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authorPaul Moore <paul@paul-moore.com>2021-09-28 18:22:26 -0400
committerPaul Moore <paul@paul-moore.com>2021-09-30 10:12:33 -0400
commitf5d0e5e9d72d3a06018efbfa3adccc0e09a129f9 (patch)
tree6abffe19f14befd033cdd93e81bdabd93e6a69f2 /security
parent8a764ef1bd43fb2bb4ff3290746e5c820a3a9716 (diff)
selinux: remove the SELinux lockdown implementation
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>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/hooks.c30
-rw-r--r--security/selinux/include/classmap.h2
2 files changed, 0 insertions, 32 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 549f631e9832..7297d1f0a9df 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7014,34 +7014,6 @@ static void selinux_bpf_prog_free(struct bpf_prog_aux *aux)
}
#endif
-static int selinux_lockdown(enum lockdown_reason what)
-{
- struct common_audit_data ad;
- u32 sid = current_sid();
- int invalid_reason = (what <= LOCKDOWN_NONE) ||
- (what == LOCKDOWN_INTEGRITY_MAX) ||
- (what >= LOCKDOWN_CONFIDENTIALITY_MAX);
-
- if (WARN(invalid_reason, "Invalid lockdown reason")) {
- audit_log(audit_context(),
- GFP_ATOMIC, AUDIT_SELINUX_ERR,
- "lockdown_reason=invalid");
- return -EINVAL;
- }
-
- ad.type = LSM_AUDIT_DATA_LOCKDOWN;
- ad.u.reason = what;
-
- if (what <= LOCKDOWN_INTEGRITY_MAX)
- return avc_has_perm(&selinux_state,
- sid, sid, SECCLASS_LOCKDOWN,
- LOCKDOWN__INTEGRITY, &ad);
- else
- return avc_has_perm(&selinux_state,
- sid, sid, SECCLASS_LOCKDOWN,
- LOCKDOWN__CONFIDENTIALITY, &ad);
-}
-
struct lsm_blob_sizes selinux_blob_sizes __lsm_ro_after_init = {
.lbs_cred = sizeof(struct task_security_struct),
.lbs_file = sizeof(struct file_security_struct),
@@ -7384,8 +7356,6 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(uring_sqpoll, selinux_uring_sqpoll),
#endif
- LSM_HOOK_INIT(locked_down, selinux_lockdown),
-
/*
* PUT "CLONING" (ACCESSING + ALLOCATING) HOOKS HERE
*/
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 698ccfdaf82d..35aac62a662e 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -250,8 +250,6 @@ struct security_class_mapping secclass_map[] = {
{ COMMON_SOCK_PERMS, NULL } },
{ "perf_event",
{ "open", "cpu", "kernel", "tracepoint", "read", "write", NULL } },
- { "lockdown",
- { "integrity", "confidentiality", NULL } },
{ "anon_inode",
{ COMMON_FILE_PERMS, NULL } },
{ "io_uring",