kernel/linux.git/security/commoncap.c, branch v6.6.131

lsm: constify the 'target' parameter in security_capget()

2023-08-08T20:48:47+00:00

Three LSMs register the implementations for the "capget" hook: AppArmor, SELinux, and the normal capability code. Looking at the function implementations we may observe that the first parameter "target" is not changing. Mark the first argument "target" of LSM hook security_capget() as "const" since it will not be changing in the LSM hook. cap_capget() LSM hook declaration exceeds the 80 characters per line limit. Split the function declaration to multiple lines to decrease the line length. Signed-off-by: Khadija Kamran Acked-by: John Johansen [PM: align the cap_capget() declaration, spelling fixes] Signed-off-by: Paul Moore

lsm: fix a number of misspellings

2023-05-25T21:52:15+00:00

A random collection of spelling fixes for source files in the LSM layer. Reviewed-by: Casey Schaufler Signed-off-by: Paul Moore

selinux: remove the runtime disable functionality

2023-03-20T16:34:23+00:00

After working with the larger SELinux-based distros for several years, we're finally at a place where we can disable the SELinux runtime disable functionality. The existing kernel deprecation notice explains the functionality and why we want to remove it: The selinuxfs "disable" node allows SELinux to be disabled at runtime prior to a policy being loaded into the kernel. If disabled via this mechanism, SELinux will remain disabled until the system is rebooted. The preferred method of disabling SELinux is via the "selinux=0" boot parameter, but the selinuxfs "disable" node was created to make it easier for systems with primitive bootloaders that did not allow for easy modification of the kernel command line. Unfortunately, allowing for SELinux to be disabled at runtime makes it difficult to secure the kernel's LSM hooks using the "__ro_after_init" feature. It is that last sentence, mentioning the '__ro_after_init' hardening, which is the real motivation for this change, and if you look at the diffstat you'll see that the impact of this patch reaches across all the different LSMs, helping prevent tampering at the LSM hook level. From a SELinux perspective, it is important to note that if you continue to disable SELinux via "/etc/selinux/config" it may appear that SELinux is disabled, but it is simply in an uninitialized state. If you load a policy with `load_policy -i`, you will see SELinux come alive just as if you had loaded the policy during early-boot. It is also worth noting that the "/sys/fs/selinux/disable" file is always writable now, regardless of the Kconfig settings, but writing to the file has no effect on the system, other than to display an error on the console if a non-zero/true value is written. Finally, in the several years where we have been working on deprecating this functionality, there has only been one instance of someone mentioning any user visible breakage. In this particular case it was an individual's kernel test system, and the workaround documented in the deprecation notice ("selinux=0" on the kernel command line) resolved the issue without problem. Acked-by: Casey Schaufler Signed-off-by: Paul Moore

capability: just use a 'u64' instead of a 'u32[2]' array

2023-03-01T18:01:22+00:00

Back in 2008 we extended the capability bits from 32 to 64, and we did it by extending the single 32-bit capability word from one word to an array of two words. It was then obfuscated by hiding the "2" behind two macro expansions, with the reasoning being that maybe it gets extended further some day. That reasoning may have been valid at the time, but the last thing we want to do is to extend the capability set any more. And the array of values not only causes source code oddities (with loops to deal with it), but also results in worse code generation. It's a lose-lose situation. So just change the 'u32[2]' into a 'u64' and be done with it. We still have to deal with the fact that the user space interface is designed around an array of these 32-bit values, but that was the case before too, since the array layouts were different (ie user space doesn't use an array of 32-bit values for individual capability masks, but an array of 32-bit slices of multiple masks). So that marshalling of data is actually simplified too, even if it does remain somewhat obscure and odd. This was all triggered by my reaction to the new "cap_isidentical()" introduced recently. By just using a saner data structure, it went from unsigned __capi; CAP_FOR_EACH_U32(__capi) { if (a.cap[__capi] != b.cap[__capi]) return false; } return true; to just being return a.val == b.val; instead. Which is rather more obvious both to humans and to compilers. Cc: Mateusz Guzik Cc: Casey Schaufler Cc: Serge Hallyn Cc: Al Viro Cc: Paul Moore Signed-off-by: Linus Torvalds

fs: port vfs{g,u}id helpers to mnt_idmap

2023-01-19T08:24:30+00:00

Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner (Microsoft)

fs: port privilege checking helpers to mnt_idmap

2023-01-19T08:24:29+00:00

fs: port xattr to mnt_idmap

2023-01-19T08:24:28+00:00

fs: port ->permission() to pass mnt_idmap

2023-01-19T08:24:28+00:00

Merge tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

2022-12-13T17:47:48+00:00

Pull lsm updates from Paul Moore: - Improve the error handling in the device cgroup such that memory allocation failures when updating the access policy do not potentially alter the policy. - Some minor fixes to reiserfs to ensure that it properly releases LSM-related xattr values. - Update the security_socket_getpeersec_stream() LSM hook to take sockptr_t values. Previously the net/BPF folks updated the getsockopt code in the network stack to leverage the sockptr_t type to make it easier to pass both kernel and __user pointers, but unfortunately when they did so they didn't convert the LSM hook. While there was/is no immediate risk by not converting the LSM hook, it seems like this is a mistake waiting to happen so this patch proactively does the LSM hook conversion. - Convert vfs_getxattr_alloc() to return an int instead of a ssize_t and cleanup the callers. Internally the function was never going to return anything larger than an int and the callers were doing some very odd things casting the return value; this patch fixes all that and helps bring a bit of sanity to vfs_getxattr_alloc() and its callers. - More verbose, and helpful, LSM debug output when the system is booted with "lsm.debug" on the command line. There are examples in the commit description, but the quick summary is that this patch provides better information about which LSMs are enabled and the ordering in which they are processed. - General comment and kernel-doc fixes and cleanups. * tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: lsm: Fix description of fs_context_parse_param lsm: Add/fix return values in lsm_hooks.h and fix formatting lsm: Clarify documentation of vm_enough_memory hook reiserfs: Add missing calls to reiserfs_security_free() lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths device_cgroup: Roll back to original exceptions after copy failure LSM: Better reporting of actual LSMs at boot lsm: make security_socket_getpeersec_stream() sockptr_t safe audit: Fix some kernel-doc warnings lsm: remove obsoleted comments for security hooks fs: edit a comment made in bad taste

Merge tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

2022-12-13T03:20:05+00:00

Pull vfsuid updates from Christian Brauner: "Last cycle we introduced the vfs{g,u}id_t types and associated helpers to gain type safety when dealing with idmapped mounts. That initial work already converted a lot of places over but there were still some left, This converts all remaining places that still make use of non-type safe idmapping helpers to rely on the new type safe vfs{g,u}id based helpers. Afterwards it removes all the old non-type safe helpers" * tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: fs: remove unused idmapping helpers ovl: port to vfs{g,u}id_t and associated helpers fuse: port to vfs{g,u}id_t and associated helpers ima: use type safe idmapping helpers apparmor: use type safe idmapping helpers caps: use type safe idmapping helpers fs: use type safe idmapping helpers mnt_idmapping: add missing helpers