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2021-10-28evm: mark evm_fixmode as __ro_after_initAustin Kim1-1/+1
The evm_fixmode is only configurable by command-line option and it is never modified outside initcalls, so declaring it with __ro_after_init is better. Signed-off-by: Austin Kim <austin.kim@lge.com> Cc: stable@vger.kernel.org Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-22smackfs: use netlbl_cfg_cipsov4_del() for deleting cipso_v4_doiTetsuo Handa1-1/+1
syzbot is reporting UAF at cipso_v4_doi_search() [1], for smk_cipso_doi() is calling kfree() without removing from the cipso_v4_doi_list list after netlbl_cfg_cipsov4_map_add() returned an error. We need to use netlbl_cfg_cipsov4_del() in order to remove from the list and wait for RCU grace period before kfree(). Link: https://syzkaller.appspot.com/bug?extid=93dba5b91f0fed312cbd [1] Reported-by: syzbot <syzbot+93dba5b91f0fed312cbd@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Fixes: 6c2e8ac0953fccdd ("netlabel: Update kernel configuration API") Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-10-22smackfs: use __GFP_NOFAIL for smk_cipso_doi()Tetsuo Handa1-3/+1
syzbot is reporting kernel panic at smk_cipso_doi() due to memory allocation fault injection [1]. The reason for need to use panic() was not explained. But since no fix was proposed for 18 months, for now let's use __GFP_NOFAIL for utilizing syzbot resource on other bugs. Link: https://syzkaller.appspot.com/bug?extid=89731ccb6fec15ce1c22 [1] Reported-by: syzbot <syzbot+89731ccb6fec15ce1c22@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-10-21Merge branch 'ucount-fixes-for-v5.15' of ↵Linus Torvalds1-0/+8
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull ucounts fixes from Eric Biederman: "There has been one very hard to track down bug in the ucount code that we have been tracking since roughly v5.14 was released. Alex managed to find a reliable reproducer a few days ago and then I was able to instrument the code and figure out what the issue was. It turns out the sigqueue_alloc single atomic operation optimization did not play nicely with ucounts multiple level rlimits. It turned out that either sigqueue_alloc or sigqueue_free could be operating on multiple levels and trigger the conditions for the optimization on more than one level at the same time. To deal with that situation I have introduced inc_rlimit_get_ucounts and dec_rlimit_put_ucounts that just focuses on the optimization and the rlimit and ucount changes. While looking into the big bug I found I couple of other little issues so I am including those fixes here as well. When I have time I would very much like to dig into process ownership of the shared signal queue and see if we could pick a single owner for the entire queue so that all of the rlimits can count to that owner. That should entirely remove the need to call get_ucounts and put_ucounts in sigqueue_alloc and sigqueue_free. It is difficult because Linux unlike POSIX supports setuid that works on a single thread" * 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring ucounts: Proper error handling in set_cred_ucounts ucounts: Pair inc_rlimit_ucounts with dec_rlimit_ucoutns in commit_creds ucounts: Fix signal ucount refcounting
2021-10-21gcc-plugins: Explicitly document purpose and deprecation scheduleKees Cook1-3/+6
GCC plugins should only exist when some compiler feature needs to be proven but does not exist in either GCC nor Clang. For example, if a desired feature is already in Clang, it should be added to GCC upstream. Document this explicitly. Additionally, mark the plugins with matching upstream GCC features as removable past their respective GCC versions. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: llvm@lists.linux.dev Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211020173554.38122-2-keescook@chromium.org
2021-10-20ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyringEric W. Biederman1-0/+8
Setting cred->ucounts in cred_alloc_blank does not make sense. The uid and user_ns are deliberately not set in cred_alloc_blank but instead the setting is delayed until key_change_session_keyring. So move dealing with ucounts into key_change_session_keyring as well. Unfortunately that movement of get_ucounts adds a new failure mode to key_change_session_keyring. I do not see anything stopping the parent process from calling setuid and changing the relevant part of it's cred while keyctl_session_to_parent is running making it fundamentally necessary to call get_ucounts in key_change_session_keyring. Which means that the new failure mode cannot be avoided. A failure of key_change_session_keyring results in a single threaded parent keeping it's existing credentials. Which results in the parent process not being able to access the session keyring and whichever keys are in the new keyring. Further get_ucounts is only expected to fail if the number of bits in the refernece count for the structure is too few. Since the code has no other way to report the failure of get_ucounts and because such failures are not expected to be common add a WARN_ONCE to report this problem to userspace. Between the WARN_ONCE and the parent process not having access to the keys in the new session keyring I expect any failure of get_ucounts will be noticed and reported and we can find another way to handle this condition. (Possibly by just making ucounts->count an atomic_long_t). Cc: stable@vger.kernel.org Fixes: 905ae01c4ae2 ("Add a reference to ucounts for each cred") Link: https://lkml.kernel.org/r/7k0ias0uf.fsf_-_@disp2133 Tested-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Alexey Gladkov <legion@kernel.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-10-20security: Return xattr name from security_dentry_init_security()Vivek Goyal2-4/+9
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>
2021-10-19selinux: fix a sock regression in selinux_ip_postroute_compat()Paul Moore1-2/+2
Unfortunately we can't rely on nf_hook_state->sk being the proper originating socket so revert to using skb_to_full_sk(skb). Fixes: 1d1e1ded1356 ("selinux: make better use of the nf_hook_state passed to the NF hooks") Reported-by: Linux Kernel Functional Testing <lkft@linaro.org> Suggested-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-14binder: use cred instead of task for selinux checksTodd Kjos2-42/+20
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: 79af73079d75 ("Add security hooks to binder and implement the hooks for SELinux.") Suggested-by: Jann Horn <jannh@google.com> Signed-off-by: Todd Kjos <tkjos@google.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-14LSM: Avoid warnings about potentially unused hook variablesKees Cook1-1/+1
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: 98e828a0650f ("security: Refactor declaration of LSM hooks") Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-13Smack: fix W=1 build warningsCasey Schaufler1-12/+18
A couple of functions had malformed comment blocks. Namespace parameters were added without updating the comment blocks. These are all repaired in the Smack code, so "% make W=1 security/smack" is warning free. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-10-13selinux: fix all of the W=1 build warningsPaul Moore6-8/+33
There were a number of places in the code where the function definition did not match the associated comment block as well at least one file where the appropriate header files were not included (missing function declaration/prototype); this patch fixes all of these issue such that building the SELinux code with "W=1" is now warning free. % make W=1 security/selinux/ Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-13selinux: make better use of the nf_hook_state passed to the NF hooksPaul Moore1-27/+25
This patch builds on a previous SELinux/netfilter patch by Florian Westphal and makes better use of the nf_hook_state variable passed into the SELinux/netfilter hooks as well as a number of other small cleanups in the related code. Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-12smack: remove duplicated hook functionFlorian Westphal1-23/+3
ipv4 and ipv6 hook functions are identical, remove one. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-10-11selinux: fix race condition when computing ocontext SIDsOndrej Mosnacek1-85/+77
Current code contains a lot of racy patterns when converting an ocontext's context structure to an SID. This is being done in a "lazy" fashion, such that the SID is looked up in the SID table only when it's first needed and then cached in the "sid" field of the ocontext structure. However, this is done without any locking or memory barriers and is thus unsafe. Between commits 24ed7fdae669 ("selinux: use separate table for initial SID lookup") and 66f8e2f03c02 ("selinux: sidtab reverse lookup hash table"), this race condition lead to an actual observable bug, because a pointer to the shared sid field was passed directly to sidtab_context_to_sid(), which was using this location to also store an intermediate value, which could have been read by other threads and interpreted as an SID. In practice this caused e.g. new mounts to get a wrong (seemingly random) filesystem context, leading to strange denials. This bug has been spotted in the wild at least twice, see [1] and [2]. Fix the race condition by making all the racy functions use a common helper that ensures the ocontext::sid accesses are made safely using the appropriate SMP constructs. Note that security_netif_sid() was populating the sid field of both contexts stored in the ocontext, but only the first one was actually used. The SELinux wiki's documentation on the "netifcon" policy statement [3] suggests that using only the first context is intentional. I kept only the handling of the first context here, as there is really no point in doing the SID lookup for the unused one. I wasn't able to reproduce the bug mentioned above on any kernel that includes commit 66f8e2f03c02, even though it has been reported that the issue occurs with that commit, too, just less frequently. Thus, I wasn't able to verify that this patch fixes the issue, but it makes sense to avoid the race condition regardless. [1] https://github.com/containers/container-selinux/issues/89 [2] https://lists.fedoraproject.org/archives/list/selinux@lists.fedoraproject.org/thread/6DMTAMHIOAOEMUAVTULJD45JZU7IBAFM/ [3] https://selinuxproject.org/page/NetworkStatements#netifcon Cc: stable@vger.kernel.org Cc: Xinjie Zheng <xinjie@google.com> Reported-by: Sujithra Periasamy <sujithra@google.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-11selinux: remove unneeded ipv6 hook wrappersFlorian Westphal1-62/+18
Netfilter places the protocol number the hook function is getting called from in state->pf, so we can use that instead of an extra wrapper. While at it, remove one-line wrappers too and make selinux_ip_{out,forward,postroute} useable as hook function. Signed-off-by: Florian Westphal <fw@strlen.de> Message-Id: <20211011202229.28289-1-fw@strlen.de> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-09ima: Use strscpy instead of strlcpyPetr Vorel2-2/+2
strlcpy is deprecated, use its safer replacement. Signed-off-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09ima_policy: Remove duplicate 'the' in docs commentPetr Vorel1-2/+1
Also join string (short enough to be on single line). Signed-off-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09ima: add gid supportCurtis Veit1-27/+174
IMA currently supports the concept of rules based on uid where the rule is based on the uid of the file owner or the uid of the user accessing the file. Provide the ability to have similar rules based on gid. Signed-off-by: Curtis Veit <veit@vpieng.com> Co-developed-by: Alex Henrie <alexh@vpitech.com> Signed-off-by: Alex Henrie <alexh@vpitech.com> Reviewed-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09ima: fix uid code style problemsAlex Henrie1-4/+6
scripts/checkpatch.pl wants function arguments to have names; and Mimi prefers to keep the line length in functions to 80 characters or less. Signed-off-by: Alex Henrie <alexh@vpitech.com> Reviewed-by: Petr Vorel <pvorel@suse.cz> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-09ima: fix deadlock when traversing "ima_default_rules".liqiong1-9/+18
The current IMA ruleset is identified by the variable "ima_rules" that default to "&ima_default_rules". When loading a custom policy for the first time, the variable is updated to "&ima_policy_rules" instead. That update isn't RCU-safe, and deadlocks are possible. Indeed, some functions like ima_match_policy() may loop indefinitely when traversing "ima_default_rules" with list_for_each_entry_rcu(). When iterating over the default ruleset back to head, if the list head is "ima_default_rules", and "ima_rules" have been updated to "&ima_policy_rules", the loop condition (&entry->list != ima_rules) stays always true, traversing won't terminate, causing a soft lockup and RCU stalls. Introduce a temporary value for "ima_rules" when iterating over the ruleset to avoid the deadlocks. Signed-off-by: liqiong <liqiong@nfschina.com> Reviewed-by: THOBY Simon <Simon.THOBY@viveris.fr> Fixes: 38d859f991f3 ("IMA: policy can now be updated multiple times") Reported-by: kernel test robot <lkp@intel.com> (Fix sparse: incompatible types in comparison expression.) Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-10-07Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/David S. Miller1-1/+3
ipsec Steffen Klassert says: ==================== pull request (net): ipsec 2021-10-07 1) Fix a sysbot reported shift-out-of-bounds in xfrm_get_default. From Pavel Skripkin. 2) Fix XFRM_MSG_MAPPING ABI breakage. The new XFRM_MSG_MAPPING messages were accidentally not paced at the end. Fix by Eugene Syromiatnikov. 3) Fix the uapi for the default policy, use explicit field and macros and make it accessible to userland. From Nicolas Dichtel. 4) Fix a missing rcu lock in xfrm_notify_userpolicy(). From Nicolas Dichtel. Please pull or let me know if there are problems. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-30selinux: remove the SELinux lockdown implementationPaul Moore2-32/+0
NOTE: This patch intentionally omits any "Fixes:" metadata or stable tagging since it removes a SELinux access control check; while removing the control point is the right thing to do moving forward, removing it in stable kernels could be seen as a regression. The original SELinux lockdown implementation in 59438b46471a ("security,lockdown,selinux: implement SELinux lockdown") used the current task's credentials as both the subject and object in the SELinux lockdown hook, selinux_lockdown(). Unfortunately that proved to be incorrect in a number of cases as the core kernel was calling the LSM lockdown hook in places where the credentials from the "current" task_struct were not the correct credentials to use in the SELinux access check. Attempts were made to resolve this by adding a credential pointer to the LSM lockdown hook as well as suggesting that the single hook be split into two: one for user tasks, one for kernel tasks; however neither approach was deemed acceptable by Linus. Faced with the prospect of either changing the subj/obj in the access check to a constant context (likely the kernel's label) or removing the SELinux lockdown check entirely, the SELinux community decided that removing the lockdown check was preferable. The supporting changes to the general LSM layer are left intact, this patch only removes the SELinux implementation. Acked-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-28selinux: enable genfscon labeling for securityfsChristian Göttsche1-1/+2
Add support for genfscon per-file labeling of securityfs files. This allows for separate labels and thereby access control for different files. For example a genfscon statement genfscon securityfs /integrity/ima/policy \ system_u:object_r:ima_policy_t:s0 will set a private label to the IMA policy file and thus allow to control the ability to set the IMA policy. Setting labels directly with setxattr(2), e.g. by chcon(1) or setfiles(8), is still not supported. Signed-off-by: Christian Göttsche <cgzones@googlemail.com> [PM: line width fixes in the commit description] Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-28Smack:- Use overlay inode label in smack_inode_copy_up()Vishal Goel1-1/+1
Currently in "smack_inode_copy_up()" function, process label is changed with the label on parent inode. Due to which, process is assigned directory label and whatever file or directory created by the process are also getting directory label which is wrong label. Changes has been done to use label of overlay inode instead of parent inode. Signed-off-by: Vishal Goel <vishal.goel@samsung.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-09-25hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZEROKees Cook1-1/+4
Currently under Clang, CC_HAS_AUTO_VAR_INIT_ZERO requires an extra -enable flag compared to CC_HAS_AUTO_VAR_INIT_PATTERN. GCC 12[1] will not, and will happily ignore the Clang-specific flag. However, its presence on the command-line is both cumbersome and confusing. Due to GCC's tolerant behavior, though, we can continue to use a single Kconfig cc-option test for the feature on both compilers, but then drop the Clang-specific option in the Makefile. In other words, this patch does not change anything other than making the compiler command line shorter once GCC supports -ftrivial-auto-var-init=zero. [1] https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=a25e0b5e6ac8a77a71c229e0a7b744603365b0e9 Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: llvm@lists.linux.dev Fixes: dcb7c0b9461c ("hardening: Clarify Kconfig text for auto-var-init") Suggested-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/lkml/20210914102837.6172-1-will@kernel.org/ Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2021-09-25fortify: Explicitly disable Clang supportKees Cook1-0/+3
Clang has never correctly compiled the FORTIFY_SOURCE defenses due to a couple bugs: Eliding inlines with matching __builtin_* names https://bugs.llvm.org/show_bug.cgi?id=50322 Incorrect __builtin_constant_p() of some globals https://bugs.llvm.org/show_bug.cgi?id=41459 In the process of making improvements to the FORTIFY_SOURCE defenses, the first (silent) bug (coincidentally) becomes worked around, but exposes the latter which breaks the build. As such, Clang must not be used with CONFIG_FORTIFY_SOURCE until at least latter bug is fixed (in Clang 13), and the fortify routines have been rearranged. Update the Kconfig to reflect the reality of the current situation. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/lkml/CAKwvOd=A+ueGV2ihdy5GtgR2fQbcXjjAtVxv3=cPjffpebZB7A@mail.gmail.com
2021-09-24smack: Guard smack_ipv6_lock definition within a SMACK_IPV6_PORT_LABELING blockSebastian Andrzej Siewior1-3/+6
The mutex smack_ipv6_lock is only used with the SMACK_IPV6_PORT_LABELING block but its definition is outside of the block. This leads to a defined-but-not-used warning on PREEMPT_RT. Moving smack_ipv6_lock down to the block where it is used where it used raises the question why is smk_ipv6_port_list read if nothing is added to it. Turns out, only smk_ipv6_port_check() is using it outside of an ifdef SMACK_IPV6_PORT_LABELING block. However two of three caller invoke smk_ipv6_port_check() from a ifdef block and only one is using __is_defined() macro which requires the function and smk_ipv6_port_list to be around. Put the lock and list inside an ifdef SMACK_IPV6_PORT_LABELING block to avoid the warning regarding unused mutex. Extend the ifdef-block to also cover smk_ipv6_port_check(). Make smack_socket_connect() use ifdef instead of __is_defined() to avoid complains about missing function. Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-09-23selinux,smack: fix subjective/objective credential use mixupsPaul Moore2-4/+4
Jann Horn reported a problem with commit eb1231f73c4d ("selinux: clarify task subjective and objective credentials") where some LSM hooks were attempting to access the subjective credentials of a task other than the current task. Generally speaking, it is not safe to access another task's subjective credentials and doing so can cause a number of problems. Further, while looking into the problem, I realized that Smack was suffering from a similar problem brought about by a similar commit 1fb057dcde11 ("smack: differentiate between subjective and objective task credentials"). This patch addresses this problem by restoring the use of the task's objective credentials in those cases where the task is other than the current executing task. Not only does this resolve the problem reported by Jann, it is arguably the correct thing to do in these cases. Cc: stable@vger.kernel.org Fixes: eb1231f73c4d ("selinux: clarify task subjective and objective credentials") Fixes: 1fb057dcde11 ("smack: differentiate between subjective and objective task credentials") Reported-by: Jann Horn <jannh@google.com> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19lsm_audit: avoid overloading the "key" audit fieldOndrej Mosnacek1-1/+1
The "key" field is used to associate records with the rule that triggered them, os it's not a good idea to overload it with an additional IPC key semantic. Moreover, as the classic "key" field is a text field, while the IPC key is numeric, AVC records containing the IPC key info actually confuse audit userspace, which tries to interpret the number as a hex-encoded string, thus showing garbage for example in the ausearch "interpret" output mode. Hence, change it to "ipc_key" to fix both issues and also make the meaning of this field more clear. Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19Smack: Brutalist io_uring supportCasey Schaufler1-0/+46
Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE for the override_creds case and CAP_MAC_ADMIN for creating a polling thread. These choices are based on conjecture regarding the intent of the surrounding code. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> [PM: make the smack_uring_* funcs static, remove debug code] Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19selinux: add support for the io_uring access controlsPaul Moore2-0/+36
This patch implements two new io_uring access controls, specifically support for controlling the io_uring "personalities" and IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves is handled via the normal file/inode labeling and sharing mechanisms. The io_uring { override_creds } permission restricts which domains the subject domain can use to override it's own credentials. Granting a domain the io_uring { override_creds } permission allows it to impersonate another domain in io_uring operations. The io_uring { sqpoll } permission restricts which domains can create asynchronous io_uring polling threads. This is important from a security perspective as operations queued by this asynchronous thread inherit the credentials of the thread creator by default; if an io_uring is shared across process/domain boundaries this could result in one domain impersonating another. Controlling the creation of sqpoll threads, and the sharing of io_urings across processes, allow policy authors to restrict the ability of one domain to impersonate another via io_uring. As a quick summary, this patch adds a new object class with two permissions: io_uring { override_creds sqpoll } These permissions can be seen in the two simple policy statements below: allow domA_t domB_t : io_uring { override_creds }; allow domA_t self : io_uring { sqpoll }; Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19lsm,io_uring: add LSM hooks to io_uringPaul Moore1-0/+12
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>
2021-09-15smackfs: Fix use-after-free in netlbl_catmap_walk()Pawan Gupta1-1/+4
Syzkaller reported use-after-free bug as described in [1]. The bug is triggered when smk_set_cipso() tries to free stale category bitmaps while there are concurrent reader(s) using the same bitmaps. Wait for RCU grace period to finish before freeing the category bitmaps in smk_set_cipso(). This makes sure that there are no more readers using the stale bitmaps and freeing them should be safe. [1] https://lore.kernel.org/netdev/000000000000a814c505ca657a4e@google.com/ Reported-by: syzbot+3f91de0b813cc3d19a80@syzkaller.appspotmail.com Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
2021-09-14include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakageEugene Syromiatnikov1-1/+3
Commit 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING enum item, thus also evading the build-time check in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper security permission checks in nlmsg_xfrm_perms. Fix it by placing XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before __XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly. Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy") References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/ Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com> Acked-by: Antony Antony <antony.antony@secunet.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2021-09-03Merge tag 'kbuild-v5.15' of ↵Linus Torvalds1-11/+0
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add -s option (strict mode) to merge_config.sh to make it fail when any symbol is redefined. - Show a warning if a different compiler is used for building external modules. - Infer --target from ARCH for CC=clang to let you cross-compile the kernel without CROSS_COMPILE. - Make the integrated assembler default (LLVM_IAS=1) for CC=clang. - Add <linux/stdarg.h> to the kernel source instead of borrowing <stdarg.h> from the compiler. - Add Nick Desaulniers as a Kbuild reviewer. - Drop stale cc-option tests. - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG to handle symbols in inline assembly. - Show a warning if 'FORCE' is missing for if_changed rules. - Various cleanups * tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kbuild: redo fake deps at include/ksym/*.h kbuild: clean up objtool_args slightly modpost: get the *.mod file path more simply checkkconfigsymbols.py: Fix the '--ignore' option kbuild: merge vmlinux_link() between ARCH=um and other architectures kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh kbuild: merge vmlinux_link() between the ordinary link and Clang LTO kbuild: remove stale *.symversions kbuild: remove unused quiet_cmd_update_lto_symversions gen_compile_commands: extract compiler command from a series of commands x86: remove cc-option-yn test for -mtune= arc: replace cc-option-yn uses with cc-option s390: replace cc-option-yn uses with cc-option ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild sparc: move the install rule to arch/sparc/Makefile security: remove unneeded subdir-$(CONFIG_...) kbuild: sh: remove unused install script kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y kbuild: Switch to 'f' variants of integrated assembler flag kbuild: Shuffle blank line to improve comment meaning ...
2021-09-03Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-4/+9
Merge misc updates from Andrew Morton: "173 patches. Subsystems affected by this series: ia64, ocfs2, block, and mm (debug, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock, oom-kill, migration, ksm, percpu, vmstat, and madvise)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits) mm/madvise: add MADV_WILLNEED to process_madvise() mm/vmstat: remove unneeded return value mm/vmstat: simplify the array size calculation mm/vmstat: correct some wrong comments mm/percpu,c: remove obsolete comments of pcpu_chunk_populated() selftests: vm: add COW time test for KSM pages selftests: vm: add KSM merging time test mm: KSM: fix data type selftests: vm: add KSM merging across nodes test selftests: vm: add KSM zero page merging test selftests: vm: add KSM unmerge test selftests: vm: add KSM merge test mm/migrate: correct kernel-doc notation mm: wire up syscall process_mrelease mm: introduce process_mrelease system call memblock: make memblock_find_in_range method private mm/mempolicy.c: use in_task() in mempolicy_slab_node() mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies mm/mempolicy: advertise new MPOL_PREFERRED_MANY mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY ...
2021-09-03mm/pagemap: add mmap_assert_locked() annotations to find_vma*()Luigi Rizzo1-4/+9
find_vma() and variants need protection when used. This patch adds mmap_assert_lock() calls in the functions. To make sure the invariant is satisfied, we also need to add a mmap_read_lock() around the get_user_pages_remote() call in get_arg_page(). The lock is not strictly necessary because the mm has been newly created, but the extra cost is limited because the same mutex was also acquired shortly before in __bprm_mm_init(), so it is hot and uncontended. [penguin-kernel@i-love.sakura.ne.jp: TOMOYO needs the same protection which get_arg_page() needs] Link: https://lkml.kernel.org/r/58bb6bf7-a57e-8a40-e74b-39584b415152@i-love.sakura.ne.jp Link: https://lkml.kernel.org/r/20210731175341.3458608-1-lrizzo@google.com Signed-off-by: Luigi Rizzo <lrizzo@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-03security: remove unneeded subdir-$(CONFIG_...)Masahiro Yamada1-11/+0
All of these are unneeded. The directories to descend are specified by obj-$(CONFIG_...). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-02Merge tag 'integrity-v5.15' of ↵Linus Torvalds11-67/+320
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull integrity subsystem updates from Mimi Zohar: - Limit the allowed hash algorithms when writing security.ima xattrs or verifying them, based on the IMA policy and the configured hash algorithms. - Return the calculated "critical data" measurement hash and size to avoid code duplication. (Preparatory change for a proposed LSM.) - and a single patch to address a compiler warning. * tag 'integrity-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: IMA: reject unknown hash algorithms in ima_get_hash_algo IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithms IMA: introduce a new policy option func=SETXATTR_CHECK IMA: add a policy option to restrict xattr hash algorithms on appraisal IMA: add support to restrict the hash algorithms used for file appraisal IMA: block writes of the security.ima xattr with unsupported algorithms IMA: remove the dependency on CRYPTO_MD5 ima: Add digest and digest_len params to the functions to measure a buffer ima: Return int in the functions to measure a buffer ima: Introduce ima_get_current_hash_algo() IMA: remove -Wmissing-prototypes warning
2021-09-02Merge tag 'hardening-v5.15-rc1' of ↵Linus Torvalds1-20/+51
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: - Expand lib/test_stackinit to include more initialization styles - Improve Kconfig for CLang's auto-var-init feature - Introduce support for GCC's zero-call-used-regs feature * tag 'hardening-v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lib/test_stackinit: Add assigned initializers lib/test_stackinit: Allow building stand-alone lib/test_stackinit: Fix static initializer test hardening: Clarify Kconfig text for auto-var-init hardening: Introduce CONFIG_ZERO_CALL_USED_REGS
2021-08-31Merge tag 'net-next-5.15' of ↵Linus Torvalds2-2/+6
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Enable memcg accounting for various networking objects. BPF: - Introduce bpf timers. - Add perf link and opaque bpf_cookie which the program can read out again, to be used in libbpf-based USDT library. - Add bpf_task_pt_regs() helper to access user space pt_regs in kprobes, to help user space stack unwinding. - Add support for UNIX sockets for BPF sockmap. - Extend BPF iterator support for UNIX domain sockets. - Allow BPF TCP congestion control progs and bpf iterators to call bpf_setsockopt(), e.g. to switch to another congestion control algorithm. Protocols: - Support IOAM Pre-allocated Trace with IPv6. - Support Management Component Transport Protocol. - bridge: multicast: add vlan support. - netfilter: add hooks for the SRv6 lightweight tunnel driver. - tcp: - enable mid-stream window clamping (by user space or BPF) - allow data-less, empty-cookie SYN with TFO_SERVER_COOKIE_NOT_REQD - more accurate DSACK processing for RACK-TLP - mptcp: - add full mesh path manager option - add partial support for MP_FAIL - improve use of backup subflows - optimize option processing - af_unix: add OOB notification support. - ipv6: add IFLA_INET6_RA_MTU to expose MTU value advertised by the router. - mac80211: Target Wake Time support in AP mode. - can: j1939: extend UAPI to notify about RX status. Driver APIs: - Add page frag support in page pool API. - Many improvements to the DSA (distributed switch) APIs. - ethtool: extend IRQ coalesce uAPI with timer reset modes. - devlink: control which auxiliary devices are created. - Support CAN PHYs via the generic PHY subsystem. - Proper cross-chip support for tag_8021q. - Allow TX forwarding for the software bridge data path to be offloaded to capable devices. Drivers: - veth: more flexible channels number configuration. - openvswitch: introduce per-cpu upcall dispatch. - Add internet mix (IMIX) mode to pktgen. - Transparently handle XDP operations in the bonding driver. - Add LiteETH network driver. - Renesas (ravb): - support Gigabit Ethernet IP - NXP Ethernet switch (sja1105): - fast aging support - support for "H" switch topologies - traffic termination for ports under VLAN-aware bridge - Intel 1G Ethernet - support getcrosststamp() with PCIe PTM (Precision Time Measurement) for better time sync - support Credit-Based Shaper (CBS) offload, enabling HW traffic prioritization and bandwidth reservation - Broadcom Ethernet (bnxt) - support pulse-per-second output - support larger Rx rings - Mellanox Ethernet (mlx5) - support ethtool RSS contexts and MQPRIO channel mode - support LAG offload with bridging - support devlink rate limit API - support packet sampling on tunnels - Huawei Ethernet (hns3): - basic devlink support - add extended IRQ coalescing support - report extended link state - Netronome Ethernet (nfp): - add conntrack offload support - Broadcom WiFi (brcmfmac): - add WPA3 Personal with FT to supported cipher suites - support 43752 SDIO device - Intel WiFi (iwlwifi): - support scanning hidden 6GHz networks - support for a new hardware family (Bz) - Xen pv driver: - harden netfront against malicious backends - Qualcomm mobile - ipa: refactor power management and enable automatic suspend - mhi: move MBIM to WWAN subsystem interfaces Refactor: - Ambient BPF run context and cgroup storage cleanup. - Compat rework for ndo_ioctl. Old code removal: - prism54 remove the obsoleted driver, deprecated by the p54 driver. - wan: remove sbni/granch driver" * tag 'net-next-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1715 commits) net: Add depends on OF_NET for LiteX's LiteETH ipv6: seg6: remove duplicated include net: hns3: remove unnecessary spaces net: hns3: add some required spaces net: hns3: clean up a type mismatch warning net: hns3: refine function hns3_set_default_feature() ipv6: remove duplicated 'net/lwtunnel.h' include net: w5100: check return value after calling platform_get_resource() net/mlxbf_gige: Make use of devm_platform_ioremap_resourcexxx() net: mdio: mscc-miim: Make use of the helper function devm_platform_ioremap_resource() net: mdio-ipq4019: Make use of devm_platform_ioremap_resource() fou: remove sparse errors ipv4: fix endianness issue in inet_rtm_getroute_build_skb() octeontx2-af: Set proper errorcode for IPv4 checksum errors octeontx2-af: Fix static code analyzer reported issues octeontx2-af: Fix mailbox errors in nix_rss_flowkey_cfg octeontx2-af: Fix loop in free and unmap counter af_unix: fix potential NULL deref in unix_dgram_connect() dpaa2-eth: Replace strlcpy with strscpy octeontx2-af: Use NDC TX for transmit packet data ...
2021-08-31Merge tag 'for-5.15/dm-changes' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - Add DM infrastructure for IMA-based remote attestion. These changes are the basis for deploying DM-based storage in a "cloud" that must validate configurations end-users run to maintain trust. These DM changes allow supported DM targets' configurations to be measured via IMA. But the policy and enforcement (of which configurations are valid) is managed by something outside the kernel (e.g. Keylime). - Fix DM crypt scalability regression on systems with many cpus due to percpu_counter spinlock contention in crypt_page_alloc(). - Use in_hardirq() instead of deprecated in_irq() in DM crypt. - Add event counters to DM writecache to allow users to further assess how the writecache is performing. - Various code cleanup in DM writecache's main IO mapping function. * tag 'for-5.15/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm crypt: use in_hardirq() instead of deprecated in_irq() dm ima: update dm documentation for ima measurement support dm ima: update dm target attributes for ima measurements dm ima: add a warning in dm_init if duplicate ima events are not measured dm ima: prefix ima event name related to device mapper with dm_ dm ima: add version info to dm related events in ima log dm ima: prefix dm table hashes in ima log with hash algorithm dm crypt: Avoid percpu_counter spinlock contention in crypt_page_alloc() dm: add documentation for IMA measurement support dm: update target status functions to support IMA measurement dm ima: measure data on device rename dm ima: measure data on table clear dm ima: measure data on device remove dm ima: measure data on device resume dm ima: measure data on table load dm writecache: add event counters dm writecache: report invalid return from writecache_map helpers dm writecache: further writecache_map() cleanup dm writecache: factor out writecache_map_remap_origin() dm writecache: split up writecache_map() to improve code readability
2021-08-31Merge tag 'Smack-for-5.15' of git://github.com/cschaufler/smack-nextLinus Torvalds3-11/+10
Pull smack updates from Casey Schaufler: "There is a variable used only during start-up that's now marked __initdata and a change where the code was working by sheer luck that is now done properly. Both have been in next for several weeks and pass the Smack testsuite" * tag 'Smack-for-5.15' of git://github.com/cschaufler/smack-next: smack: mark 'smack_enabled' global variable as __initdata Smack: Fix wrong semantics in smk_access_entry()
2021-08-31Merge tag 'selinux-pr-20210830' of ↵Linus Torvalds2-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux Pull selinux update from Paul Moore: "We've got an unusually small SELinux pull request for v5.15 that consists of only one (?!) patch that is really pretty minor when you look at it. Unsurprisingly it passes all of our tests and merges cleanly on top of your tree right now, please merge this for v5.15" * tag 'selinux-pr-20210830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: selinux: return early for possible NULL audit buffers
2021-08-30Merge tag 'efi-core-2021-08-30' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull EFI updates from Ingo Molnar: "A handful of EFI changes for this cycle: - EFI CPER parsing improvements - Don't take the address of efi_guid_t internal fields" * tag 'efi-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: cper: check section header more appropriately efi: Don't use knowledge about efi_guid_t internals efi: cper: fix scnprintf() use in cper_mem_err_location()
2021-08-27efi: Don't use knowledge about efi_guid_t internalsAndy Shevchenko1-1/+1
When print GUIDs supply pointer to the efi_guid_t (guid_t) type rather its internal members. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2021-08-23IMA: reject unknown hash algorithms in ima_get_hash_algoTHOBY Simon1-1/+2
The new function validate_hash_algo() assumed that ima_get_hash_algo() always return a valid 'enum hash_algo', but it returned the user-supplied value present in the digital signature without any bounds checks. Update ima_get_hash_algo() to always return a valid hash algorithm, defaulting on 'ima_hash_algo' when the user-supplied value inside the xattr is invalid. Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr> Reported-by: syzbot+e8bafe7b82c739eaf153@syzkaller.appspotmail.com Fixes: 50f742dd9147 ("IMA: block writes of the security.ima xattr with unsupported algorithms") Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16IMA: prevent SETXATTR_CHECK policy rules with unavailable algorithmsTHOBY Simon1-0/+6
SETXATTR_CHECK policy rules assume that any algorithm listed in the 'appraise_algos' flag must be accepted when performing setxattr() on the security.ima xattr. However nothing checks that they are available in the current kernel. A userland application could hash a file with a digest that the kernel wouldn't be able to verify. However, if SETXATTR_CHECK is not in use, the kernel already forbids that xattr write. Verify that algorithms listed in appraise_algos are available to the current kernel and reject the policy update otherwise. This will fix the inconsistency between SETXATTR_CHECK and non-SETXATTR_CHECK behaviors. That filtering is only performed in ima_parse_appraise_algos() when updating policies so that we do not have to pay the price of allocating a hash object every time validate_hash_algo() is called in ima_inode_setxattr(). Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-08-16IMA: introduce a new policy option func=SETXATTR_CHECKTHOBY Simon4-17/+96
While users can restrict the accepted hash algorithms for the security.ima xattr file signature when appraising said file, users cannot restrict the algorithms that can be set on that attribute: any algorithm built in the kernel is accepted on a write. Define a new value for the ima policy option 'func' that restricts globally the hash algorithms accepted when writing the security.ima xattr. When a policy contains a rule of the form appraise func=SETXATTR_CHECK appraise_algos=sha256,sha384,sha512 only values corresponding to one of these three digest algorithms will be accepted for writing the security.ima xattr. Attempting to write the attribute using another algorithm (or "free-form" data) will be denied with an audit log message. In the absence of such a policy rule, the default is still to only accept hash algorithms built in the kernel (with all the limitations that entails). Signed-off-by: THOBY Simon <Simon.THOBY@viveris.fr> Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>