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2024-09-24Merge tag 'bpf-next-6.12-struct-fd' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Pull bpf 'struct fd' updates from Alexei Starovoitov: "This includes struct_fd BPF changes from Al and Andrii" * tag 'bpf-next-6.12-struct-fd' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: bpf: convert bpf_token_create() to CLASS(fd, ...) security,bpf: constify struct path in bpf_token_create() LSM hook bpf: more trivial fdget() conversions bpf: trivial conversions for fdget() bpf: switch maps to CLASS(fd, ...) bpf: factor out fetching bpf_map from FD and adding it to used_maps list bpf: switch fdget_raw() uses to CLASS(fd_raw, ...) bpf: convert __bpf_prog_get() to CLASS(fd, ...)
2024-09-12security,bpf: constify struct path in bpf_token_create() LSM hookAndrii Nakryiko
There is no reason why struct path pointer shouldn't be const-qualified when being passed into bpf_token_create() LSM hook. Add that const. Acked-by: Paul Moore <paul@paul-moore.com> (LSM/SELinux) Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2024-09-09security: Update file_set_fowner documentationMickaël Salaün
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>
2024-08-26lsm: remove LSM_COUNT and LSM_CONFIG_COUNTTetsuo Handa
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>
2024-08-22lsm: replace indirect LSM hook calls with static callsKP Singh
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>
2024-08-20lsm: add security_inode_setintegrity() hookFan Wu
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>
2024-08-20ipe: add support for dm-verity as a trust providerDeven Bowers
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>
2024-08-20block,lsm: add LSM blob and new LSM hooks for block devicesDeven Bowers
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>
2024-08-20initramfs,lsm: add a security hook to do_populate_rootfs()Fan Wu
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>
2024-08-19lsm: add IPE lsmDeven Bowers
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>
2024-08-12lsm: add the inode_free_security_rcu() LSM implementation hookPaul Moore
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>
2024-08-12lsm: cleanup lsm_hooks.hPaul Moore
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>
2024-07-31lsm: Refactor return value of LSM hook inode_copy_up_xattrXu Kuohai
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>
2024-07-31lsm: Refactor return value of LSM hook vm_enough_memoryXu Kuohai
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>
2024-07-29lsm: infrastructure management of the perf_event security blobCasey Schaufler
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>
2024-07-29lsm: infrastructure management of the infiniband blobCasey Schaufler
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>
2024-07-29lsm: infrastructure management of the dev_tun blobCasey Schaufler
Move management of the dev_tun 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 dev_tun_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>
2024-07-29lsm: add helper for blob allocationsCasey Schaufler
Create a helper function lsm_blob_alloc() for general use in the hook specific functions that allocate LSM blobs. Change the hook specific functions to use this helper. This reduces the code size by a small amount and will make adding new instances of infrastructure managed security blobs easier. 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>
2024-07-29lsm: infrastructure management of the key security blobCasey Schaufler
Move management of the key->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 existing modules that require a key_free hook, so the call to it and the definition for it have 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>
2024-07-29lsm: infrastructure management of the sock securityCasey Schaufler
Move management of the sock->sk_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. Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-16Merge tag 'lsm-pr-20240715' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm updates from Paul Moore: "Two LSM patches focused on cleaning up the inode xattr capability handling" * tag 'lsm-pr-20240715' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: selinux,smack: remove the capability checks in the removexattr hooks lsm: fixup the inode xattr capability handling
2024-06-13ima: Avoid blocking in RCU read-side critical sectionGUO Zihua
A panic happens in ima_match_policy: BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 PGD 42f873067 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 5 PID: 1286325 Comm: kubeletmonit.sh Kdump: loaded Tainted: P Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 RIP: 0010:ima_match_policy+0x84/0x450 Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39 7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea 44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f RSP: 0018:ff71570009e07a80 EFLAGS: 00010207 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200 RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739 R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970 R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001 FS: 00007f5195b51740(0000) GS:ff3e278b12d40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ima_get_action+0x22/0x30 process_measurement+0xb0/0x830 ? page_add_file_rmap+0x15/0x170 ? alloc_set_pte+0x269/0x4c0 ? prep_new_page+0x81/0x140 ? simple_xattr_get+0x75/0xa0 ? selinux_file_open+0x9d/0xf0 ima_file_check+0x64/0x90 path_openat+0x571/0x1720 do_filp_open+0x9b/0x110 ? page_counter_try_charge+0x57/0xc0 ? files_cgroup_alloc_fd+0x38/0x60 ? __alloc_fd+0xd4/0x250 ? do_sys_open+0x1bd/0x250 do_sys_open+0x1bd/0x250 do_syscall_64+0x5d/0x1d0 entry_SYSCALL_64_after_hwframe+0x65/0xca Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a RCU read-side critical section which contains kmalloc with GFP_KERNEL. This implies a possible sleep and violates limitations of RCU read-side critical sections on non-PREEMPT systems. Sleeping within RCU read-side critical section might cause synchronize_rcu() returning early and break RCU protection, allowing a UAF to happen. The root cause of this issue could be described as follows: | Thread A | Thread B | | |ima_match_policy | | | rcu_read_lock | |ima_lsm_update_rule | | | synchronize_rcu | | | | kmalloc(GFP_KERNEL)| | | sleep | ==> synchronize_rcu returns early | kfree(entry) | | | | entry = entry->next| ==> UAF happens and entry now becomes NULL (or could be anything). | | entry->action | ==> Accessing entry might cause panic. To fix this issue, we are converting all kmalloc that is called within RCU read-side critical section to use GFP_ATOMIC. Fixes: c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()") Cc: stable@vger.kernel.org Signed-off-by: GUO Zihua <guozihua@huawei.com> Acked-by: John Johansen <john.johansen@canonical.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-06-03lsm: fixup the inode xattr capability handlingPaul Moore
The current security_inode_setxattr() and security_inode_removexattr() hooks rely on individual LSMs to either call into the associated capability hooks (cap_inode_setxattr() or cap_inode_removexattr()), or return a magic value of 1 to indicate that the LSM layer itself should perform the capability checks. Unfortunately, with the default return value for these LSM hooks being 0, an individual LSM hook returning a 1 will cause the LSM hook processing to exit early, potentially skipping a LSM. Thankfully, with the exception of the BPF LSM, none of the LSMs which currently register inode xattr hooks should end up returning a value of 1, and in the BPF LSM case, with the BPF LSM hooks executing last there should be no real harm in stopping processing of the LSM hooks. However, the reliance on the individual LSMs to either call the capability hooks themselves, or signal the LSM with a return value of 1, is fragile and relies on a specific set of LSMs being enabled. This patch is an effort to resolve, or minimize, these issues. Before we discuss the solution, there are a few observations and considerations that we need to take into account: * BPF LSM registers an implementation for every LSM hook, and that implementation simply returns the hook's default return value, a 0 in this case. We want to ensure that the default BPF LSM behavior results in the capability checks being called. * SELinux and Smack do not expect the traditional capability checks to be applied to the xattrs that they "own". * SELinux and Smack are currently written in such a way that the xattr capability checks happen before any additional LSM specific access control checks. SELinux does apply SELinux specific access controls to all xattrs, even those not "owned" by SELinux. * IMA and EVM also register xattr hooks but assume that the LSM layer and specific LSMs have already authorized the basic xattr operation. In order to ensure we perform the capability based access controls before the individual LSM access controls, perform only one capability access control check for each operation, and clarify the logic around applying the capability controls, we need a mechanism to determine if any of the enabled LSMs "own" a particular xattr and want to take responsibility for controlling access to that xattr. The solution in this patch is to create a new LSM hook, 'inode_xattr_skipcap', that is not exported to the rest of the kernel via a security_XXX() function, but is used by the LSM layer to determine if a LSM wants to control access to a given xattr and avoid the traditional capability controls. Registering an inode_xattr_skipcap hook is optional, if a LSM declines to register an implementation, or uses an implementation that simply returns the default value (0), there is no effect as the LSM continues to enforce the capability based controls (unless another LSM takes ownership of the xattr). If none of the LSMs signal that the capability checks should be skipped, the capability check is performed and if access is granted the individual LSM xattr access control hooks are executed, keeping with the DAC-before-LSM convention. Cc: stable@vger.kernel.org Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-04-09security: allow finer granularity in permitting copy-up of security xattrsStefan Berger
Copying up xattrs is solely based on the security xattr name. For finer granularity add a dentry parameter to the security_inode_copy_up_xattr hook definition, allowing decisions to be based on the xattr content as well. Co-developed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Paul Moore <paul@paul-moore.com> (LSM,SELinux) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2024-04-03security: Place security_path_post_mknod() where the original IMA call wasRoberto Sassu
Commit 08abce60d63f ("security: Introduce path_post_mknod hook") introduced security_path_post_mknod(), to replace the IMA-specific call to ima_post_path_mknod(). For symmetry with security_path_mknod(), security_path_post_mknod() was called after a successful mknod operation, for any file type, rather than only for regular files at the time there was the IMA call. However, as reported by VFS maintainers, successful mknod operation does not mean that the dentry always has an inode attached to it (for example, not for FIFOs on a SAMBA mount). If that condition happens, the kernel crashes when security_path_post_mknod() attempts to verify if the inode associated to the dentry is private. Move security_path_post_mknod() where the ima_post_path_mknod() call was, which is obviously correct from IMA/EVM perspective. IMA/EVM are the only in-kernel users, and only need to inspect regular files. Reported-by: Steve French <smfrench@gmail.com> Closes: https://lore.kernel.org/linux-kernel/CAH2r5msAVzxCUHHG8VKrMPUKQHmBpE6K9_vjhgDa1uAvwx4ppw@mail.gmail.com/ Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Fixes: 08abce60d63f ("security: Introduce path_post_mknod hook") Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-03-14lsm: handle the NULL buffer case in lsm_fill_user_ctx()Paul Moore
Passing a NULL buffer into the lsm_get_self_attr() syscall is a valid way to quickly determine the minimum size of the buffer needed to for the syscall to return all of the LSM attributes to the caller. Unfortunately we/I broke that behavior in commit d7cf3412a9f6 ("lsm: consolidate buffer size handling into lsm_fill_user_ctx()") such that it returned an error to the caller; this patch restores the original desired behavior of using the NULL buffer as a quick way to correctly size the attribute buffer. Cc: stable@vger.kernel.org Fixes: d7cf3412a9f6 ("lsm: consolidate buffer size handling into lsm_fill_user_ctx()") Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-03-14lsm: use 32-bit compatible data types in LSM syscallsCasey Schaufler
Change the size parameters in lsm_list_modules(), lsm_set_self_attr() and lsm_get_self_attr() from size_t to u32. This avoids the need to have different interfaces for 32 and 64 bit systems. Cc: stable@vger.kernel.org Fixes: a04a1198088a ("LSM: syscalls for current process attributes") Fixes: ad4aff9ec25f ("LSM: Create lsm_list_modules system call") Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reported-and-reviewed-by: Dmitry V. Levin <ldv@strace.io> [PM: subject and metadata tweaks, syscall.h fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-03-12Merge tag 'lsm-pr-20240312' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm updates from Paul Moore: - Promote IMA/EVM to a proper LSM This is the bulk of the diffstat, and the source of all the changes in the VFS code. Prior to the start of the LSM stacking work it was important that IMA/EVM were separate from the rest of the LSMs, complete with their own hooks, infrastructure, etc. as it was the only way to enable IMA/EVM at the same time as a LSM. However, now that the bulk of the LSM infrastructure supports multiple simultaneous LSMs, we can simplify things greatly by bringing IMA/EVM into the LSM infrastructure as proper LSMs. This is something I've wanted to see happen for quite some time and Roberto was kind enough to put in the work to make it happen. - Use the LSM hook default values to simplify the call_int_hook() macro Previously the call_int_hook() macro required callers to supply a default return value, despite a default value being specified when the LSM hook was defined. This simplifies the macro by using the defined default return value which makes life easier for callers and should also reduce the number of return value bugs in the future (we've had a few pop up recently, hence this work). - Use the KMEM_CACHE() macro instead of kmem_cache_create() The guidance appears to be to use the KMEM_CACHE() macro when possible and there is no reason why we can't use the macro, so let's use it. - Fix a number of comment typos in the LSM hook comment blocks Not much to say here, we fixed some questionable grammar decisions in the LSM hook comment blocks. * tag 'lsm-pr-20240312' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (28 commits) cred: Use KMEM_CACHE() instead of kmem_cache_create() lsm: use default hook return value in call_int_hook() lsm: fix typos in security/security.c comment headers integrity: Remove LSM ima: Make it independent from 'integrity' LSM evm: Make it independent from 'integrity' LSM evm: Move to LSM infrastructure ima: Move IMA-Appraisal to LSM infrastructure ima: Move to LSM infrastructure integrity: Move integrity_kernel_module_request() to IMA security: Introduce key_post_create_or_update hook security: Introduce inode_post_remove_acl hook security: Introduce inode_post_set_acl hook security: Introduce inode_post_create_tmpfile hook security: Introduce path_post_mknod hook security: Introduce file_release hook security: Introduce file_post_open hook security: Introduce inode_post_removexattr hook security: Introduce inode_post_setattr hook security: Align inode_setattr hook definition with EVM ...
2024-02-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. Conflicts: net/ipv4/udp.c f796feabb9f5 ("udp: add local "peek offset enabled" flag") 56667da7399e ("net: implement lockless setsockopt(SO_PEEK_OFF)") Adjacent changes: net/unix/garbage.c aa82ac51d633 ("af_unix: Drop oob_skb ref before purging queue in GC.") 11498715f266 ("af_unix: Remove io_uring code for GC.") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-22lsm: use default hook return value in call_int_hook()Ondrej Mosnacek
Change the definition of call_int_hook() to treat LSM_RET_DEFAULT(...) as the "continue" value instead of 0. To further simplify this macro, also drop the IRC argument and replace it with LSM_RET_DEFAULT(...). After this the macro can be used in a couple more hooks, where similar logic is currently open-coded. At the same time, some other existing call_int_hook() users now need to be open-coded, but overall it's still a net simplification. There should be no functional change resulting from this patch. Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> [PM: merge fuzz due to other hook changes, tweaks from list discussion] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-21lsm: fix typos in security/security.c comment headersPairman Guo
This commit fixes several typos in comment headers in security/security.c where "Check is" should be "Check if". Signed-off-by: Pairman Guo <pairmanxlr@gmail.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15integrity: Remove LSMRoberto Sassu
Since now IMA and EVM use their own integrity metadata, it is safe to remove the 'integrity' LSM, with its management of integrity metadata. Keep the iint.c file only for loading IMA and EVM keys at boot, and for creating the integrity directory in securityfs (we need to keep it for retrocompatibility reasons). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15evm: Make it independent from 'integrity' LSMRoberto Sassu
Define a new structure for EVM-specific metadata, called evm_iint_cache, and embed it in the inode security blob. Introduce evm_iint_inode() to retrieve metadata, and register evm_inode_alloc_security() for the inode_alloc_security LSM hook, to initialize the structure (before splitting metadata, this task was done by iint_init_always()). Keep the non-NULL checks after calling evm_iint_inode() except in evm_inode_alloc_security(), to take into account inodes for which security_inode_alloc() was not called. When using shared metadata, obtaining a NULL pointer from integrity_iint_find() meant that the file wasn't in the IMA policy. Now, because IMA and EVM use disjoint metadata, the EVM status has to be stored for every inode regardless of the IMA policy. Given that from now on EVM relies on its own metadata, remove the iint parameter from evm_verifyxattr(). Also, directly retrieve the iint in evm_verify_hmac(), called by both evm_verifyxattr() and evm_verify_current_integrity(), since now there is no performance penalty in retrieving EVM metadata (constant time). Replicate the management of the IMA_NEW_FILE flag, by introducing evm_post_path_mknod() and evm_file_release() to respectively set and clear the newly introduced flag EVM_NEW_FILE, at the same time IMA does. Like for IMA, select CONFIG_SECURITY_PATH when EVM is enabled, to ensure that files are marked as new. Unlike ima_post_path_mknod(), evm_post_path_mknod() cannot check if a file must be appraised. Thus, it marks all affected files. Also, it does not clear EVM_NEW_FILE depending on i_version, but that is not a problem because IMA_NEW_FILE is always cleared when set in ima_check_last_writer(). Move the EVM-specific flag EVM_IMMUTABLE_DIGSIG to security/integrity/evm/evm.h, since that definition is now unnecessary in the common integrity layer. Finally, switch to the LSM reservation mechanism for the EVM xattr, and consequently decrement by one the number of xattrs to allocate in security_inode_init_security(). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15evm: Move to LSM infrastructureRoberto Sassu
As for IMA, move hardcoded EVM function calls from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'evm' (last and always enabled like 'ima'). The order in the Makefile ensures that 'evm' hooks are executed after 'ima' ones. Make EVM functions as static (except for evm_inode_init_security(), which is exported), and register them as hook implementations in init_evm_lsm(). Also move the inline functions evm_inode_remove_acl(), evm_inode_post_remove_acl(), and evm_inode_post_set_acl() from the public evm.h header to evm_main.c. Unlike before (see commit to move IMA to the LSM infrastructure), evm_inode_post_setattr(), evm_inode_post_set_acl(), evm_inode_post_remove_acl(), and evm_inode_post_removexattr() are not executed for private inodes. Finally, add the LSM_ID_EVM case in lsm_list_modules_test.c Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15ima: Move IMA-Appraisal to LSM infrastructureRoberto Sassu
A few additional IMA hooks are needed to reset the cached appraisal status, causing the file's integrity to be re-evaluated on next access. Register these IMA-appraisal only functions separately from the rest of IMA functions, as appraisal is a separate feature not necessarily enabled in the kernel configuration. Reuse the same approach as for other IMA functions, move hardcoded calls from various places in the kernel to the LSM infrastructure. Declare the functions as static and register them as hook implementations in init_ima_appraise_lsm(), called by init_ima_lsm(). Also move the inline function ima_inode_remove_acl() from the public ima.h header to ima_appraise.c. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15ima: Move to LSM infrastructureRoberto Sassu
Move hardcoded IMA function calls (not appraisal-specific functions) from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'ima' (at the end of the LSM list and always enabled like 'integrity'). Having IMA before EVM in the Makefile is sufficient to preserve the relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM, and thus the order of IMA and EVM function calls as when they were hardcoded. Make moved functions as static (except ima_post_key_create_or_update(), which is not in ima_main.c), and register them as implementation of the respective hooks in the new function init_ima_lsm(). Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook path_post_mknod is always available and ima_post_path_mknod() is always executed to mark files as new, as before the move. A slight difference is that IMA and EVM functions registered for the inode_post_setattr, inode_post_removexattr, path_post_mknod, inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl won't be executed for private inodes. Since those inodes are supposed to be fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub and kernel-internal tmpfs files. Conditionally register ima_post_key_create_or_update() if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled. Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15integrity: Move integrity_kernel_module_request() to IMARoberto Sassu
In preparation for removing the 'integrity' LSM, move integrity_kernel_module_request() to IMA, and rename it to ima_kernel_module_request(). Rewrite the function documentation, to explain better what the problem is. Compile it conditionally if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled, and call it from security.c (removed afterwards with the move of IMA to the LSM infrastructure). Adding this hook cannot be avoided, since IMA has no control on the flags passed to crypto_alloc_sig() in public_key_verify_signature(), and thus cannot pass CRYPTO_NOLOAD, which solved the problem for EVM hashing with commit e2861fa71641 ("evm: Don't deadlock if a crypto algorithm is unavailable"). EVM alone does not need to implement this hook, first because there is no mutex to deadlock, and second because even if it had it, there should be a recursive call. However, since verification from EVM can be initiated only by setting inode metadata, deadlock would occur if modprobe would do the same while loading a kernel module (which is unlikely). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce key_post_create_or_update hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the key_post_create_or_update hook. Depending on policy, IMA measures the key content after creation or update, so that remote verifiers are aware of the operation. Other LSMs could similarly take some action after successful key creation or update. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce inode_post_remove_acl hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_remove_acl hook. At inode_remove_acl hook, EVM verifies the file's existing HMAC value. At inode_post_remove_acl, EVM re-calculates the file's HMAC with the passed POSIX ACL removed and other file metadata. Other LSMs could similarly take some action after successful POSIX ACL removal. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce inode_post_set_acl hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_set_acl hook. At inode_set_acl hook, EVM verifies the file's existing HMAC value. At inode_post_set_acl, EVM re-calculates the file's HMAC based on the modified POSIX ACL and other file metadata. Other LSMs could similarly take some action after successful POSIX ACL change. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce inode_post_create_tmpfile hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_create_tmpfile hook. As temp files can be made persistent, treat new temp files like other new files, so that the file hash is calculated and stored in the security xattr. LSMs could also take some action after temp files have been created. The new hook cannot return an error and cannot cause the operation to be canceled. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce path_post_mknod hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the path_post_mknod hook. IMA-appraisal requires all existing files in policy to have a file hash/signature stored in security.ima. An exception is made for empty files created by mknod, by tagging them as new files. LSMs could also take some action after files are created. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce file_release hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_release hook. IMA calculates at file close the new digest of the file content and writes it to security.ima, so that appraisal at next file access succeeds. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Acked-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce file_post_open hookRoberto Sassu
In preparation to move IMA and EVM to the LSM infrastructure, introduce the file_post_open hook. Also, export security_file_post_open() for NFS. Based on policy, IMA calculates the digest of the file content and extends the TPM with the digest, verifies the file's integrity based on the digest, and/or includes the file digest in the audit log. LSMs could similarly take action depending on the file content and the access mask requested with open(). The new hook returns a value and can cause the open to be aborted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce inode_post_removexattr hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_removexattr hook. At inode_removexattr hook, EVM verifies the file's existing HMAC value. At inode_post_removexattr, EVM re-calculates the file's HMAC with the passed xattr removed and other file metadata. Other LSMs could similarly take some action after successful xattr removal. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Introduce inode_post_setattr hookRoberto Sassu
In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_setattr hook. At inode_setattr hook, EVM verifies the file's existing HMAC value. At inode_post_setattr, EVM re-calculates the file's HMAC based on the modified file attributes and other file metadata. Other LSMs could similarly take some action after successful file attribute change. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15security: Align inode_setattr hook definition with EVMRoberto Sassu
Add the idmap parameter to the definition, so that evm_inode_setattr() can be registered as this hook implementation. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15evm: Align evm_inode_post_setxattr() definition with LSM infrastructureRoberto Sassu
Change evm_inode_post_setxattr() definition, so that it can be registered as implementation of the inode_post_setxattr hook. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15evm: Align evm_inode_setxattr() definition with LSM infrastructureRoberto Sassu
Change evm_inode_setxattr() definition, so that it can be registered as implementation of the inode_setxattr hook. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15ima: Align ima_inode_removexattr() definition with LSM infrastructureRoberto Sassu
Change ima_inode_removexattr() definition, so that it can be registered as implementation of the inode_removexattr hook. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Acked-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Paul Moore <paul@paul-moore.com>