user/sven/linux.git/security/security.c, branch v6.10.14

lsm: infrastructure management of the sock security

2024-10-04T14:33:46Z

[ Upstream commit 2aff9d20d50ac45dd13a013ef5231f4fb8912356 ] 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 Reviewed-by: Kees Cook Reviewed-by: John Johansen Acked-by: Stephen Smalley Signed-off-by: Casey Schaufler [PM: subject tweak] Signed-off-by: Paul Moore Stable-dep-of: 63dff3e48871 ("lsm: add the inode_free_security_rcu() LSM implementation hook") Signed-off-by: Sasha Levin

lsm: add the inode_free_security_rcu() LSM implementation hook

2024-10-04T14:33:42Z

commit 63dff3e48871b0583be5032ff8fb7260c349a18c upstream. The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable@vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

lsm: fixup the inode xattr capability handling

2024-08-03T07:00:34Z

commit 61df7b82820494368bd46071ca97e43a3dfc3b11 upstream. 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 Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

ima: Avoid blocking in RCU read-side critical section

2024-06-13T18:26:50Z

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 Acked-by: John Johansen Reviewed-by: Mimi Zohar Reviewed-by: Casey Schaufler [PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case] Signed-off-by: Paul Moore

security: allow finer granularity in permitting copy-up of security xattrs

2024-04-09T21:14:57Z

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 Signed-off-by: Stefan Berger Acked-by: Amir Goldstein Acked-by: Paul Moore (LSM,SELinux) Signed-off-by: Mimi Zohar

security: Place security_path_post_mknod() where the original IMA call was

2024-04-03T17:21:32Z

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 Closes: https://lore.kernel.org/linux-kernel/CAH2r5msAVzxCUHHG8VKrMPUKQHmBpE6K9_vjhgDa1uAvwx4ppw@mail.gmail.com/ Suggested-by: Al Viro Fixes: 08abce60d63f ("security: Introduce path_post_mknod hook") Signed-off-by: Roberto Sassu Reviewed-by: Christian Brauner Reviewed-by: Mimi Zohar Acked-by: Paul Moore Signed-off-by: Linus Torvalds

lsm: handle the NULL buffer case in lsm_fill_user_ctx()

2024-03-14T15:31:26Z

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

lsm: use 32-bit compatible data types in LSM syscalls

2024-03-14T15:31:26Z

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 Reported-and-reviewed-by: Dmitry V. Levin [PM: subject and metadata tweaks, syscall.h fixes] Signed-off-by: Paul Moore

Merge tag 'lsm-pr-20240312' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2024-03-13T03:03:34Z

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 ...

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-02-22T23:29:26Z

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