures, and 2) It aligns with the software architecture by keeping
the core memory management within the mm layer, while delegating the
decision of sealing system mappings to the individual architecture, which
is particularly relevant since 32-bit architectures never require sealing.

Prior to this patch series, we explored sealing special mappings from
userspace using glibc's dynamic linker.  This approach revealed several
issues:

- The PT_LOAD header may report an incorrect length for vdso, (smaller
  than its actual size).  The dynamic linker, which relies on PT_LOAD
  information to determine mapping size, would then split and partially
  seal the vdso mapping.  Since each architecture has its own vdso/vvar
  code, fixing this in the kernel would require going through each
  archiecture.  Our initial goal was to enable sealing readonly mappings,
  e.g.  .text, across all architectures, sealing vdso from kernel since
  creation appears to be simpler than sealing vdso at glibc.

- The [vvar] mapping header only contains address information, not
  length information.  Similar issues might exist for other special
  mappings.

- Mappings like uprobe are not covered by the dynamic linker, and there
  is no effective solution for them.

This feature's security enhancements will benefit ChromeOS, Android, and
other high security systems.

Testing:
This feature was tested on ChromeOS and Android for both x86-64 and ARM64.
- Enable sealing and verify vdso/vvar, sigpage, vector are sealed properly,
  i.e. "sl" shown in the smaps for those mappings, and mremap is blocked.
- Passing various automation tests (e.g. pre-checkin) on ChromeOS and
  Android to ensure the sealing doesn't affect the functionality of
  Chromebook and Android phone.

I also tested the feature on Ubuntu on x86-64:
- With config disabled, vdso/vvar is not sealed,
- with config enabled, vdso/vvar is sealed, and booting up Ubuntu is OK,
  normal operations such as browsing the web, open/edit doc are OK.

Link: https://lore.kernel.org/all/20240415163527.626541-1-jeffxu@chromium.org/ [1]
Link: Documentation/userspace-api/mseal.rst [2]
Link: https://lore.kernel.org/all/CABi2SkU9BRUnqf70-nksuMCQ+yyiWjo3fM4XkRkL-NrCZxYAyg@mail.gmail.com/ [3]
Link: https://lore.kernel.org/all/CABi2SkV6JJwJeviDLsq9N4ONvQ=EFANsiWkgiEOjyT9TQSt+HA@mail.gmail.com/ [4]
Link: https://lore.kernel.org/all/202502251035.239B85A93@keescook/ [5]


This patch (of 7):

Provide infrastructure to mseal system mappings.  Establish two kernel
configs (CONFIG_MSEAL_SYSTEM_MAPPINGS,
ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS) and VM_SEALED_SYSMAP macro for future
patches.

Link: https://lkml.kernel.org/r/20250305021711.3867874-1-jeffxu@google.com
Link: https://lkml.kernel.org/r/20250305021711.3867874-2-jeffxu@google.com
Signed-off-by: Jeff Xu &lt;jeffxu@chromium.org&gt;
Reviewed-by: Kees Cook &lt;kees@kernel.org&gt;
Reviewed-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Reviewed-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Cc: Adhemerval Zanella &lt;adhemerval.zanella@linaro.org&gt;
Cc: Alexander Mikhalitsyn &lt;aleksandr.mikhalitsyn@canonical.com&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Anna-Maria Behnsen &lt;anna-maria@linutronix.de&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Benjamin Berg &lt;benjamin@sipsolutions.net&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Elliot Hughes &lt;enh@google.com&gt;
Cc: Florian Faineli &lt;f.fainelli@gmail.com&gt;
Cc: Greg Ungerer &lt;gerg@kernel.org&gt;
Cc: Guenter Roeck &lt;groeck@chromium.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Hyeonggon Yoo &lt;42.hyeyoo@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jason A. Donenfeld &lt;jason@zx2c4.com&gt;
Cc: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Cc: Jorge Lucangeli Obes &lt;jorgelo@chromium.org&gt;
Cc: Linus Waleij &lt;linus.walleij@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Matthew Wilcow (Oracle) &lt;willy@infradead.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Mike Rapoport &lt;mike.rapoport@gmail.com&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Pedro Falcato &lt;pedro.falcato@gmail.com&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Stephen Röttger &lt;sroettger@google.com&gt;
Cc: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Patch series "mseal system mappings", v9.

As discussed during mseal() upstream process [1], mseal() protects the
VMAs of a given virtual memory range against modifications, such as the
read/write (RW) and no-execute (NX) bits.  For complete descriptions of
memory sealing, please see mseal.rst [2].

The mseal() is useful to mitigate memory corruption issues where a
corrupted pointer is passed to a memory management system.  For example,
such an attacker primitive can break control-flow integrity guarantees
since read-only memory that is supposed to be trusted can become writable
or .text pages can get remapped.

The system mappings are readonly only, memory sealing can protect them
from ever changing to writable or unmmap/remapped as different attributes.

System mappings such as vdso, vvar, vvar_vclock, vectors (arm
compat-mode), sigpage (arm compat-mode), are created by the kernel during
program initialization, and could be sealed after creation.

Unlike the aforementioned mappings, the uprobe mapping is not established
during program startup.  However, its lifetime is the same as the
process's lifetime [3].  It could be sealed from creation.

The vsyscall on x86-64 uses a special address (0xffffffffff600000), which
is outside the mm managed range.  This means mprotect, munmap, and mremap
won't work on the vsyscall.  Since sealing doesn't enhance the vsyscall's
security, it is skipped in this patch.  If we ever seal the vsyscall, it
is probably only for decorative purpose, i.e.  showing the 'sl' flag in
the /proc/pid/smaps.  For this patch, it is ignored.

It is important to note that the CHECKPOINT_RESTORE feature (CRIU) may
alter the system mappings during restore operations.  UML(User Mode Linux)
and gVisor, rr are also known to change the vdso/vvar mappings. 
Consequently, this feature cannot be universally enabled across all
systems.  As such, CONFIG_MSEAL_SYSTEM_MAPPINGS is disabled by default.

To support mseal of system mappings, architectures must define
CONFIG_ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS and update their special
mappings calls to pass mseal flag.  Additionally, architectures must
confirm they do not unmap/remap system mappings during the process
lifetime.  The existence of this flag for an architecture implies that it
does not require the remapping of thest system mappings during process
lifetime, so sealing these mappings is safe from a kernel perspective.

This version covers x86-64 and arm64 archiecture as minimum viable feature.

While no specific CPU hardware features are required for enable this
feature on an archiecture, memory sealing requires a 64-bit kernel.  Other
architectures can choose whether or not to adopt this feature.  Currently,
I'm not aware of any instances in the kernel code that actively
munmap/mremap a system mapping without a request from userspace.  The PPC
does call munmap when _install_special_mapping fails for vdso; however,
it's uncertain if this will ever fail for PPC - this needs to be
investigated by PPC in the future [4].  The UML kernel can add this
support when KUnit tests require it [5].

In this version, we've improved the handling of system mapping sealing
from previous versions, instead of modifying the _install_special_mapping
function itself, which would affect all architectures, we now call
_install_special_mapping with a sealing flag only within the specific
architecture that requires it.  This targeted approach offers two key
advantages: 1) It limits the code change's impact to the necessary
architectures, and 2) It aligns with the software architecture by keeping
the core memory management within the mm layer, while delegating the
decision of sealing system mappings to the individual architecture, which
is particularly relevant since 32-bit architectures never require sealing.

Prior to this patch series, we explored sealing special mappings from
userspace using glibc's dynamic linker.  This approach revealed several
issues:

- The PT_LOAD header may report an incorrect length for vdso, (smaller
  than its actual size).  The dynamic linker, which relies on PT_LOAD
  information to determine mapping size, would then split and partially
  seal the vdso mapping.  Since each architecture has its own vdso/vvar
  code, fixing this in the kernel would require going through each
  archiecture.  Our initial goal was to enable sealing readonly mappings,
  e.g.  .text, across all architectures, sealing vdso from kernel since
  creation appears to be simpler than sealing vdso at glibc.

- The [vvar] mapping header only contains address information, not
  length information.  Similar issues might exist for other special
  mappings.

- Mappings like uprobe are not covered by the dynamic linker, and there
  is no effective solution for them.

This feature's security enhancements will benefit ChromeOS, Android, and
other high security systems.

Testing:
This feature was tested on ChromeOS and Android for both x86-64 and ARM64.
- Enable sealing and verify vdso/vvar, sigpage, vector are sealed properly,
  i.e. "sl" shown in the smaps for those mappings, and mremap is blocked.
- Passing various automation tests (e.g. pre-checkin) on ChromeOS and
  Android to ensure the sealing doesn't affect the functionality of
  Chromebook and Android phone.

I also tested the feature on Ubuntu on x86-64:
- With config disabled, vdso/vvar is not sealed,
- with config enabled, vdso/vvar is sealed, and booting up Ubuntu is OK,
  normal operations such as browsing the web, open/edit doc are OK.

Link: https://lore.kernel.org/all/20240415163527.626541-1-jeffxu@chromium.org/ [1]
Link: Documentation/userspace-api/mseal.rst [2]
Link: https://lore.kernel.org/all/CABi2SkU9BRUnqf70-nksuMCQ+yyiWjo3fM4XkRkL-NrCZxYAyg@mail.gmail.com/ [3]
Link: https://lore.kernel.org/all/CABi2SkV6JJwJeviDLsq9N4ONvQ=EFANsiWkgiEOjyT9TQSt+HA@mail.gmail.com/ [4]
Link: https://lore.kernel.org/all/202502251035.239B85A93@keescook/ [5]


This patch (of 7):

Provide infrastructure to mseal system mappings.  Establish two kernel
configs (CONFIG_MSEAL_SYSTEM_MAPPINGS,
ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS) and VM_SEALED_SYSMAP macro for future
patches.

Link: https://lkml.kernel.org/r/20250305021711.3867874-1-jeffxu@google.com
Link: https://lkml.kernel.org/r/20250305021711.3867874-2-jeffxu@google.com
Signed-off-by: Jeff Xu &lt;jeffxu@chromium.org&gt;
Reviewed-by: Kees Cook &lt;kees@kernel.org&gt;
Reviewed-by: Liam R. Howlett &lt;Liam.Howlett@oracle.com&gt;
Reviewed-by: Lorenzo Stoakes &lt;lorenzo.stoakes@oracle.com&gt;
Cc: Adhemerval Zanella &lt;adhemerval.zanella@linaro.org&gt;
Cc: Alexander Mikhalitsyn &lt;aleksandr.mikhalitsyn@canonical.com&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Andrei Vagin &lt;avagin@gmail.com&gt;
Cc: Anna-Maria Behnsen &lt;anna-maria@linutronix.de&gt;
Cc: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Cc: Benjamin Berg &lt;benjamin@sipsolutions.net&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Elliot Hughes &lt;enh@google.com&gt;
Cc: Florian Faineli &lt;f.fainelli@gmail.com&gt;
Cc: Greg Ungerer &lt;gerg@kernel.org&gt;
Cc: Guenter Roeck &lt;groeck@chromium.org&gt;
Cc: Heiko Carstens &lt;hca@linux.ibm.com&gt;
Cc: Helge Deller &lt;deller@gmx.de&gt;
Cc: Hyeonggon Yoo &lt;42.hyeyoo@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Jann Horn &lt;jannh@google.com&gt;
Cc: Jason A. Donenfeld &lt;jason@zx2c4.com&gt;
Cc: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Cc: Jorge Lucangeli Obes &lt;jorgelo@chromium.org&gt;
Cc: Linus Waleij &lt;linus.walleij@linaro.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Matthew Wilcow (Oracle) &lt;willy@infradead.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Cc: Mike Rapoport &lt;mike.rapoport@gmail.com&gt;
Cc: Oleg Nesterov &lt;oleg@redhat.com&gt;
Cc: Pedro Falcato &lt;pedro.falcato@gmail.com&gt;
Cc: Peter Xu &lt;peterx@redhat.com&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Cc: Stephen Röttger &lt;sroettger@google.com&gt;
Cc: Thomas Weißschuh &lt;thomas.weissschuh@linutronix.de&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core</title>
<updated>2025-04-01T18:02:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-04-01T18:02:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2cd5769fb0b78b8ef583ab4c0015c2c48d525dac'/>
<id>2cd5769fb0b78b8ef583ab4c0015c2c48d525dac</id>
<content type='text'>
Pull driver core updatesk from Greg KH:
 "Here is the big set of driver core updates for 6.15-rc1. Lots of stuff
  happened this development cycle, including:

   - kernfs scaling changes to make it even faster thanks to rcu

   - bin_attribute constify work in many subsystems

   - faux bus minor tweaks for the rust bindings

   - rust binding updates for driver core, pci, and platform busses,
     making more functionaliy available to rust drivers. These are all
     due to people actually trying to use the bindings that were in
     6.14.

   - make Rafael and Danilo full co-maintainers of the driver core
     codebase

   - other minor fixes and updates"

* tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (52 commits)
  rust: platform: require Send for Driver trait implementers
  rust: pci: require Send for Driver trait implementers
  rust: platform: impl Send + Sync for platform::Device
  rust: pci: impl Send + Sync for pci::Device
  rust: platform: fix unrestricted &amp;mut platform::Device
  rust: pci: fix unrestricted &amp;mut pci::Device
  rust: device: implement device context marker
  rust: pci: use to_result() in enable_device_mem()
  MAINTAINERS: driver core: mark Rafael and Danilo as co-maintainers
  rust/kernel/faux: mark Registration methods inline
  driver core: faux: only create the device if probe() succeeds
  rust/faux: Add missing parent argument to Registration::new()
  rust/faux: Drop #[repr(transparent)] from faux::Registration
  rust: io: fix devres test with new io accessor functions
  rust: io: rename `io::Io` accessors
  kernfs: Move dput() outside of the RCU section.
  efi: rci2: mark bin_attribute as __ro_after_init
  rapidio: constify 'struct bin_attribute'
  firmware: qemu_fw_cfg: constify 'struct bin_attribute'
  powerpc/perf/hv-24x7: Constify 'struct bin_attribute'
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull driver core updatesk from Greg KH:
 "Here is the big set of driver core updates for 6.15-rc1. Lots of stuff
  happened this development cycle, including:

   - kernfs scaling changes to make it even faster thanks to rcu

   - bin_attribute constify work in many subsystems

   - faux bus minor tweaks for the rust bindings

   - rust binding updates for driver core, pci, and platform busses,
     making more functionaliy available to rust drivers. These are all
     due to people actually trying to use the bindings that were in
     6.14.

   - make Rafael and Danilo full co-maintainers of the driver core
     codebase

   - other minor fixes and updates"

* tag 'driver-core-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (52 commits)
  rust: platform: require Send for Driver trait implementers
  rust: pci: require Send for Driver trait implementers
  rust: platform: impl Send + Sync for platform::Device
  rust: pci: impl Send + Sync for pci::Device
  rust: platform: fix unrestricted &amp;mut platform::Device
  rust: pci: fix unrestricted &amp;mut pci::Device
  rust: device: implement device context marker
  rust: pci: use to_result() in enable_device_mem()
  MAINTAINERS: driver core: mark Rafael and Danilo as co-maintainers
  rust/kernel/faux: mark Registration methods inline
  driver core: faux: only create the device if probe() succeeds
  rust/faux: Add missing parent argument to Registration::new()
  rust/faux: Drop #[repr(transparent)] from faux::Registration
  rust: io: fix devres test with new io accessor functions
  rust: io: rename `io::Io` accessors
  kernfs: Move dput() outside of the RCU section.
  efi: rci2: mark bin_attribute as __ro_after_init
  rapidio: constify 'struct bin_attribute'
  firmware: qemu_fw_cfg: constify 'struct bin_attribute'
  powerpc/perf/hv-24x7: Constify 'struct bin_attribute'
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next</title>
<updated>2025-03-30T19:43:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-03-30T19:43:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=fa593d0f969dcfa41d390822fdf1a0ab48cd882c'/>
<id>fa593d0f969dcfa41d390822fdf1a0ab48cd882c</id>
<content type='text'>
Pull bpf updates from Alexei Starovoitov:
 "For this merge window we're splitting BPF pull request into three for
  higher visibility: main changes, res_spin_lock, try_alloc_pages.

  These are the main BPF changes:

   - Add DFA-based live registers analysis to improve verification of
     programs with loops (Eduard Zingerman)

   - Introduce load_acquire and store_release BPF instructions and add
     x86, arm64 JIT support (Peilin Ye)

   - Fix loop detection logic in the verifier (Eduard Zingerman)

   - Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet)

   - Add kfunc for populating cpumask bits (Emil Tsalapatis)

   - Convert various shell based tests to selftests/bpf/test_progs
     format (Bastien Curutchet)

   - Allow passing referenced kptrs into struct_ops callbacks (Amery
     Hung)

   - Add a flag to LSM bpf hook to facilitate bpf program signing
     (Blaise Boscaccy)

   - Track arena arguments in kfuncs (Ihor Solodrai)

   - Add copy_remote_vm_str() helper for reading strings from remote VM
     and bpf_copy_from_user_task_str() kfunc (Jordan Rome)

   - Add support for timed may_goto instruction (Kumar Kartikeya
     Dwivedi)

   - Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy)

   - Reduce bpf_cgrp_storage_busy false positives when accessing cgroup
     local storage (Martin KaFai Lau)

   - Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko)

   - Allow retrieving BTF data with BTF token (Mykyta Yatsenko)

   - Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix
     (Song Liu)

   - Reject attaching programs to noreturn functions (Yafang Shao)

   - Introduce pre-order traversal of cgroup bpf programs (Yonghong
     Song)"

* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits)
  selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid
  bpf: Fix out-of-bounds read in check_atomic_load/store()
  libbpf: Add namespace for errstr making it libbpf_errstr
  bpf: Add struct_ops context information to struct bpf_prog_aux
  selftests/bpf: Sanitize pointer prior fclose()
  selftests/bpf: Migrate test_xdp_vlan.sh into test_progs
  selftests/bpf: test_xdp_vlan: Rename BPF sections
  bpf: clarify a misleading verifier error message
  selftests/bpf: Add selftest for attaching fexit to __noreturn functions
  bpf: Reject attaching fexit/fmod_ret to __noreturn functions
  bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
  bpf: Make perf_event_read_output accessible in all program types.
  bpftool: Using the right format specifiers
  bpftool: Add -Wformat-signedness flag to detect format errors
  selftests/bpf: Test freplace from user namespace
  libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID
  bpf: Return prog btf_id without capable check
  bpf: BPF token support for BPF_BTF_GET_FD_BY_ID
  bpf, x86: Fix objtool warning for timed may_goto
  bpf: Check map-&gt;record at the beginning of check_and_free_fields()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull bpf updates from Alexei Starovoitov:
 "For this merge window we're splitting BPF pull request into three for
  higher visibility: main changes, res_spin_lock, try_alloc_pages.

  These are the main BPF changes:

   - Add DFA-based live registers analysis to improve verification of
     programs with loops (Eduard Zingerman)

   - Introduce load_acquire and store_release BPF instructions and add
     x86, arm64 JIT support (Peilin Ye)

   - Fix loop detection logic in the verifier (Eduard Zingerman)

   - Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet)

   - Add kfunc for populating cpumask bits (Emil Tsalapatis)

   - Convert various shell based tests to selftests/bpf/test_progs
     format (Bastien Curutchet)

   - Allow passing referenced kptrs into struct_ops callbacks (Amery
     Hung)

   - Add a flag to LSM bpf hook to facilitate bpf program signing
     (Blaise Boscaccy)

   - Track arena arguments in kfuncs (Ihor Solodrai)

   - Add copy_remote_vm_str() helper for reading strings from remote VM
     and bpf_copy_from_user_task_str() kfunc (Jordan Rome)

   - Add support for timed may_goto instruction (Kumar Kartikeya
     Dwivedi)

   - Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy)

   - Reduce bpf_cgrp_storage_busy false positives when accessing cgroup
     local storage (Martin KaFai Lau)

   - Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko)

   - Allow retrieving BTF data with BTF token (Mykyta Yatsenko)

   - Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix
     (Song Liu)

   - Reject attaching programs to noreturn functions (Yafang Shao)

   - Introduce pre-order traversal of cgroup bpf programs (Yonghong
     Song)"

* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits)
  selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid
  bpf: Fix out-of-bounds read in check_atomic_load/store()
  libbpf: Add namespace for errstr making it libbpf_errstr
  bpf: Add struct_ops context information to struct bpf_prog_aux
  selftests/bpf: Sanitize pointer prior fclose()
  selftests/bpf: Migrate test_xdp_vlan.sh into test_progs
  selftests/bpf: test_xdp_vlan: Rename BPF sections
  bpf: clarify a misleading verifier error message
  selftests/bpf: Add selftest for attaching fexit to __noreturn functions
  bpf: Reject attaching fexit/fmod_ret to __noreturn functions
  bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
  bpf: Make perf_event_read_output accessible in all program types.
  bpftool: Using the right format specifiers
  bpftool: Add -Wformat-signedness flag to detect format errors
  selftests/bpf: Test freplace from user namespace
  libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID
  bpf: Return prog btf_id without capable check
  bpf: BPF token support for BPF_BTF_GET_FD_BY_ID
  bpf, x86: Fix objtool warning for timed may_goto
  bpf: Check map-&gt;record at the beginning of check_and_free_fields()
  ...
</pre>
</div>
</content>
</entry>
</feed>
