- 19 Sep, 2024 1 commit
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Shu Han authored
The remap_file_pages syscall handler calls do_mmap() directly, which doesn't contain the LSM security check. And if the process has called personality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for RW pages, this will actually result in remapping the pages to RWX, bypassing a W^X policy enforced by SELinux. So we should check prot by security_mmap_file LSM hook in the remap_file_pages syscall handler before do_mmap() is called. Otherwise, it potentially permits an attacker to bypass a W^X policy enforced by SELinux. The bypass is similar to CVE-2016-10044, which bypass the same thing via AIO and can be found in [1]. The PoC: $ cat > test.c int main(void) { size_t pagesz = sysconf(_SC_PAGE_SIZE); int mfd = syscall(SYS_memfd_create, "test", 0); const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); unsigned int old = syscall(SYS_personality, 0xffffffff); syscall(SYS_personality, READ_IMPLIES_EXEC | old); syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0); syscall(SYS_personality, old); // show the RWX page exists even if W^X policy is enforced int fd = open("/proc/self/maps", O_RDONLY); unsigned char buf2[1024]; while (1) { int ret = read(fd, buf2, 1024); if (ret <= 0) break; write(1, buf2, ret); } close(fd); } $ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted) Link: https://project-zero.issues.chromium.org/issues/42452389 [1] Cc: stable@vger.kernel.org Signed-off-by:Shu Han <ebpqwerty472123@gmail.com> Acked-by:
Stephen Smalley <stephen.smalley.work@gmail.com> [PM: subject line tweaks] Signed-off-by:
Paul Moore <paul@paul-moore.com>
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- 09 Sep, 2024 2 commits
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Mickaël Salaün authored
Highlight that the file_set_fowner hook is now called with a lock held. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Christian Brauner <brauner@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Signed-off-by:
Mickaël Salaün <mic@digikod.net> Signed-off-by:
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Mickaël Salaün authored
The fcntl's F_SETOWN command sets the process that handle SIGIO/SIGURG for the related file descriptor. Before this change, the file_set_fowner LSM hook was always called, ignoring the VFS logic which may not actually change the process that handles SIGIO (e.g. TUN, TTY, dnotify), nor update the related UID/EUID. Moreover, because security_file_set_fowner() was called without lock (e.g. f_owner.lock), concurrent F_SETOWN commands could result to a race condition and inconsistent LSM states (e.g. SELinux's fown_sid) compared to struct fown_struct's UID/EUID. This change makes sure the LSM states are always in sync with the VFS state by moving the security_file_set_fowner() call close to the UID/EUID updates and using the same f_owner.lock . Rename f_modown() to __f_setown() to simplify code. Cc: stable@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Christian Brauner <brauner@kernel.org> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Fixes: 1da177e4 ("Linux-2.6.12-rc2") Signed-off-by:
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- 29 Aug, 2024 1 commit
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Hongbo Li authored
Use the IS_ERR_OR_NULL() helper instead of open-coding a NULL and an error pointer checks to simplify the code and improve readability. Signed-off-by:
Hongbo Li <lihongbo22@huawei.com> Signed-off-by:
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- 26 Aug, 2024 1 commit
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Tetsuo Handa authored
Because these are equals to MAX_LSM_COUNT. Also, we can avoid dynamic memory allocation for ordered_lsms because MAX_LSM_COUNT is a constant. Signed-off-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by:
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- 22 Aug, 2024 3 commits
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Yang Li authored
The header files eval.h is included twice in ipe.c, so one inclusion of each can be removed. Reported-by:
Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9796Signed-off-by:
Yang Li <yang.lee@linux.alibaba.com> Signed-off-by:
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KP Singh authored
LSM hooks are currently invoked from a linked list as indirect calls which are invoked using retpolines as a mitigation for speculative attacks (Branch History / Target injection) and add extra overhead which is especially bad in kernel hot paths: security_file_ioctl: 0xff...0320 <+0>: endbr64 0xff...0324 <+4>: push %rbp 0xff...0325 <+5>: push %r15 0xff...0327 <+7>: push %r14 0xff...0329 <+9>: push %rbx 0xff...032a <+10>: mov %rdx,%rbx 0xff...032d <+13>: mov %esi,%ebp 0xff...032f <+15>: mov %rdi,%r14 0xff...0332 <+18>: mov $0xff...7030,%r15 0xff...0339 <+25>: mov (%r15),%r15 0xff...033c <+28>: test %r15,%r15 0xff...033f <+31>: je 0xff...0358 <security_file_ioctl+56> 0xff...0341 <+33>: mov 0x18(%r15),%r11 0xff...0345 <+37>: mov %r14,%rdi 0xff...0348 <+40>: mov %ebp,%esi 0xff...034a <+42>: mov %rbx,%rdx 0xff...034d <+45>: call 0xff...2e0 <__x86_indirect_thunk_array+352> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Indirect calls that use retpolines leading to overhead, not just due to extra instruction but also branch misses. 0xff...0352 <+50>: test %eax,%eax 0xff...0354 <+52>: je 0xff...0339 <security_file_ioctl+25> 0xff...0356 <+54>: jmp 0xff...035a <security_file_ioctl+58> 0xff...0358 <+56>: xor %eax,%eax 0xff...035a <+58>: pop %rbx 0xff...035b <+59>: pop %r14 0xff...035d <+61>: pop %r15 0xff...035f <+63>: pop %rbp 0xff...0360 <+64>: jmp 0xff...47c4 <__x86_return_thunk> The indirect calls are not really needed as one knows the addresses of enabled LSM callbacks at boot time and only the order can possibly change at boot time with the lsm= kernel command line parameter. An array of static calls is defined per LSM hook and the static calls are updated at boot time once the order has been determined. With the hook now exposed as a static call, one can see that the retpolines are no longer there and the LSM callbacks are invoked directly: security_file_ioctl: 0xff...0ca0 <+0>: endbr64 0xff...0ca4 <+4>: nopl 0x0(%rax,%rax,1) 0xff...0ca9 <+9>: push %rbp 0xff...0caa <+10>: push %r14 0xff...0cac <+12>: push %rbx 0xff...0cad <+13>: mov %rdx,%rbx 0xff...0cb0 <+16>: mov %esi,%ebp 0xff...0cb2 <+18>: mov %rdi,%r14 0xff...0cb5 <+21>: jmp 0xff...0cc7 <security_file_ioctl+39> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Static key enabled for SELinux 0xffffffff818f0cb7 <+23>: jmp 0xff...0cde <security_file_ioctl+62> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Static key enabled for BPF LSM. This is something that is changed to default to false to avoid the existing side effect issues of BPF LSM [1] in a subsequent patch. 0xff...0cb9 <+25>: xor %eax,%eax 0xff...0cbb <+27>: xchg %ax,%ax 0xff...0cbd <+29>: pop %rbx 0xff...0cbe <+30>: pop %r14 0xff...0cc0 <+32>: pop %rbp 0xff...0cc1 <+33>: cs jmp 0xff...0000 <__x86_return_thunk> 0xff...0cc7 <+39>: endbr64 0xff...0ccb <+43>: mov %r14,%rdi 0xff...0cce <+46>: mov %ebp,%esi 0xff...0cd0 <+48>: mov %rbx,%rdx 0xff...0cd3 <+51>: call 0xff...3230 <selinux_file_ioctl> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct call to SELinux. 0xff...0cd8 <+56>: test %eax,%eax 0xff...0cda <+58>: jne 0xff...0cbd <security_file_ioctl+29> 0xff...0cdc <+60>: jmp 0xff...0cb7 <security_file_ioctl+23> 0xff...0cde <+62>: endbr64 0xff...0ce2 <+66>: mov %r14,%rdi 0xff...0ce5 <+69>: mov %ebp,%esi 0xff...0ce7 <+71>: mov %rbx,%rdx 0xff...0cea <+74>: call 0xff...e220 <bpf_lsm_file_ioctl> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct call to BPF LSM. 0xff...0cef <+79>: test %eax,%eax 0xff...0cf1 <+81>: jne 0xff...0cbd <security_file_ioctl+29> 0xff...0cf3 <+83>: jmp 0xff...0cb9 <security_file_ioctl+25> 0xff...0cf5 <+85>: endbr64 0xff...0cf9 <+89>: mov %r14,%rdi 0xff...0cfc <+92>: mov %ebp,%esi 0xff...0cfe <+94>: mov %rbx,%rdx 0xff...0d01 <+97>: pop %rbx 0xff...0d02 <+98>: pop %r14 0xff...0d04 <+100>: pop %rbp 0xff...0d05 <+101>: ret 0xff...0d06 <+102>: int3 0xff...0d07 <+103>: int3 0xff...0d08 <+104>: int3 0xff...0d09 <+105>: int3 While this patch uses static_branch_unlikely indicating that an LSM hook is likely to be not present. In most cases this is still a better choice as even when an LSM with one hook is added, empty slots are created for all LSM hooks (especially when many LSMs that do not initialize most hooks are present on the system). There are some hooks that don't use the call_int_hook or call_void_hook. These hooks are updated to use a new macro called lsm_for_each_hook where the lsm_callback is directly invoked as an indirect call. Below are results of the relevant Unixbench system benchmarks with BPF LSM and SELinux enabled with default policies enabled with and without these patches. Benchmark Delta(%): (+ is better) ========================================================================== Execl Throughput +1.9356 File Write 1024 bufsize 2000 maxblocks +6.5953 Pipe Throughput +9.5499 Pipe-based Context Switching +3.0209 Process Creation +2.3246 Shell Scripts (1 concurrent) +1.4975 System Call Overhead +2.7815 System Benchmarks Index Score (Partial Only): +3.4859 In the best case, some syscalls like eventfd_create benefitted to about ~10%. Tested-by:Guenter Roeck <linux@roeck-us.net> Reviewed-by:
Casey Schaufler <casey@schaufler-ca.com> Reviewed-by:
Kees Cook <keescook@chromium.org> Acked-by:
Song Liu <song@kernel.org> Acked-by:
Andrii Nakryiko <andrii@kernel.org> Signed-off-by:
KP Singh <kpsingh@kernel.org> Signed-off-by:
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KP Singh authored
These macros are a clever trick to determine a count of the number of LSMs that are enabled in the config to ascertain the maximum number of static calls that need to be configured per LSM hook. Without this one would need to generate static calls for the total number of LSMs in the kernel (even if they are not compiled) times the number of LSM hooks which ends up being quite wasteful. Tested-by:
Kui-Feng Lee <sinquersw@gmail.com> Suggested-by:
John Johansen <john.johansen@canonical.com> Acked-by:
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- 20 Aug, 2024 22 commits
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KP Singh authored
This helps in easily initializing blocks of code (e.g. static calls and keys). UNROLL(N, MACRO, __VA_ARGS__) calls MACRO N times with the first argument as the index of the iteration. This allows string pasting to create unique tokens for variable names, function calls etc. As an example: #include <linux/unroll.h> #define MACRO(N, a, b) \ int add_##N(int a, int b) \ { \ return a + b + N; \ } UNROLL(2, MACRO, x, y) expands to: int add_0(int x, int y) { return x + y + 0; } int add_1(int x, int y) { return x + y + 1; } Tested-by:Jiri Olsa <jolsa@kernel.org> Acked-by:
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KP Singh authored
With LSMs using static calls and static keys, early_lsm_init needs to wait for setup_arch for architecture specific functionality which includes jump tables and static calls to be initialized. Since not all architectures call jump_table_init in setup_arch, explicitly call both jump_table_init and static_call_init before early_security_init. This only affects "early LSMs" i.e. only lockdown when CONFIG_SECURITY_LOCKDOWN_LSM_EARLY is set. Tested-by:
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Fan Wu authored
Add a MAINTAINERS entry for the Integrity Policy Enforcement (IPE) LSM. Signed-off-by:
Fan Wu <wufan@linux.microsoft.com> [PM: removed changelog, updated description per email thread] Signed-off-by:
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Deven Bowers authored
Add IPE's admin and developer documentation to the kernel tree. Co-developed-by:
Deven Bowers <deven.desai@linux.microsoft.com> Signed-off-by:
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Deven Bowers authored
Add various happy/unhappy unit tests for both IPE's policy parser. Besides, a test suite for IPE functionality is available at https://github.com/microsoft/ipe/tree/test-suiteSigned-off-by:
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Deven Bowers authored
Enables an IPE policy to be enforced from kernel start, enabling access control based on trust from kernel startup. This is accomplished by transforming an IPE policy indicated by CONFIG_IPE_BOOT_POLICY into a c-string literal that is parsed at kernel startup as an unsigned policy. Signed-off-by:
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Fan Wu authored
Enable IPE policy authors to indicate trust for a singular fsverity file, identified by the digest information, through "fsverity_digest" and all files using valid fsverity builtin signatures via "fsverity_signature". This enables file-level integrity claims to be expressed in IPE, allowing individual files to be authorized, giving some flexibility for policy authors. Such file-level claims are important to be expressed for enforcing the integrity of packages, as well as address some of the scalability issues in a sole dm-verity based solution (# of loop back devices, etc). This solution cannot be done in userspace as the minimum threat that IPE should mitigate is an attacker downloads malicious payload with all required dependencies. These dependencies can lack the userspace check, bypassing the protection entirely. A similar attack succeeds if the userspace component is replaced with a version that does not perform the check. As a result, this can only be done in the common entry point - the kernel. Signed-off-by:
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Fan Wu authored
This patch enhances fsverity's capabilities to support both integrity and authenticity protection by introducing the exposure of built-in signatures through a new LSM hook. This functionality allows LSMs, e.g. IPE, to enforce policies based on the authenticity and integrity of files, specifically focusing on built-in fsverity signatures. It enables a policy enforcement layer within LSMs for fsverity, offering granular control over the usage of authenticity claims. For instance, a policy could be established to only permit the execution of all files with verified built-in fsverity signatures. The introduction of a security_inode_setintegrity() hook call within fsverity's workflow ensures that the verified built-in signature of a file is exposed to LSMs. This enables LSMs to recognize and label fsverity files that contain a verified built-in fsverity signature. This hook is invoked subsequent to the fsverity_verify_signature() process, guaranteeing the signature's verification against fsverity's keyring. This mechanism is crucial for maintaining system security, as it operates in kernel space, effectively thwarting attempts by malicious binaries to bypass user space stack interactions. The second to last commit in this patch set will add a link to the IPE documentation in fsverity.rst. Signed-off-by:
Eric Biggers <ebiggers@google.com> Signed-off-by:
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Fan Wu authored
This patch introduces a new hook to save inode's integrity data. For example, for fsverity enabled files, LSMs can use this hook to save the existence of verified fsverity builtin signature into the inode's security blob, and LSMs can make access decisions based on this data. Signed-off-by:
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Deven Bowers authored
Allows author of IPE policy to indicate trust for a singular dm-verity volume, identified by roothash, through "dmverity_roothash" and all signed and validated dm-verity volumes, through "dmverity_signature". Signed-off-by:
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Deven Bowers authored
dm-verity provides a strong guarantee of a block device's integrity. As a generic way to check the integrity of a block device, it provides those integrity guarantees to its higher layers, including the filesystem level. However, critical security metadata like the dm-verity roothash and its signing information are not easily accessible to the LSMs. To address this limitation, this patch introduces a mechanism to store and manage these essential security details within a newly added LSM blob in the block_device structure. This addition allows LSMs to make access control decisions on the integrity data stored within the block_device, enabling more flexible security policies. For instance, LSMs can now revoke access to dm-verity devices based on their roothashes, ensuring that only authorized and verified content is accessible. Additionally, LSMs can enforce policies to only allow files from dm-verity devices that have a valid digital signature to execute, effectively blocking any unsigned files from execution, thus enhancing security against unauthorized modifications. The patch includes new hook calls, `security_bdev_setintegrity()`, in dm-verity to expose the dm-verity roothash and the roothash signature to LSMs via preresume() callback. By using the preresume() callback, it ensures that the security metadata is consistently in sync with the metadata of the dm-verity target in the current active mapping table. The hook calls are depended on CONFIG_SECURITY. Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> [PM: moved sig_size field as discussed] Signed-off-by:
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Deven Bowers authored
This patch introduces a new LSM blob to the block_device structure, enabling the security subsystem to store security-sensitive data related to block devices. Currently, for a device mapper's mapped device containing a dm-verity target, critical security information such as the roothash and its signing state are not readily accessible. Specifically, while the dm-verity volume creation process passes the dm-verity roothash and its signature from userspace to the kernel, the roothash is stored privately within the dm-verity target, and its signature is discarded post-verification. This makes it extremely hard for the security subsystem to utilize these data. With the addition of the LSM blob to the block_device structure, the security subsystem can now retain and manage important security metadata such as the roothash and the signing state of a dm-verity by storing them inside the blob. Access decisions can then be based on these stored data. The implementation follows the same approach used for security blobs in other structures like struct file, struct inode, and struct superblock. The initialization of the security blob occurs after the creation of the struct block_device, performed by the security subsystem. Similarly, the security blob is freed by the security subsystem before the struct block_device is deallocated or freed. This patch also introduces a new hook security_bdev_setintegrity() to save block device's integrity data to the new LSM blob. For example, for dm-verity, it can use this hook to expose its roothash and signing state to LSMs, then LSMs can save these data into the LSM blob. Please note that the new hook should be invoked every time the security information is updated to keep these data current. For example, in dm-verity, if the mapping table is reloaded and configured to use a different dm-verity target with a new roothash and signing information, the previously stored data in the LSM blob will become obsolete. It is crucial to re-invoke the hook to refresh these data and ensure they are up to date. This necessity arises from the design of device-mapper, where a device-mapper device is first created, and then targets are subsequently loaded into it. These targets can be modified multiple times during the device's lifetime. Therefore, while the LSM blob is allocated during the creation of the block device, its actual contents are not initialized at this stage and can change substantially over time. This includes alterations from data that the LSM 'trusts' to those it does not, making it essential to handle these changes correctly. Failure to address this dynamic aspect could potentially allow for bypassing LSM checks. Signed-off-by:
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Deven Bowers authored
IPE, like SELinux, supports a permissive mode. This mode allows policy authors to test and evaluate IPE policy without it affecting their programs. When the mode is changed, a 1404 AUDIT_MAC_STATUS will be reported. This patch adds the following audit records: audit: MAC_STATUS enforcing=0 old_enforcing=1 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 audit: MAC_STATUS enforcing=1 old_enforcing=0 auid=4294967295 ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1 The audit record only emit when the value from the user input is different from the current enforce value. Signed-off-by: -
Deven Bowers authored
Users of IPE require a way to identify when and why an operation fails, allowing them to both respond to violations of policy and be notified of potentially malicious actions on their systems with respect to IPE itself. This patch introduces 3 new audit events. AUDIT_IPE_ACCESS(1420) indicates the result of an IPE policy evaluation of a resource. AUDIT_IPE_CONFIG_CHANGE(1421) indicates the current active IPE policy has been changed to another loaded policy. AUDIT_IPE_POLICY_LOAD(1422) indicates a new IPE policy has been loaded into the kernel. This patch also adds support for success auditing, allowing users to identify why an allow decision was made for a resource. However, it is recommended to use this option with caution, as it is quite noisy. Here are some examples of the new audit record types: AUDIT_IPE_ACCESS(1420): audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=297 comm="sh" path="/root/vol/bin/hello" dev="tmpfs" ino=3897 rule="op=EXECUTE boot_verified=TRUE action=ALLOW" audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=299 comm="sh" path="/mnt/ipe/bin/hello" dev="dm-0" ino=2 rule="DEFAULT action=DENY" audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=300 path="/tmp/tmpdp2h1lub/deny/bin/hello" dev="tmpfs" ino=131 rule="DEFAULT action=DENY" The above three records were generated when the active IPE policy only allows binaries from the initramfs to run. The three identical `hello` binary were placed at different locations, only the first hello from the rootfs(initramfs) was allowed. Field ipe_op followed by the IPE operation name associated with the log. Field ipe_hook followed by the name of the LSM hook that triggered the IPE event. Field enforcing followed by the enforcement state of IPE. (it will be introduced in the next commit) Field pid followed by the pid of the process that triggered the IPE event. Field comm followed by the command line program name of the process that triggered the IPE event. Field path followed by the file's path name. Field dev followed by the device name as found in /dev where the file is from. Note that for device mappers it will use the name `dm-X` instead of the name in /dev/mapper. For a file in a temp file system, which is not from a device, it will use `tmpfs` for the field. The implementation of this part is following another existing use case LSM_AUDIT_DATA_INODE in security/lsm_audit.c Field ino followed by the file's inode number. Field rule followed by the IPE rule made the access decision. The whole rule must be audited because the decision is based on the combination of all property conditions in the rule. Along with the syscall audit event, user can know why a blocked happened. For example: audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1 pid=2138 comm="bash" path="/mnt/ipe/bin/hello" dev="dm-0" ino=2 rule="DEFAULT action=DENY" audit[1956]: SYSCALL arch=c000003e syscall=59 success=no exit=-13 a0=556790138df0 a1=556790135390 a2=5567901338b0 a3=ab2a41a67f4f1f4e items=1 ppid=147 pid=1956 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null) The above two records showed bash used execve to run "hello" and got blocked by IPE. Note that the IPE records are always prior to a SYSCALL record. AUDIT_IPE_CONFIG_CHANGE(1421): audit: AUDIT1421 old_active_pol_name="Allow_All" old_active_pol_version=0.0.0 old_policy_digest=sha256:E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649 new_active_pol_name="boot_verified" new_active_pol_version=0.0.0 new_policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F auid=4294967295 ses=4294967295 lsm=ipe res=1 The above record showed the current IPE active policy switch from `Allow_All` to `boot_verified` along with the version and the hash digest of the two policies. Note IPE can only have one policy active at a time, all access decision evaluation is based on the current active policy. The normal procedure to deploy a policy is loading the policy to deploy into the kernel first, then switch the active policy to it. AUDIT_IPE_POLICY_LOAD(1422): audit: AUDIT1422 policy_name="boot_verified" policy_version=0.0.0 policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F2676 auid=4294967295 ses=4294967295 lsm=ipe res=1 The above record showed a new policy has been loaded into the kernel with the policy name, policy version and policy hash. Signed-off-by: -
Deven Bowers authored
As is typical with LSMs, IPE uses securityfs as its interface with userspace. for a complete list of the interfaces and the respective inputs/outputs, please see the documentation under admin-guide/LSM/ipe.rst Signed-off-by:
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Fan Wu authored
When deleting a directory in the security file system, the existing securityfs_remove requires the directory to be empty, otherwise it will do nothing. This leads to a potential risk that the security file system might be in an unclean state when the intended deletion did not happen. This commit introduces a new function securityfs_recursive_remove to recursively delete a directory without leaving an unclean state. Co-developed-by:
Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by:
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Fan Wu authored
IPE is designed to provide system level trust guarantees, this usually implies that trust starts from bootup with a hardware root of trust, which validates the bootloader. After this, the bootloader verifies the kernel and the initramfs. As there's no currently supported integrity method for initramfs, and it's typically already verified by the bootloader. This patch introduces a new IPE property `boot_verified` which allows author of IPE policy to indicate trust for files from initramfs. The implementation of this feature utilizes the newly added `initramfs_populated` hook. This hook marks the superblock of the rootfs after the initramfs has been unpacked into it. Before mounting the real rootfs on top of the initramfs, initramfs script will recursively remove all files and directories on the initramfs. This is typically implemented by using switch_root(8) (https://man7.org/linux/man-pages/man8/switch_root.8.html). Therefore the initramfs will be empty and not accessible after the real rootfs takes over. It is advised to switch to a different policy that doesn't rely on the `boot_verified` property after this point. This ensures that the trust policies remain relevant and effective throughout the system's operation. Signed-off-by:
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Fan Wu authored
This patch introduces a new hook to notify security system that the content of initramfs has been unpacked into the rootfs. Upon receiving this notification, the security system can activate a policy to allow only files that originated from the initramfs to execute or load into kernel during the early stages of booting. This approach is crucial for minimizing the attack surface by ensuring that only trusted files from the initramfs are operational in the critical boot phase. Signed-off-by:
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Deven Bowers authored
IPE's initial goal is to control both execution and the loading of kernel modules based on the system's definition of trust. It accomplishes this by plugging into the security hooks for bprm_check_security, file_mprotect, mmap_file, kernel_load_data, and kernel_read_data. Signed-off-by:
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Deven Bowers authored
Introduce a core evaluation function in IPE that will be triggered by various security hooks (e.g., mmap, bprm_check, kexec). This function systematically assesses actions against the defined IPE policy, by iterating over rules specific to the action being taken. This critical addition enables IPE to enforce its security policies effectively, ensuring that actions intercepted by these hooks are scrutinized for policy compliance before they are allowed to proceed. Signed-off-by:
Serge Hallyn <serge@hallyn.com> Signed-off-by:
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Deven Bowers authored
IPE's interpretation of the what the user trusts is accomplished through its policy. IPE's design is to not provide support for a single trust provider, but to support multiple providers to enable the end-user to choose the best one to seek their needs. This requires the policy to be rather flexible and modular so that integrity providers, like fs-verity, dm-verity, or some other system, can plug into the policy with minimal code changes. Signed-off-by:
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Deven Bowers authored
Integrity Policy Enforcement (IPE) is an LSM that provides an complimentary approach to Mandatory Access Control than existing LSMs today. Existing LSMs have centered around the concept of access to a resource should be controlled by the current user's credentials. IPE's approach, is that access to a resource should be controlled by the system's trust of a current resource. The basis of this approach is defining a global policy to specify which resource can be trusted. Signed-off-by:
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- 15 Aug, 2024 1 commit
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Yue Haibing authored
Fix sparse warning: security/lockdown/lockdown.c:79:21: warning: symbol 'lockdown_lsmid' was not declared. Should it be static? Signed-off-by:
Yue Haibing <yuehaibing@huawei.com> Reviewed-by:
Kees Cook <kees@kernel.org> Signed-off-by:
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- 12 Aug, 2024 2 commits
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Paul Moore authored
The LSM framework has an existing inode_free_security() hook which is used by LSMs that manage state associated with an inode, but due to the use of RCU to protect the inode, special care must be taken to ensure that the LSMs do not fully release the inode state until it is safe from a RCU perspective. This patch implements a new inode_free_security_rcu() implementation hook which is called when it is safe to free the LSM's internal inode state. Unfortunately, this new hook does not have access to the inode itself as it may already be released, so the existing inode_free_security() hook is retained for those LSMs which require access to the inode. Cc: stable@vger.kernel.org Reported-by: syzbot+5446fbf332b0602ede0b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.comSigned-off-by:
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Paul Moore authored
Some cleanup and style corrections for lsm_hooks.h. * Drop the lsm_inode_alloc() extern declaration, it is not needed. * Relocate lsm_get_xattr_slot() and extern variables in the file to improve grouping of related objects. * Don't use tabs to needlessly align structure fields. Reviewed-by:
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- 31 Jul, 2024 2 commits
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Xu Kuohai authored
To be consistent with most LSM hooks, convert the return value of hook inode_copy_up_xattr to 0 or a negative error code. Before: - Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. After: - Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED* when discarding xattr, -EOPNOTSUPP if it does not know xattr, or any other negative error code otherwise. Signed-off-by:
Xu Kuohai <xukuohai@huawei.com> Reviewed-by:
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Xu Kuohai authored
To be consistent with most LSM hooks, convert the return value of hook vm_enough_memory to 0 or a negative error code. Before: - Hook vm_enough_memory returns 1 if permission is granted, 0 if not. - LSM_RET_DEFAULT(vm_enough_memory_mm) is 1. After: - Hook vm_enough_memory reutrns 0 if permission is granted, negative error code if not. - LSM_RET_DEFAULT(vm_enough_memory_mm) is 0. Signed-off-by:
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- 29 Jul, 2024 5 commits
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Casey Schaufler authored
Move management of the perf_event->security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. There are no longer any modules that require the perf_event_free() hook. The hook definition has been removed. Signed-off-by:
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Casey Schaufler authored
Move management of the infiniband security blob out of the individual security modules and into the LSM infrastructure. The security modules tell the infrastructure how much space they require at initialization. There are no longer any modules that require the ib_free() hook. The hook definition has been removed. Signed-off-by:
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Casey Schaufler authored
Move management of the dev_tun security blob out of the individual security modules and into the LSM infrastructure. The security modules tell the infrastructure how much space they require at initialization. There are no longer any modules that require the dev_tun_free hook. The hook definition has been removed. Signed-off-by:
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Casey Schaufler authored
Create a helper function lsm_blob_alloc() for general use in the hook specific functions that allocate LSM blobs. Change the hook specific functions to use this helper. This reduces the code size by a small amount and will make adding new instances of infrastructure managed security blobs easier. Signed-off-by:
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Casey Schaufler authored
Move management of the key->security blob out of the individual security modules and into the security infrastructure. Instead of allocating the blobs from within the modules the modules tell the infrastructure how much space is required, and the space is allocated there. There are no existing modules that require a key_free hook, so the call to it and the definition for it have been removed. Signed-off-by:
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