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* samples/landlock: Add support for signal scopingTahera Fahimi2024-09-161-5/+14
| | | | | | | | | | | | | | | | | | | | | | | The sandboxer can receive the character "s" as input from the environment variable LL_SCOPE to restrict sandboxed processes from sending signals to processes outside of the sandbox. Example ======= Create a sandboxed shell and pass the character "s" to LL_SCOPED: LL_FS_RO=/ LL_FS_RW=. LL_SCOPED="s" ./sandboxer /bin/bash Try to send a SIGTRAP to a process with process ID <PID> through: kill -SIGTRAP <PID> The sandboxed process should not be able to send the signal. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/1f3f1992b2abeb8e5d7aa61b854e1b0721978b9a.1725657728.git.fahimitahera@gmail.com [mic: Improve commit message, simplify code, rebase on previous sample change] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test signal created by out-of-bound messageTahera Fahimi2024-09-161-0/+184
| | | | | | | | | | | | | | | | | | Add a test to verify that the SIGURG signal created by an out-of-bound message in UNIX sockets is well controlled by the file_send_sigiotask hook. Test coverage for security/landlock is 92.2% of 1046 lines according to gcc/gcov-14. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/50daeed4d4f60d71e9564d0f24004a373fc5f7d5.1725657728.git.fahimitahera@gmail.com [mic: Improve commit message and add test coverage, improve test with four variants to fully cover the hook, use abstract unix socket to avoid managing a file, use dedicated variable per process, add comments, avoid negative ASSERT, move close calls] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test signal scoping for threadsTahera Fahimi2024-09-161-0/+49
| | | | | | | | | | | Expand the signal scoping tests with pthread_kill(3). Test if a scoped thread can send signal to a process in the same scoped domain, or a non-sandboxed thread. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/c15e9eafbb2da1210e46ba8db7b8907f5ea11009.1725657728.git.fahimitahera@gmail.com [mic: Improve commit message] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test signal scopingTahera Fahimi2024-09-161-0/+251
| | | | | | | | | | | | | | Provide tests for the signal scoping. If the signal is 0, no signal will be sent, but the permission of a process to send a signal will be checked. Likewise, this test consider one signal for each signal category: SIGTRAP, SIGURG, SIGHUP, and SIGTSTP. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/15dc202bb7f0a462ddeaa0c1cd630d2a7c6fa5c5.1725657728.git.fahimitahera@gmail.com [mic: Fix commit message, use dedicated variables per process, properly close FDs, extend send_sig_to_parent to make sure scoping works as expected] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* landlock: Add signal scopingTahera Fahimi2024-09-167-3/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
* landlock: Document LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKETTahera Fahimi2024-09-161-2/+42
| | | | | | | | | | | | Introduce LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET as an IPC scoping mechanism available since Landlock ABI version 6. Update ruleset_attr, Landlock ABI version, and access rights code blocks based on that. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/ac75151861724c19ed62b500cfe497612d9a6607.1725494372.git.fahimitahera@gmail.com [mic: Improve commit message and documentation, add a missing fallthrough, reformat to 80 columns, improve some wording] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* samples/landlock: Add support for abstract UNIX socket scopingTahera Fahimi2024-09-161-4/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sandboxer can receive the character "a" as input from the environment variable LL_SCOPE to restrict sandboxed processes from connecting to an abstract UNIX socket created by a process outside of the sandbox. Example ======= Create an abstract UNIX socket to listen with socat(1): socat abstract-listen:mysocket - Create a sandboxed shell and pass the character "a" to LL_SCOPED: LL_FS_RO=/ LL_FS_RW=. LL_SCOPED="a" ./sandboxer /bin/bash Note that any other form of input (e.g. "a:a", "aa", etc) is not acceptable. If the sandboxed process tries to connect to the listening socket, the connection will fail: socat - abstract-connect:mysocket Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/d8af908f00b77415caa3eb0f4de631c3794e4909.1725494372.git.fahimitahera@gmail.com [mic: Improve commit message, simplify check_ruleset_scope() with inverted error code and only one scoped change, always unset environment variable] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test inherited restriction of abstract UNIX socketTahera Fahimi2024-09-161-0/+64
| | | | | | | | | | | | | | | | A socket can be shared between multiple processes, so it can connect and send data to them. Provide a test scenario where a sandboxed process inherits a socket's file descriptor. The process cannot connect or send data to the inherited socket since the process is scoped. Test coverage for security/landlock is 92.0% of 1013 lines according to gcc/gcov-14. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/1428574deec13603b6ab2f2ed68ecbfa3b63bcb3.1725494372.git.fahimitahera@gmail.com [mic: Remove negative ASSERT, fix potential race condition because of closed connections, remove useless buffer, add test coverage] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test connected and unconnected datagram UNIX socketTahera Fahimi2024-09-161-0/+103
| | | | | | | | | | | | Check the specific case where a scoped datagram socket is connected and send(2) works, whereas sendto(2) is denied if the datagram socket is not connected. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/c28c9cd8feef67dd25e115c401a2389a75f9983b.1725494372.git.fahimitahera@gmail.com [mic: Use more EXPECT and avoid negative ASSERT, use variables dedicated per process, remove useless buffer] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test UNIX sockets with any address formatsTahera Fahimi2024-09-163-1/+252
| | | | | | | | | | | | | | | | | | | | | Expand abstract UNIX socket restriction tests by examining different scenarios for UNIX sockets with pathname or unnamed address formats connection with scoped domain. The various_address_sockets tests ensure that UNIX sockets bound to a filesystem pathname and unnamed sockets created by socketpair can still connect to a socket outside of their scoped domain, meaning that even if the domain is scoped with LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET, the socket can connect to a socket outside the scoped domain. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/a9e8016aaa5846252623b158c8f1ce0d666944f4.1725494372.git.fahimitahera@gmail.com [mic: Remove useless clang-format tags, fix unlink/rmdir calls, drop capabilities, rename variables, remove useless mknod/unlink calls, clean up fixture, test write/read on sockets, test sendto() on datagram sockets, close sockets as soon as possible] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test abstract UNIX socket scopingTahera Fahimi2024-09-166-30/+998
| | | | | | | | | | | | | | | | | | | | | | | | | | Add three tests that examine different scenarios for abstract UNIX socket: 1) scoped_domains: Base tests of the abstract socket scoping mechanism for a landlocked process, same as the ptrace test. 2) scoped_vs_unscoped: Generates three processes with different domains and tests if a process with a non-scoped domain can connect to other processes. 3) outside_socket: Since the socket's creator credentials are used for scoping sockets, this test examines the cases where the socket's credentials are different from the process using it. Move protocol_variant, service_fixture, and sys_gettid() from net_test.c to common.h, and factor out code into a new set_unix_address() helper. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/9321c3d3bcd9212ceb4b50693e29349f8d625e16.1725494372.git.fahimitahera@gmail.com [mic: Fix commit message, remove useless clang-format tags, move drop_caps() calls, move and rename variables, rename variants, use more EXPECT, improve comments, simplify the outside_socket test] Signed-off-by: Mickaël Salaün <mic@digikod.net>
* selftests/landlock: Test handling of unknown scopeTahera Fahimi2024-09-161-0/+33
| | | | | | | | | | Add a new ruleset_with_unknown_scope test designed to validate the behaviour of landlock_create_ruleset(2) when called with an unsupported or unknown scope mask. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/74b363aaa7ddf80e1e5e132ce3d550a3a8bbf6da.1725494372.git.fahimitahera@gmail.com Signed-off-by: Mickaël Salaün <mic@digikod.net>
* landlock: Add abstract UNIX socket scopingTahera Fahimi2024-09-167-9/+208
| | | | | | | | | | | | | | | | | | Introduce a new "scoped" member to landlock_ruleset_attr that can specify LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET to restrict connection to abstract UNIX sockets from a process outside of the socket's domain. Two hooks are implemented to enforce these restrictions: unix_stream_connect and unix_may_send. Closes: https://github.com/landlock-lsm/linux/issues/7 Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Link: https://lore.kernel.org/r/5f7ad85243b78427242275b93481cfc7c127764b.1725494372.git.fahimitahera@gmail.com [mic: Fix commit message formatting, improve documentation, simplify hook_unix_may_send(), and cosmetic fixes including rename of LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
* Merge tag 'lsm-pr-20240911' of ↵Linus Torvalds2024-09-1671-483/+6062
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm updates from Paul Moore: - Move the LSM framework to static calls This transitions the vast majority of the LSM callbacks into static calls. Those callbacks which haven't been converted were left as-is due to the general ugliness of the changes required to support the static call conversion; we can revisit those callbacks at a future date. - Add the Integrity Policy Enforcement (IPE) LSM This adds a new LSM, Integrity Policy Enforcement (IPE). There is plenty of documentation about IPE in this patches, so I'll refrain from going into too much detail here, but the basic motivation behind IPE is to provide a mechanism such that administrators can restrict execution to only those binaries which come from integrity protected storage, e.g. a dm-verity protected filesystem. You will notice that IPE requires additional LSM hooks in the initramfs, dm-verity, and fs-verity code, with the associated patches carrying ACK/review tags from the associated maintainers. We couldn't find an obvious maintainer for the initramfs code, but the IPE patchset has been widely posted over several years. Both Deven Bowers and Fan Wu have contributed to IPE's development over the past several years, with Fan Wu agreeing to serve as the IPE maintainer moving forward. Once IPE is accepted into your tree, I'll start working with Fan to ensure he has the necessary accounts, keys, etc. so that he can start submitting IPE pull requests to you directly during the next merge window. - Move the lifecycle management of the LSM blobs to the LSM framework Management of the LSM blobs (the LSM state buffers attached to various kernel structs, typically via a void pointer named "security" or similar) has been mixed, some blobs were allocated/managed by individual LSMs, others were managed by the LSM framework itself. Starting with this pull we move management of all the LSM blobs, minus the XFRM blob, into the framework itself, improving consistency across LSMs, and reducing the amount of duplicated code across LSMs. Due to some additional work required to migrate the XFRM blob, it has been left as a todo item for a later date; from a practical standpoint this omission should have little impact as only SELinux provides a XFRM LSM implementation. - Fix problems with the LSM's handling of F_SETOWN The LSM hook for the fcntl(F_SETOWN) operation had a couple of problems: it was racy with itself, and it was disconnected from the associated DAC related logic in such a way that the LSM state could be updated in cases where the DAC state would not. We fix both of these problems by moving the security_file_set_fowner() hook into the same section of code where the DAC attributes are updated. Not only does this resolve the DAC/LSM synchronization issue, but as that code block is protected by a lock, it also resolve the race condition. - Fix potential problems with the security_inode_free() LSM hook Due to use of RCU to protect inodes and the placement of the LSM hook associated with freeing the inode, there is a bit of a challenge when it comes to managing any LSM state associated with an inode. The VFS folks are not open to relocating the LSM hook so we have to get creative when it comes to releasing an inode's LSM state. Traditionally we have used a single LSM callback within the hook that is triggered when the inode is "marked for death", but not actually released due to RCU. Unfortunately, this causes problems for LSMs which want to take an action when the inode's associated LSM state is actually released; so we add an additional LSM callback, inode_free_security_rcu(), that is called when the inode's LSM state is released in the RCU free callback. - Refactor two LSM hooks to better fit the LSM return value patterns The vast majority of the LSM hooks follow the "return 0 on success, negative values on failure" pattern, however, there are a small handful that have unique return value behaviors which has caused confusion in the past and makes it difficult for the BPF verifier to properly vet BPF LSM programs. This includes patches to convert two of these"special" LSM hooks to the common 0/-ERRNO pattern. - Various cleanups and improvements A handful of patches to remove redundant code, better leverage the IS_ERR_OR_NULL() helper, add missing "static" markings, and do some minor style fixups. * tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (40 commits) security: Update file_set_fowner documentation fs: Fix file_set_fowner LSM hook inconsistencies lsm: Use IS_ERR_OR_NULL() helper function lsm: remove LSM_COUNT and LSM_CONFIG_COUNT ipe: Remove duplicated include in ipe.c lsm: replace indirect LSM hook calls with static calls lsm: count the LSMs enabled at compile time kernel: Add helper macros for loop unrolling init/main.c: Initialize early LSMs after arch code, static keys and calls. MAINTAINERS: add IPE entry with Fan Wu as maintainer documentation: add IPE documentation ipe: kunit test for parser scripts: add boot policy generation program ipe: enable support for fs-verity as a trust provider fsverity: expose verified fsverity built-in signatures to LSMs lsm: add security_inode_setintegrity() hook ipe: add support for dm-verity as a trust provider dm-verity: expose root hash digest and signature data to LSMs block,lsm: add LSM blob and new LSM hooks for block devices ipe: add permissive toggle ...
| * security: Update file_set_fowner documentationMickaël Salaün2024-09-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Highlight that the file_set_fowner hook is now called with a lock held. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Christian Brauner <brauner@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * fs: Fix file_set_fowner LSM hook inconsistenciesMickaël Salaün2024-09-091-10/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The fcntl's F_SETOWN command sets the process that handle SIGIO/SIGURG for the related file descriptor. Before this change, the file_set_fowner LSM hook was always called, ignoring the VFS logic which may not actually change the process that handles SIGIO (e.g. TUN, TTY, dnotify), nor update the related UID/EUID. Moreover, because security_file_set_fowner() was called without lock (e.g. f_owner.lock), concurrent F_SETOWN commands could result to a race condition and inconsistent LSM states (e.g. SELinux's fown_sid) compared to struct fown_struct's UID/EUID. This change makes sure the LSM states are always in sync with the VFS state by moving the security_file_set_fowner() call close to the UID/EUID updates and using the same f_owner.lock . Rename f_modown() to __f_setown() to simplify code. Cc: stable@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Christian Brauner <brauner@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: Use IS_ERR_OR_NULL() helper functionHongbo Li2024-08-291-1/+1
| | | | | | | | | | | | | | | | | | Use the IS_ERR_OR_NULL() helper instead of open-coding a NULL and an error pointer checks to simplify the code and improve readability. Signed-off-by: Hongbo Li <lihongbo22@huawei.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: remove LSM_COUNT and LSM_CONFIG_COUNTTetsuo Handa2024-08-271-33/+4
| | | | | | | | | | | | | | | | Because these are equals to MAX_LSM_COUNT. Also, we can avoid dynamic memory allocation for ordered_lsms because MAX_LSM_COUNT is a constant. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: Remove duplicated include in ipe.cYang Li2024-08-221-1/+0
| | | | | | | | | | | | | | | | | | | | The header files eval.h is included twice in ipe.c, so one inclusion of each can be removed. Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9796 Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: replace indirect LSM hook calls with static callsKP Singh2024-08-222-73/+198
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | LSM hooks are currently invoked from a linked list as indirect calls which are invoked using retpolines as a mitigation for speculative attacks (Branch History / Target injection) and add extra overhead which is especially bad in kernel hot paths: security_file_ioctl: 0xff...0320 <+0>: endbr64 0xff...0324 <+4>: push %rbp 0xff...0325 <+5>: push %r15 0xff...0327 <+7>: push %r14 0xff...0329 <+9>: push %rbx 0xff...032a <+10>: mov %rdx,%rbx 0xff...032d <+13>: mov %esi,%ebp 0xff...032f <+15>: mov %rdi,%r14 0xff...0332 <+18>: mov $0xff...7030,%r15 0xff...0339 <+25>: mov (%r15),%r15 0xff...033c <+28>: test %r15,%r15 0xff...033f <+31>: je 0xff...0358 <security_file_ioctl+56> 0xff...0341 <+33>: mov 0x18(%r15),%r11 0xff...0345 <+37>: mov %r14,%rdi 0xff...0348 <+40>: mov %ebp,%esi 0xff...034a <+42>: mov %rbx,%rdx 0xff...034d <+45>: call 0xff...2e0 <__x86_indirect_thunk_array+352> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Indirect calls that use retpolines leading to overhead, not just due to extra instruction but also branch misses. 0xff...0352 <+50>: test %eax,%eax 0xff...0354 <+52>: je 0xff...0339 <security_file_ioctl+25> 0xff...0356 <+54>: jmp 0xff...035a <security_file_ioctl+58> 0xff...0358 <+56>: xor %eax,%eax 0xff...035a <+58>: pop %rbx 0xff...035b <+59>: pop %r14 0xff...035d <+61>: pop %r15 0xff...035f <+63>: pop %rbp 0xff...0360 <+64>: jmp 0xff...47c4 <__x86_return_thunk> The indirect calls are not really needed as one knows the addresses of enabled LSM callbacks at boot time and only the order can possibly change at boot time with the lsm= kernel command line parameter. An array of static calls is defined per LSM hook and the static calls are updated at boot time once the order has been determined. With the hook now exposed as a static call, one can see that the retpolines are no longer there and the LSM callbacks are invoked directly: security_file_ioctl: 0xff...0ca0 <+0>: endbr64 0xff...0ca4 <+4>: nopl 0x0(%rax,%rax,1) 0xff...0ca9 <+9>: push %rbp 0xff...0caa <+10>: push %r14 0xff...0cac <+12>: push %rbx 0xff...0cad <+13>: mov %rdx,%rbx 0xff...0cb0 <+16>: mov %esi,%ebp 0xff...0cb2 <+18>: mov %rdi,%r14 0xff...0cb5 <+21>: jmp 0xff...0cc7 <security_file_ioctl+39> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Static key enabled for SELinux 0xffffffff818f0cb7 <+23>: jmp 0xff...0cde <security_file_ioctl+62> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Static key enabled for BPF LSM. This is something that is changed to default to false to avoid the existing side effect issues of BPF LSM [1] in a subsequent patch. 0xff...0cb9 <+25>: xor %eax,%eax 0xff...0cbb <+27>: xchg %ax,%ax 0xff...0cbd <+29>: pop %rbx 0xff...0cbe <+30>: pop %r14 0xff...0cc0 <+32>: pop %rbp 0xff...0cc1 <+33>: cs jmp 0xff...0000 <__x86_return_thunk> 0xff...0cc7 <+39>: endbr64 0xff...0ccb <+43>: mov %r14,%rdi 0xff...0cce <+46>: mov %ebp,%esi 0xff...0cd0 <+48>: mov %rbx,%rdx 0xff...0cd3 <+51>: call 0xff...3230 <selinux_file_ioctl> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct call to SELinux. 0xff...0cd8 <+56>: test %eax,%eax 0xff...0cda <+58>: jne 0xff...0cbd <security_file_ioctl+29> 0xff...0cdc <+60>: jmp 0xff...0cb7 <security_file_ioctl+23> 0xff...0cde <+62>: endbr64 0xff...0ce2 <+66>: mov %r14,%rdi 0xff...0ce5 <+69>: mov %ebp,%esi 0xff...0ce7 <+71>: mov %rbx,%rdx 0xff...0cea <+74>: call 0xff...e220 <bpf_lsm_file_ioctl> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct call to BPF LSM. 0xff...0cef <+79>: test %eax,%eax 0xff...0cf1 <+81>: jne 0xff...0cbd <security_file_ioctl+29> 0xff...0cf3 <+83>: jmp 0xff...0cb9 <security_file_ioctl+25> 0xff...0cf5 <+85>: endbr64 0xff...0cf9 <+89>: mov %r14,%rdi 0xff...0cfc <+92>: mov %ebp,%esi 0xff...0cfe <+94>: mov %rbx,%rdx 0xff...0d01 <+97>: pop %rbx 0xff...0d02 <+98>: pop %r14 0xff...0d04 <+100>: pop %rbp 0xff...0d05 <+101>: ret 0xff...0d06 <+102>: int3 0xff...0d07 <+103>: int3 0xff...0d08 <+104>: int3 0xff...0d09 <+105>: int3 While this patch uses static_branch_unlikely indicating that an LSM hook is likely to be not present. In most cases this is still a better choice as even when an LSM with one hook is added, empty slots are created for all LSM hooks (especially when many LSMs that do not initialize most hooks are present on the system). There are some hooks that don't use the call_int_hook or call_void_hook. These hooks are updated to use a new macro called lsm_for_each_hook where the lsm_callback is directly invoked as an indirect call. Below are results of the relevant Unixbench system benchmarks with BPF LSM and SELinux enabled with default policies enabled with and without these patches. Benchmark Delta(%): (+ is better) ========================================================================== Execl Throughput +1.9356 File Write 1024 bufsize 2000 maxblocks +6.5953 Pipe Throughput +9.5499 Pipe-based Context Switching +3.0209 Process Creation +2.3246 Shell Scripts (1 concurrent) +1.4975 System Call Overhead +2.7815 System Benchmarks Index Score (Partial Only): +3.4859 In the best case, some syscalls like eventfd_create benefitted to about ~10%. Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Song Liu <song@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: KP Singh <kpsingh@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: count the LSMs enabled at compile timeKP Singh2024-08-222-3/+138
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These macros are a clever trick to determine a count of the number of LSMs that are enabled in the config to ascertain the maximum number of static calls that need to be configured per LSM hook. Without this one would need to generate static calls for the total number of LSMs in the kernel (even if they are not compiled) times the number of LSM hooks which ends up being quite wasteful. Tested-by: Guenter Roeck <linux@roeck-us.net> Suggested-by: Kui-Feng Lee <sinquersw@gmail.com> Suggested-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Song Liu <song@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Nacked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: KP Singh <kpsingh@kernel.org> [PM: added IPE to the count during merge] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * kernel: Add helper macros for loop unrollingKP Singh2024-08-201-0/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This helps in easily initializing blocks of code (e.g. static calls and keys). UNROLL(N, MACRO, __VA_ARGS__) calls MACRO N times with the first argument as the index of the iteration. This allows string pasting to create unique tokens for variable names, function calls etc. As an example: #include <linux/unroll.h> #define MACRO(N, a, b) \ int add_##N(int a, int b) \ { \ return a + b + N; \ } UNROLL(2, MACRO, x, y) expands to: int add_0(int x, int y) { return x + y + 0; } int add_1(int x, int y) { return x + y + 1; } Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Song Liu <song@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Nacked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: KP Singh <kpsingh@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * init/main.c: Initialize early LSMs after arch code, static keys and calls.KP Singh2024-08-201-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With LSMs using static calls and static keys, early_lsm_init needs to wait for setup_arch for architecture specific functionality which includes jump tables and static calls to be initialized. Since not all architectures call jump_table_init in setup_arch, explicitly call both jump_table_init and static_call_init before early_security_init. This only affects "early LSMs" i.e. only lockdown when CONFIG_SECURITY_LOCKDOWN_LSM_EARLY is set. Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: KP Singh <kpsingh@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * MAINTAINERS: add IPE entry with Fan Wu as maintainerFan Wu2024-08-201-0/+10
| | | | | | | | | | | | | | | | Add a MAINTAINERS entry for the Integrity Policy Enforcement (IPE) LSM. Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: removed changelog, updated description per email thread] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * documentation: add IPE documentationDeven Bowers2024-08-206-1/+1255
| | | | | | | | | | | | | | | | | | 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>
| * ipe: kunit test for parserDeven Bowers2024-08-203-0/+316
| | | | | | | | | | | | | | | | | | | | | | Add various happy/unhappy unit tests for both IPE's policy parser. Besides, a test suite for IPE functionality is available at https://github.com/microsoft/ipe/tree/test-suite 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>
| * scripts: add boot policy generation programDeven Bowers2024-08-2010-0/+198
| | | | | | | | | | | | | | | | | | | | | | Enables an IPE policy to be enforced from kernel start, enabling access control based on trust from kernel startup. This is accomplished by transforming an IPE policy indicated by CONFIG_IPE_BOOT_POLICY into a c-string literal that is parsed at kernel startup as an unsigned policy. 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>
| * ipe: enable support for fs-verity as a trust providerFan Wu2024-08-2010-1/+237
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable IPE policy authors to indicate trust for a singular fsverity file, identified by the digest information, through "fsverity_digest" and all files using valid fsverity builtin signatures via "fsverity_signature". This enables file-level integrity claims to be expressed in IPE, allowing individual files to be authorized, giving some flexibility for policy authors. Such file-level claims are important to be expressed for enforcing the integrity of packages, as well as address some of the scalability issues in a sole dm-verity based solution (# of loop back devices, etc). This solution cannot be done in userspace as the minimum threat that IPE should mitigate is an attacker downloads malicious payload with all required dependencies. These dependencies can lack the userspace check, bypassing the protection entirely. A similar attack succeeds if the userspace component is replaced with a version that does not perform the check. As a result, this can only be done in the common entry point - the kernel. 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>
| * fsverity: expose verified fsverity built-in signatures to LSMsFan Wu2024-08-203-3/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enhances fsverity's capabilities to support both integrity and authenticity protection by introducing the exposure of built-in signatures through a new LSM hook. This functionality allows LSMs, e.g. IPE, to enforce policies based on the authenticity and integrity of files, specifically focusing on built-in fsverity signatures. It enables a policy enforcement layer within LSMs for fsverity, offering granular control over the usage of authenticity claims. For instance, a policy could be established to only permit the execution of all files with verified built-in fsverity signatures. The introduction of a security_inode_setintegrity() hook call within fsverity's workflow ensures that the verified built-in signature of a file is exposed to LSMs. This enables LSMs to recognize and label fsverity files that contain a verified built-in fsverity signature. This hook is invoked subsequent to the fsverity_verify_signature() process, guaranteeing the signature's verification against fsverity's keyring. This mechanism is crucial for maintaining system security, as it operates in kernel space, effectively thwarting attempts by malicious binaries to bypass user space stack interactions. The second to last commit in this patch set will add a link to the IPE documentation in fsverity.rst. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: add security_inode_setintegrity() hookFan Wu2024-08-203-0/+32
| | | | | | | | | | | | | | | | | | | | | | This patch introduces a new hook to save inode's integrity data. For example, for fsverity enabled files, LSMs can use this hook to save the existence of verified fsverity builtin signature into the inode's security blob, and LSMs can make access decisions based on this data. Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: subject line tweak, removed changelog] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: add support for dm-verity as a trust providerDeven Bowers2024-08-2014-15/+460
| | | | | | | | | | | | | | | | | | | | | | Allows author of IPE policy to indicate trust for a singular dm-verity volume, identified by roothash, through "dmverity_roothash" and all signed and validated dm-verity volumes, through "dmverity_signature". Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: fixed some line length issues in the comments] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * dm-verity: expose root hash digest and signature data to LSMsDeven Bowers2024-08-203-1/+130
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | dm-verity provides a strong guarantee of a block device's integrity. As a generic way to check the integrity of a block device, it provides those integrity guarantees to its higher layers, including the filesystem level. However, critical security metadata like the dm-verity roothash and its signing information are not easily accessible to the LSMs. To address this limitation, this patch introduces a mechanism to store and manage these essential security details within a newly added LSM blob in the block_device structure. This addition allows LSMs to make access control decisions on the integrity data stored within the block_device, enabling more flexible security policies. For instance, LSMs can now revoke access to dm-verity devices based on their roothashes, ensuring that only authorized and verified content is accessible. Additionally, LSMs can enforce policies to only allow files from dm-verity devices that have a valid digital signature to execute, effectively blocking any unsigned files from execution, thus enhancing security against unauthorized modifications. The patch includes new hook calls, `security_bdev_setintegrity()`, in dm-verity to expose the dm-verity roothash and the roothash signature to LSMs via preresume() callback. By using the preresume() callback, it ensures that the security metadata is consistently in sync with the metadata of the dm-verity target in the current active mapping table. The hook calls are depended on CONFIG_SECURITY. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> [PM: moved sig_size field as discussed] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * block,lsm: add LSM blob and new LSM hooks for block devicesDeven Bowers2024-08-206-0/+145
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces a new LSM blob to the block_device structure, enabling the security subsystem to store security-sensitive data related to block devices. Currently, for a device mapper's mapped device containing a dm-verity target, critical security information such as the roothash and its signing state are not readily accessible. Specifically, while the dm-verity volume creation process passes the dm-verity roothash and its signature from userspace to the kernel, the roothash is stored privately within the dm-verity target, and its signature is discarded post-verification. This makes it extremely hard for the security subsystem to utilize these data. With the addition of the LSM blob to the block_device structure, the security subsystem can now retain and manage important security metadata such as the roothash and the signing state of a dm-verity by storing them inside the blob. Access decisions can then be based on these stored data. The implementation follows the same approach used for security blobs in other structures like struct file, struct inode, and struct superblock. The initialization of the security blob occurs after the creation of the struct block_device, performed by the security subsystem. Similarly, the security blob is freed by the security subsystem before the struct block_device is deallocated or freed. This patch also introduces a new hook security_bdev_setintegrity() to save block device's integrity data to the new LSM blob. For example, for dm-verity, it can use this hook to expose its roothash and signing state to LSMs, then LSMs can save these data into the LSM blob. Please note that the new hook should be invoked every time the security information is updated to keep these data current. For example, in dm-verity, if the mapping table is reloaded and configured to use a different dm-verity target with a new roothash and signing information, the previously stored data in the LSM blob will become obsolete. It is crucial to re-invoke the hook to refresh these data and ensure they are up to date. This necessity arises from the design of device-mapper, where a device-mapper device is first created, and then targets are subsequently loaded into it. These targets can be modified multiple times during the device's lifetime. Therefore, while the LSM blob is allocated during the creation of the block device, its actual contents are not initialized at this stage and can change substantially over time. This includes alterations from data that the LSM 'trusts' to those it does not, making it essential to handle these changes correctly. Failure to address this dynamic aspect could potentially allow for bypassing LSM checks. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: merge fuzz, subject line tweaks] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: add permissive toggleDeven Bowers2024-08-205-4/+102
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | IPE, like SELinux, supports a permissive mode. This mode allows policy authors to test and evaluate IPE policy without it affecting their programs. When the mode is changed, a 1404 AUDIT_MAC_STATUS will be reported. This patch adds the following audit records: audit: MAC_STATUS enforcing=0 old_enforcing=1 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 audit: MAC_STATUS enforcing=1 old_enforcing=0 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 The audit record only emit when the value from the user input is different from the current enforce value. 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>
| * audit,ipe: add IPE auditing supportDeven Bowers2024-08-2011-18/+384
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 itself. This patch introduces 3 new audit events. AUDIT_IPE_ACCESS(1420) indicates the result of an IPE policy evaluation of a resource. AUDIT_IPE_CONFIG_CHANGE(1421) indicates the current active IPE policy has been changed to another loaded policy. AUDIT_IPE_POLICY_LOAD(1422) indicates a new IPE policy has been loaded into the kernel. This patch also adds support for success auditing, allowing users to identify why an allow decision was made for a resource. However, it is recommended to use this option with caution, as it is quite noisy. Here are some examples of the new audit record types: AUDIT_IPE_ACCESS(1420): audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=297 comm="sh" path="/root/vol/bin/hello" dev="tmpfs" ino=3897 rule="op=EXECUTE boot_verified=TRUE action=ALLOW" audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=299 comm="sh" path="/mnt/ipe/bin/hello" dev="dm-0" ino=2 rule="DEFAULT action=DENY" audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=300 path="/tmp/tmpdp2h1lub/deny/bin/hello" dev="tmpfs" ino=131 rule="DEFAULT action=DENY" The above three records were generated when the active IPE policy only allows binaries from the initramfs to run. The three identical `hello` binary were placed at different locations, only the first hello from the rootfs(initramfs) was allowed. Field ipe_op followed by the IPE operation name associated with the log. Field ipe_hook followed by the name of the LSM hook that triggered the IPE event. Field enforcing followed by the enforcement state of IPE. (it will be introduced in the next commit) Field pid followed by the pid of the process that triggered the IPE event. Field comm followed by the command line program name of the process that triggered the IPE event. Field path followed by the file's path name. Field dev followed by the device name as found in /dev where the file is from. Note that for device mappers it will use the name `dm-X` instead of the name in /dev/mapper. For a file in a temp file system, which is not from a device, it will use `tmpfs` for the field. The implementation of this part is following another existing use case LSM_AUDIT_DATA_INODE in security/lsm_audit.c Field ino followed by the file's inode number. Field rule followed by the IPE rule made the access decision. The whole rule must be audited because the decision is based on the combination of all property conditions in the rule. Along with the syscall audit event, user can know why a blocked happened. For example: audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=2138 comm="bash" path="/mnt/ipe/bin/hello" dev="dm-0" ino=2 rule="DEFAULT action=DENY" audit[1956]: SYSCALL arch=c000003e syscall=59 success=no exit=-13 a0=556790138df0 a1=556790135390 a2=5567901338b0 a3=ab2a41a67f4f1f4e items=1 ppid=147 pid=1956 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null) The above two records showed bash used execve to run "hello" and got blocked by IPE. Note that the IPE records are always prior to a SYSCALL record. AUDIT_IPE_CONFIG_CHANGE(1421): audit: AUDIT1421 old_active_pol_name="Allow_All" old_active_pol_version=0.0.0 old_policy_digest=sha256:E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649 new_active_pol_name="boot_verified" new_active_pol_version=0.0.0 new_policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F auid=4294967295 ses=4294967295 lsm=ipe res=1 The above record showed the current IPE active policy switch from `Allow_All` to `boot_verified` along with the version and the hash digest of the two policies. Note IPE can only have one policy active at a time, all access decision evaluation is based on the current active policy. The normal procedure to deploy a policy is loading the policy to deploy into the kernel first, then switch the active policy to it. AUDIT_IPE_POLICY_LOAD(1422): audit: AUDIT1422 policy_name="boot_verified" policy_version=0.0.0 policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F2676 auid=4294967295 ses=4294967295 lsm=ipe res=1 The above record showed a new policy has been loaded into the kernel with the policy name, policy version and policy hash. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: add userspace interfaceDeven Bowers2024-08-208-0/+727
| | | | | | | | | | | | | | | | | | | | | | As is typical with LSMs, IPE uses securityfs as its interface with userspace. for a complete list of the interfaces and the respective inputs/outputs, please see the documentation under admin-guide/LSM/ipe.rst 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>
| * lsm: add new securityfs delete functionFan Wu2024-08-202-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When deleting a directory in the security file system, the existing securityfs_remove requires the directory to be empty, otherwise it will do nothing. This leads to a potential risk that the security file system might be in an unclean state when the intended deletion did not happen. This commit introduces a new function securityfs_recursive_remove to recursively delete a directory without leaving an unclean state. Co-developed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: introduce 'boot_verified' as a trust providerFan Wu2024-08-208-6/+101
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | IPE is designed to provide system level trust guarantees, this usually implies that trust starts from bootup with a hardware root of trust, which validates the bootloader. After this, the bootloader verifies the kernel and the initramfs. As there's no currently supported integrity method for initramfs, and it's typically already verified by the bootloader. This patch introduces a new IPE property `boot_verified` which allows author of IPE policy to indicate trust for files from initramfs. The implementation of this feature utilizes the newly added `initramfs_populated` hook. This hook marks the superblock of the rootfs after the initramfs has been unpacked into it. Before mounting the real rootfs on top of the initramfs, initramfs script will recursively remove all files and directories on the initramfs. This is typically implemented by using switch_root(8) (https://man7.org/linux/man-pages/man8/switch_root.8.html). Therefore the initramfs will be empty and not accessible after the real rootfs takes over. It is advised to switch to a different policy that doesn't rely on the `boot_verified` property after this point. This ensures that the trust policies remain relevant and effective throughout the system's operation. 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>
| * initramfs,lsm: add a security hook to do_populate_rootfs()Fan Wu2024-08-204-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces a new hook to notify security system that the content of initramfs has been unpacked into the rootfs. Upon receiving this notification, the security system can activate a policy to allow only files that originated from the initramfs to execute or load into kernel during the early stages of booting. This approach is crucial for minimizing the attack surface by ensuring that only trusted files from the initramfs are operational in the critical boot phase. Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: add LSM hooks on execution and kernel readDeven Bowers2024-08-206-0/+235
| | | | | | | | | | | | | | | | | | | | | | | | IPE's initial goal is to control both execution and the loading of kernel modules based on the system's definition of trust. It accomplishes this by plugging into the security hooks for bprm_check_security, file_mprotect, mmap_file, kernel_load_data, and kernel_read_data. 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>
| * ipe: add evaluation loopDeven Bowers2024-08-203-0/+127
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a core evaluation function in IPE that will be triggered by various security hooks (e.g., mmap, bprm_check, kexec). This function systematically assesses actions against the defined IPE policy, by iterating over rules specific to the action being taken. This critical addition enables IPE to enforce its security policies effectively, ensuring that actions intercepted by these hooks are scrutinized for policy compliance before they are allowed to proceed. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * ipe: add policy parserDeven Bowers2024-08-205-0/+697
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | IPE's interpretation of the what the user trusts is accomplished through its policy. IPE's design is to not provide support for a single trust provider, but to support multiple providers to enable the end-user to choose the best one to seek their needs. This requires the policy to be rather flexible and modular so that integrity providers, like fs-verity, dm-verity, or some other system, can plug into the policy with minimal code changes. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: added NULL check in parse_rule() as discussed] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: add IPE lsmDeven Bowers2024-08-209-6/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Integrity Policy Enforcement (IPE) is an LSM that provides an complimentary approach to Mandatory Access Control than existing LSMs today. Existing LSMs have centered around the concept of access to a resource should be controlled by the current user's credentials. IPE's approach, is that access to a resource should be controlled by the system's trust of a current resource. The basis of this approach is defining a global policy to specify which resource can be trusted. Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lockdown: Make lockdown_lsmid staticYue Haibing2024-08-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | Fix sparse warning: security/lockdown/lockdown.c:79:21: warning: symbol 'lockdown_lsmid' was not declared. Should it be static? Signed-off-by: Yue Haibing <yuehaibing@huawei.com> Reviewed-by: Kees Cook <kees@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: add the inode_free_security_rcu() LSM implementation hookPaul Moore2024-08-126-33/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable@vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: cleanup lsm_hooks.hPaul Moore2024-08-122-45/+44
| | | | | | | | | | | | | | | | | | | | | | | | Some cleanup and style corrections for lsm_hooks.h. * Drop the lsm_inode_alloc() extern declaration, it is not needed. * Relocate lsm_get_xattr_slot() and extern variables in the file to improve grouping of related objects. * Don't use tabs to needlessly align structure fields. Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: Refactor return value of LSM hook inode_copy_up_xattrXu Kuohai2024-07-315-17/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To be consistent with most LSM hooks, convert the return value of hook inode_copy_up_xattr to 0 or a negative error code. Before: - Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. After: - Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED* when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. Signed-off-by: Xu Kuohai <xukuohai@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: Refactor return value of LSM hook vm_enough_memoryXu Kuohai2024-07-315-27/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To be consistent with most LSM hooks, convert the return value of hook vm_enough_memory to 0 or a negative error code. Before: - Hook vm_enough_memory returns 1 if permission is granted, 0 if not. - LSM_RET_DEFAULT(vm_enough_memory_mm) is 1. After: - Hook vm_enough_memory reutrns 0 if permission is granted, negative error code if not. - LSM_RET_DEFAULT(vm_enough_memory_mm) is 0. Signed-off-by: Xu Kuohai <xukuohai@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: infrastructure management of the perf_event security blobCasey Schaufler2024-07-295-17/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Move management of the perf_event->security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. There are no longer any modules that require the perf_event_free() hook. The hook definition has been removed. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> [PM: subject tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
| * lsm: infrastructure management of the infiniband blobCasey Schaufler2024-07-295-17/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | Move management of the infiniband security blob out of the individual security modules and into the LSM infrastructure. The security modules tell the infrastructure how much space they require at initialization. There are no longer any modules that require the ib_free() hook. The hook definition has been removed. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> [PM: subject tweak, selinux style fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-06 01:03:47 +0100