- Oct 19, 2022
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GONG, Ruiqi authored
The following warning was triggered on a hardware environment: SELinux: Converting 162 SID table entries... BUG: sleeping function called from invalid context at __might_sleep+0x60/0x74 0x0 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1 Call trace: dump_backtrace+0x0/0x1c8 show_stack+0x18/0x28 dump_stack+0xe8/0x15c ___might_sleep+0x168/0x17c __might_sleep+0x60/0x74 __kmalloc_track_caller+0xa0/0x7dc kstrdup+0x54/0xac convert_context+0x48/0x2e4 sidtab_context_to_sid+0x1c4/0x36c security_context_to_sid_core+0x168/0x238 security_context_to_sid_default+0x14/0x24 inode_doinit_use_xattr+0x164/0x1e4 inode_doinit_with_dentry+0x1c0/0x488 selinux_d_instantiate+0x20/0x34 security_d_instantiate+0x70/0xbc d_splice_alias+0x4c/0x3c0 ext4_lookup+0x1d8/0x200 [ext4] __lookup_slow+0x12c/0x1e4 walk_component+0x100/0x200 path_lookupat+0x88/0x118 filename_lookup+0x98/0x130 user_path_at_empty+0x48/0x60 vfs_statx+0x84/0x140 vfs_fstatat+0x20/0x30 __se_sys_newfstatat+0x30/0x74 __arm64_sys_newfstatat+0x1c/0x2c el0_svc_common.constprop.0+0x100/0x184 do_el0_svc+0x1c/0x2c el0_svc+0x20/0x34 el0_sync_handler+0x80/0x17c el0_sync+0x13c/0x140 SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is not valid (left unmapped). It was found that within a critical section of spin_lock_irqsave in sidtab_context_to_sid(), convert_context() (hooked by sidtab_convert_params.func) might cause the process to sleep via allocating memory with GFP_KERNEL, which is problematic. As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL. Therefore, fix this problem by adding a gfp_t argument for convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC properly in individual callers. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1] Reported-by:
Tan Ninghao <tanninghao1@huawei.com> Fixes: ee1a84fd ("selinux: overhaul sidtab to fix bug and improve performance") Signed-off-by:
GONG, Ruiqi <gongruiqi1@huawei.com> Reviewed-by:
Ondrej Mosnacek <omosnace@redhat.com> [PM: wrap long BUG() output lines, tweak subject line] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- Oct 04, 2022
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Vincenzo Frascino authored
The declaration of keyring_read does not match the definition (security/keys/keyring.c). In this case the definition is correct because it matches what defined in "struct key_type::read" (linux/key-type.h). Fix the declaration removing the inconsistent __user annotation. Cc: David Howells <dhowells@redhat.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: James Morris <jmorris@namei.org> Signed-off-by:
Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by:
Paul Moore <paul@paul-moore.com> Acked-by:
Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by:
Jarkko Sakkinen <jarkko@kernel.org>
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- Oct 03, 2022
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Alexander Potapenko authored
Heap and stack initialization is great, but not when we are trying uses of uninitialized memory. When the kernel is built with KMSAN, having kernel memory initialization enabled may introduce false negatives. We disable CONFIG_INIT_STACK_ALL_PATTERN and CONFIG_INIT_STACK_ALL_ZERO under CONFIG_KMSAN, making it impossible to auto-initialize stack variables in KMSAN builds. We also disable CONFIG_INIT_ON_ALLOC_DEFAULT_ON and CONFIG_INIT_ON_FREE_DEFAULT_ON to prevent accidental use of heap auto-initialization. We however still let the users enable heap auto-initialization at boot-time (by setting init_on_alloc=1 or init_on_free=1), in which case a warning is printed. Link: https://lkml.kernel.org/r/20220915150417.722975-31-glider@google.com Signed-off-by:
Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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- Sep 30, 2022
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Orlando Chamberlain authored
It turns out Apple doesn't capitalise the "mini" in "Macmini" in DMI, which is inconsistent with other model line names. Correct the capitalisation of Macmini in the quirk for skipping loading platform certs on T2 Macs. Currently users get: ------------[ cut here ]------------ [Firmware Bug]: Page fault caused by firmware at PA: 0xffffa30640054000 WARNING: CPU: 1 PID: 8 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x55/0xe0 Modules linked in: CPU: 1 PID: 8 Comm: kworker/u12:0 Not tainted 5.18.14-arch1-2-t2 #1 4535eb3fc40fd08edab32a509fbf4c9bc52d111e Hardware name: Apple Inc. Macmini8,1/Mac-7BA5B2DFE22DDD8C, BIOS 1731.120.10.0.0 (iBridge: 19.16.15071.0.0,0) 04/24/2022 Workqueue: efi_rts_wq efi_call_rts ... ---[ end trace 0000000000000000 ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list Fixes: 155ca952 ("efi: Do not import certificates from UEFI Secure Boot for T2 Macs") Cc: stable@vger.kernel.org Cc: Aditya Garg <gargaditya08@live.com> Tested-by:
Samuel Jiang <chyishian.jiang@gmail.com> Signed-off-by:
Orlando Chamberlain <redecorating@protonmail.com> Signed-off-by:
Mimi Zohar <zohar@linux.ibm.com>
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Kees Cook authored
Now that Clang's -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang option is no longer required, remove it from the command line. Clang 16 and later will warn when it is used, which will cause Kconfig to think it can't use -ftrivial-auto-var-init=zero at all. Check for whether it is required and only use it when so. Cc: Nathan Chancellor <nathan@kernel.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: linux-kbuild@vger.kernel.org Cc: llvm@lists.linux.dev Cc: stable@vger.kernel.org Fixes: f02003c8 ("hardening: Avoid harmless Clang option under CONFIG_INIT_STACK_ALL_ZERO") Signed-off-by:
Kees Cook <keescook@chromium.org>
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- Sep 29, 2022
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Mickaël Salaün authored
It seems that all code should use double backquotes, which is also used to convert "%" defines. Let's use an homogeneous style and remove all use of simple backquotes (which should only be used for emphasis). Cc: Günther Noack <gnoack3000@gmail.com> Cc: Paul Moore <paul@paul-moore.com> Signed-off-by:
Mickaël Salaün <mic@digikod.net> Link: https://lore.kernel.org/r/20220923154207.3311629-4-mic@digikod.net
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Mickaël Salaün authored
Now that we have more than one ABI version, make limitation explanation more consistent by replacing "ABI 1" with "ABI < 2". This also indicates which ABIs support such past limitation. Improve documentation consistency by not using contractions. Fix spelling in fs.c . Cc: Paul Moore <paul@paul-moore.com> Signed-off-by:
Mickaël Salaün <mic@digikod.net> Reviewed-by:
Günther Noack <gnoack3000@gmail.com> Link: https://lore.kernel.org/r/20220923154207.3311629-3-mic@digikod.net
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- Sep 28, 2022
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Nathan Lynch authored
The error injection facility on pseries VMs allows corruption of arbitrary guest memory, potentially enabling a sufficiently privileged user to disable lockdown or perform other modifications of the running kernel via the rtas syscall. Block the PAPR error injection facility from being opened or called when locked down. Signed-off-by:
Nathan Lynch <nathanl@linux.ibm.com> Acked-by: Paul Moore <paul@paul-moore.com> (LSM) Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926131643.146502-3-nathanl@linux.ibm.com
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Nathan Lynch authored
The /proc/powerpc/ofdt interface allows the root user to freely alter the in-kernel device tree, enabling arbitrary physical address writes via drivers that could bind to malicious device nodes, thus making it possible to disable lockdown. Historically this interface has been used on the pseries platform to facilitate the runtime addition and removal of processor, memory, and device resources (aka Dynamic Logical Partitioning or DLPAR). Years ago, the processor and memory use cases were migrated to designs that happen to be lockdown-friendly: device tree updates are communicated directly to the kernel from firmware without passing through untrusted user space. I/O device DLPAR via the "drmgr" command in powerpc-utils remains the sole legitimate user of /proc/powerpc/ofdt, but it is already broken in lockdown since it uses /dev/mem to allocate argument buffers for the rtas syscall. So only illegitimate uses of the interface should see a behavior change when running on a locked down kernel. Signed-off-by:
Nathan Lynch <nathanl@linux.ibm.com> Acked-by: Paul Moore <paul@paul-moore.com> (LSM) Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926131643.146502-2-nathanl@linux.ibm.com
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- Sep 27, 2022
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Xiu Jianfeng authored
These mount option flags are obsolete since commit 12085b14 ("smack: switch to private smack_mnt_opts"), remove them. Signed-off-by:
Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com>
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Xu Panda authored
Return the value smk_ptrace_rule_check() directly instead of storing it in another redundant variable. Reported-by:
Zeal Robot <zealci@zte.com.cn> Signed-off-by:
Xu Panda <xu.panda@zte.com.cn> Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com>
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Lontke Michael authored
Using smk_of_current() during sk_alloc_security hook leads in rare cases to a faulty initialization of the security context of the created socket. By adding the LSM hook sk_clone_security to SMACK this initialization fault is corrected by copying the security context of the old socket pointer to the newly cloned one. Co-authored-by:
Martin Ostertag: <martin.ostertag@elektrobit.com> Signed-off-by:
Lontke Michael <michael.lontke@elektrobit.com> Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com>
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- Sep 22, 2022
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Roberto Sassu authored
In preparation for the patch that introduces the bpf_lookup_user_key() eBPF kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to validate the kfunc parameters. Add them to enum key_lookup_flag, so that all the current ones and the ones defined in the future are automatically exported through BTF and available to eBPF programs. Also, add KEY_LOOKUP_ALL to the enum, with the logical OR of currently defined flags as value, to facilitate checking whether a variable contains only those flags. Signed-off-by:
Roberto Sassu <roberto.sassu@huawei.com> Acked-by:
Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/r/20220920075951.929132-7-roberto.sassu@huaweicloud.com Signed-off-by:
Alexei Starovoitov <ast@kernel.org>
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- Sep 14, 2022
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Xu Panda authored
Return the value avc_has_perm() directly instead of storing it in another redundant variable. Reported-by:
Zeal Robot <zealci@zte.com.cn> Signed-off-by:
Xu Panda <xu.panda@zte.com.cn> [PM: subject line tweak] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Nathan Lynch authored
User space can flood the log with lockdown denial messages: [ 662.555584] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 [ 662.563237] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 [ 662.571134] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 [ 662.578668] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 [ 662.586021] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 [ 662.593398] Lockdown: bash: debugfs access is restricted; see man kernel_lockdown.7 Ratelimiting these shouldn't meaningfully degrade the quality of the information logged. Signed-off-by:
Nathan Lynch <nathanl@linux.ibm.com> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- Sep 07, 2022
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Matthias Kaehlcke authored
LoadPin expects the file with trusted verity root digests to be an ASCII file with one digest (hex value) per line. A pinned root could contain files that meet these format requirements, even though the hex values don't represent trusted root digests. Add a new requirement to the file format which consists in the first line containing a fixed string. This prevents attackers from feeding files with an otherwise valid format to LoadPin. Suggested-by:
Sarthak Kukreti <sarthakkukreti@chromium.org> Signed-off-by:
Matthias Kaehlcke <mka@chromium.org> Signed-off-by:
Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220906181725.1.I3f51d1bb0014e5a5951be4ad3c5ad7c7ca1dfc32@changeid
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Matthias Kaehlcke authored
The doc for CONFIG_SECURITY_LOADPIN_VERITY says that the file with verity digests must contain a comma separated list of digests. That was the case at some stage of the development, but was changed during the review process to one digest per line. Update the Kconfig doc accordingly. Reported-by:
Jae Hoon Kim <kimjae@chromium.org> Signed-off-by:
Matthias Kaehlcke <mka@chromium.org> Fixes: 3f805f8c ("LoadPin: Enable loading from trusted dm-verity devices") Cc: stable@vger.kernel.org Signed-off-by:
Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220829174557.1.I5d202d1344212a3800d9828f936df6511eb2d0d1@changeid
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- Sep 02, 2022
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Mickaël Salaün authored
This change fixes a mis-handling of the LANDLOCK_ACCESS_FS_REFER right when multiple rulesets/domains are stacked. The expected behaviour was that an additional ruleset can only restrict the set of permitted operations, but in this particular case, it was potentially possible to re-gain the LANDLOCK_ACCESS_FS_REFER right. With the introduction of LANDLOCK_ACCESS_FS_REFER, we added the first globally denied-by-default access right. Indeed, this lifted an initial Landlock limitation to rename and link files, which was initially always denied when the source or the destination were different directories. This led to an inconsistent backward compatibility behavior which was only taken into account if no domain layer were using the new LANDLOCK_ACCESS_FS_REFER right. However, when restricting a thread with a new ruleset handling LANDLOCK_ACCESS_FS_REFER, all inherited parent rulesets/layers not explicitly handling LANDLOCK_ACCESS_FS_REFER would behave as if they were handling this access right and with all their rules allowing it. This means that renaming and linking files could became allowed by these parent layers, but all the other required accesses must also be granted: all layers must allow file removal or creation, and renaming and linking operations cannot lead to privilege escalation according to the Landlock policy. See detailed explanation in commit b91c3e4e ("landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER"). To say it another way, this bug may lift the renaming and linking limitations of the initial Landlock version, and a same ruleset can enforce different restrictions depending on previous or next enforced ruleset (i.e. inconsistent behavior). The LANDLOCK_ACCESS_FS_REFER right cannot give access to data not already allowed, but this doesn't follow the contract of the first Landlock ABI. This fix puts back the limitation for sandboxes that didn't opt-in for this additional right. For instance, if a first ruleset allows LANDLOCK_ACCESS_FS_MAKE_REG on /dst and LANDLOCK_ACCESS_FS_REMOVE_FILE on /src, renaming /src/file to /dst/file is denied. However, without this fix, stacking a new ruleset which allows LANDLOCK_ACCESS_FS_REFER on / would now permit the sandboxed thread to rename /src/file to /dst/file . This change fixes the (absolute) rule access rights, which now always forbid LANDLOCK_ACCESS_FS_REFER except when it is explicitly allowed when creating a rule. Making all domain handle LANDLOCK_ACCESS_FS_REFER was an initial approach but there is two downsides: * it makes the code more complex because we still want to check that a rule allowing LANDLOCK_ACCESS_FS_REFER is legitimate according to the ruleset's handled access rights (i.e. ABI v1 != ABI v2); * it would not allow to identify if the user created a ruleset explicitly handling LANDLOCK_ACCESS_FS_REFER or not, which will be an issue to audit Landlock. Instead, this change adds an ACCESS_INITIALLY_DENIED list of denied-by-default rights, which (only) contains LANDLOCK_ACCESS_FS_REFER. All domains are treated as if they are also handling this list, but without modifying their fs_access_masks field. A side effect is that the errno code returned by rename(2) or link(2) *may* be changed from EXDEV to EACCES according to the enforced restrictions. Indeed, we now have the mechanic to identify if an access is denied because of a required right (e.g. LANDLOCK_ACCESS_FS_MAKE_REG, LANDLOCK_ACCESS_FS_REMOVE_FILE) or if it is denied because of missing LANDLOCK_ACCESS_FS_REFER rights. This may result in different errno codes than for the initial Landlock version, but this approach is more consistent and better for rename/link compatibility reasons, and it wasn't possible before (hence no backport to ABI v1). The layout1.rename_file test reflects this change. Add 4 layout1.refer_denied_by_default* test suites to check that the behavior of a ruleset not handling LANDLOCK_ACCESS_FS_REFER (ABI v1) is unchanged even if another layer handles LANDLOCK_ACCESS_FS_REFER (i.e. ABI v1 precedence). Make sure rule's absolute access rights are correct by testing with and without a matching path. Add test_rename() and test_exchange() helpers. Extend layout1.inval tests to check that a denied-by-default access right is not necessarily part of a domain's handled access rights. Test coverage for security/landlock is 95.3% of 599 lines according to gcc/gcov-11. Fixes: b91c3e4e ("landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER") Reviewed-by:
Paul Moore <paul@paul-moore.com> Reviewed-by:
Günther Noack <gnoack3000@gmail.com> Link: https://lore.kernel.org/r/20220831203840.1370732-1-mic@digikod.net Cc: stable@vger.kernel.org [mic: Constify and slightly simplify test helpers] Signed-off-by:
Mickaël Salaün <mic@digikod.net>
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- Sep 01, 2022
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Al Viro authored
cast of ->d_name.name to char * is completely wrong - nothing is allowed to modify its contents. Reviewed-by:
Christian Brauner (Microsoft) <brauner@kernel.org> Acked-by:
Paul Moore <paul@paul-moore.com> Acked-by:
Casey Schaufler <casey@schaufler-ca.com> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- Aug 31, 2022
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Christian Brauner authored
The uapi POSIX ACL struct passed through the value argument during setxattr() contains {g,u}id values encoded via ACL_{GROUP,USER} entries that should actually be stored in the form of k{g,u}id_t (See [1] for a long explanation of the issue.). In 0c5fd887 ("acl: move idmapped mount fixup into vfs_{g,s}etxattr()") we took the mount's idmapping into account in order to let overlayfs handle POSIX ACLs on idmapped layers correctly. The fixup is currently performed directly in vfs_setxattr() which piles on top of the earlier hackiness by handling the mount's idmapping and stuff the vfs{g,u}id_t values into the uapi struct as well. While that is all correct and works fine it's just ugly. Now that we have introduced vfs_make_posix_acl() earlier move handling idmapped mounts out of vfs_setxattr() and into the POSIX ACL handler where it belongs. Note that we also need to call vfs_make_posix_acl() for EVM which interpretes POSIX ACLs during security_inode_setxattr(). Leave them a longer comment for future reference. All filesystems that support idmapped mounts via FS_ALLOW_IDMAP use the standard POSIX ACL xattr handlers and are covered by this change. This includes overlayfs which simply calls vfs_{g,s}etxattr(). The following filesystems use custom POSIX ACL xattr handlers: 9p, cifs, ecryptfs, and ntfs3 (and overlayfs but we've covered that in the paragraph above) and none of them support idmapped mounts yet. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org/ [1] Signed-off-by:
Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by:
Seth Forshee (DigitalOcean) <sforshee@kernel.org>
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- Aug 30, 2022
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Christian Göttsche authored
Declare ebitmap, mls_level and mls_context parameters const where they are only read from. This allows callers to supply pointers to const as arguments and increases readability. Signed-off-by:
Christian Göttsche <cgzones@googlemail.com> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Christian Göttsche authored
Do not cast pointers of signed integers to pointers of unsigned integers and vice versa. It should currently not be an issue since they hold SELinux boolean values which should only contain either 0's or 1's, which should have the same representation. Reported by sparse: .../selinuxfs.c:1485:30: warning: incorrect type in assignment (different signedness) .../selinuxfs.c:1485:30: expected unsigned int * .../selinuxfs.c:1485:30: got int *[addressable] values .../selinuxfs.c:1402:48: warning: incorrect type in argument 3 (different signedness) .../selinuxfs.c:1402:48: expected int *values .../selinuxfs.c:1402:48: got unsigned int *bool_pending_values Signed-off-by:
Christian Göttsche <cgzones@googlemail.com> [PM: minor whitespace fixes, sparse output cleanup] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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ye xingchen authored
Return the value sel_make_perm_files() directly instead of storing it in another redundant variable. Reported-by:
Zeal Robot <zealci@zte.com.cn> Signed-off-by:
ye xingchen <ye.xingchen@zte.com.cn> [PM: subject line tweak] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- Aug 26, 2022
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Casey Schaufler authored
Limit io_uring "cmd" options to files for which the caller has Smack read access. There may be cases where the cmd option may be closer to a write access than a read, but there is no way to make that determination. Cc: stable@vger.kernel.org Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Paul Moore authored
Add a SELinux access control for the iouring IORING_OP_URING_CMD command. This includes the addition of a new permission in the existing "io_uring" object class: "cmd". The subject of the new permission check is the domain of the process requesting access, the object is the open file which points to the device/file that is the target of the IORING_OP_URING_CMD operation. A sample policy rule is shown below: allow <domain> <file>:io_uring { cmd }; Cc: stable@vger.kernel.org Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Luis Chamberlain authored
io-uring cmd support was added through ee692a21 ("fs,io_uring: add infrastructure for uring-cmd"), this extended the struct file_operations to allow a new command which each subsystem can use to enable command passthrough. Add an LSM specific for the command passthrough which enables LSMs to inspect the command details. This was discussed long ago without no clear pointer for something conclusive, so this enables LSMs to at least reject this new file operation. [0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com Cc: stable@vger.kernel.org Fixes: ee692a21 ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by:
Luis Chamberlain <mcgrof@kernel.org> Acked-by:
Jens Axboe <axboe@kernel.dk> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- Aug 23, 2022
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Mimi Zohar authored
Limit validating the hash algorithm to just security.ima xattr, not the security.evm xattr or any of the protected EVM security xattrs, nor posix acls. Fixes: 50f742dd ("IMA: block writes of the security.ima xattr with unsupported algorithms") Reported-by:
Christian Brauner <brauner@kernel.org> Acked-by:
Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by:
Mimi Zohar <zohar@linux.ibm.com>
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- Aug 21, 2022
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Al Viro authored
Acked-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Idiomatic way to find how much space sprintf output would take is len = snprintf(NULL, 0, ...) + 1; Once upon a time there'd been libc implementations that blew chunks on that and somebody had come up with the following "cute" trick: len = snprintf((char *) &len, 1, ...) + 1; for doing the same. However, that's unidiomatic, harder to follow *and* any such libc implementation would violate both C99 and POSIX (since 2001). IOW, this kludge is best buried along with such libc implementations, nevermind getting cargo-culted into newer code. Our vsnprintf() does not suffer that braindamage, TYVM. Acked-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk>
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- Aug 16, 2022
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Frederick Lawler authored
Unprivileged user namespace creation is an intended feature to enable sandboxing, however this feature is often used to as an initial step to perform a privilege escalation attack. This patch implements a new user_namespace { create } access control permission to restrict which domains allow or deny user namespace creation. This is necessary for system administrators to quickly protect their systems while waiting for vulnerability patches to be applied. This permission can be used in the following way: allow domA_t domA_t : user_namespace { create }; Signed-off-by:
Frederick Lawler <fred@cloudflare.com> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Frederick Lawler authored
User namespaces are an effective tool to allow programs to run with permission without requiring the need for a program to run as root. User namespaces may also be used as a sandboxing technique. However, attackers sometimes leverage user namespaces as an initial attack vector to perform some exploit. [1,2,3] While it is not the unprivileged user namespace functionality, which causes the kernel to be exploitable, users/administrators might want to more granularly limit or at least monitor how various processes use this functionality, while vulnerable kernel subsystems are being patched. Preventing user namespace already creation comes in a few of forms in order of granularity: 1. /proc/sys/user/max_user_namespaces sysctl 2. Distro specific patch(es) 3. CONFIG_USER_NS To block a task based on its attributes, the LSM hook cred_prepare is a decent candidate for use because it provides more granular control, and it is called before create_user_ns(): cred = prepare_creds() security_prepare_creds() call_int_hook(cred_prepare, ... if (cred) create_user_ns(cred) Since security_prepare_creds() is meant for LSMs to copy and prepare credentials, access control is an unintended use of the hook. [4] Further, security_prepare_creds() will always return a ENOMEM if the hook returns any non-zero error code. This hook also does not handle the clone3 case which requires us to access a user space pointer to know if we're in the CLONE_NEW_USER call path which may be subject to a TOCTTOU attack. Lastly, cred_prepare is called in many call paths, and a targeted hook further limits the frequency of calls which is a beneficial outcome. Therefore introduce a new function security_create_user_ns() with an accompanying userns_create LSM hook. With the new userns_create hook, users will have more control over the observability and access control over user namespace creation. Users should expect that normal operation of user namespaces will behave as usual, and only be impacted when controls are implemented by users or administrators. This hook takes the prepared creds for LSM authors to write policy against. On success, the new namespace is applied to credentials, otherwise an error is returned. Links: 1. https://nvd.nist.gov/vuln/detail/CVE-2022-0492 2. https://nvd.nist.gov/vuln/detail/CVE-2022-25636 3. https://nvd.nist.gov/vuln/detail/CVE-2022-34918 4. https://lore.kernel.org/all/1c4b1c0d-12f6-6e9e-a6a3-cdce7418110c@schaufler-ca.com/ Reviewed-by:
Christian Brauner (Microsoft) <brauner@kernel.org> Reviewed-by:
KP Singh <kpsingh@kernel.org> Signed-off-by:
Frederick Lawler <fred@cloudflare.com> Signed-off-by:
Paul Moore <paul@paul-moore.com>
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Kees Cook authored
The copy_from_user() function returns the number of bytes remaining to be copied on a failure. Such failures should return -EFAULT to high levels. Reported-by:
kernel test robot <lkp@intel.com> Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Fixes: 3f805f8c ("LoadPin: Enable loading from trusted dm-verity devices") Cc: Matthias Kaehlcke <mka@chromium.org> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: linux-security-module@vger.kernel.org Signed-off-by:
Kees Cook <keescook@chromium.org>
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Xiu Jianfeng authored
The implements of {ip,tcp,udp,dccp,sctp,ipv6}_hdr(skb) guarantee that they will never return NULL, and elsewhere users don't do the check as well, so remove the check here. Signed-off-by:
Xiu Jianfeng <xiujianfeng@huawei.com> [PM: subject line tweaks] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- Aug 01, 2022
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Xiu Jianfeng authored
It's not possible for inode->i_security to be NULL here because every inode will call inode_init_always and then lsm_inode_alloc to alloc memory for inode->security, this is what LSM infrastructure management do, so remove this redundant code. Signed-off-by:
Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com>
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GONG, Ruiqi authored
Simplify the code by using kstrndup instead of kzalloc and strncpy in smk_parse_smack(), which meanwhile remove strncpy as [1] suggests. [1]: https://github.com/KSPP/linux/issues/90 Signed-off-by:
GONG, Ruiqi <gongruiqi1@huawei.com> Signed-off-by:
Casey Schaufler <casey@schaufler-ca.com>
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- Jul 20, 2022
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Lukas Bulwahn authored
Commit 5bfcbd22 ("apparmor: Enable tuning of policy paranoid load for embedded systems") introduces the config SECURITY_APPARMOR_PARANOID_LOAD, but then refers in the code to SECURITY_PARANOID_LOAD; note the missing APPARMOR in the middle. Correct this to the introduced and intended config option. Fixes: 5bfcbd22 ("apparmor: Enable tuning of policy paranoid load for embedded systems") Signed-off-by:
Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by:
John Johansen <john.johansen@canonical.com>
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Eric Snowberg authored
The lockdown LSM is primarily used in conjunction with UEFI Secure Boot. This LSM may also be used on machines without UEFI. It can also be enabled when UEFI Secure Boot is disabled. One of lockdown's features is to prevent kexec from loading untrusted kernels. Lockdown can be enabled through a bootparam or after the kernel has booted through securityfs. If IMA appraisal is used with the "ima_appraise=log" boot param, lockdown can be defeated with kexec on any machine when Secure Boot is disabled or unavailable. IMA prevents setting "ima_appraise=log" from the boot param when Secure Boot is enabled, but this does not cover cases where lockdown is used without Secure Boot. To defeat lockdown, boot without Secure Boot and add ima_appraise=log to the kernel command line; then: $ echo "integrity" > /sys/kernel/security/lockdown $ echo "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig" > \ /sys/kernel/security/ima/policy $ kexec -ls unsigned-kernel Add a call to verify ima appraisal is set to "enforce" whenever lockdown is enabled. This fixes CVE-2022-21505. Cc: stable@vger.kernel.org Fixes: 29d3c1c8 ("kexec: Allow kexec_file() with appropriate IMA policy when locked down") Signed-off-by:
Eric Snowberg <eric.snowberg@oracle.com> Acked-by:
Mimi Zohar <zohar@linux.ibm.com> Reviewed-by:
John Haxby <john.haxby@oracle.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- Jul 19, 2022
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John Johansen authored
AppArmor split out task oriented controls to their own logical file a while ago. Ptrace mediation is better grouped with task than ipc, so move it. Signed-off-by:
John Johansen <john.johansen@canonical.com>
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John Johansen authored
The policydb permission set has left the xbits unused. Make them available for mediation. Signed-off-by:
John Johansen <john.johansen@canonical.com>
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John Johansen authored
Allow labels to have debug flags that can be used to trigger debug output only from profiles/labels that are marked. This can help reduce debug output by allowing debug to be target to a specific confinement condition. Signed-off-by:
John Johansen <john.johansen@canonical.com>
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