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2018-04-11ipc/msg: introduce msgctl(MSG_STAT_ANY)Davidlohr Bueso
There is a permission discrepancy when consulting msq ipc object metadata between /proc/sysvipc/msg (0444) and the MSG_STAT shmctl command. The later does permission checks for the object vs S_IRUGO. As such there can be cases where EACCESS is returned via syscall but the info is displayed anyways in the procfs files. While this might have security implications via info leaking (albeit no writing to the msq metadata), this behavior goes way back and showing all the objects regardless of the permissions was most likely an overlook - so we are stuck with it. Furthermore, modifying either the syscall or the procfs file can cause userspace programs to break (ie ipcs). Some applications require getting the procfs info (without root privileges) and can be rather slow in comparison with a syscall -- up to 500x in some reported cases for shm. This patch introduces a new MSG_STAT_ANY command such that the msq ipc object permissions are ignored, and only audited instead. In addition, I've left the lsm security hook checks in place, as if some policy can block the call, then the user has no other choice than just parsing the procfs file. Link: http://lkml.kernel.org/r/20180215162458.10059-4-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reported-by: Robert Kettler <robert.kettler@outlook.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11ipc/sem: introduce semctl(SEM_STAT_ANY)Davidlohr Bueso
There is a permission discrepancy when consulting shm ipc object metadata between /proc/sysvipc/sem (0444) and the SEM_STAT semctl command. The later does permission checks for the object vs S_IRUGO. As such there can be cases where EACCESS is returned via syscall but the info is displayed anyways in the procfs files. While this might have security implications via info leaking (albeit no writing to the sma metadata), this behavior goes way back and showing all the objects regardless of the permissions was most likely an overlook - so we are stuck with it. Furthermore, modifying either the syscall or the procfs file can cause userspace programs to break (ie ipcs). Some applications require getting the procfs info (without root privileges) and can be rather slow in comparison with a syscall -- up to 500x in some reported cases for shm. This patch introduces a new SEM_STAT_ANY command such that the sem ipc object permissions are ignored, and only audited instead. In addition, I've left the lsm security hook checks in place, as if some policy can block the call, then the user has no other choice than just parsing the procfs file. Link: http://lkml.kernel.org/r/20180215162458.10059-3-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reported-by: Robert Kettler <robert.kettler@outlook.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11ipc/shm: introduce shmctl(SHM_STAT_ANY)Davidlohr Bueso
Patch series "sysvipc: introduce STAT_ANY commands", v2. The following patches adds the discussed (see [1]) new command for shm as well as for sems and msq as they are subject to the same discrepancies for ipc object permission checks between the syscall and via procfs. These new commands are justified in that (1) we are stuck with this semantics as changing syscall and procfs can break userland; and (2) some users can benefit from performance (for large amounts of shm segments, for example) from not having to parse the procfs interface. Once merged, I will submit the necesary manpage updates. But I'm thinking something like: : diff --git a/man2/shmctl.2 b/man2/shmctl.2 : index 7bb503999941..bb00bbe21a57 100644 : --- a/man2/shmctl.2 : +++ b/man2/shmctl.2 : @@ -41,6 +41,7 @@ : .\" 2005-04-25, mtk -- noted aberrant Linux behavior w.r.t. new : .\" attaches to a segment that has already been marked for deletion. : .\" 2005-08-02, mtk: Added IPC_INFO, SHM_INFO, SHM_STAT descriptions. : +.\" 2018-02-13, dbueso: Added SHM_STAT_ANY description. : .\" : .TH SHMCTL 2 2017-09-15 "Linux" "Linux Programmer's Manual" : .SH NAME : @@ -242,6 +243,18 @@ However, the : argument is not a segment identifier, but instead an index into : the kernel's internal array that maintains information about : all shared memory segments on the system. : +.TP : +.BR SHM_STAT_ANY " (Linux-specific)" : +Return a : +.I shmid_ds : +structure as for : +.BR SHM_STAT . : +However, the : +.I shm_perm.mode : +is not checked for read access for : +.IR shmid , : +resembing the behaviour of : +/proc/sysvipc/shm. : .PP : The caller can prevent or allow swapping of a shared : memory segment with the following \fIcmd\fP values: : @@ -287,7 +300,7 @@ operation returns the index of the highest used entry in the : kernel's internal array recording information about all : shared memory segments. : (This information can be used with repeated : -.B SHM_STAT : +.B SHM_STAT/SHM_STAT_ANY : operations to obtain information about all shared memory segments : on the system.) : A successful : @@ -328,7 +341,7 @@ isn't accessible. : \fIshmid\fP is not a valid identifier, or \fIcmd\fP : is not a valid command. : Or: for a : -.B SHM_STAT : +.B SHM_STAT/SHM_STAT_ANY : operation, the index value specified in : .I shmid : referred to an array slot that is currently unused. This patch (of 3): There is a permission discrepancy when consulting shm ipc object metadata between /proc/sysvipc/shm (0444) and the SHM_STAT shmctl command. The later does permission checks for the object vs S_IRUGO. As such there can be cases where EACCESS is returned via syscall but the info is displayed anyways in the procfs files. While this might have security implications via info leaking (albeit no writing to the shm metadata), this behavior goes way back and showing all the objects regardless of the permissions was most likely an overlook - so we are stuck with it. Furthermore, modifying either the syscall or the procfs file can cause userspace programs to break (ie ipcs). Some applications require getting the procfs info (without root privileges) and can be rather slow in comparison with a syscall -- up to 500x in some reported cases. This patch introduces a new SHM_STAT_ANY command such that the shm ipc object permissions are ignored, and only audited instead. In addition, I've left the lsm security hook checks in place, as if some policy can block the call, then the user has no other choice than just parsing the procfs file. [1] https://lkml.org/lkml/2017/12/19/220 Link: http://lkml.kernel.org/r/20180215162458.10059-2-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Robert Kettler <robert.kettler@outlook.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-07Merge branch 'next-integrity' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull integrity updates from James Morris: "A mixture of bug fixes, code cleanup, and continues to close IMA-measurement, IMA-appraisal, and IMA-audit gaps. Also note the addition of a new cred_getsecid LSM hook by Matthew Garrett: For IMA purposes, we want to be able to obtain the prepared secid in the bprm structure before the credentials are committed. Add a cred_getsecid hook that makes this possible. which is used by a new CREDS_CHECK target in IMA: In ima_bprm_check(), check with both the existing process credentials and the credentials that will be committed when the new process is started. This will not change behaviour unless the system policy is extended to include CREDS_CHECK targets - BPRM_CHECK will continue to check the same credentials that it did previously" * 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: ima: Fallback to the builtin hash algorithm ima: Add smackfs to the default appraise/measure list evm: check for remount ro in progress before writing ima: Improvements in ima_appraise_measurement() ima: Simplify ima_eventsig_init() integrity: Remove unused macro IMA_ACTION_RULE_FLAGS ima: drop vla in ima_audit_measurement() ima: Fix Kconfig to select TPM 2.0 CRB interface evm: Constify *integrity_status_msg[] evm: Move evm_hmac and evm_hash from evm_main.c to evm_crypto.c fuse: define the filesystem as untrusted ima: fail signature verification based on policy ima: clear IMA_HASH ima: re-evaluate files on privileged mounted filesystems ima: fail file signature verification on non-init mounted filesystems IMA: Support using new creds in appraisal policy security: Add a cred_getsecid hook
2018-04-07Merge branch 'next-smack' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull smack update from James Morris: "One small change for Automotive Grade Linux" * 'next-smack' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: Smack: Handle CGROUP2 in the same way that CGROUP
2018-04-07Merge branch 'next-general' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull general security layer updates from James Morris: - Convert security hooks from list to hlist, a nice cleanup, saving about 50% of space, from Sargun Dhillon. - Only pass the cred, not the secid, to kill_pid_info_as_cred and security_task_kill (as the secid can be determined from the cred), from Stephen Smalley. - Close a potential race in kernel_read_file(), by making the file unwritable before calling the LSM check (vs after), from Kees Cook. * 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: security: convert security hooks to use hlist exec: Set file unwritable before LSM check usb, signal, security: only pass the cred, not the secid, to kill_pid_info_as_cred and security_task_kill
2018-03-27ipc/smack: Tidy up from the change in type of the ipc security hooksEric W. Biederman
Rename the variables shp, sma, msq to isp. As that is how the code already refers to those variables. Collapse smack_of_shm, smack_of_sem, and smack_of_msq into smack_of_ipc, as the three functions had become completely identical. Collapse smack_shm_alloc_security, smack_sem_alloc_security and smack_msg_queue_alloc_security into smack_ipc_alloc_security as the three functions had become identical. Collapse smack_shm_free_security, smack_sem_free_security and smack_msg_queue_free_security into smack_ipc_free_security as the three functions had become identical. Requested-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-27Merge branch 'smack-for-4.17' of git://github.com/cschaufler/next-smack into ↵James Morris
next-smack Pull request from Casey.
2018-03-23security: Add a cred_getsecid hookMatthew Garrett
For IMA purposes, we want to be able to obtain the prepared secid in the bprm structure before the credentials are committed. Add a cred_getsecid hook that makes this possible. Signed-off-by: Matthew Garrett <mjg59@google.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2018-03-22msg/security: Pass kern_ipc_perm not msg_queue into the msg_queue security hooksEric W. Biederman
All of the implementations of security hooks that take msg_queue only access q_perm the struct kern_ipc_perm member. This means the dependencies of the msg_queue security hooks can be simplified by passing the kern_ipc_perm member of msg_queue. Making this change will allow struct msg_queue to become private to ipc/msg.c. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22shm/security: Pass kern_ipc_perm not shmid_kernel into the shm security hooksEric W. Biederman
All of the implementations of security hooks that take shmid_kernel only access shm_perm the struct kern_ipc_perm member. This means the dependencies of the shm security hooks can be simplified by passing the kern_ipc_perm member of shmid_kernel.. Making this change will allow struct shmid_kernel to become private to ipc/shm.c. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-22sem/security: Pass kern_ipc_perm not sem_array into the sem security hooksEric W. Biederman
All of the implementations of security hooks that take sem_array only access sem_perm the struct kern_ipc_perm member. This means the dependencies of the sem security hooks can be simplified by passing the kern_ipc_perm member of sem_array. Making this change will allow struct sem and struct sem_array to become private to ipc/sem.c. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-03-07usb, signal, security: only pass the cred, not the secid, to ↵Stephen Smalley
kill_pid_info_as_cred and security_task_kill commit d178bc3a708f39cbfefc3fab37032d3f2511b4ec ("user namespace: usb: make usb urbs user namespace aware (v2)") changed kill_pid_info_as_uid to kill_pid_info_as_cred, saving and passing a cred structure instead of uids. Since the secid can be obtained from the cred, drop the secid fields from the usb_dev_state and async structures, and drop the secid argument to kill_pid_info_as_cred. Replace the secid argument to security_task_kill with the cred. Update SELinux, Smack, and AppArmor to use the cred, which avoids the need for Smack and AppArmor to use a secid at all in this hook. Further changes to Smack might still be required to take full advantage of this change, since it should now be possible to perform capability checking based on the supplied cred. The changes to Smack and AppArmor have only been compile-tested. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: John Johansen <john.johansen@canonical.com> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-02-28Smack: Handle CGROUP2 in the same way that CGROUPJosé Bollo
The new file system CGROUP2 isn't actually handled by smack. This changes makes Smack treat equally CGROUP and CGROUP2 items. Signed-off-by: José Bollo <jose.bollo@iot.bzh> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2018-01-10Smack: Privilege check on key operationsCasey Schaufler
Smack: Privilege check on key operations Operations on key objects are subjected to Smack policy even if the process is privileged. This is inconsistent with the general behavior of Smack and may cause issues with authentication by privileged daemons. This patch allows processes with CAP_MAC_OVERRIDE to access keys even if the Smack rules indicate otherwise. Reported-by: Jose Bollo <jobol@nonadev.net> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-12-27Smack: fix dereferenced before checkVasyl Gomonovych
This patch fixes the warning reported by smatch: security/smack/smack_lsm.c:2872 smack_socket_connect() warn: variable dereferenced before check 'sock->sk' (see line 2869) Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-11-13Merge branch 'next-general' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull general security subsystem updates from James Morris: "TPM (from Jarkko): - essential clean up for tpm_crb so that ARM64 and x86 versions do not distract each other as much as before - /dev/tpm0 rejects now too short writes (shorter buffer than specified in the command header - use DMA-safe buffer in tpm_tis_spi - otherwise mostly minor fixes. Smack: - base support for overlafs Capabilities: - BPRM_FCAPS fixes, from Richard Guy Briggs: The audit subsystem is adding a BPRM_FCAPS record when auditing setuid application execution (SYSCALL execve). This is not expected as it was supposed to be limited to when the file system actually had capabilities in an extended attribute. It lists all capabilities making the event really ugly to parse what is happening. The PATH record correctly records the setuid bit and owner. Suppress the BPRM_FCAPS record on set*id. TOMOYO: - Y2038 timestamping fixes" * 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (28 commits) MAINTAINERS: update the IMA, EVM, trusted-keys, encrypted-keys entries Smack: Base support for overlayfs MAINTAINERS: remove David Safford as maintainer for encrypted+trusted keys tomoyo: fix timestamping for y2038 capabilities: audit log other surprising conditions capabilities: fix logic for effective root or real root capabilities: invert logic for clarity capabilities: remove a layer of conditional logic capabilities: move audit log decision to function capabilities: use intuitive names for id changes capabilities: use root_priveleged inline to clarify logic capabilities: rename has_cap to has_fcap capabilities: intuitive names for cap gain status capabilities: factor out cap_bprm_set_creds privileged root tpm, tpm_tis: use ARRAY_SIZE() to define TPM_HID_USR_IDX tpm: fix duplicate inline declaration specifier tpm: fix type of a local variables in tpm_tis_spi.c tpm: fix type of a local variable in tpm2_map_command() tpm: fix type of a local variable in tpm2_get_cc_attrs_tbl() tpm-dev-common: Reject too short writes ...
2017-11-02Smack: Base support for overlayfsCasey Schaufler
Supply the Smack module hooks in support of overlayfs. Ensure that the Smack label of new files gets the correct value when a directory is transmuting. Original implementation by Romanini Daniele, with a few tweaks added. Signed-off-by: Romanini Daniele <daniele.romanini@aalto.fi> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-10-04lsm: fix smack_inode_removexattr and xattr_getsecurity memleakCasey Schaufler
security_inode_getsecurity() provides the text string value of a security attribute. It does not provide a "secctx". The code in xattr_getsecurity() that calls security_inode_getsecurity() and then calls security_release_secctx() happened to work because SElinux and Smack treat the attribute and the secctx the same way. It fails for cap_inode_getsecurity(), because that module has no secctx that ever needs releasing. It turns out that Smack is the one that's doing things wrong by not allocating memory when instructed to do so by the "alloc" parameter. The fix is simple enough. Change the security_release_secctx() to kfree() because it isn't a secctx being returned by security_inode_getsecurity(). Change Smack to allocate the string when told to do so. Note: this also fixes memory leaks for LSMs which implement inode_getsecurity but not release_secctx, such as capabilities. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: stable@vger.kernel.org Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-08-01smack: Remove redundant pdeath_signal clearingKees Cook
This removes the redundant pdeath_signal clearing in Smack: the check in smack_bprm_committing_creds() matches the check in smack_bprm_set_creds() (which used to be in the now-removed smack_bprm_securexec() hook) and since secureexec is now being checked for clearing pdeath_signal, this is redundant to the common exec code. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2017-08-01smack: Refactor to remove bprm_secureexec hookKees Cook
The Smack bprm_secureexec hook can be merged with the bprm_set_creds hook since it's dealing with the same information, and all of the details are finalized during the first call to the bprm_set_creds hook via prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored via bprm->called_set_creds). Here, the test can just happen at the end of the bprm_set_creds hook, and the bprm_secureexec hook can be dropped. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
2017-08-01exec: Rename bprm->cred_prepared to called_set_credsKees Cook
The cred_prepared bprm flag has a misleading name. It has nothing to do with the bprm_prepare_cred hook, and actually tracks if bprm_set_creds has been called. Rename this flag and improve its comment. Cc: David Howells <dhowells@redhat.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: James Morris <james.l.morris@oracle.com> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Serge Hallyn <serge@hallyn.com>
2017-06-01Smack: Safer check for a socket in file_receiveCasey Schaufler
The check of S_ISSOCK() in smack_file_receive() is not appropriate if the passed descriptor is a socket. Reported-by: Stephen Smalley <sds@tyco.nsa.gov> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-04-04smack: fix double free in smack_parse_opts_str()Tetsuo Handa
smack_parse_opts_str() calls kfree(opts->mnt_opts) when kcalloc() for opts->mnt_opts_flags failed. But it should not have called it because security_free_mnt_opts() will call kfree(opts->mnt_opts). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> fixes: 3bf2789cad9e6573 ("smack: allow mount opts setting over filesystems with binary mount data") Cc: Vivek Trivedi <t.vivek@samsung.com> Cc: Amit Sahrawat <a.sahrawat@samsung.com> Cc: Casey Schaufler <casey@schaufler-ca.com>
2017-03-06security: mark LSM hooks as __ro_after_initJames Morris
Mark all of the registration hooks as __ro_after_init (via the __lsm_ro_after_init macro). Signed-off-by: James Morris <james.l.morris@oracle.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Kees Cook <keescook@chromium.org>
2017-02-23Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull namespace updates from Eric Biederman: "There is a lot here. A lot of these changes result in subtle user visible differences in kernel behavior. I don't expect anything will care but I will revert/fix things immediately if any regressions show up. From Seth Forshee there is a continuation of the work to make the vfs ready for unpriviled mounts. We had thought the previous changes prevented the creation of files outside of s_user_ns of a filesystem, but it turns we missed the O_CREAT path. Ooops. Pavel Tikhomirov and Oleg Nesterov worked together to fix a long standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only children that are forked after the prctl are considered and not children forked before the prctl. The only known user of this prctl systemd forks all children after the prctl. So no userspace regressions will occur. Holding earlier forked children to the same rules as later forked children creates a semantic that is sane enough to allow checkpoing of processes that use this feature. There is a long delayed change by Nikolay Borisov to limit inotify instances inside a user namespace. Michael Kerrisk extends the API for files used to maniuplate namespaces with two new trivial ioctls to allow discovery of the hierachy and properties of namespaces. Konstantin Khlebnikov with the help of Al Viro adds code that when a network namespace exits purges it's sysctl entries from the dcache. As in some circumstances this could use a lot of memory. Vivek Goyal fixed a bug with stacked filesystems where the permissions on the wrong inode were being checked. I continue previous work on ptracing across exec. Allowing a file to be setuid across exec while being ptraced if the tracer has enough credentials in the user namespace, and if the process has CAP_SETUID in it's own namespace. Proc files for setuid or otherwise undumpable executables are now owned by the root in the user namespace of their mm. Allowing debugging of setuid applications in containers to work better. A bug I introduced with permission checking and automount is now fixed. The big change is to mark the mounts that the kernel initiates as a result of an automount. This allows the permission checks in sget to be safely suppressed for this kind of mount. As the permission check happened when the original filesystem was mounted. Finally a special case in the mount namespace is removed preventing unbounded chains in the mount hash table, and making the semantics simpler which benefits CRIU. The vfs fix along with related work in ima and evm I believe makes us ready to finish developing and merge fully unprivileged mounts of the fuse filesystem. The cleanups of the mount namespace makes discussing how to fix the worst case complexity of umount. The stacked filesystem fixes pave the way for adding multiple mappings for the filesystem uids so that efficient and safer containers can be implemented" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc/sysctl: Don't grab i_lock under sysctl_lock. vfs: Use upper filesystem inode in bprm_fill_uid() proc/sysctl: prune stale dentries during unregistering mnt: Tuck mounts under others instead of creating shadow/side mounts. prctl: propagate has_child_subreaper flag to every descendant introduce the walk_process_tree() helper nsfs: Add an ioctl() to return owner UID of a userns fs: Better permission checking for submounts exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction vfs: open() with O_CREAT should not create inodes with unknown ids nsfs: Add an ioctl() to return the namespace type proc: Better ownership of files for non-dumpable tasks in user namespaces exec: Remove LSM_UNSAFE_PTRACE_CAP exec: Test the ptracer's saved cred to see if the tracee can gain caps exec: Don't reset euid and egid when the tracee has CAP_SETUID inotify: Convert to using per-namespace limits
2017-02-10Merge branch 'stable-4.11' of git://git.infradead.org/users/pcmoore/selinux ↵James Morris
into next
2017-01-27Merge branch 'smack-for-4.11' of git://github.com/cschaufler/smack-next into ↵James Morris
next
2017-01-24exec: Remove LSM_UNSAFE_PTRACE_CAPEric W. Biederman
With previous changes every location that tests for LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the LSM_UNSAFE_PTRACE_CAP redundant, so remove it. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2017-01-19LSM: Add /sys/kernel/security/lsmCasey Schaufler
I am still tired of having to find indirect ways to determine what security modules are active on a system. I have added /sys/kernel/security/lsm, which contains a comma separated list of the active security modules. No more groping around in /proc/filesystems or other clever hacks. Unchanged from previous versions except for being updated to the latest security next branch. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-01-12security,selinux,smack: kill security_task_wait hookStephen Smalley
As reported by yangshukui, a permission denial from security_task_wait() can lead to a soft lockup in zap_pid_ns_processes() since it only expects sys_wait4() to return 0 or -ECHILD. Further, security_task_wait() can in general lead to zombies; in the absence of some way to automatically reparent a child process upon a denial, the hook is not useful. Remove the security hook and its implementations in SELinux and Smack. Smack already removed its check from its hook. Reported-by: yangshukui <yangshukui@huawei.com> Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-01-10Smack: ignore private inode for file functionsSeung-Woo Kim
The access to fd from anon_inode is always failed because there is no set xattr operations. So this patch fixes to ignore private inode including anon_inode for file functions. It was only ignored for smack_file_receive() to share dma-buf fd, but dma-buf has other functions like ioctl and mmap. Reference: https://lkml.org/lkml/2015/4/17/16 Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10Smack: fix d_instantiate logic for sockfs and pipefsRafal Krypa
Since 4b936885a (v2.6.32) all inodes on sockfs and pipefs are disconnected. It caused filesystem specific code in smack_d_instantiate to be skipped, because all inodes on those pseudo filesystems were treated as root inodes. As a result all sockfs inodes had the Smack label set to floor. In most cases access checks for sockets use socket_smack data so the inode label is not important. But there are special cases that were broken. One example would be calling fcntl with F_SETOWN command on a socket fd. Now smack_d_instantiate expects all pipefs and sockfs inodes to be disconnected and has the logic in appropriate place. Signed-off-by: Rafal Krypa <r.krypa@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10SMACK: Use smk_tskacc() instead of smk_access() for proper loggingHimanshu Shukla
smack_file_open() is first checking the capability of calling subject, this check will skip the SMACK logging for success case. Use smk_tskacc() for proper logging and SMACK access check. Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10Smack: Traverse the smack_known_list using list_for_each_entry_rcu macroVishal Goel
In smack_from_secattr function,"smack_known_list" is being traversed using list_for_each_entry macro, although it is a rcu protected structure. So it should be traversed using "list_for_each_entry_rcu" macro to fetch the rcu protected entry. Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10SMACK: Free the i_security blob in inode using RCUHimanshu Shukla
There is race condition issue while freeing the i_security blob in SMACK module. There is existing condition where i_security can be freed while inode_permission is called from path lookup on second CPU. There has been observed the page fault with such condition. VFS code and Selinux module takes care of this condition by freeing the inode and i_security field using RCU via call_rcu(). But in SMACK directly the i_secuirty blob is being freed. Use call_rcu() to fix this race condition issue. Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10SMACK: Delete list_head repeated initializationHimanshu Shukla
smk_copy_rules() and smk_copy_relabel() are initializing list_head though they have been initialized already in new_task_smack() function. Delete repeated initialization. Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10Smack: Fix the issue of wrong SMACK label update in socket bind fail caseVishal Goel
Fix the issue of wrong SMACK label (SMACK64IPIN) update when a second bind call is made to same IP address & port, but with different SMACK label (SMACK64IPIN) by second instance of server. In this case server returns with "Bind:Address already in use" error but before returning, SMACK label is updated in SMACK port-label mapping list inside smack_socket_bind() hook To fix this issue a new check has been added in smk_ipv6_port_label() function before updating the existing port entry. It checks whether the socket for matching port entry is closed or not. If it is closed then it means port is not bound and it is safe to update the existing port entry else return if port is still getting used. For checking whether socket is closed or not, one more field "smk_can_reuse" has been added in the "smk_port_label" structure. This field will be set to '1' in "smack_sk_free_security()" function which is called to free the socket security blob when the socket is being closed. In this function, port entry is searched in the SMACK port-label mapping list for the closing socket. If entry is found then "smk_can_reuse" field is set to '1'.Initially "smk_can_reuse" field is set to '0' in smk_ipv6_port_label() function after creating a new entry in the list which indicates that socket is in use. Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10Smack: Fix the issue of permission denied error in ipv6 hookVishal Goel
Permission denied error comes when 2 IPv6 servers are running and client tries to connect one of them. Scenario is that both servers are using same IP and port but different protocols(Udp and tcp). They are using different SMACK64IPIN labels.Tcp server is using "test" and udp server is using "test-in". When we try to run tcp client with SMACK64IPOUT label as "test", then connection denied error comes. It should not happen since both tcp server and client labels are same.This happens because there is no check for protocol in smk_ipv6_port_label() function while searching for the earlier port entry. It checks whether there is an existing port entry on the basis of port only. So it updates the earlier port entry in the list. Due to which smack label gets changed for earlier entry in the "smk_ipv6_port_list" list and permission denied error comes. Now a check is added for socket type also.Now if 2 processes use same port but different protocols (tcp or udp), then 2 different port entries will be added in the list. Similarly while checking smack access in smk_ipv6_port_check() function, port entry is searched on the basis of both port and protocol. Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Himanshu Shukla <Himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-10SMACK: Add the rcu synchronization mechanism in ipv6 hooksVishal Goel
Add the rcu synchronization mechanism for accessing smk_ipv6_port_list in smack IPv6 hooks. Access to the port list is vulnerable to a race condition issue,it does not apply proper synchronization methods while working on critical section. It is possible that when one thread is reading the list, at the same time another thread is modifying the same port list, which can cause the major problems. To ensure proper synchronization between two threads, rcu mechanism has been applied while accessing and modifying the port list. RCU will also not affect the performance, as there are more accesses than modification where RCU is most effective synchronization mechanism. Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2017-01-09proc,security: move restriction on writing /proc/pid/attr nodes to procStephen Smalley
Processes can only alter their own security attributes via /proc/pid/attr nodes. This is presently enforced by each individual security module and is also imposed by the Linux credentials implementation, which only allows a task to alter its own credentials. Move the check enforcing this restriction from the individual security modules to proc_pid_attr_write() before calling the security hook, and drop the unnecessary task argument to the security hook since it can only ever be the current task. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-12-16Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: - more ->d_init() stuff (work.dcache) - pathname resolution cleanups (work.namei) - a few missing iov_iter primitives - copy_from_iter_full() and friends. Either copy the full requested amount, advance the iterator and return true, or fail, return false and do _not_ advance the iterator. Quite a few open-coded callers converted (and became more readable and harder to fuck up that way) (work.iov_iter) - several assorted patches, the big one being logfs removal * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: logfs: remove from tree vfs: fix put_compat_statfs64() does not handle errors namei: fold should_follow_link() with the step into not-followed link namei: pass both WALK_GET and WALK_MORE to should_follow_link() namei: invert WALK_PUT logics namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link() namei: saner calling conventions for mountpoint_last() namei.c: get rid of user_path_parent() switch getfrag callbacks to ..._full() primitives make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success [iov_iter] new primitives - copy_from_iter_full() and friends don't open-code file_inode() ceph: switch to use of ->d_init() ceph: unify dentry_operations instances lustre: switch to use of ->d_init()
2016-12-04don't open-code file_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-11-15Smack: Remove unnecessary smack_known_invalidCasey Schaufler
The invalid Smack label ("") and the Huh ("?") Smack label serve the same purpose and having both is unnecessary. While pulling out the invalid label it became clear that the use of smack_from_secid() was inconsistent, so that is repaired. The setting of inode labels to the invalid label could never happen in a functional system, has never been observed in the wild and is not what you'd really want for a failure behavior in any case. That is removed. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-14Smack: Use GFP_KERNEL for smack_parse_opts_str().Tetsuo Handa
Since smack_parse_opts_str() is calling match_strdup() which uses GFP_KERNEL, it is safe to use GFP_KERNEL from kcalloc() which is called by smack_parse_opts_str(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10Smack: ipv6 label match fixCasey Schaufler
The check for a deleted entry in the list of IPv6 host addresses was being performed in the wrong place, leading to most peculiar results in some cases. This puts the check into the right place. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10SMACK: Fix the memory leak in smack_cred_prepare() hookHimanshu Shukla
Memory leak in smack_cred_prepare()function. smack_cred_prepare() hook returns error if there is error in allocating memory in smk_copy_rules() or smk_copy_relabel() function. If smack_cred_prepare() function returns error then the calling function should call smack_cred_free() function for cleanup. In smack_cred_free() function first credential is extracted and then all rules are deleted. In smack_cred_prepare() function security field is assigned in the end when all function return success. But this function may return before and memory will not be freed. Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10SMACK: Do not apply star label in smack_setprocattr hookHimanshu Shukla
Smack prohibits processes from using the star ("*") and web ("@") labels. Checks have been added in other functions. In smack_setprocattr() hook, only check for web ("@") label has been added and restricted from applying web ("@") label. Check for star ("*") label should also be added in smack_setprocattr() hook. Return error should be "-EINVAL" not "-EPERM" as permission is there for setting label but not the label value as star ("*") or web ("@"). Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-10smack: parse mnt opts after privileges checkHimanshu Shukla
In smack_set_mnt_opts()first the SMACK mount options are being parsed and later it is being checked whether the user calling mount has CAP_MAC_ADMIN capability. This sequence of operationis will allow unauthorized user to add SMACK labels in label list and may cause denial of security attack by adding many labels by allocating kernel memory by unauthorized user. Superblock smack flag is also being set as initialized though function may return with EPERM error. First check the capability of calling user then set the SMACK attributes and smk_flags. Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2016-11-04Smack: Assign smack_known_web label for kernel thread'sjooseong lee
Assign smack_known_web label for kernel thread's socket Creating struct sock by sk_alloc function in various kernel subsystems like bluetooth doesn't call smack_socket_post_create(). In such case, received sock label is the floor('_') label and makes access deny. Signed-off-by: jooseong lee <jooseong.lee@samsung.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>