linux-dev/security/selinux, branch master

selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context()

2022-10-19T13:55:53Z

The following warning was triggered on a hardware environment: SELinux: Converting 162 SID table entries... BUG: sleeping function called from invalid context at __might_sleep+0x60/0x74 0x0 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1 Call trace: dump_backtrace+0x0/0x1c8 show_stack+0x18/0x28 dump_stack+0xe8/0x15c ___might_sleep+0x168/0x17c __might_sleep+0x60/0x74 __kmalloc_track_caller+0xa0/0x7dc kstrdup+0x54/0xac convert_context+0x48/0x2e4 sidtab_context_to_sid+0x1c4/0x36c security_context_to_sid_core+0x168/0x238 security_context_to_sid_default+0x14/0x24 inode_doinit_use_xattr+0x164/0x1e4 inode_doinit_with_dentry+0x1c0/0x488 selinux_d_instantiate+0x20/0x34 security_d_instantiate+0x70/0xbc d_splice_alias+0x4c/0x3c0 ext4_lookup+0x1d8/0x200 [ext4] __lookup_slow+0x12c/0x1e4 walk_component+0x100/0x200 path_lookupat+0x88/0x118 filename_lookup+0x98/0x130 user_path_at_empty+0x48/0x60 vfs_statx+0x84/0x140 vfs_fstatat+0x20/0x30 __se_sys_newfstatat+0x30/0x74 __arm64_sys_newfstatat+0x1c/0x2c el0_svc_common.constprop.0+0x100/0x184 do_el0_svc+0x1c/0x2c el0_svc+0x20/0x34 el0_sync_handler+0x80/0x17c el0_sync+0x13c/0x140 SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is not valid (left unmapped). It was found that within a critical section of spin_lock_irqsave in sidtab_context_to_sid(), convert_context() (hooked by sidtab_convert_params.func) might cause the process to sleep via allocating memory with GFP_KERNEL, which is problematic. As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL. Therefore, fix this problem by adding a gfp_t argument for convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC properly in individual callers. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1] Reported-by: Tan Ninghao Fixes: ee1a84fdfeed ("selinux: overhaul sidtab to fix bug and improve performance") Signed-off-by: GONG, Ruiqi Reviewed-by: Ondrej Mosnacek [PM: wrap long BUG() output lines, tweak subject line] Signed-off-by: Paul Moore

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

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

2022-10-04T00:45:15Z

Pull SELinux updates from Paul Moore: "Six SELinux patches, all are simple and easily understood, but a list of the highlights is below: - Use 'grep -E' instead of 'egrep' in the SELinux policy install script. Fun fact, this seems to be GregKH's *second* dedicated SELinux patch since we transitioned to git (ignoring merges, the SPDX stuff, and a trivial fs reference removal when lustre was yanked); the first was back in 2011 when selinuxfs was placed in /sys/fs/selinux. Oh, the memories ... - Convert the SELinux policy boolean values to use signed integer types throughout the SELinux kernel code. Prior to this we were using a mix of signed and unsigned integers which was probably okay in this particular case, but it is definitely not a good idea in general. - Remove a reference to the SELinux runtime disable functionality in /etc/selinux/config as we are in the process of deprecating that. See [1] for more background on this if you missed the previous notes on the deprecation. - Minor cleanups: remove unneeded variables and function parameter constification" Link: https://github.com/SELinuxProject/selinux-kernel/wiki/DEPRECATE-runtime-disable [1] * tag 'selinux-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: remove runtime disable message in the install_policy.sh script selinux: use "grep -E" instead of "egrep" selinux: remove the unneeded result variable selinux: declare read-only parameters const selinux: use int arrays for boolean values selinux: remove an unneeded variable in sel_make_class_dir_entries()

selinux: remove the unneeded result variable

2022-09-14T11:47:27Z

Return the value avc_has_perm() directly instead of storing it in another redundant variable. Reported-by: Zeal Robot Signed-off-by: Xu Panda [PM: subject line tweak] Signed-off-by: Paul Moore

->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

selinux: declare read-only parameters const

2022-08-30T21:14:36Z

Declare ebitmap, mls_level and mls_context parameters const where they are only read from. This allows callers to supply pointers to const as arguments and increases readability. Signed-off-by: Christian Göttsche Signed-off-by: Paul Moore

selinux: use int arrays for boolean values

2022-08-30T21:03:33Z

Do not cast pointers of signed integers to pointers of unsigned integers and vice versa. It should currently not be an issue since they hold SELinux boolean values which should only contain either 0's or 1's, which should have the same representation. Reported by sparse: .../selinuxfs.c:1485:30: warning: incorrect type in assignment (different signedness) .../selinuxfs.c:1485:30: expected unsigned int * .../selinuxfs.c:1485:30: got int *[addressable] values .../selinuxfs.c:1402:48: warning: incorrect type in argument 3 (different signedness) .../selinuxfs.c:1402:48: expected int *values .../selinuxfs.c:1402:48: got unsigned int *bool_pending_values Signed-off-by: Christian Göttsche [PM: minor whitespace fixes, sparse output cleanup] Signed-off-by: Paul Moore

selinux: remove an unneeded variable in sel_make_class_dir_entries()

2022-08-30T20:26:01Z

Return the value sel_make_perm_files() directly instead of storing it in another redundant variable. Reported-by: Zeal Robot Signed-off-by: ye xingchen [PM: subject line tweak] Signed-off-by: Paul Moore

selinux: implement the security_uring_cmd() LSM hook

2022-08-26T15:19:43Z

Add a SELinux access control for the iouring IORING_OP_URING_CMD command. This includes the addition of a new permission in the existing "io_uring" object class: "cmd". The subject of the new permission check is the domain of the process requesting access, the object is the open file which points to the device/file that is the target of the IORING_OP_URING_CMD operation. A sample policy rule is shown below: allow :io_uring { cmd }; Cc: stable@vger.kernel.org Fixes: ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by: Paul Moore