user/sven/linux.git/include/linux/security.h, branch v6.1.83

lsm: new security_file_ioctl_compat() hook

2024-02-01T00:17:00Z

commit f1bb47a31dff6d4b34fb14e99850860ee74bb003 upstream. 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 Reviewed-by: Stephen Smalley [PM: subject tweak, line length fixes, and alignment corrections] Signed-off-by: Paul Moore Signed-off-by: Greg Kroah-Hartman

vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing

2023-09-13T07:42:28Z

[ Upstream commit d80a8f1b58c2bc8d7c6bfb65401ea4f7ec8cddc2 ] When NFS superblocks are created by automounting, their LSM parameters aren't set in the fs_context struct prior to sget_fc() being called, leading to failure to match existing superblocks. This bug leads to messages like the following appearing in dmesg when fscache is enabled: NFS: Cache volume key already in use (nfs,4.2,2,108,106a8c0,1,,,,100000,100000,2ee,3a98,1d4c,3a98,1) Fix this by adding a new LSM hook to load fc->security for submount creation. Signed-off-by: David Howells Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/165962680944.3334508.6610023900349142034.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165962729225.3357250.14350728846471527137.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/165970659095.2812394.6868894171102318796.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/166133579016.3678898.6283195019480567275.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/217595.1662033775@warthog.procyon.org.uk/ # v5 Fixes: 9bc61ab18b1d ("vfs: Introduce fs_context, switch vfs_kern_mount() to it.") Fixes: 779df6a5480f ("NFS: Ensure security label is set for root inode") Tested-by: Jeff Layton Acked-by: Casey Schaufler Acked-by: "Christian Brauner (Microsoft)" Acked-by: Paul Moore Reviewed-by: Jeff Layton Message-Id: <20230808-master-v9-1-e0ecde888221@kernel.org> Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

Merge tag 'powerpc-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2022-10-09T21:05:15Z

Pull powerpc updates from Michael Ellerman: - Remove our now never-true definitions for pgd_huge() and p4d_leaf(). - Add pte_needs_flush() and huge_pmd_needs_flush() for 64-bit. - Add support for syscall wrappers. - Add support for KFENCE on 64-bit. - Update 64-bit HV KVM to use the new guest state entry/exit accounting API. - Support execute-only memory when using the Radix MMU (P9 or later). - Implement CONFIG_PARAVIRT_TIME_ACCOUNTING for pseries guests. - Updates to our linker script to move more data into read-only sections. - Allow the VDSO to be randomised on 32-bit. - Many other small features and fixes. Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev, Christophe Leroy, David Hildenbrand, Disha Goel, Fabiano Rosas, Gaosheng Cui, Gustavo A. R. Silva, Haren Myneni, Hari Bathini, Jilin Yuan, Joel Stanley, Kajol Jain, Kees Cook, Krzysztof Kozlowski, Laurent Dufour, Liang He, Li Huafei, Lukas Bulwahn, Madhavan Srinivasan, Nathan Chancellor, Nathan Lynch, Nicholas Miehlbradt, Nicholas Piggin, Pali Rohár, Rohan McLure, Russell Currey, Sachin Sant, Segher Boessenkool, Shrikanth Hegde, Tyrel Datwyler, Wolfram Sang, ye xingchen, and Zheng Yongjun. * tag 'powerpc-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (214 commits) KVM: PPC: Book3S HV: Fix stack frame regs marker powerpc: Don't add __powerpc_ prefix to syscall entry points powerpc/64s/interrupt: Fix stack frame regs marker powerpc/64: Fix msr_check_and_set/clear MSR[EE] race powerpc/64s/interrupt: Change must-hard-mask interrupt check from BUG to WARN powerpc/pseries: Add firmware details to the hardware description powerpc/powernv: Add opal details to the hardware description powerpc: Add device-tree model to the hardware description powerpc/64: Add logical PVR to the hardware description powerpc: Add PVR & CPU name to hardware description powerpc: Add hardware description string powerpc/configs: Enable PPC_UV in powernv_defconfig powerpc/configs: Update config files for removed/renamed symbols powerpc/mm: Fix UBSAN warning reported on hugetlb powerpc/mm: Always update max/min_low_pfn in mem_topology_setup() powerpc/mm/book3s/hash: Rename flush_tlb_pmd_range powerpc: Drops STABS_DEBUG from linker scripts powerpc/64s: Remove lost/old comment powerpc/64s: Remove old STAB comment powerpc: remove orphan systbl_chk.sh ...

Merge tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-10-07T00:31:02Z

Pull vfs constification updates from Al Viro: "whack-a-mole: constifying struct path *" * tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: ecryptfs: constify path spufs: constify path nd_jump_link(): constify path audit_init_parent(): constify path __io_setxattr(): constify path do_proc_readlink(): constify path overlayfs: constify path fs/notify: constify path may_linkat(): constify path do_sys_name_to_handle(): constify path ->getprocattr(): attribute name is const char *, TYVM...

Merge tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2022-10-04T00:51:52Z

Pull LSM updates from Paul Moore: "Seven patches for the LSM layer and we've got a mix of trivial and significant patches. Highlights below, starting with the smaller bits first so they don't get lost in the discussion of the larger items: - Remove some redundant NULL pointer checks in the common LSM audit code. - Ratelimit the lockdown LSM's access denial messages. With this change there is a chance that the last visible lockdown message on the console is outdated/old, but it does help preserve the initial series of lockdown denials that started the denial message flood and my gut feeling is that these might be the more valuable messages. - Open userfaultfds as readonly instead of read/write. While this code obviously lives outside the LSM, it does have a noticeable impact on the LSMs with Ondrej explaining the situation in the commit description. It is worth noting that this patch languished on the VFS list for over a year without any comments (objections or otherwise) so I took the liberty of pulling it into the LSM tree after giving fair notice. It has been in linux-next since the end of August without any noticeable problems. - Add a LSM hook for user namespace creation, with implementations for both the BPF LSM and SELinux. Even though the changes are fairly small, this is the bulk of the diffstat as we are also including BPF LSM selftests for the new hook. It's also the most contentious of the changes in this pull request with Eric Biederman NACK'ing the LSM hook multiple times during its development and discussion upstream. While I've never taken NACK's lightly, I'm sending these patches to you because it is my belief that they are of good quality, satisfy a long-standing need of users and distros, and are in keeping with the existing nature of the LSM layer and the Linux Kernel as a whole. The patches in implement a LSM hook for user namespace creation that allows for a granular approach, configurable at runtime, which enables both monitoring and control of user namespaces. The general consensus has been that this is far preferable to the other solutions that have been adopted downstream including outright removal from the kernel, disabling via system wide sysctls, or various other out-of-tree mechanisms that users have been forced to adopt since we haven't been able to provide them an upstream solution for their requests. Eric has been steadfast in his objections to this LSM hook, explaining that any restrictions on the user namespace could have significant impact on userspace. While there is the possibility of impacting userspace, it is important to note that this solution only impacts userspace when it is requested based on the runtime configuration supplied by the distro/admin/user. Frederick (the pathset author), the LSM/security community, and myself have tried to work with Eric during development of this patchset to find a mutually acceptable solution, but Eric's approach and unwillingness to engage in a meaningful way have made this impossible. I have CC'd Eric directly on this pull request so he has a chance to provide his side of the story; there have been no objections outside of Eric's" * tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: lockdown: ratelimit denial messages userfaultfd: open userfaultfds with O_RDONLY selinux: Implement userns_create hook selftests/bpf: Add tests verifying bpf lsm userns_create hook bpf-lsm: Make bpf_lsm_userns_create() sleepable security, lsm: Introduce security_create_user_ns() lsm: clean up redundant NULL pointer check

powerpc/rtas: block error injection when locked down

2022-09-28T09:22:14Z

The error injection facility on pseries VMs allows corruption of arbitrary guest memory, potentially enabling a sufficiently privileged user to disable lockdown or perform other modifications of the running kernel via the rtas syscall. Block the PAPR error injection facility from being opened or called when locked down. Signed-off-by: Nathan Lynch Acked-by: Paul Moore (LSM) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926131643.146502-3-nathanl@linux.ibm.com

powerpc/pseries: block untrusted device tree changes when locked down

2022-09-28T09:22:14Z

The /proc/powerpc/ofdt interface allows the root user to freely alter the in-kernel device tree, enabling arbitrary physical address writes via drivers that could bind to malicious device nodes, thus making it possible to disable lockdown. Historically this interface has been used on the pseries platform to facilitate the runtime addition and removal of processor, memory, and device resources (aka Dynamic Logical Partitioning or DLPAR). Years ago, the processor and memory use cases were migrated to designs that happen to be lockdown-friendly: device tree updates are communicated directly to the kernel from firmware without passing through untrusted user space. I/O device DLPAR via the "drmgr" command in powerpc-utils remains the sole legitimate user of /proc/powerpc/ofdt, but it is already broken in lockdown since it uses /dev/mem to allocate argument buffers for the rtas syscall. So only illegitimate uses of the interface should see a behavior change when running on a locked down kernel. Signed-off-by: Nathan Lynch Acked-by: Paul Moore (LSM) Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220926131643.146502-2-nathanl@linux.ibm.com

->getprocattr(): attribute name is const char *, TYVM...

2022-09-01T21:34:39Z

cast of ->d_name.name to char * is completely wrong - nothing is allowed to modify its contents. Reviewed-by: Christian Brauner (Microsoft) Acked-by: Paul Moore Acked-by: Casey Schaufler Signed-off-by: Al Viro

lsm,io_uring: add LSM hooks for the new uring_cmd file op

2022-08-26T15:19:43Z

io-uring cmd support was added through ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd"), this extended the struct file_operations to allow a new command which each subsystem can use to enable command passthrough. Add an LSM specific for the command passthrough which enables LSMs to inspect the command details. This was discussed long ago without no clear pointer for something conclusive, so this enables LSMs to at least reject this new file operation. [0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com Cc: stable@vger.kernel.org Fixes: ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by: Luis Chamberlain Acked-by: Jens Axboe Signed-off-by: Paul Moore

security, lsm: Introduce security_create_user_ns()

2022-08-16T21:32:46Z

User namespaces are an effective tool to allow programs to run with permission without requiring the need for a program to run as root. User namespaces may also be used as a sandboxing technique. However, attackers sometimes leverage user namespaces as an initial attack vector to perform some exploit. [1,2,3] While it is not the unprivileged user namespace functionality, which causes the kernel to be exploitable, users/administrators might want to more granularly limit or at least monitor how various processes use this functionality, while vulnerable kernel subsystems are being patched. Preventing user namespace already creation comes in a few of forms in order of granularity: 1. /proc/sys/user/max_user_namespaces sysctl 2. Distro specific patch(es) 3. CONFIG_USER_NS To block a task based on its attributes, the LSM hook cred_prepare is a decent candidate for use because it provides more granular control, and it is called before create_user_ns(): cred = prepare_creds() security_prepare_creds() call_int_hook(cred_prepare, ... if (cred) create_user_ns(cred) Since security_prepare_creds() is meant for LSMs to copy and prepare credentials, access control is an unintended use of the hook. [4] Further, security_prepare_creds() will always return a ENOMEM if the hook returns any non-zero error code. This hook also does not handle the clone3 case which requires us to access a user space pointer to know if we're in the CLONE_NEW_USER call path which may be subject to a TOCTTOU attack. Lastly, cred_prepare is called in many call paths, and a targeted hook further limits the frequency of calls which is a beneficial outcome. Therefore introduce a new function security_create_user_ns() with an accompanying userns_create LSM hook. With the new userns_create hook, users will have more control over the observability and access control over user namespace creation. Users should expect that normal operation of user namespaces will behave as usual, and only be impacted when controls are implemented by users or administrators. This hook takes the prepared creds for LSM authors to write policy against. On success, the new namespace is applied to credentials, otherwise an error is returned. Links: 1. https://nvd.nist.gov/vuln/detail/CVE-2022-0492 2. https://nvd.nist.gov/vuln/detail/CVE-2022-25636 3. https://nvd.nist.gov/vuln/detail/CVE-2022-34918 4. https://lore.kernel.org/all/1c4b1c0d-12f6-6e9e-a6a3-cdce7418110c@schaufler-ca.com/ Reviewed-by: Christian Brauner (Microsoft) Reviewed-by: KP Singh Signed-off-by: Frederick Lawler Signed-off-by: Paul Moore