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2024-11-25Merge tag 'mm-nonmm-stable-2024-11-24-02-05' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - The series "resource: A couple of cleanups" from Andy Shevchenko performs some cleanups in the resource management code - The series "Improve the copy of task comm" from Yafang Shao addresses possible race-induced overflows in the management of task_struct.comm[] - The series "Remove unnecessary header includes from {tools/}lib/list_sort.c" from Kuan-Wei Chiu adds some cleanups and a small fix to the list_sort library code and to its selftest - The series "Enhance min heap API with non-inline functions and optimizations" also from Kuan-Wei Chiu optimizes and cleans up the min_heap library code - The series "nilfs2: Finish folio conversion" from Ryusuke Konishi finishes off nilfs2's folioification - The series "add detect count for hung tasks" from Lance Yang adds more userspace visibility into the hung-task detector's activity - Apart from that, singelton patches in many places - please see the individual changelogs for details * tag 'mm-nonmm-stable-2024-11-24-02-05' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits) gdb: lx-symbols: do not error out on monolithic build kernel/reboot: replace sprintf() with sysfs_emit() lib: util_macros_kunit: add kunit test for util_macros.h util_macros.h: fix/rework find_closest() macros Improve consistency of '#error' directive messages ocfs2: fix uninitialized value in ocfs2_file_read_iter() hung_task: add docs for hung_task_detect_count hung_task: add detect count for hung tasks dma-buf: use atomic64_inc_return() in dma_buf_getfile() fs/proc/kcore.c: fix coccinelle reported ERROR instances resource: avoid unnecessary resource tree walking in __region_intersects() ocfs2: remove unused errmsg function and table ocfs2: cluster: fix a typo lib/scatterlist: use sg_phys() helper checkpatch: always parse orig_commit in fixes tag nilfs2: convert metadata aops from writepage to writepages nilfs2: convert nilfs_recovery_copy_block() to take a folio nilfs2: convert nilfs_page_count_clean_buffers() to take a folio nilfs2: remove nilfs_writepage nilfs2: convert checkpoint file to be folio-based ...
2024-11-18Merge tag 'lsm-pr-20241112' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm updates from Paul Moore: "Thirteen patches, all focused on moving away from the current 'secid' LSM identifier to a richer 'lsm_prop' structure. This move will help reduce the translation that is necessary in many LSMs, offering better performance, and make it easier to support different LSMs in the future" * tag 'lsm-pr-20241112' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: lsm: remove lsm_prop scaffolding netlabel,smack: use lsm_prop for audit data audit: change context data from secid to lsm_prop lsm: create new security_cred_getlsmprop LSM hook audit: use an lsm_prop in audit_names lsm: use lsm_prop in security_inode_getsecid lsm: use lsm_prop in security_current_getsecid audit: update shutdown LSM data lsm: use lsm_prop in security_ipc_getsecid audit: maintain an lsm_prop in audit_context lsm: add lsmprop_to_secctx hook lsm: use lsm_prop in security_audit_rule_match lsm: add the lsm_prop data structure
2024-11-05security: replace memcpy() with get_task_comm()Yafang Shao
Quoted from Linus [0]: selinux never wanted a lock, and never wanted any kind of *consistent* result, it just wanted a *stable* result. Using get_task_comm() to read the task comm ensures that the name is always NUL-terminated, regardless of the source string. This approach also facilitates future extensions to the task comm. Link: https://lkml.kernel.org/r/20241007144911.27693-4-laoar.shao@gmail.com Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com/ [0] Acked-by: Paul Moore <paul@paul-moore.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Alejandro Colomar <alx@kernel.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@gmail.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Eric Paris <eparis@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Justin Stitt <justinstitt@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matus Jokay <matus.jokay@stuba.sk> Cc: Maxime Ripard <mripard@kernel.org> Cc: Quentin Monnet <qmo@kernel.org> Cc: Simon Horman <horms@kernel.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-11lsm: remove lsm_prop scaffoldingCasey Schaufler
Remove the scaffold member from the lsm_prop. Remove the remaining places it is being set. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subj line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: create new security_cred_getlsmprop LSM hookCasey Schaufler
Create a new LSM hook security_cred_getlsmprop() which, like security_cred_getsecid(), fetches LSM specific attributes from the cred structure. The associated data elements in the audit sub-system are changed from a secid to a lsm_prop to accommodate multiple possible LSM audit users. Cc: linux-integrity@vger.kernel.org Cc: audit@vger.kernel.org Cc: selinux@vger.kernel.org Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subj line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: use lsm_prop in security_inode_getsecidCasey Schaufler
Change the security_inode_getsecid() interface to fill in a lsm_prop structure instead of a u32 secid. This allows for its callers to gather data from all registered LSMs. Data is provided for IMA and audit. Change the name to security_inode_getlsmprop(). Cc: linux-integrity@vger.kernel.org Cc: selinux@vger.kernel.org Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subj line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: use lsm_prop in security_current_getsecidCasey Schaufler
Change the security_current_getsecid_subj() and security_task_getsecid_obj() interfaces to fill in a lsm_prop structure instead of a u32 secid. Audit interfaces will need to collect all possible security data for possible reporting. Cc: linux-integrity@vger.kernel.org Cc: audit@vger.kernel.org Cc: selinux@vger.kernel.org Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: use lsm_prop in security_ipc_getsecidCasey Schaufler
There may be more than one LSM that provides IPC data for auditing. Change security_ipc_getsecid() to fill in a lsm_prop structure instead of the u32 secid. Change the name to security_ipc_getlsmprop() to reflect the change. Cc: audit@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: selinux@vger.kernel.org Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: add lsmprop_to_secctx hookCasey Schaufler
Add a new hook security_lsmprop_to_secctx() and its LSM specific implementations. The LSM specific code will use the lsm_prop element allocated for that module. This allows for the possibility that more than one module may be called upon to translate a secid to a string, as can occur in the audit code. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-11lsm: use lsm_prop in security_audit_rule_matchCasey Schaufler
Change the secid parameter of security_audit_rule_match to a lsm_prop structure pointer. Pass the entry from the lsm_prop structure for the approprite slot to the LSM hook. Change the users of security_audit_rule_match to use the lsm_prop instead of a u32. The scaffolding function lsmprop_init() fills the structure with the value of the old secid, ensuring that it is available to the appropriate module hook. The sources of the secid, security_task_getsecid() and security_inode_getsecid(), will be converted to use the lsm_prop structure later in the series. At that point the use of lsmprop_init() is dropped. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-07selinux: Deprecate /sys/fs/selinux/userStephen Smalley
The only known user of this interface was libselinux and its internal usage of this interface for get_ordered_context_list(3) was removed in Feb 2020, with a deprecation warning added to security_compute_user(3) at the same time. Add a deprecation warning to the kernel and schedule it for final removal in 2025. Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-07selinux: apply clang format to security/selinux/nlmsgtab.cPaul Moore
Update nlmsgtab.c to better adhere to the kernel coding style guidelines. Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-07selinux: streamline selinux_nlmsg_lookup()Paul Moore
Streamline the code in selinux_nlmsg_lookup() to improve the code flow, readability, and remove the unnecessary local variables. Tested-by: Thiébaud Weksteen <tweek@google.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-07selinux: Add netlink xperm supportThiébaud Weksteen
Reuse the existing extended permissions infrastructure to support policies based on the netlink message types. A new policy capability "netlink_xperm" is introduced. When disabled, the previous behaviour is preserved. That is, netlink_send will rely on the permission mappings defined in nlmsgtab.c (e.g, nlmsg_read for RTM_GETADDR on NETLINK_ROUTE). When enabled, the mappings are ignored and the generic "nlmsg" permission is used instead. The new "nlmsg" permission is an extended permission. The 16 bits of the extended permission are mapped to the nlmsg_type field. Example policy on Android, preventing regular apps from accessing the device's MAC address and ARP table, but allowing this access to privileged apps, looks as follows: allow netdomain self:netlink_route_socket { create read getattr write setattr lock append connect getopt setopt shutdown nlmsg }; allowxperm netdomain self:netlink_route_socket nlmsg ~{ RTM_GETLINK RTM_GETNEIGH RTM_GETNEIGHTBL }; allowxperm priv_app self:netlink_route_socket nlmsg { RTM_GETLINK RTM_GETNEIGH RTM_GETNEIGHTBL }; The constants in the example above (e.g., RTM_GETLINK) are explicitly defined in the policy. It is possible to generate policies to support kernels that may or may not have the capability enabled by generating a rule for each scenario. For instance: allow domain self:netlink_audit_socket nlmsg_read; allow domain self:netlink_audit_socket nlmsg; allowxperm domain self:netlink_audit_socket nlmsg { AUDIT_GET }; The approach of defining a new permission ("nlmsg") instead of relying on the existing permissions (e.g., "nlmsg_read", "nlmsg_readpriv" or "nlmsg_tty_audit") has been preferred because: 1. This is similar to the other extended permission ("ioctl"); 2. With the new extended permission, the coarse-grained mapping is not necessary anymore. It could eventually be removed, which would be impossible if the extended permission was defined below these. 3. Having a single extra extended permission considerably simplifies the implementation here and in libselinux. Signed-off-by: Thiébaud Weksteen <tweek@google.com> Signed-off-by: Bram Bonné <brambonne@google.com> [PM: manual merge fixes for sock_skip_has_perm()] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-03selinux: move genheaders to security/selinux/Masahiro Yamada
This tool is only used in security/selinux/Makefile. Move it to security/selinux/ so that 'make clean' can clean it up. Please note 'make clean' does not clean scripts/ because tools under scripts/ are often used for external module builds. Obviously, genheaders is not the case here. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-03selinux: do not include <linux/*.h> headers from host programsMasahiro Yamada
The header, security/selinux/include/classmap.h, is included not only from kernel space but also from host programs. It includes <linux/capability.h> and <linux/socket.h>, which pull in more <linux/*.h> headers. This makes the host programs less portable, specifically causing build errors on macOS. Those headers are included for the following purposes: - <linux/capability.h> for checking CAP_LAST_CAP - <linux/socket.h> for checking PF_MAX These checks can be guarded by __KERNEL__ so they are skipped when building host programs. Testing them when building the kernel should be sufficient. The header, security/selinux/include/initial_sid_to_string.h, includes <linux/stddef.h> for the NULL definition, but this is not portable either. Instead, <stddef.h> should be included for host programs. Reported-by: Daniel Gomez <da.gomez@samsung.com> Closes: https://lore.kernel.org/lkml/20240807-macos-build-support-v1-6-4cd1ded85694@samsung.com/ Closes: https://lore.kernel.org/lkml/20240807-macos-build-support-v1-7-4cd1ded85694@samsung.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com>
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, ...)
2024-09-24Merge tag 'lsm-pr-20240923' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull LSM fixes from Paul Moore: - Add a missing security_mmap_file() check to the remap_file_pages() syscall - Properly reference the SELinux and Smack LSM blobs in the security_watch_key() LSM hook - Fix a random IPE selftest crash caused by a missing list terminator in the test * tag 'lsm-pr-20240923' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: ipe: Add missing terminator to list of unit tests selinux,smack: properly reference the LSM blob in security_watch_key() mm: call the security_mmap_file() LSM hook in remap_file_pages()
2024-09-19selinux,smack: properly reference the LSM blob in security_watch_key()Paul Moore
Unfortunately when we migrated the lifecycle management of the key LSM blob to the LSM framework we forgot to convert the security_watch_key() callbacks for SELinux and Smack. This patch corrects this by making use of the selinux_key() and smack_key() helper functions respectively. This patch also removes some input checking in the Smack callback as it is no longer needed. Fixes: 5f8d28f6d7d5 ("lsm: infrastructure management of the key security blob") Reported-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com Tested-by: syzbot+044fdf24e96093584232@syzkaller.appspotmail.com Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-09-16Merge tag 'lsm-pr-20240911' of ↵Linus Torvalds
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 ...
2024-09-16Merge tag 'selinux-pr-20240911' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux Pull selinux updates from Paul Moore: - Ensure that both IPv4 and IPv6 connections are properly initialized While we always properly initialized IPv4 connections early in their life, we missed the necessary IPv6 change when we were adding IPv6 support. - Annotate the SELinux inode revalidation function to quiet KCSAN KCSAN correctly identifies a race in __inode_security_revalidate() when we check to see if an inode's SELinux has been properly initialized. While KCSAN is correct, it is an intentional choice made for performance reasons; if necessary, we check the state a second time, this time with a lock held, before initializing the inode's state. - Code cleanups, simplification, etc. A handful of individual patches to simplify some SELinux kernel logic, improve return code granularity via ERR_PTR(), follow the guidance on using KMEM_CACHE(), and correct some minor style problems. * tag 'selinux-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: fix style problems in security/selinux/include/audit.h selinux: simplify avc_xperms_audit_required() selinux: mark both IPv4 and IPv6 accepted connection sockets as labeled selinux: replace kmem_cache_create() with KMEM_CACHE() selinux: annotate false positive data race to avoid KCSAN warnings selinux: refactor code to return ERR_PTR in selinux_netlbl_sock_genattr selinux: Streamline type determination in security_compute_sid
2024-09-16Merge tag 'vfs-6.12.file' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs file updates from Christian Brauner: "This is the work to cleanup and shrink struct file significantly. Right now, (focusing on x86) struct file is 232 bytes. After this series struct file will be 184 bytes aka 3 cacheline and a spare 8 bytes for future extensions at the end of the struct. With struct file being as ubiquitous as it is this should make a difference for file heavy workloads and allow further optimizations in the future. - struct fown_struct was embedded into struct file letting it take up 32 bytes in total when really it shouldn't even be embedded in struct file in the first place. Instead, actual users of struct fown_struct now allocate the struct on demand. This frees up 24 bytes. - Move struct file_ra_state into the union containg the cleanup hooks and move f_iocb_flags out of the union. This closes a 4 byte hole we created earlier and brings struct file to 192 bytes. Which means struct file is 3 cachelines and we managed to shrink it by 40 bytes. - Reorder struct file so that nothing crosses a cacheline. I suspect that in the future we will end up reordering some members to mitigate false sharing issues or just because someone does actually provide really good perf data. - Shrinking struct file to 192 bytes is only part of the work. Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache is created with SLAB_TYPESAFE_BY_RCU the free pointer must be located outside of the object because the cache doesn't know what part of the memory can safely be overwritten as it may be needed to prevent object recycling. That has the consequence that SLAB_TYPESAFE_BY_RCU may end up adding a new cacheline. So this also contains work to add a new kmem_cache_create_rcu() function that allows the caller to specify an offset where the freelist pointer is supposed to be placed. Thus avoiding the implicit addition of a fourth cacheline. - And finally this removes the f_version member in struct file. The f_version member isn't particularly well-defined. It is mainly used as a cookie to detect concurrent seeks when iterating directories. But it is also abused by some subsystems for completely unrelated things. It is mostly a directory and filesystem specific thing that doesn't really need to live in struct file and with its wonky semantics it really lacks a specific function. For pipes, f_version is (ab)used to defer poll notifications until a write has happened. And struct pipe_inode_info is used by multiple struct files in their ->private_data so there's no chance of pushing that down into file->private_data without introducing another pointer indirection. But pipes don't rely on f_pos_lock so this adds a union into struct file encompassing f_pos_lock and a pipe specific f_pipe member that pipes can use. This union of course can be extended to other file types and is similar to what we do in struct inode already" * tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits) fs: remove f_version pipe: use f_pipe fs: add f_pipe ubifs: store cookie in private data ufs: store cookie in private data udf: store cookie in private data proc: store cookie in private data ocfs2: store cookie in private data input: remove f_version abuse ext4: store cookie in private data ext2: store cookie in private data affs: store cookie in private data fs: add generic_llseek_cookie() fs: use must_set_pos() fs: add must_set_pos() fs: add vfs_setpos_cookie() s390: remove unused f_version ceph: remove unused f_version adi: remove unused f_version mm: Removed @freeptr_offset to prevent doc warning ...
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>
2024-09-03selinux: fix style problems in security/selinux/include/audit.hPaul Moore
Remove the needless indent in the function comment header blocks. Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-31Merge tag 'lsm-pr-20240830' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull lsm fix from Paul Moore: "One small patch to correct a NFS permissions problem with SELinux and Smack" * tag 'lsm-pr-20240830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: selinux,smack: don't bypass permissions check in inode_setsecctx hook
2024-08-28selinux,smack: don't bypass permissions check in inode_setsecctx hookScott Mayhew
Marek Gresko reports that the root user on an NFS client is able to change the security labels on files on an NFS filesystem that is exported with root squashing enabled. The end of the kerneldoc comment for __vfs_setxattr_noperm() states: * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the caller will make the appropriate * permission checks. nfsd_setattr() does do permissions checking via fh_verify() and nfsd_permission(), but those don't do all the same permissions checks that are done by security_inode_setxattr() and its related LSM hooks do. Since nfsd_setattr() is the only consumer of security_inode_setsecctx(), simplest solution appears to be to replace the call to __vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This fixes the above issue and has the added benefit of causing nfsd to recall conflicting delegations on a file when a client tries to change its security label. Cc: stable@kernel.org Reported-by: Marek Gresko <marek.gresko@protonmail.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=218809 Signed-off-by: Scott Mayhew <smayhew@redhat.com> Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-28selinux: simplify avc_xperms_audit_required()Zhen Lei
By associative and commutative laws, the result of the two 'audited' is zero. Take the second 'audited' as an example: 1) audited = requested & avd->auditallow; 2) audited &= ~requested; ==> audited = ~requested & (requested & avd->auditallow); ==> audited = (~requested & requested) & avd->auditallow; ==> audited = 0 & avd->auditallow; ==> audited = 0; In fact, it is more readable to directly write zero. The value of the first 'audited' is 0 because AUDIT is not allowed. The second 'audited' is zero because there is no AUDITALLOW permission. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-28selinux: mark both IPv4 and IPv6 accepted connection sockets as labeledGuido Trentalancia
The current partial labeling was introduced in 389fb800ac8b ("netlabel: Label incoming TCP connections correctly in SELinux") due to the fact that IPv6 labeling was not supported yet at the time. Signed-off-by: Guido Trentalancia <guido@trentalancia.com> [PM: properly format the referenced commit ID, adjust subject] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-28file: reclaim 24 bytes from f_ownerChristian Brauner
We do embedd struct fown_struct into struct file letting it take up 32 bytes in total. We could tweak struct fown_struct to be more compact but really it shouldn't even be embedded in struct file in the first place. Instead, actual users of struct fown_struct should allocate the struct on demand. This frees up 24 bytes in struct file. That will have some potentially user-visible changes for the ownership fcntl()s. Some of them can now fail due to allocation failures. Practically, that probably will almost never happen as the allocations are small and they only happen once per file. The fown_struct is used during kill_fasync() which is used by e.g., pipes to generate a SIGIO signal. Sending of such signals is conditional on userspace having set an owner for the file using one of the F_OWNER fcntl()s. Such users will be unaffected if struct fown_struct is allocated during the fcntl() call. There are a few subsystems that call __f_setown() expecting file->f_owner to be allocated: (1) tun devices file->f_op->fasync::tun_chr_fasync() -> __f_setown() There are no callers of tun_chr_fasync(). (2) tty devices file->f_op->fasync::tty_fasync() -> __tty_fasync() -> __f_setown() tty_fasync() has no additional callers but __tty_fasync() has. Note that __tty_fasync() only calls __f_setown() if the @on argument is true. It's called from: file->f_op->release::tty_release() -> tty_release() -> __tty_fasync() -> __f_setown() tty_release() calls __tty_fasync() with @on false => __f_setown() is never called from tty_release(). => All callers of tty_release() are safe as well. file->f_op->release::tty_open() -> tty_release() -> __tty_fasync() -> __f_setown() __tty_hangup() calls __tty_fasync() with @on false => __f_setown() is never called from tty_release(). => All callers of __tty_hangup() are safe as well. From the callchains it's obvious that (1) and (2) end up getting called via file->f_op->fasync(). That can happen either through the F_SETFL fcntl() with the FASYNC flag raised or via the FIOASYNC ioctl(). If FASYNC is requested and the file isn't already FASYNC then file->f_op->fasync() is called with @on true which ends up causing both (1) and (2) to call __f_setown(). (1) and (2) are the only subsystems that call __f_setown() from the file->f_op->fasync() handler. So both (1) and (2) have been updated to allocate a struct fown_struct prior to calling fasync_helper() to register with the fasync infrastructure. That's safe as they both call fasync_helper() which also does allocations if @on is true. The other interesting case are file leases: (3) file leases lease_manager_ops->lm_setup::lease_setup() -> __f_setown() Which in turn is called from: generic_add_lease() -> lease_manager_ops->lm_setup::lease_setup() -> __f_setown() So here again we can simply make generic_add_lease() allocate struct fown_struct prior to the lease_manager_ops->lm_setup::lease_setup() which happens under a spinlock. With that the two remaining subsystems that call __f_setown() are: (4) dnotify (5) sockets Both have their own custom ioctls to set struct fown_struct and both have been converted to allocate a struct fown_struct on demand from their respective ioctls. Interactions with O_PATH are fine as well e.g., when opening a /dev/tty as O_PATH then no file->f_op->open() happens thus no file->f_owner is allocated. That's fine as no file operation will be set for those and the device has never been opened. fcntl()s called on such things will just allocate a ->f_owner on demand. Although I have zero idea why'd you care about f_owner on an O_PATH fd. Link: https://lore.kernel.org/r/20240813-work-f_owner-v2-1-4e9343a79f9f@kernel.org Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-08-27selinux: replace kmem_cache_create() with KMEM_CACHE()Eric Suen
Based on guidance in include/linux/slab.h, replace kmem_cache_create() with KMEM_CACHE() for sources under security/selinux to simplify creation of SLAB caches. Signed-off-by: Eric Suen <ericsu@linux.microsoft.com> [PM: minor grammar nits in the description] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-26selinux: annotate false positive data race to avoid KCSAN warningsStephen Smalley
KCSAN flags the check of isec->initialized by __inode_security_revalidate() as a data race. This is indeed a racy check, but inode_doinit_with_dentry() will recheck with isec->lock held. Annotate the check with the data_race() macro to silence the KCSAN false positive. Reported-by: syzbot+319ed1769c0078257262@syzkaller.appspotmail.com Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-08selinux: revert our use of vma_is_initial_heap()Paul Moore
Unfortunately it appears that vma_is_initial_heap() is currently broken for applications that do not currently have any heap allocated, e.g. brk == start_brk. The breakage is such that it will cause SELinux to check for the process/execheap permission on memory regions that cross brk/start_brk even when there is no heap. The proper fix would be to correct vma_is_initial_heap(), but as there are multiple callers I am hesitant to unilaterally modify the helper out of concern that I would end up breaking some other subsystem. The mm developers have been made aware of the situation and hopefully they will have a fix at some point in the future, but we need a fix soon so we are simply going to revert our use of vma_is_initial_heap() in favor of our old logic/code which works as expected, even in the face of a zero size heap. We can return to using vma_is_initial_heap() at some point in the future when it is fixed. Cc: stable@vger.kernel.org Reported-by: Marc Reisner <reisner.marc@gmail.com> Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com Fixes: 68df1baf158f ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()") Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-07selinux: add the processing of the failure of avc_add_xperms_decision()Zhen Lei
When avc_add_xperms_decision() fails, the information recorded by the new avc node is incomplete. In this case, the new avc node should be released instead of replacing the old avc node. Cc: stable@vger.kernel.org Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls") Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-06selinux: fix potential counting error in avc_add_xperms_decision()Zhen Lei
The count increases only when a node is successfully added to the linked list. Cc: stable@vger.kernel.org Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls") Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.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: 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>
2024-07-29selinux: refactor code to return ERR_PTR in selinux_netlbl_sock_genattrGaosheng Cui
Refactor the code in selinux_netlbl_sock_genattr to return ERR_PTR when an error occurs. Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29selinux: Streamline type determination in security_compute_sidCanfeng Guo
Simplifies the logic for determining the security context type in security_compute_sid, enhancing readability and efficiency. Consolidates default type assignment logic next to type transition checks, removing redundancy and improving code flow. Signed-off-by: Canfeng Guo <guocanfeng@uniontech.com> 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
2024-07-16Merge tag 'selinux-pr-20240715' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux Pull selinux update from Paul Moore: "A single SELinux patch to change the type of a pre-processor constant to better match its use" * tag 'selinux-pr-20240715' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: Use 1UL for EBITMAP_BIT to match maps type
2024-07-09selinux,smack: remove the capability checks in the removexattr hooksPaul Moore
Commit 61df7b828204 ("lsm: fixup the inode xattr capability handling") moved the responsibility of doing the inode xattr capability checking out of the individual LSMs and into the LSM framework itself. Unfortunately, while the original commit added the capability checks to both the setxattr and removexattr code in the LSM framework, it only removed the setxattr capability checks from the individual LSMs, leaving duplicated removexattr capability checks in both the SELinux and Smack code. This patch removes the duplicated code from SELinux and Smack. Fixes: 61df7b828204 ("lsm: fixup the inode xattr capability handling") Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-02selinux: Use 1UL for EBITMAP_BIT to match maps typeCanfeng Guo
This patch modifies the definition of EBITMAP_BIT in security/selinux/ss/ebitmap.h from 1ULL to 1UL to match the type of elements in the ebitmap_node maps array. This change does not affect the functionality or correctness of the code but aims to enhance code quality by adhering to good programming practices and avoiding unnecessary type conversions. Signed-off-by: Canfeng Guo <guocanfeng@uniontech.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
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>
2024-05-15Merge tag 'integrity-v6.10' of ↵Linus Torvalds
ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull integrity updates from Mimi Zohar: "Two IMA changes, one EVM change, a use after free bug fix, and a code cleanup to address "-Wflex-array-member-not-at-end" warnings: - The existing IMA {ascii, binary}_runtime_measurements lists include a hard coded SHA1 hash. To address this limitation, define per TPM enabled hash algorithm {ascii, binary}_runtime_measurements lists - Close an IMA integrity init_module syscall measurement gap by defining a new critical-data record - Enable (partial) EVM support on stacked filesystems (overlayfs). Only EVM portable & immutable file signatures are copied up, since they do not contain filesystem specific metadata" * tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: ima: add crypto agility support for template-hash algorithm evm: Rename is_unsupported_fs to is_unsupported_hmac_fs fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509 ima: re-evaluate file integrity on file metadata change evm: Store and detect metadata inode attributes changes ima: Move file-change detection variables into new structure evm: Use the metadata inode to calculate metadata hash evm: Implement per signature type decision in security_inode_copy_up_xattr security: allow finer granularity in permitting copy-up of security xattrs ima: Rename backing_inode to real_inode integrity: Avoid -Wflex-array-member-not-at-end warnings ima: define an init_module critical data record ima: Fix use-after-free on a dentry's dname.name