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Merge tag 'ipe-pr-20251202' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe
Pull IPE udates from Fan Wu:
"The primary change is the addition of support for the AT_EXECVE_CHECK
flag. This allows interpreters to signal the kernel to perform IPE
security checks on script files before execution, extending IPE
enforcement to indirectly executed scripts.
Update documentation for it, and also fix a comment"
* tag 'ipe-pr-20251202' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe:
ipe: Update documentation for script enforcement
ipe: Add AT_EXECVE_CHECK support for script enforcement
ipe: Drop a duplicated CONFIG_ prefix in the ifdeffery
This patch adds explanation of script enforcement mechanism in admin
guide documentation. Describes how IPE supports integrity enforcement
for indirectly executed scripts through the AT_EXECVE_CHECK flag, and
how this differs from kernel enforcement for compiled executables.
Signed-off-by: Yanzhu Huang <yanzhuhuang@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@kernel.org>
This command:
# echo foo/bar >/proc/$$/attr/smack/current
gives the task a label 'foo' w/o indication
that label does not match input.
Setting the label with lsm_set_self_attr() syscall
behaves identically.
This occures because:
1) smk_parse_smack() is used to convert input to a label
2) smk_parse_smack() takes only that part from the
beginning of the input that looks like a label.
3) `/' is prohibited in labels, so only "foo" is taken.
(2) is by design, because smk_parse_smack() is used
for parsing strings which are more than just a label.
Silent failure is not a good thing, and there are two
indicators that this was not done intentionally:
(size >= SMK_LONGLABEL) ~> invalid
clause at the beginning of the do_setattr() and the
"Returns the length of the smack label" claim
in the do_setattr() description.
So I fixed this by adding one tiny check:
the taken label length == input length.
Since input length is now strictly controlled,
I changed the two ways of setting label
smack_setselfattr(): lsm_set_self_attr() syscall
smack_setprocattr(): > /proc/.../current
to accommodate the divergence in
what they understand by "input length":
smack_setselfattr counts mandatory \0 into input length,
smack_setprocattr does not.
smack_setprocattr allows various trailers after label
Related changes:
* fixed description for smk_parse_smack
* allow unprivileged tasks validate label syntax.
* extract smk_parse_label_len() from smk_parse_smack()
so parsing may be done w/o string allocation.
* extract smk_import_valid_label() from smk_import_entry()
to avoid repeated parsing.
* smk_parse_smack(): scan null-terminated strings
for no more than SMK_LONGLABEL(256) characters
* smack_setselfattr(): require struct lsm_ctx . flags == 0
to reserve them for future.
Fixes: e114e47377 ("Smack: Simplified Mandatory Access Control Kernel")
Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
According to [1], the label of a UNIX domain socket (UDS)
file (i.e., the filesystem object representing the socket)
is not supposed to participate in Smack security.
To achieve this, [1] labels UDS files with "*"
in smack_d_instantiate().
Before [2], smack_d_instantiate() was responsible
for initializing Smack security for all inodes,
except ones under /proc
[2] imposed the sole responsibility for initializing
inode security for newly created filesystem objects
on smack_inode_init_security().
However, smack_inode_init_security() lacks some logic
present in smack_d_instantiate().
In particular, it does not label UDS files with "*".
This patch adds the missing labeling of UDS files
with "*" to smack_inode_init_security().
Labeling UDS files with "*" in smack_d_instantiate()
still works for stale UDS files that already exist on
disk. Stale UDS files are useless, but I keep labeling
them for consistency and maybe to make easier for user
to delete them.
Compared to [1], this version introduces the following
improvements:
* UDS file label is held inside inode only
and not saved to xattrs.
* relabeling UDS files (setxattr, removexattr, etc.)
is blocked.
[1] 2010-11-24 Casey Schaufler
commit b4e0d5f079 ("Smack: UDS revision")
[2] 2023-11-16 roberto.sassu
Fixes: e63d86b8b7 ("smack: Initialize the in-memory inode in smack_inode_init_security()")
Link: https://lore.kernel.org/linux-security-module/20231116090125.187209-5-roberto.sassu@huaweicloud.com/
Signed-off-by: Konstantin Andreev <andreev@swemel.ru>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Add links to the SELinux kernel subsystem README.md file, the
SELinux kernel wiki, and the SELinux userspace wiki to the
SELinux guide.
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
[PM: spacing and style corrections, subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Users of IPE require a way to identify when and why an operation fails,
allowing them to both respond to violations of policy and be notified
of potentially malicious actions on their systems with respect to IPE.
This patch introduces a new error field to the AUDIT_IPE_POLICY_LOAD event
to log policy loading failures. Currently, IPE only logs successful policy
loads, but not failures. Tracking failures is crucial to detect malicious
attempts and ensure a complete audit trail for security events.
The new error field will capture the following error codes:
* -ENOKEY: Key used to sign the IPE policy not found in the keyring
* -ESTALE: Attempting to update an IPE policy with an older version
* -EKEYREJECTED: IPE signature verification failed
* -ENOENT: Policy was deleted while updating
* -EEXIST: Same name policy already deployed
* -ERANGE: Policy version number overflow
* -EINVAL: Policy version parsing error
* -EPERM: Insufficient permission
* -ENOMEM: Out of memory (OOM)
* -EBADMSG: Policy is invalid
Here are some examples of the updated audit record types:
AUDIT_IPE_POLICY_LOAD(1422):
audit: AUDIT1422 policy_name="Test_Policy" policy_version=0.0.1
policy_digest=sha256:84EFBA8FA71E62AE0A537FAB962F8A2BD1053964C4299DCA
92BFFF4DB82E86D3 auid=1000 ses=3 lsm=ipe res=1 errno=0
The above record shows a new policy has been successfully loaded into
the kernel with the policy name, version, and hash with the errno=0.
AUDIT_IPE_POLICY_LOAD(1422) with error:
audit: AUDIT1422 policy_name=? policy_version=? policy_digest=?
auid=1000 ses=3 lsm=ipe res=0 errno=-74
The above record shows a policy load failure due to an invalid policy
(-EBADMSG).
By adding this error field, we ensure that all policy load attempts,
whether successful or failed, are logged, providing a comprehensive
audit trail for IPE policy management.
Signed-off-by: Jasjiv Singh <jasjivsingh@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@kernel.org>
Because audit is dedicated to the system administrator, create a new
entry in Documentation/admin-guide/LSM . Extend other Landlock
documentation's pages with this new one.
Extend UAPI with the new log flags.
Extend the guiding principles with logs.
Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250320190717.2287696-29-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
After the deprecation of CONFIG_DEFAULT_SECURITY, it is no longer used
to enable and configure AppArmor. Since kernel 5.0,
`CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE` is not used either.
Instead, the CONFIG_LSM parameter manages the order and selection of LSMs.
Signed-off-by: Siddharth Menon <simeddon@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
The current policy management makes it impossible to use IPE
in a general purpose distribution. In such cases the users are not
building the kernel, the distribution is, and access to the private
key included in the trusted keyring is, for obvious reason, not
available.
This means that users have no way to enable IPE, since there will
be no built-in generic policy, and no access to the key to sign
updates validated by the trusted keyring.
Just as we do for dm-verity, kernel modules and more, allow the
secondary and platform keyrings to also validate policies. This
allows users enrolling their own keys in UEFI db or MOK to also
sign policies, and enroll them. This makes it sensible to enable
IPE in general purpose distributions, as it becomes usable by
any user wishing to do so. Keys in these keyrings can already
load kernels and kernel modules, so there is no security
downgrade.
Add a kconfig each, like dm-verity does, but default to enabled if
the dependencies are available.
Signed-off-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
[FW: fixed some style issues]
Signed-off-by: Fan Wu <wufan@kernel.org>
Currently IPE accepts an update that has the same version as the policy
being updated, but it doesn't make it a no-op nor it checks that the
old and new policyes are the same. So it is possible to change the
content of a policy, without changing its version. This is very
confusing from userspace when managing policies.
Instead change the update logic to reject updates that have the same
version with ESTALE, as that is much clearer and intuitive behaviour.
Signed-off-by: Luca Boccassi <bluca@debian.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Fan Wu <wufan@kernel.org>
Add IPE's admin and developer documentation to the kernel tree.
Co-developed-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Loadpin cmdline interface "enabled" has been renamed to "enforce"
for a long time, but the User Description Document was not updated.
(Meaning unchanged)
And kernel_read_file* were moved from linux/fs.h to its own
linux/kernel_read_file.h include file. So update that change here.
Signed-off-by: Jiele zhao <unclexiaole@gmail.com>
Link: https://lore.kernel.org/r/20210308020358.102836-1-unclexiaole@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The SafeSetID LSM has functionality for restricting setuid() calls based
on its configured security policies. This patch adds the analogous
functionality for setgid() calls. This is mostly a copy-and-paste change
with some code deduplication, plus slight modifications/name changes to
the policy-rule-related structs (now contain GID rules in addition to
the UID ones) and some type generalization since SafeSetID now needs to
deal with kgid_t and kuid_t types.
Signed-off-by: Thomas Cedeno <thomascedeno@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
Replace one dead link for the same person's original presentation on the
topic and swap an HTTP URL with HTTPS. While here, linkify the text to
make it more readable when rendered.
Link: https://lore.kernel.org/lkml/20200708073346.13177-1-grandmaster@al2klimov.de/
Co-developed-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/202007091141.C008B89EC@keescook
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200526060544.25127-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
It appears that some smart quotes were changed to "???" by even smarter
software; change them to the dumb but legible variety.
Signed-off-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Linux kernel already provide MODULE_SIG and KEXEC_VERIFY_SIG to
make sure loaded kernel module and kernel image are trusted. This
patch adds a kernel command line option "loadpin.exclude" which
allows to exclude specific file types from LoadPin. This is useful
when people want to use different mechanisms to verify module and
kernel image while still use LoadPin to protect the integrity of
other files kernel loads.
Signed-off-by: Ke Wu <mikewu@google.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
[kees: fix array size issue reported by Coverity via Colin Ian King]
Signed-off-by: Kees Cook <keescook@chromium.org>
SafeSetID gates the setid family of syscalls to restrict UID/GID
transitions from a given UID/GID to only those approved by a
system-wide whitelist. These restrictions also prohibit the given
UIDs/GIDs from obtaining auxiliary privileges associated with
CAP_SET{U/G}ID, such as allowing a user to set up user namespace UID
mappings. For now, only gating the set*uid family of syscalls is
supported, with support for set*gid coming in a future patch set.
Signed-off-by: Micah Morton <mortonm@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
Back in 2007 I made what turned out to be a rather serious
mistake in the implementation of the Smack security module.
The SELinux module used an interface in /proc to manipulate
the security context on processes. Rather than use a similar
interface, I used the same interface. The AppArmor team did
likewise. Now /proc/.../attr/current will tell you the
security "context" of the process, but it will be different
depending on the security module you're using.
This patch provides a subdirectory in /proc/.../attr for
Smack. Smack user space can use the "current" file in
this subdirectory and never have to worry about getting
SELinux attributes by mistake. Programs that use the
old interface will continue to work (or fail, as the case
may be) as before.
The proposed S.A.R.A security module is dependent on
the mechanism to create its own attr subdirectory.
The original implementation is by Kees Cook.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull smack updates from James Morris:
"Two Smack patches for 4.21.
Jose's patch adds missing documentation and Zoran's fleshes out the
access checks on keyrings"
* 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: Improve Documentation
smack: fix access permissions for keyring
Add some words about the mount option "smackfstransmute=label".
Signed-off-by: José Bollo <jobol@nonadev.net>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Current phrasing is ambiguous since it's unclear if attaching to a
children through PTRACE_TRACEME requires CAP_SYS_PTRACE. Rephrase the
sentence to make that clear.
Signed-off-by: Yves-Alexis Perez <corsac@corsac.net>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The apparmor information in the apparmor.rst file is out of date.
Update it to the correct git reference for the master apparmor tree.
Update the wiki location to use apparmor.net which forwards to the
current wiki location on gitlab.com. Update user space tools address
to gitlab.com.
Signed-off-by: Jordan Glover <Golden_Miller83@protonmail.ch>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Adjusts for ReST markup and moves under LSM admin guide.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Adjusts for ReST markup and moves under LSM admin guide.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Adjusts for ReST markup and moves under LSM admin guide.
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Adjusts for ReST markup and moves under LSM admin guide.
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The existing LSM.txt file covered both usage and development, so split
this into two files, one under admin-guide and one under kernel
development.
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Linus Torvalds