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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>
2024-04-09security: 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>
2024-02-15ima: Align ima_inode_setxattr() definition with LSM infrastructureRoberto Sassu
Change ima_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_file_mprotect() definition with LSM infrastructureRoberto Sassu
Change ima_file_mprotect() definition, so that it can be registered as implementation of the file_mprotect 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>
2024-02-14lsm: fix integer overflow in lsm_set_self_attr() syscallJann Horn
security_setselfattr() has an integer overflow bug that leads to out-of-bounds access when userspace provides bogus input: `lctx->ctx_len + sizeof(*lctx)` is checked against `lctx->len` (and, redundantly, also against `size`), but there are no checks on `lctx->ctx_len`. Therefore, userspace can provide an `lsm_ctx` with `->ctx_len` set to a value between `-sizeof(struct lsm_ctx)` and -1, and this bogus `->ctx_len` will then be passed to an LSM module as a buffer length, causing LSM modules to perform out-of-bounds accesses. The following reproducer will demonstrate this under ASAN (if AppArmor is loaded as an LSM): ``` struct lsm_ctx { uint64_t id; uint64_t flags; uint64_t len; uint64_t ctx_len; char ctx[]; }; int main(void) { size_t size = sizeof(struct lsm_ctx); struct lsm_ctx *ctx = malloc(size); ctx->id = 104/*LSM_ID_APPARMOR*/; ctx->flags = 0; ctx->len = size; ctx->ctx_len = -sizeof(struct lsm_ctx); syscall( 460/*__NR_lsm_set_self_attr*/, /*attr=*/ 100/*LSM_ATTR_CURRENT*/, /*ctx=*/ ctx, /*size=*/ size, /*flags=*/ 0 ); } ``` Fixes: a04a1198088a ("LSM: syscalls for current process attributes") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subj tweak, removed ref to ASAN splat that isn't included] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-01-30lsm: fix default return value of the socket_getpeersec_*() hooksOndrej Mosnacek
For these hooks the true "neutral" value is -EOPNOTSUPP, which is currently what is returned when no LSM provides this hook and what LSMs return when there is no security context set on the socket. Correct the value in <linux/lsm_hooks.h> and adjust the dispatch functions in security/security.c to avoid issues when the BPF LSM is enabled. Cc: stable@vger.kernel.org Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-01-26lsm: fix the logic in security_inode_getsecctx()Ondrej Mosnacek
The inode_getsecctx LSM hook has previously been corrected to have -EOPNOTSUPP instead of 0 as the default return value to fix BPF LSM behavior. However, the call_int_hook()-generated loop in security_inode_getsecctx() was left treating 0 as the neutral value, so after an LSM returns 0, the loop continues to try other LSMs, and if one of them returns a non-zero value, the function immediately returns with said value. So in a situation where SELinux and the BPF LSMs registered this hook, -EOPNOTSUPP would be incorrectly returned whenever SELinux returned 0. Fix this by open-coding the call_int_hook() loop and making it use the correct LSM_RET_DEFAULT() value as the neutral one, similar to what other hooks do. Cc: stable@vger.kernel.org Reported-by: Stephen Smalley <stephen.smalley.work@gmail.com> Link: https://lore.kernel.org/selinux/CAEjxPJ4ev-pasUwGx48fDhnmjBnq_Wh90jYPwRQRAqXxmOKD4Q@mail.gmail.com/ Link: https://bugzilla.redhat.com/show_bug.cgi?id=2257983 Fixes: b36995b8609a ("lsm: fix default return value for inode_getsecctx") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-01-24bpf,lsm: Add BPF token LSM hooksAndrii Nakryiko
Wire up bpf_token_create and bpf_token_free LSM hooks, which allow to allocate LSM security blob (we add `void *security` field to struct bpf_token for that), but also control who can instantiate BPF token. This follows existing pattern for BPF map and BPF prog. Also add security_bpf_token_allow_cmd() and security_bpf_token_capable() LSM hooks that allow LSM implementation to control and negate (if necessary) BPF token's delegation of a specific bpf_cmd and capability, respectively. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-12-andrii@kernel.org
2024-01-24bpf,lsm: Refactor bpf_map_alloc/bpf_map_free LSM hooksAndrii Nakryiko
Similarly to bpf_prog_alloc LSM hook, rename and extend bpf_map_alloc hook into bpf_map_create, taking not just struct bpf_map, but also bpf_attr and bpf_token, to give a fuller context to LSMs. Unlike bpf_prog_alloc, there is no need to move the hook around, as it currently is firing right before allocating BPF map ID and FD, which seems to be a sweet spot. But like bpf_prog_alloc/bpf_prog_free combo, make sure that bpf_map_free LSM hook is called even if bpf_map_create hook returned error, as if few LSMs are combined together it could be that one LSM successfully allocated security blob for its needs, while subsequent LSM rejected BPF map creation. The former LSM would still need to free up LSM blob, so we need to ensure security_bpf_map_free() is called regardless of the outcome. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-11-andrii@kernel.org
2024-01-24bpf,lsm: Refactor bpf_prog_alloc/bpf_prog_free LSM hooksAndrii Nakryiko
Based on upstream discussion ([0]), rework existing bpf_prog_alloc_security LSM hook. Rename it to bpf_prog_load and instead of passing bpf_prog_aux, pass proper bpf_prog pointer for a full BPF program struct. Also, we pass bpf_attr union with all the user-provided arguments for BPF_PROG_LOAD command. This will give LSMs as much information as we can basically provide. The hook is also BPF token-aware now, and optional bpf_token struct is passed as a third argument. bpf_prog_load LSM hook is called after a bunch of sanity checks were performed, bpf_prog and bpf_prog_aux were allocated and filled out, but right before performing full-fledged BPF verification step. bpf_prog_free LSM hook is now accepting struct bpf_prog argument, for consistency. SELinux code is adjusted to all new names, types, and signatures. Note, given that bpf_prog_load (previously bpf_prog_alloc) hook can be used by some LSMs to allocate extra security blob, but also by other LSMs to reject BPF program loading, we need to make sure that bpf_prog_free LSM hook is called after bpf_prog_load/bpf_prog_alloc one *even* if the hook itself returned error. If we don't do that, we run the risk of leaking memory. This seems to be possible today when combining SELinux and BPF LSM, as one example, depending on their relative ordering. Also, for BPF LSM setup, add bpf_prog_load and bpf_prog_free to sleepable LSM hooks list, as they are both executed in sleepable context. Also drop bpf_prog_load hook from untrusted, as there is no issue with refcount or anything else anymore, that originally forced us to add it to untrusted list in c0c852dd1876 ("bpf: Do not mark certain LSM hook arguments as trusted"). We now trigger this hook much later and it should not be an issue anymore. [0] https://lore.kernel.org/bpf/9fe88aef7deabbe87d3fc38c4aea3c69.paul@paul-moore.com/ Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-10-andrii@kernel.org
2024-01-09Merge tag 'integrity-v6.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull integrity updates from Mimi Zohar: - Add a new IMA/EVM maintainer and reviewer - Disable EVM on overlayfs The EVM HMAC and the original file signatures contain filesystem specific metadata (e.g. i_ino, i_generation and s_uuid), preventing the security.evm xattr from directly being copied up to the overlay. Further before calculating and writing out the overlay file's EVM HMAC, EVM must first verify the existing backing file's 'security.evm' value. For now until a solution is developed, disable EVM on overlayfs. - One bug fix and two cleanups * tag 'integrity-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: overlay: disable EVM evm: add support to disable EVM on unsupported filesystems evm: don't copy up 'security.evm' xattr MAINTAINERS: Add Eric Snowberg as a reviewer to IMA MAINTAINERS: Add Roberto Sassu as co-maintainer to IMA and EVM KEYS: encrypted: Add check for strsep ima: Remove EXPERIMENTAL from Kconfig ima: Reword IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY
2024-01-09Merge tag 'lsm-pr-20240105' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm Pull security module updates from Paul Moore: - Add three new syscalls: lsm_list_modules(), lsm_get_self_attr(), and lsm_set_self_attr(). The first syscall simply lists the LSMs enabled, while the second and third get and set the current process' LSM attributes. Yes, these syscalls may provide similar functionality to what can be found under /proc or /sys, but they were designed to support multiple, simultaneaous (stacked) LSMs from the start as opposed to the current /proc based solutions which were created at a time when only one LSM was allowed to be active at a given time. We have spent considerable time discussing ways to extend the existing /proc interfaces to support multiple, simultaneaous LSMs and even our best ideas have been far too ugly to support as a kernel API; after +20 years in the kernel, I felt the LSM layer had established itself enough to justify a handful of syscalls. Support amongst the individual LSM developers has been nearly unanimous, with a single objection coming from Tetsuo (TOMOYO) as he is worried that the LSM_ID_XXX token concept will make it more difficult for out-of-tree LSMs to survive. Several members of the LSM community have demonstrated the ability for out-of-tree LSMs to continue to exist by picking high/unused LSM_ID values as well as pointing out that many kernel APIs rely on integer identifiers, e.g. syscalls (!), but unfortunately Tetsuo's objections remain. My personal opinion is that while I have no interest in penalizing out-of-tree LSMs, I'm not going to penalize in-tree development to support out-of-tree development, and I view this as a necessary step forward to support the push for expanded LSM stacking and reduce our reliance on /proc and /sys which has occassionally been problematic for some container users. Finally, we have included the linux-api folks on (all?) recent revisions of the patchset and addressed all of their concerns. - Add a new security_file_ioctl_compat() LSM hook to handle the 32-bit ioctls on 64-bit systems problem. This patch includes support for all of the existing LSMs which provide ioctl hooks, although it turns out only SELinux actually cares about the individual ioctls. It is worth noting that while Casey (Smack) and Tetsuo (TOMOYO) did not give explicit ACKs to this patch, they did both indicate they are okay with the changes. - Fix a potential memory leak in the CALIPSO code when IPv6 is disabled at boot. While it's good that we are fixing this, I doubt this is something users are seeing in the wild as you need to both disable IPv6 and then attempt to configure IPv6 labeled networking via NetLabel/CALIPSO; that just doesn't make much sense. Normally this would go through netdev, but Jakub asked me to take this patch and of all the trees I maintain, the LSM tree seemed like the best fit. - Update the LSM MAINTAINERS entry with additional information about our process docs, patchwork, bug reporting, etc. I also noticed that the Lockdown LSM is missing a dedicated MAINTAINERS entry so I've added that to the pull request. I've been working with one of the major Lockdown authors/contributors to see if they are willing to step up and assume a Lockdown maintainer role; hopefully that will happen soon, but in the meantime I'll continue to look after it. - Add a handful of mailmap entries for Serge Hallyn and myself. * tag 'lsm-pr-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (27 commits) lsm: new security_file_ioctl_compat() hook lsm: Add a __counted_by() annotation to lsm_ctx.ctx calipso: fix memory leak in netlbl_calipso_add_pass() selftests: remove the LSM_ID_IMA check in lsm/lsm_list_modules_test MAINTAINERS: add an entry for the lockdown LSM MAINTAINERS: update the LSM entry mailmap: add entries for Serge Hallyn's dead accounts mailmap: update/replace my old email addresses lsm: mark the lsm_id variables are marked as static lsm: convert security_setselfattr() to use memdup_user() lsm: align based on pointer length in lsm_fill_user_ctx() lsm: consolidate buffer size handling into lsm_fill_user_ctx() lsm: correct error codes in security_getselfattr() lsm: cleanup the size counters in security_getselfattr() lsm: don't yet account for IMA in LSM_CONFIG_COUNT calculation lsm: drop LSM_ID_IMA LSM: selftests for Linux Security Module syscalls SELinux: Add selfattr hooks AppArmor: Add selfattr hooks Smack: implement setselfattr and getselfattr hooks ...
2023-12-24lsm: new security_file_ioctl_compat() hookAlfred Piccioni
Some ioctl commands do not require ioctl permission, but are routed to other permissions such as FILE_GETATTR or FILE_SETATTR. This routing is done by comparing the ioctl cmd to a set of 64-bit flags (FS_IOC_*). However, if a 32-bit process is running on a 64-bit kernel, it emits 32-bit flags (FS_IOC32_*) for certain ioctl operations. These flags are being checked erroneously, which leads to these ioctl operations being routed to the ioctl permission, rather than the correct file permissions. This was also noted in a RED-PEN finding from a while back - "/* RED-PEN how should LSM module know it's handling 32bit? */". This patch introduces a new hook, security_file_ioctl_compat(), that is called from the compat ioctl syscall. All current LSMs have been changed to support this hook. Reviewing the three places where we are currently using security_file_ioctl(), it appears that only SELinux needs a dedicated compat change; TOMOYO and SMACK appear to be functional without any change. Cc: stable@vger.kernel.org Fixes: 0b24dcb7f2f7 ("Revert "selinux: simplify ioctl checking"") Signed-off-by: Alfred Piccioni <alpic@google.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> [PM: subject tweak, line length fixes, and alignment corrections] Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-12-20evm: don't copy up 'security.evm' xattrMimi Zohar
The security.evm HMAC and the original file signatures contain filesystem specific data. As a result, the HMAC and signature are not the same on the stacked and backing filesystems. Don't copy up 'security.evm'. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2023-12-12fsnotify: optionally pass access range in file permission hooksAmir Goldstein
In preparation for pre-content permission events with file access range, move fsnotify_file_perm() hook out of security_file_permission() and into the callers. Callers that have the access range information call the new hook fsnotify_file_area_perm() with the access range. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-6-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-12-12fsnotify: split fsnotify_perm() into two hooksAmir Goldstein
We would like to make changes to the fsnotify access permission hook - add file range arguments and add the pre modify event. In preparation for these changes, split the fsnotify_perm() hook into fsnotify_open_perm() and fsnotify_file_perm(). This is needed for fanotify "pre content" events. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231212094440.250945-4-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-11-12lsm: convert security_setselfattr() to use memdup_user()Paul Moore
As suggested by the kernel test robot, memdup_user() is a better option than the combo of kmalloc()/copy_from_user(). Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202310270805.2ArE52i5-lkp@intel.com/ Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12lsm: align based on pointer length in lsm_fill_user_ctx()Paul Moore
Using the size of a void pointer is much cleaner than BITS_PER_LONG / 8. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12lsm: consolidate buffer size handling into lsm_fill_user_ctx()Paul Moore
While we have a lsm_fill_user_ctx() helper function designed to make life easier for LSMs which return lsm_ctx structs to userspace, we didn't include all of the buffer length safety checks and buffer padding adjustments in the helper. This led to code duplication across the different LSMs and the possibility for mistakes across the different LSM subsystems. In order to reduce code duplication and decrease the chances of silly mistakes, we're consolidating all of this code into the lsm_fill_user_ctx() helper. The buffer padding is also modified from a fixed 8-byte alignment to an alignment that matches the word length of the machine (BITS_PER_LONG / 8). Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12lsm: correct error codes in security_getselfattr()Paul Moore
We should return -EINVAL if the user specifies LSM_FLAG_SINGLE without supplying a valid lsm_ctx struct buffer. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12lsm: cleanup the size counters in security_getselfattr()Paul Moore
Zero out all of the size counters in the -E2BIG case (buffer too small) to help make the current code a bit more robust in the face of future code changes. Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12lsm: don't yet account for IMA in LSM_CONFIG_COUNT calculationRoberto Sassu
Since IMA is not yet an LSM, don't account for it in the LSM_CONFIG_COUNT calculation, used to limit how many LSMs can invoke security_add_hooks(). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> [PM: subject line tweak] Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12LSM: Helpers for attribute names and filling lsm_ctxCasey Schaufler
Add lsm_name_to_attr(), which translates a text string to a LSM_ATTR value if one is available. Add lsm_fill_user_ctx(), which fills a struct lsm_ctx, including the trailing attribute value. Both are used in module specific components of LSM system calls. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: John Johansen <john.johansen@canonical.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Paul Moore <paul@paul-moore.com>