BMC/Intel-BMC/linux.git/security/selinux, branch dev-4.10

selinux: fix off-by-one in setprocattr

2017-02-08T08:09:53+00:00

SELinux tries to support setting/clearing of /proc/pid/attr attributes from the shell by ignoring terminating newlines and treating an attribute value that begins with a NUL or newline as an attempt to clear the attribute. However, the test for clearing attributes has always been wrong; it has an off-by-one error, and this could further lead to reading past the end of the allocated buffer since commit bb646cdb12e75d82258c2f2e7746d5952d3e321a ("proc_pid_attr_write(): switch to memdup_user()"). Fix the off-by-one error. Even with this fix, setting and clearing /proc/pid/attr attributes from the shell is not straightforward since the interface does not support multiple write() calls (so shells that write the value and newline separately will set and then immediately clear the attribute, requiring use of echo -n to set the attribute), whereas trying to use echo -n "" to clear the attribute causes the shell to skip the write() call altogether since POSIX says that a zero-length write causes no side effects. Thus, one must use echo -n to set and echo without -n to clear, as in the following example: $ echo -n unconfined_u:object_r:user_home_t:s0 > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate unconfined_u:object_r:user_home_t:s0 $ echo "" > /proc/$$/attr/fscreate $ cat /proc/$$/attr/fscreate Note the use of /proc/$$ rather than /proc/self, as otherwise the cat command will read its own attribute value, not that of the shell. There are no users of this facility to my knowledge; possibly we should just get rid of it. UPDATE: Upon further investigation it appears that a local process with the process:setfscreate permission can cause a kernel panic as a result of this bug. This patch fixes CVE-2017-2618. Signed-off-by: Stephen Smalley [PM: added the update about CVE-2017-2618 to the commit description] Cc: stable@vger.kernel.org # 3.5: d6ea83ec6864e Signed-off-by: Paul Moore Signed-off-by: James Morris

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2016-12-22T18:03:52+00:00

Pull SElinux fix from James Morris: "From Paul: 'A small SELinux patch to fix some clang/llvm compiler warnings and ensure the tools under scripts work well in the face of kernel changes'" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: selinux: use the kernel headers when building scripts/selinux

selinux: use the kernel headers when building scripts/selinux

2016-12-21T15:39:25+00:00

Commit 3322d0d64f4e ("selinux: keep SELinux in sync with new capability definitions") added a check on the defined capabilities without explicitly including the capability header file which caused problems when building genheaders for users of clang/llvm. Resolve this by using the kernel headers when building genheaders, which is arguably the right thing to do regardless, and explicitly including the kernel's capability.h header file in classmap.h. We also update the mdp build, even though it wasn't causing an error we really should be using the headers from the kernel we are building. Reported-by: Nicolas Iooss Signed-off-by: Paul Moore

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2016-12-14T21:57:44+00:00

Pull security subsystem updates from James Morris: "Generally pretty quiet for this release. Highlights: Yama: - allow ptrace access for original parent after re-parenting TPM: - add documentation - many bugfixes & cleanups - define a generic open() method for ascii & bios measurements Integrity: - Harden against malformed xattrs SELinux: - bugfixes & cleanups Smack: - Remove unnecessary smack_known_invalid label - Do not apply star label in smack_setprocattr hook - parse mnt opts after privileges check (fixes unpriv DoS vuln)" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (56 commits) Yama: allow access for the current ptrace parent tpm: adjust return value of tpm_read_log tpm: vtpm_proxy: conditionally call tpm_chip_unregister tpm: Fix handling of missing event log tpm: Check the bios_dir entry for NULL before accessing it tpm: return -ENODEV if np is not set tpm: cleanup of printk error messages tpm: replace of_find_node_by_name() with dev of_node property tpm: redefine read_log() to handle ACPI/OF at runtime tpm: fix the missing .owner in tpm_bios_measurements_ops tpm: have event log use the tpm_chip tpm: drop tpm1_chip_register(/unregister) tpm: replace dynamically allocated bios_dir with a static array tpm: replace symbolic permission with octal for securityfs files char: tpm: fix kerneldoc tpm2_unseal_trusted name typo tpm_tis: Allow tpm_tis to be bound using DT tpm, tpm_vtpm_proxy: add kdoc comments for VTPM_PROXY_IOC_NEW_DEV tpm: Only call pm_runtime_get_sync if device has a parent tpm: define a generic open() method for ascii & bios measurements Documentation: tpm: add the Physical TPM device tree binding documentation ...

selinux: Convert isec->lock into a spinlock

2016-11-22T22:44:02+00:00

Convert isec->lock from a mutex into a spinlock. Instead of holding the lock while sleeping in inode_doinit_with_dentry, set isec->initialized to LABEL_PENDING and release the lock. Then, when the sid has been determined, re-acquire the lock. If isec->initialized is still set to LABEL_PENDING, set isec->sid; otherwise, the sid has been set by another task (LABEL_INITIALIZED) or invalidated (LABEL_INVALID) in the meantime. This fixes a deadlock on gfs2 where * one task is in inode_doinit_with_dentry -> gfs2_getxattr, holds isec->lock, and tries to acquire the inode's glock, and * another task is in do_xmote -> inode_go_inval -> selinux_inode_invalidate_secctx, holds the inode's glock, and tries to acquire isec->lock. Signed-off-by: Andreas Gruenbacher [PM: minor tweaks to keep checkpatch.pl happy] Signed-off-by: Paul Moore

selinux: keep SELinux in sync with new capability definitions

2016-11-21T20:37:24+00:00

When a new capability is defined, SELinux needs to be updated. Trigger a build error if a new capability is defined without corresponding update to security/selinux/include/classmap.h's COMMON_CAP2_PERMS. This is similar to BUILD_BUG_ON() guards in the SELinux nlmsgtab code to ensure that SELinux tracks new netlink message types as needed. Note that there is already a similar build guard in security/selinux/hooks.c to detect when more than 64 capabilities are defined, since that will require adding a third capability class to SELinux. A nicer way to do this would be to extend scripts/selinux/genheaders or a similar tool to auto-generate the necessary definitions and code for SELinux capability checking from include/uapi/linux/capability.h. AppArmor does something similar in its Makefile, although it only needs to generate a single table of names. That is left as future work. Signed-off-by: Stephen Smalley [PM: reformat the description to keep checkpatch.pl happy] Signed-off-by: Paul Moore

selinux: normalize input to /sys/fs/selinux/enforce

2016-11-20T22:13:19+00:00

At present, one can write any signed integer value to /sys/fs/selinux/enforce and it will be stored, e.g. echo -1 > /sys/fs/selinux/enforce or echo 2 > /sys/fs/selinux/enforce. This makes no real difference to the kernel, since it only ever cares if it is zero or non-zero, but some userspace code compares it with 1 to decide if SELinux is enforcing, and this could confuse it. Only a process that is already root and is allowed the setenforce permission in SELinux policy can write to /sys/fs/selinux/enforce, so this is not considered to be a security issue, but it should be fixed. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore

posix-timers: Make them configurable

2016-11-16T08:26:35+00:00

Some embedded systems have no use for them. This removes about 25KB from the kernel binary size when configured out. Corresponding syscalls are routed to a stub logging the attempt to use those syscalls which should be enough of a clue if they were disabled without proper consideration. They are: timer_create, timer_gettime: timer_getoverrun, timer_settime, timer_delete, clock_adjtime, setitimer, getitimer, alarm. The clock_settime, clock_gettime, clock_getres and clock_nanosleep syscalls are replaced by simple wrappers compatible with CLOCK_REALTIME, CLOCK_MONOTONIC and CLOCK_BOOTTIME only which should cover the vast majority of use cases with very little code. Signed-off-by: Nicolas Pitre Acked-by: Richard Cochran Acked-by: Thomas Gleixner Acked-by: John Stultz Reviewed-by: Josh Triplett Cc: Paul Bolle Cc: linux-kbuild@vger.kernel.org Cc: netdev@vger.kernel.org Cc: Michal Marek Cc: Edward Cree Link: http://lkml.kernel.org/r/1478841010-28605-7-git-send-email-nicolas.pitre@linaro.org Signed-off-by: Thomas Gleixner

selinux: Clean up initialization of isec->sclass

2016-11-14T20:53:04+00:00

Now that isec->initialized == LABEL_INITIALIZED implies that isec->sclass is valid, skip such inodes immediately in inode_doinit_with_dentry. For the remaining inodes, initialize isec->sclass at the beginning of inode_doinit_with_dentry to simplify the code. Signed-off-by: Andreas Gruenbacher Signed-off-by: Paul Moore

proc: Pass file mode to proc_pid_make_inode

2016-11-14T20:39:48+00:00

Pass the file mode of the proc inode to be created to proc_pid_make_inode. In proc_pid_make_inode, initialize inode->i_mode before calling security_task_to_inode. This allows selinux to set isec->sclass right away without introducing "half-initialized" inode security structs. Signed-off-by: Andreas Gruenbacher Signed-off-by: Paul Moore