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390 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
c269497d24 |
selinux/stable-5.18 PR 20220321
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Merge tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"We've got a number of SELinux patches queued up, the highlights are:
- Fixup the security_fs_context_parse_param() LSM hook so it executes
all of the LSM hook implementations unless a serious error occurs.
We also correct the SELinux hook implementation so that it returns
zero on success.
- In addition to a few SELinux mount option parsing fixes, we
simplified the parsing by moving it earlier in the process.
The logic was that it was unlikely an admin/user would use the new
mount API and not have the policy loaded before passing the SELinux
options.
- Properly fixed the LSM/SELinux/SCTP hooks with the addition of the
security_sctp_assoc_established() hook.
This work was done in conjunction with the netdev folks and should
complete the move of the SCTP labeling from the endpoints to the
associations.
- Fixed a variety of sparse warnings caused by changes in the "__rcu"
markings of some core kernel structures.
- Ensure we access the superblock's LSM security blob using the
stacking-safe accessors.
- Added the ability for the kernel to always allow FIOCLEX and
FIONCLEX if the "ioctl_skip_cloexec" policy capability is
specified.
- Various constifications improvements, type casting improvements,
additional return value checks, and dead code/parameter removal.
- Documentation fixes"
* tag 'selinux-pr-20220321' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: (23 commits)
selinux: shorten the policy capability enum names
docs: fix 'make htmldocs' warning in SCTP.rst
selinux: allow FIOCLEX and FIONCLEX with policy capability
selinux: use correct type for context length
selinux: drop return statement at end of void functions
security: implement sctp_assoc_established hook in selinux
security: add sctp_assoc_established hook
selinux: parse contexts for mount options early
selinux: various sparse fixes
selinux: try to use preparsed sid before calling parse_sid()
selinux: Fix selinux_sb_mnt_opts_compat()
LSM: general protection fault in legacy_parse_param
selinux: fix a type cast problem in cred_init_security()
selinux: drop unused macro
selinux: simplify cred_init_security
selinux: do not discard const qualifier in cast
selinux: drop unused parameter of avtab_insert_node
selinux: drop cast to same type
selinux: enclose macro arguments in parenthesis
selinux: declare name parameter of hash_eval const
...
|
||
Ondrej Mosnacek
|
5e50f5d4ff |
security: add sctp_assoc_established hook
security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.
Fixes:
|
||
|
Linus Torvalds
|
d1e7f0919e |
Fix NULL pointer crash in LSM via Ceph, from Vivek Goyal <vgoyal@redhat.com>.
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||
Vivek Goyal
|
7f5056b9e7 |
security, lsm: dentry_init_security() Handle multi LSM registration
A ceph user has reported that ceph is crashing with kernel NULL pointer dereference. Following is the backtrace. /proc/version: Linux version 5.16.2-arch1-1 (linux@archlinux) (gcc (GCC) 11.1.0, GNU ld (GNU Binutils) 2.36.1) #1 SMP PREEMPT Thu, 20 Jan 2022 16:18:29 +0000 distro / arch: Arch Linux / x86_64 SELinux is not enabled ceph cluster version: 16.2.7 (dd0603118f56ab514f133c8d2e3adfc983942503) relevant dmesg output: [ 30.947129] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 30.947206] #PF: supervisor read access in kernel mode [ 30.947258] #PF: error_code(0x0000) - not-present page [ 30.947310] PGD 0 P4D 0 [ 30.947342] Oops: 0000 [#1] PREEMPT SMP PTI [ 30.947388] CPU: 5 PID: 778 Comm: touch Not tainted 5.16.2-arch1-1 #1 86fbf2c313cc37a553d65deb81d98e9dcc2a3659 [ 30.947486] Hardware name: Gigabyte Technology Co., Ltd. B365M DS3H/B365M DS3H, BIOS F5 08/13/2019 [ 30.947569] RIP: 0010:strlen+0x0/0x20 [ 30.947616] Code: b6 07 38 d0 74 16 48 83 c7 01 84 c0 74 05 48 39 f7 75 ec 31 c0 31 d2 89 d6 89 d7 c3 48 89 f8 31 d2 89 d6 89 d7 c3 0 f 1f 40 00 <80> 3f 00 74 12 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 31 ff [ 30.947782] RSP: 0018:ffffa4ed80ffbbb8 EFLAGS: 00010246 [ 30.947836] RAX: 0000000000000000 RBX: ffffa4ed80ffbc60 RCX: 0000000000000000 [ 30.947904] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 30.947971] RBP: ffff94b0d15c0ae0 R08: 0000000000000000 R09: 0000000000000000 [ 30.948040] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 30.948106] R13: 0000000000000001 R14: ffffa4ed80ffbc60 R15: 0000000000000000 [ 30.948174] FS: 00007fc7520f0740(0000) GS:ffff94b7ced40000(0000) knlGS:0000000000000000 [ 30.948252] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 30.948308] CR2: 0000000000000000 CR3: 0000000104a40001 CR4: 00000000003706e0 [ 30.948376] Call Trace: [ 30.948404] <TASK> [ 30.948431] ceph_security_init_secctx+0x7b/0x240 [ceph 49f9c4b9bf5be8760f19f1747e26da33920bce4b] [ 30.948582] ceph_atomic_open+0x51e/0x8a0 [ceph 49f9c4b9bf5be8760f19f1747e26da33920bce4b] [ 30.948708] ? get_cached_acl+0x4d/0xa0 [ 30.948759] path_openat+0x60d/0x1030 [ 30.948809] do_filp_open+0xa5/0x150 [ 30.948859] do_sys_openat2+0xc4/0x190 [ 30.948904] __x64_sys_openat+0x53/0xa0 [ 30.948948] do_syscall_64+0x5c/0x90 [ 30.948989] ? exc_page_fault+0x72/0x180 [ 30.949034] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 30.949091] RIP: 0033:0x7fc7521e25bb [ 30.950849] Code: 25 00 00 41 00 3d 00 00 41 00 74 4b 64 8b 04 25 18 00 00 00 85 c0 75 67 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 0 0 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 91 00 00 00 48 8b 54 24 28 64 48 2b 14 25 Core of the problem is that ceph checks for return code from security_dentry_init_security() and if return code is 0, it assumes everything is fine and continues to call strlen(name), which crashes. Typically SELinux LSM returns 0 and sets name to "security.selinux" and it is not a problem. Or if selinux is not compiled in or disabled, it returns -EOPNOTSUP and ceph deals with it. But somehow in this configuration, 0 is being returned and "name" is not being initialized and that's creating the problem. Our suspicion is that BPF LSM is registering a hook for dentry_init_security() and returns hook default of 0. LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry,...) I have not been able to reproduce it just by doing CONFIG_BPF_LSM=y. Stephen has tested the patch though and confirms it solves the problem for him. dentry_init_security() is written in such a way that it expects only one LSM to register the hook. Atleast that's the expectation with current code. If another LSM returns a hook and returns default, it will simply return 0 as of now and that will break ceph. Hence, suggestion is that change semantics of this hook a bit. If there are no LSMs or no LSM is taking ownership and initializing security context, then return -EOPNOTSUP. Also allow at max one LSM to initialize security context. This hook can't deal with multiple LSMs trying to init security context. This patch implements this new behavior. Reported-by: Stephen Muth <smuth4@gmail.com> Tested-by: Stephen Muth <smuth4@gmail.com> Suggested-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: <stable@vger.kernel.org> # 5.16.0 Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: James Morris <jmorris@namei.org> |
||
Casey Schaufler
|
ecff30575b |
LSM: general protection fault in legacy_parse_param
The usual LSM hook "bail on fail" scheme doesn't work for cases where a security module may return an error code indicating that it does not recognize an input. In this particular case Smack sees a mount option that it recognizes, and returns 0. A call to a BPF hook follows, which returns -ENOPARAM, which confuses the caller because Smack has processed its data. The SELinux hook incorrectly returns 1 on success. There was a time when this was correct, however the current expectation is that it return 0 on success. This is repaired. Reported-by: syzbot+d1e3b1d92d25abf97943@syzkaller.appspotmail.com Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com> |
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Ondrej Mosnacek
|
52f982f00b |
security,selinux: remove security_add_mnt_opt()
Its last user has been removed in commit
|
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Paul Moore
|
6326948f94 |
lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
The security_task_getsecid_subj() LSM hook invites misuse by allowing callers to specify a task even though the hook is only safe when the current task is referenced. Fix this by removing the task_struct argument to the hook, requiring LSM implementations to use the current task. While we are changing the hook declaration we also rename the function to security_current_getsecid_subj() in an effort to reinforce that the hook captures the subjective credentials of the current task and not an arbitrary task on the system. Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
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Paul Moore
|
32a370abf1 |
net,lsm,selinux: revert the security_sctp_assoc_established() hook
This patch reverts two prior patches, |
||
Xin Long
|
7c2ef0240e |
security: add sctp_assoc_established hook
security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.
v1->v2:
- fix the return value of security_sctp_assoc_established() in
security.h, found by kernel test robot and Ondrej.
Fixes:
|
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Xin Long
|
c081d53f97 |
security: pass asoc to sctp_assoc_request and sctp_sk_clone
This patch is to move secid and peer_secid from endpoint to association,
and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As
ep is the local endpoint and asoc represents a connection, and in SCTP
one sk/ep could have multiple asoc/connection, saving secid/peer_secid
for new asoc will overwrite the old asoc's.
Note that since asoc can be passed as NULL, security_sctp_assoc_request()
is moved to the place right after the new_asoc is created in
sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init().
v1->v2:
- fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed.
- fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed.
Fixes:
|
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Vivek Goyal
|
15bf32398a |
security: Return xattr name from security_dentry_init_security()
Right now security_dentry_init_security() only supports single security label and is used by SELinux only. There are two users of this hook, namely ceph and nfs. NFS does not care about xattr name. Ceph hardcodes the xattr name to security.selinux (XATTR_NAME_SELINUX). I am making changes to fuse/virtiofs to send security label to virtiofsd and I need to send xattr name as well. I also hardcoded the name of xattr to security.selinux. Stephen Smalley suggested that it probably is a good idea to modify security_dentry_init_security() to also return name of xattr so that we can avoid this hardcoding in the callers. This patch adds a new parameter "const char **xattr_name" to security_dentry_init_security() and LSM puts the name of xattr too if caller asked for it (xattr_name != NULL). Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: James Morris <jamorris@linux.microsoft.com> [PM: fixed typos in the commit description] Signed-off-by: Paul Moore <paul@paul-moore.com> |
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Todd Kjos
|
52f8869337 |
binder: use cred instead of task for selinux checks
Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.
Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.
Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes:
|
||
Kees Cook
|
86dd9fd52e |
LSM: Avoid warnings about potentially unused hook variables
Building with W=1 shows many unused const variable warnings. These can
be silenced, as we're well aware of their being potentially unused:
./include/linux/lsm_hook_defs.h:36:18: error: 'ptrace_access_check_default' defined but not used [-Werror=unused-const-variable=]
36 | LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child,
| ^~~~~~~~~~~~~~~~~~~
security/security.c:706:32: note: in definition of macro 'LSM_RET_DEFAULT'
706 | #define LSM_RET_DEFAULT(NAME) (NAME##_default)
| ^~~~
security/security.c:711:9: note: in expansion of macro 'DECLARE_LSM_RET_DEFAULT_int'
711 | DECLARE_LSM_RET_DEFAULT_##RET(DEFAULT, NAME)
| ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/lsm_hook_defs.h:36:1: note: in expansion of macro 'LSM_HOOK'
36 | LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child,
| ^~~~~~~~
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: KP Singh <kpsingh@chromium.org>
Cc: linux-security-module@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/linux-mm/202110131608.zms53FPR-lkp@intel.com/
Fixes:
|
||
|
Paul Moore
|
cdc1404a40 |
lsm,io_uring: add LSM hooks to io_uring
A full expalantion of io_uring is beyond the scope of this commit description, but in summary it is an asynchronous I/O mechanism which allows for I/O requests and the resulting data to be queued in memory mapped "rings" which are shared between the kernel and userspace. Optionally, io_uring offers the ability for applications to spawn kernel threads to dequeue I/O requests from the ring and submit the requests in the kernel, helping to minimize the syscall overhead. Rings are accessed in userspace by memory mapping a file descriptor provided by the io_uring_setup(2), and can be shared between applications as one might do with any open file descriptor. Finally, process credentials can be registered with a given ring and any process with access to that ring can submit I/O requests using any of the registered credentials. While the io_uring functionality is widely recognized as offering a vastly improved, and high performing asynchronous I/O mechanism, its ability to allow processes to submit I/O requests with credentials other than its own presents a challenge to LSMs. When a process creates a new io_uring ring the ring's credentials are inhertied from the calling process; if this ring is shared with another process operating with different credentials there is the potential to bypass the LSMs security policy. Similarly, registering credentials with a given ring allows any process with access to that ring to submit I/O requests with those credentials. In an effort to allow LSMs to apply security policy to io_uring I/O operations, this patch adds two new LSM hooks. These hooks, in conjunction with the LSM anonymous inode support previously submitted, allow an LSM to apply access control policy to the sharing of io_uring rings as well as any io_uring credential changes requested by a process. The new LSM hooks are described below: * int security_uring_override_creds(cred) Controls if the current task, executing an io_uring operation, is allowed to override it's credentials with @cred. In cases where the current task is a user application, the current credentials will be those of the user application. In cases where the current task is a kernel thread servicing io_uring requests the current credentials will be those of the io_uring ring (inherited from the process that created the ring). * int security_uring_sqpoll(void) Controls if the current task is allowed to create an io_uring polling thread (IORING_SETUP_SQPOLL). Without a SQPOLL thread in the kernel processes must submit I/O requests via io_uring_enter(2) which allows us to compare any requested credential changes against the application making the request. With a SQPOLL thread, we can no longer compare requested credential changes against the application making the request, the comparison is made against the ring's credentials. Signed-off-by: Paul Moore <paul@paul-moore.com> |
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Daniel Borkmann
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51e1bb9eea |
bpf: Add lockdown check for probe_write_user helper
Back then, commit |
||
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Daniel Borkmann
|
71330842ff |
bpf: Add _kernel suffix to internal lockdown_bpf_read
Rename LOCKDOWN_BPF_READ into LOCKDOWN_BPF_READ_KERNEL so we have naming more consistent with a LOCKDOWN_BPF_WRITE_USER option that we are adding. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> |
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Linus Torvalds
|
6bd344e55f |
selinux/stable-5.14 PR 20210629
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||
Roberto Sassu
|
7e135dc725 |
evm: Pass user namespace to set/remove xattr hooks
In preparation for 'evm: Allow setxattr() and setattr() for unmodified metadata', this patch passes mnt_userns to the inode set/remove xattr hooks so that the GID of the inode on an idmapped mount is correctly determined by posix_acl_update_mode(). Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> |
||
Zhongjun Tan
|
8a922805fb |
selinux: delete selinux_xfrm_policy_lookup() useless argument
seliunx_xfrm_policy_lookup() is hooks of security_xfrm_policy_lookup(). The dir argument is uselss in security_xfrm_policy_lookup(). So remove the dir argument from selinux_xfrm_policy_lookup() and security_xfrm_policy_lookup(). Signed-off-by: Zhongjun Tan <tanzhongjun@yulong.com> [PM: reformat the subject line] Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
|
Linus Torvalds
|
17ae69aba8 |
Add Landlock, a new LSM from Mickaël Salaün <mic@linux.microsoft.com>
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Merge tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
Pull Landlock LSM from James Morris:
"Add Landlock, a new LSM from Mickaël Salaün.
Briefly, Landlock provides for unprivileged application sandboxing.
From Mickaël's cover letter:
"The goal of Landlock is to enable to restrict ambient rights (e.g.
global filesystem access) for a set of processes. Because Landlock
is a stackable LSM [1], it makes possible to create safe security
sandboxes as new security layers in addition to the existing
system-wide access-controls. This kind of sandbox is expected to
help mitigate the security impact of bugs or unexpected/malicious
behaviors in user-space applications. Landlock empowers any
process, including unprivileged ones, to securely restrict
themselves.
Landlock is inspired by seccomp-bpf but instead of filtering
syscalls and their raw arguments, a Landlock rule can restrict the
use of kernel objects like file hierarchies, according to the
kernel semantic. Landlock also takes inspiration from other OS
sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD
Pledge/Unveil.
In this current form, Landlock misses some access-control features.
This enables to minimize this patch series and ease review. This
series still addresses multiple use cases, especially with the
combined use of seccomp-bpf: applications with built-in sandboxing,
init systems, security sandbox tools and security-oriented APIs [2]"
The cover letter and v34 posting is here:
https://lore.kernel.org/linux-security-module/20210422154123.13086-1-mic@digikod.net/
See also:
https://landlock.io/
This code has had extensive design discussion and review over several
years"
Link: https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com/ [1]
Link: https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.net/ [2]
* tag 'landlock_v34' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
landlock: Enable user space to infer supported features
landlock: Add user and kernel documentation
samples/landlock: Add a sandbox manager example
selftests/landlock: Add user space tests
landlock: Add syscall implementations
arch: Wire up Landlock syscalls
fs,security: Add sb_delete hook
landlock: Support filesystem access-control
LSM: Infrastructure management of the superblock
landlock: Add ptrace restrictions
landlock: Set up the security framework and manage credentials
landlock: Add ruleset and domain management
landlock: Add object management
|
||
Mickaël Salaün
|
83e804f0bf |
fs,security: Add sb_delete hook
The sb_delete security hook is called when shutting down a superblock, which may be useful to release kernel objects tied to the superblock's lifetime (e.g. inodes). This new hook is needed by Landlock to release (ephemerally) tagged struct inodes. This comes from the unprivileged nature of Landlock described in the next commit. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: James Morris <jmorris@namei.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422154123.13086-7-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com> |
||
|
Casey Schaufler
|
1aea780837 |
LSM: Infrastructure management of the superblock
Move management of the superblock->sb_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. Cc: John Johansen <john.johansen@canonical.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422154123.13086-6-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com> |
||
|
Paul Moore
|
4ebd7651bf |
lsm: separate security_task_getsecid() into subjective and objective variants
Of the three LSMs that implement the security_task_getsecid() LSM hook, all three LSMs provide the task's objective security credentials. This turns out to be unfortunate as most of the hook's callers seem to expect the task's subjective credentials, although a small handful of callers do correctly expect the objective credentials. This patch is the first step towards fixing the problem: it splits the existing security_task_getsecid() hook into two variants, one for the subjective creds, one for the objective creds. void security_task_getsecid_subj(struct task_struct *p, u32 *secid); void security_task_getsecid_obj(struct task_struct *p, u32 *secid); While this patch does fix all of the callers to use the correct variant, in order to keep this patch focused on the callers and to ease review, the LSMs continue to use the same implementation for both hooks. The net effect is that this patch should not change the behavior of the kernel in any way, it will be up to the latter LSM specific patches in this series to change the hook implementations and return the correct credentials. Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA) Acked-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
Olga Kornievskaia
|
69c4a42d72 |
lsm,selinux: add new hook to compare new mount to an existing mount
Add a new hook that takes an existing super block and a new mount with new options and determines if new options confict with an existing mount or not. A filesystem can use this new hook to determine if it can share the an existing superblock with a new superblock for the new mount. Signed-off-by: Olga Kornievskaia <kolga@netapp.com> Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com> [PM: tweak the subject line, fix tab/space problems] Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
|
Linus Torvalds
|
7d6beb71da |
idmapped-mounts-v5.12
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
|
||
Christian Brauner
|
71bc356f93
|
commoncap: handle idmapped mounts
When interacting with user namespace and non-user namespace aware filesystem capabilities the vfs will perform various security checks to determine whether or not the filesystem capabilities can be used by the caller, whether they need to be removed and so on. The main infrastructure for this resides in the capability codepaths but they are called through the LSM security infrastructure even though they are not technically an LSM or optional. This extends the existing security hooks security_inode_removexattr(), security_inode_killpriv(), security_inode_getsecurity() to pass down the mount's user namespace and makes them aware of idmapped mounts. In order to actually get filesystem capabilities from disk the capability infrastructure exposes the get_vfs_caps_from_disk() helper. For user namespace aware filesystem capabilities a root uid is stored alongside the capabilities. In order to determine whether the caller can make use of the filesystem capability or whether it needs to be ignored it is translated according to the superblock's user namespace. If it can be translated to uid 0 according to that id mapping the caller can use the filesystem capabilities stored on disk. If we are accessing the inode that holds the filesystem capabilities through an idmapped mount we map the root uid according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts: reading filesystem caps from disk enforces that the root uid associated with the filesystem capability must have a mapping in the superblock's user namespace and that the caller is either in the same user namespace or is a descendant of the superblock's user namespace. For filesystems that are mountable inside user namespace the caller can just mount the filesystem and won't usually need to idmap it. If they do want to idmap it they can create an idmapped mount and mark it with a user namespace they created and which is thus a descendant of s_user_ns. For filesystems that are not mountable inside user namespaces the descendant rule is trivially true because the s_user_ns will be the initial user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> |
||
Lokesh Gidra
|
215b674b84 |
security: add inode_init_security_anon() LSM hook
This change adds a new LSM hook, inode_init_security_anon(), that will be used while creating secure anonymous inodes. The hook allows/denies its creation and assigns a security context to the inode. The new hook accepts an optional context_inode parameter that callers can use to provide additional contextual information to security modules for granting/denying permission to create an anon-inode of the same type. This context_inode's security_context can also be used to initialize the newly created anon-inode's security_context. Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
|
Linus Torvalds
|
ca5b877b6c |
selinux/stable-5.11 PR 20201214
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Merge tag 'selinux-pr-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
"While we have a small number of SELinux patches for v5.11, there are a
few changes worth highlighting:
- Change the LSM network hooks to pass flowi_common structs instead
of the parent flowi struct as the LSMs do not currently need the
full flowi struct and they do not have enough information to use it
safely (missing information on the address family).
This patch was discussed both with Herbert Xu (representing team
netdev) and James Morris (representing team
LSMs-other-than-SELinux).
- Fix how we handle errors in inode_doinit_with_dentry() so that we
attempt to properly label the inode on following lookups instead of
continuing to treat it as unlabeled.
- Tweak the kernel logic around allowx, auditallowx, and dontauditx
SELinux policy statements such that the auditx/dontauditx are
effective even without the allowx statement.
Everything passes our test suite"
* tag 'selinux-pr-20201214' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
lsm,selinux: pass flowi_common instead of flowi to the LSM hooks
selinux: Fix fall-through warnings for Clang
selinux: drop super_block backpointer from superblock_security_struct
selinux: fix inode_doinit_with_dentry() LABEL_INVALID error handling
selinux: allow dontauditx and auditallowx rules to take effect without allowx
selinux: fix error initialization in inode_doinit_with_dentry()
|
||
Jakub Kicinski
|
e2437ac2f5 |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next
Steffen Klassert says: ==================== pull request (net-next): ipsec-next 2020-12-12 Just one patch this time: 1) Redact the SA keys with kernel lockdown confidentiality. If enabled, no secret keys are sent to uuserspace. From Antony Antony. * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next: xfrm: redact SA secret with lockdown confidentiality ==================== Link: https://lore.kernel.org/r/20201212085737.2101294-1-steffen.klassert@secunet.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
||
Florian Westphal
|
41dd9596d6 |
security: add const qualifier to struct sock in various places
A followup change to tcp_request_sock_op would have to drop the 'const' qualifier from the 'route_req' function as the 'security_inet_conn_request' call is moved there - and that function expects a 'struct sock *'. However, it turns out its also possible to add a const qualifier to security_inet_conn_request instead. Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
||
Antony Antony
|
c7a5899eb2 |
xfrm: redact SA secret with lockdown confidentiality
redact XFRM SA secret in the netlink response to xfrm_get_sa() or dumpall sa. Enable lockdown, confidentiality mode, at boot or at run time. e.g. when enabled: cat /sys/kernel/security/lockdown none integrity [confidentiality] ip xfrm state src 172.16.1.200 dst 172.16.1.100 proto esp spi 0x00000002 reqid 2 mode tunnel replay-window 0 aead rfc4106(gcm(aes)) 0x0000000000000000000000000000000000000000 96 note: the aead secret is redacted. Redacting secret is also a FIPS 140-2 requirement. v1->v2 - add size checks before memset calls v2->v3 - replace spaces with tabs for consistency v3->v4 - use kernel lockdown instead of a /proc setting v4->v5 - remove kconfig option Reviewed-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Antony Antony <antony.antony@secunet.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> |
||
|
Paul Moore
|
3df98d7921 |
lsm,selinux: pass flowi_common instead of flowi to the LSM hooks
As pointed out by Herbert in a recent related patch, the LSM hooks do not have the necessary address family information to use the flowi struct safely. As none of the LSMs currently use any of the protocol specific flowi information, replace the flowi pointers with pointers to the address family independent flowi_common struct. Reported-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com> |
||
|
Kees Cook
|
2039bda1fa |
LSM: Add "contents" flag to kernel_read_file hook
As with the kernel_load_data LSM hook, add a "contents" flag to the kernel_read_file LSM hook that indicates whether the LSM can expect a matching call to the kernel_post_read_file LSM hook with the full contents of the file. With the coming addition of partial file read support for kernel_read_file*() API, the LSM will no longer be able to always see the entire contents of a file during the read calls. For cases where the LSM must read examine the complete file contents, it will need to do so on its own every time the kernel_read_file hook is called with contents=false (or reject such cases). Adjust all existing LSMs to retain existing behavior. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|
Kees Cook
|
b64fcae74b |
LSM: Introduce kernel_post_load_data() hook
There are a few places in the kernel where LSMs would like to have visibility into the contents of a kernel buffer that has been loaded or read. While security_kernel_post_read_file() (which includes the buffer) exists as a pairing for security_kernel_read_file(), no such hook exists to pair with security_kernel_load_data(). Earlier proposals for just using security_kernel_post_read_file() with a NULL file argument were rejected (i.e. "file" should always be valid for the security_..._file hooks, but it appears at least one case was left in the kernel during earlier refactoring. (This will be fixed in a subsequent patch.) Since not all cases of security_kernel_load_data() can have a single contiguous buffer made available to the LSM hook (e.g. kexec image segments are separately loaded), there needs to be a way for the LSM to reason about its expectations of the hook coverage. In order to handle this, add a "contents" argument to the "kernel_load_data" hook that indicates if the newly added "kernel_post_load_data" hook will be called with the full contents once loaded. That way, LSMs requiring full contents can choose to unilaterally reject "kernel_load_data" with contents=false (which is effectively the existing hook coverage), but when contents=true they can allow it and later evaluate the "kernel_post_load_data" hook once the buffer is loaded. With this change, LSMs can gain coverage over non-file-backed data loads (e.g. init_module(2) and firmware userspace helper), which will happen in subsequent patches. Additionally prepare IMA to start processing these cases. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: KP Singh <kpsingh@google.com> Link: https://lore.kernel.org/r/20201002173828.2099543-9-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
Scott Branden
|
b89999d004 |
fs/kernel_read_file: Split into separate include file
Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h include file. That header gets pulled in just about everywhere and doesn't really need functions not related to the general fs interface. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Scott Branden <scott.branden@broadcom.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
KP Singh
|
23e390cdbe |
security: Fix hook iteration and default value for inode_copy_up_xattr
inode_copy_up_xattr returns 0 to indicate the acceptance of the xattr
and 1 to reject it. If the LSM does not know about the xattr, it's
expected to return -EOPNOTSUPP, which is the correct default value for
this hook. BPF LSM, currently, uses 0 as the default value and thereby
falsely allows all overlay fs xattributes to be copied up.
The iteration logic is also updated from the "bail-on-fail"
call_int_hook to continue on the non-decisive -EOPNOTSUPP and bail out
on other values.
Fixes:
|
||
|
Linus Torvalds
|
4a87b197c1 |
Add additional LSM hooks for SafeSetID
SafeSetID is capable of making allow/deny decisions for set*uid calls on a system, and we want to add similar functionality for set*gid calls. The work to do that is not yet complete, so probably won't make it in for v5.8, but we are looking to get this simple patch in for v5.8 since we have it ready. We are planning on the rest of the work for extending the SafeSetID LSM being merged during the v5.9 merge window. This patch was sent to the security mailing list and there were no objections. -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEgvWslnM+qUy+sgVg5n2WYw6TPBAFAl7mZCoACgkQ5n2WYw6T PBAk1RAAl8t3/m3lELf8qIir4OAd4nK0kc4e+7W8WkznX2ljUl2IetlNxDCBmEXr T5qoW6uPsr6kl5AKnbl9Ii7WpW/halsslpKSUNQCs6zbecoVdxekJ8ISW7xHuboZ SvS1bqm+t++PM0c0nWSFEr7eXYmPH8OGbCqu6/+nnbxPZf2rJX03e5LnHkEFDFnZ 0D/rsKgzMt01pdBJQXeoKk79etHO5MjuAkkYVEKJKCR1fM16lk7ECaCp0KJv1Mmx I88VncbLvI+um4t82d1Z8qDr2iLgogjJrMZC4WKfxDTmlmxox2Fz9ZJo+8sIWk6k T3a95x0s/mYCO4gWtpCVICt9+71Z3ie9T2iaI+CIe/kJvI/ysb+7LSkF+PD33bdz 0yv6Y9+VMRdzb3pW69R28IoP4wdYQOJRomsY49z6ypH0RgBWcBvyE6e4v+WJGRNK E164Imevf6rrZeqJ0kGSBS1nL9WmQHMaXabAwxg1jK1KRZD+YZj3EKC9S/+PAkaT 1qXUgvGuXHGjQrwU0hclQjgc6BAudWfAGdfrVr7IWwNKJmjgBf6C35my/azrkOg9 wHCEpUWVmZZLIZLM69/6QXdmMA+iR+rPz5qlVnWhWTfjRYJUXM455Zk+aNo+Qnwi +saCcdU+9xqreLeDIoYoebcV/ctHeW0XCQi/+ebjexXVlyeSfYs= =I+0L -----END PGP SIGNATURE----- Merge tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux Pull SafeSetID update from Micah Morton: "Add additional LSM hooks for SafeSetID SafeSetID is capable of making allow/deny decisions for set*uid calls on a system, and we want to add similar functionality for set*gid calls. The work to do that is not yet complete, so probably won't make it in for v5.8, but we are looking to get this simple patch in for v5.8 since we have it ready. We are planning on the rest of the work for extending the SafeSetID LSM being merged during the v5.9 merge window" * tag 'LSM-add-setgid-hook-5.8-author-fix' of git://github.com/micah-morton/linux: security: Add LSM hooks to set*gid syscalls |
||
Thomas Cedeno
|
39030e1351 |
security: Add LSM hooks to set*gid syscalls
The SafeSetID LSM uses the security_task_fix_setuid hook to filter set*uid() syscalls according to its configured security policy. In preparation for adding analagous support in the LSM for set*gid() syscalls, we add the requisite hook here. Tested by putting print statements in the security_task_fix_setgid hook and seeing them get hit during kernel boot. Signed-off-by: Thomas Cedeno <thomascedeno@google.com> Signed-off-by: Micah Morton <mortonm@chromium.org> |
||
|
Linus Torvalds
|
6c32978414 |
Notifications over pipes + Keyring notifications
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Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull notification queue from David Howells:
"This adds a general notification queue concept and adds an event
source for keys/keyrings, such as linking and unlinking keys and
changing their attributes.
Thanks to Debarshi Ray, we do have a pull request to use this to fix a
problem with gnome-online-accounts - as mentioned last time:
https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47
Without this, g-o-a has to constantly poll a keyring-based kerberos
cache to find out if kinit has changed anything.
[ There are other notification pending: mount/sb fsinfo notifications
for libmount that Karel Zak and Ian Kent have been working on, and
Christian Brauner would like to use them in lxc, but let's see how
this one works first ]
LSM hooks are included:
- A set of hooks are provided that allow an LSM to rule on whether or
not a watch may be set. Each of these hooks takes a different
"watched object" parameter, so they're not really shareable. The
LSM should use current's credentials. [Wanted by SELinux & Smack]
- A hook is provided to allow an LSM to rule on whether or not a
particular message may be posted to a particular queue. This is
given the credentials from the event generator (which may be the
system) and the watch setter. [Wanted by Smack]
I've provided SELinux and Smack with implementations of some of these
hooks.
WHY
===
Key/keyring notifications are desirable because if you have your
kerberos tickets in a file/directory, your Gnome desktop will monitor
that using something like fanotify and tell you if your credentials
cache changes.
However, we also have the ability to cache your kerberos tickets in
the session, user or persistent keyring so that it isn't left around
on disk across a reboot or logout. Keyrings, however, cannot currently
be monitored asynchronously, so the desktop has to poll for it - not
so good on a laptop. This facility will allow the desktop to avoid the
need to poll.
DESIGN DECISIONS
================
- The notification queue is built on top of a standard pipe. Messages
are effectively spliced in. The pipe is opened with a special flag:
pipe2(fds, O_NOTIFICATION_PIPE);
The special flag has the same value as O_EXCL (which doesn't seem
like it will ever be applicable in this context)[?]. It is given up
front to make it a lot easier to prohibit splice&co from accessing
the pipe.
[?] Should this be done some other way? I'd rather not use up a new
O_* flag if I can avoid it - should I add a pipe3() system call
instead?
The pipe is then configured::
ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
Messages are then read out of the pipe using read().
- It should be possible to allow write() to insert data into the
notification pipes too, but this is currently disabled as the
kernel has to be able to insert messages into the pipe *without*
holding pipe->mutex and the code to make this work needs careful
auditing.
- sendfile(), splice() and vmsplice() are disabled on notification
pipes because of the pipe->mutex issue and also because they
sometimes want to revert what they just did - but one or more
notification messages might've been interleaved in the ring.
- The kernel inserts messages with the wait queue spinlock held. This
means that pipe_read() and pipe_write() have to take the spinlock
to update the queue pointers.
- Records in the buffer are binary, typed and have a length so that
they can be of varying size.
This allows multiple heterogeneous sources to share a common
buffer; there are 16 million types available, of which I've used
just a few, so there is scope for others to be used. Tags may be
specified when a watchpoint is created to help distinguish the
sources.
- Records are filterable as types have up to 256 subtypes that can be
individually filtered. Other filtration is also available.
- Notification pipes don't interfere with each other; each may be
bound to a different set of watches. Any particular notification
will be copied to all the queues that are currently watching for it
- and only those that are watching for it.
- When recording a notification, the kernel will not sleep, but will
rather mark a queue as having lost a message if there's
insufficient space. read() will fabricate a loss notification
message at an appropriate point later.
- The notification pipe is created and then watchpoints are attached
to it, using one of:
keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);
where in both cases, fd indicates the queue and the number after is
a tag between 0 and 255.
- Watches are removed if either the notification pipe is destroyed or
the watched object is destroyed. In the latter case, a message will
be generated indicating the enforced watch removal.
Things I want to avoid:
- Introducing features that make the core VFS dependent on the
network stack or networking namespaces (ie. usage of netlink).
- Dumping all this stuff into dmesg and having a daemon that sits
there parsing the output and distributing it as this then puts the
responsibility for security into userspace and makes handling
namespaces tricky. Further, dmesg might not exist or might be
inaccessible inside a container.
- Letting users see events they shouldn't be able to see.
TESTING AND MANPAGES
====================
- The keyutils tree has a pipe-watch branch that has keyctl commands
for making use of notifications. Proposed manual pages can also be
found on this branch, though a couple of them really need to go to
the main manpages repository instead.
If the kernel supports the watching of keys, then running "make
test" on that branch will cause the testing infrastructure to spawn
a monitoring process on the side that monitors a notifications pipe
for all the key/keyring changes induced by the tests and they'll
all be checked off to make sure they happened.
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch
- A test program is provided (samples/watch_queue/watch_test) that
can be used to monitor for keyrings, mount and superblock events.
Information on the notifications is simply logged to stdout"
* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
smack: Implement the watch_key and post_notification hooks
selinux: Implement the watch_key security hook
keys: Make the KEY_NEED_* perms an enum rather than a mask
pipe: Add notification lossage handling
pipe: Allow buffers to be marked read-whole-or-error for notifications
Add sample notification program
watch_queue: Add a key/keyring notification facility
security: Add hooks to rule on setting a watch
pipe: Add general notification queue support
pipe: Add O_NOTIFICATION_PIPE
security: Add a hook for the point of notification insertion
uapi: General notification queue definitions
|
||
|
Linus Torvalds
|
52435c86bf |
overlayfs update for 5.8
-----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCXt9klAAKCRDh3BK/laaZ PBeeAP9GRI0yajPzBzz2ZK9KkDc6A7wPiaAec+86Q+c02VncVwEAvq5Pi4um5RTZ 7SVv56ggKO3Cqx779zVyZTRYDs3+YA4= =bpKI -----END PGP SIGNATURE----- Merge tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "Fixes: - Resolve mount option conflicts consistently - Sync before remount R/O - Fix file handle encoding corner cases - Fix metacopy related issues - Fix an unintialized return value - Add missing permission checks for underlying layers Optimizations: - Allow multipe whiteouts to share an inode - Optimize small writes by inheriting SB_NOSEC from upper layer - Do not call ->syncfs() multiple times for sync(2) - Do not cache negative lookups on upper layer - Make private internal mounts longterm" * tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (27 commits) ovl: remove unnecessary lock check ovl: make oip->index bool ovl: only pass ->ki_flags to ovl_iocb_to_rwf() ovl: make private mounts longterm ovl: get rid of redundant members in struct ovl_fs ovl: add accessor for ofs->upper_mnt ovl: initialize error in ovl_copy_xattr ovl: drop negative dentry in upper layer ovl: check permission to open real file ovl: call secutiry hook in ovl_real_ioctl() ovl: verify permissions in ovl_path_open() ovl: switch to mounter creds in readdir ovl: pass correct flags for opening real directory ovl: fix redirect traversal on metacopy dentries ovl: initialize OVL_UPPERDATA in ovl_lookup() ovl: use only uppermetacopy state in ovl_lookup() ovl: simplify setting of origin for index lookup ovl: fix out of bounds access warning in ovl_check_fb_len() ovl: return required buffer size for file handles ovl: sync dirty data when remounting to ro mode ... |
||
|
Linus Torvalds
|
3c0ad98c2e |
integrity-v5.8
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Merge tag 'integrity-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
"The main changes are extending the TPM 2.0 PCR banks with bank
specific file hashes, calculating the "boot_aggregate" based on other
TPM PCR banks, using the default IMA hash algorithm, instead of SHA1,
as the basis for the cache hash table key, and preventing the mprotect
syscall to circumvent an IMA mmap appraise policy rule.
- In preparation for extending TPM 2.0 PCR banks with bank specific
digests, commit
|
||
|
Linus Torvalds
|
15a2bc4dbb |
Merge branch 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman: "Last cycle for the Nth time I ran into bugs and quality of implementation issues related to exec that could not be easily be fixed because of the way exec is implemented. So I have been digging into exec and cleanup up what I can. I don't think I have exec sorted out enough to fix the issues I started with but I have made some headway this cycle with 4 sets of changes. - promised cleanups after introducing exec_update_mutex - trivial cleanups for exec - control flow simplifications - remove the recomputation of bprm->cred The net result is code that is a bit easier to understand and work with and a decrease in the number of lines of code (if you don't count the added tests)" * 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits) exec: Compute file based creds only once exec: Add a per bprm->file version of per_clear binfmt_elf_fdpic: fix execfd build regression selftests/exec: Add binfmt_script regression test exec: Remove recursion from search_binary_handler exec: Generic execfd support exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC exec: Move the call of prepare_binprm into search_binary_handler exec: Allow load_misc_binary to call prepare_binprm unconditionally exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds exec: Teach prepare_exec_creds how exec treats uids & gids exec: Set the point of no return sooner exec: Move handling of the point of no return to the top level exec: Run sync_mm_rss before taking exec_update_mutex exec: Fix spelling of search_binary_handler in a comment exec: Move the comment from above de_thread to above unshare_sighand exec: Rename flush_old_exec begin_new_exec exec: Move most of setup_new_exec into flush_old_exec exec: In setup_new_exec cache current in the local variable me ... |
||
Miklos Szeredi
|
292f902a40 |
ovl: call secutiry hook in ovl_real_ioctl()
Verify LSM permissions for underlying file, since vfs_ioctl() doesn't do it. [Stephen Rothwell] export security_file_ioctl Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> |
||
Eric W. Biederman
|
56305aa9b6 |
exec: Compute file based creds only once
Move the computation of creds from prepare_binfmt into begin_new_exec so that the creds need only be computed once. This is just code reorganization no semantic changes of any kind are made. Moving the computation is safe. I have looked through the kernel and verified none of the binfmts look at bprm->cred directly, and that there are no helpers that look at bprm->cred indirectly. Which means that it is not a problem to compute the bprm->cred later in the execution flow as it is not used until it becomes current->cred. A new function bprm_creds_from_file is added to contain the work that needs to be done. bprm_creds_from_file first computes which file bprm->executable or most likely bprm->file that the bprm->creds will be computed from. The funciton bprm_fill_uid is updated to receive the file instead of accessing bprm->file. The now unnecessary work needed to reset the bprm->cred->euid, and bprm->cred->egid is removed from brpm_fill_uid. A small comment to document that bprm_fill_uid now only deals with the work to handle suid and sgid files. The default case is already heandled by prepare_exec_creds. The function security_bprm_repopulate_creds is renamed security_bprm_creds_from_file and now is explicitly passed the file from which to compute the creds. The documentation of the bprm_creds_from_file security hook is updated to explain when the hook is called and what it needs to do. The file is passed from cap_bprm_creds_from_file into get_file_caps so that the caps are computed for the appropriate file. The now unnecessary work in cap_bprm_creds_from_file to reset the ambient capabilites has been removed. A small comment to document that the work of cap_bprm_creds_from_file is to read capabilities from the files secureity attribute and derive capabilities from the fact the user had uid 0 has been added. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
||
Mimi Zohar
|
8eb613c0b8 |
ima: verify mprotect change is consistent with mmap policy
Files can be mmap'ed read/write and later changed to execute to circumvent IMA's mmap appraise policy rules. Due to locking issues (mmap semaphore would be taken prior to i_mutex), files can not be measured or appraised at this point. Eliminate this integrity gap, by denying the mprotect PROT_EXECUTE change, if an mmap appraise policy rule exists. On mprotect change success, return 0. On failure, return -EACESS. Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> |
||
|
Eric W. Biederman
|
112b714759 |
exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds
Rename bprm->cap_elevated to bprm->active_secureexec and initialize it in prepare_binprm instead of in cap_bprm_set_creds. Initializing bprm->active_secureexec in prepare_binprm allows multiple implementations of security_bprm_repopulate_creds to play nicely with each other. Rename security_bprm_set_creds to security_bprm_reopulate_creds to emphasize that this path recomputes part of bprm->cred. This recomputation avoids the time of check vs time of use problems that are inherent in unix #! interpreters. In short two renames and a move in the location of initializing bprm->active_secureexec. Link: https://lkml.kernel.org/r/87o8qkzrxp.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
||
|
KP Singh
|
0550cfe8c2 |
security: Fix hook iteration for secid_to_secctx
secid_to_secctx is not stackable, and since the BPF LSM registers this hook by default, the call_int_hook logic is not suitable which "bails-on-fail" and casues issues when other LSMs register this hook and eventually breaks Audit. In order to fix this, directly iterate over the security hooks instead of using call_int_hook as suggested in: https: //lore.kernel.org/bpf/9d0eb6c6-803a-ff3a-5603-9ad6d9edfc00@schaufler-ca.com/#t Fixes: |
||
|
Eric W. Biederman
|
b8bff59926 |
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
Today security_bprm_set_creds has several implementations: apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds, smack_bprm_set_creds, and tomoyo_bprm_set_creds. Except for cap_bprm_set_creds they all test bprm->called_set_creds and return immediately if it is true. The function cap_bprm_set_creds ignores bprm->calld_sed_creds entirely. Create a new LSM hook security_bprm_creds_for_exec that is called just before prepare_binprm in __do_execve_file, resulting in a LSM hook that is called exactly once for the entire of exec. Modify the bits of security_bprm_set_creds that only want to be called once per exec into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds behind. Remove bprm->called_set_creds all of it's former users have been moved to security_bprm_creds_for_exec. Add or upate comments a appropriate to bring them up to date and to reflect this change. Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.org Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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David Howells
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8c0637e950 |
keys: Make the KEY_NEED_* perms an enum rather than a mask
Since the meaning of combining the KEY_NEED_* constants is undefined, make
it so that you can't do that by turning them into an enum.
The enum is also given some extra values to represent special
circumstances, such as:
(1) The '0' value is reserved and causes a warning to trap the parameter
being unset.
(2) The key is to be unlinked and we require no permissions on it, only
the keyring, (this replaces the KEY_LOOKUP_FOR_UNLINK flag).
(3) An override due to CAP_SYS_ADMIN.
(4) An override due to an instantiation token being present.
(5) The permissions check is being deferred to later key_permission()
calls.
The extra values give the opportunity for LSMs to audit these situations.
[Note: This really needs overhauling so that lookup_user_key() tells
key_task_permission() and the LSM what operation is being done and leaves
it to those functions to decide how to map that onto the available
permits. However, I don't really want to make these change in the middle
of the notifications patchset.]
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
cc: Paul Moore <paul@paul-moore.com>
cc: Stephen Smalley <stephen.smalley.work@gmail.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: keyrings@vger.kernel.org
cc: selinux@vger.kernel.org
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David Howells
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998f50407f |
security: Add hooks to rule on setting a watch
Add security hooks that will allow an LSM to rule on whether or not a watch may be set. More than one hook is required as the watches watch different types of object. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jamorris@linux.microsoft.com> cc: Casey Schaufler <casey@schaufler-ca.com> cc: Stephen Smalley <sds@tycho.nsa.gov> cc: linux-security-module@vger.kernel.org |