From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- security/selinux/ima.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 security/selinux/ima.c (limited to 'security/selinux/ima.c') diff --git a/security/selinux/ima.c b/security/selinux/ima.c new file mode 100644 index 000000000..cda68122e --- /dev/null +++ b/security/selinux/ima.c @@ -0,0 +1,121 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2021 Microsoft Corporation + * + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) + * + * Measure critical data structures maintained by SELinux + * using IMA subsystem. + */ +#include +#include +#include +#include "security.h" +#include "ima.h" + +static int selinux_ima_config_len __ro_after_init; + +/* + * selinux_ima_config_len_init - Compute the configuration settings string length + * + * The string is fixed text plus one digit per setting, so its length + * is known at boot. + */ +void __init selinux_ima_config_len_init(void) +{ + int buf_len, suffix_len, i; + + buf_len = strlen("initialized=0;enforcing=0;checkreqprot=0;") + 1; + suffix_len = strlen("=0;"); + + for (i = 0; i < __POLICYDB_CAP_MAX; i++) + buf_len += strlen(selinux_policycap_names[i]) + suffix_len; + + selinux_ima_config_len = buf_len; +} + +/* + * selinux_ima_collect_state - Read selinux configuration settings + * + * On success returns the configuration settings string. + * On error, returns NULL. + */ +static char *selinux_ima_collect_state(void) +{ + struct seq_buf s; + char *buf; + int i; + + buf = kzalloc(selinux_ima_config_len, GFP_KERNEL); + if (!buf) + return NULL; + + seq_buf_init(&s, buf, selinux_ima_config_len); + + seq_buf_printf(&s, "initialized=%d;enforcing=%d;checkreqprot=%d;", + selinux_initialized(), enforcing_enabled(), + checkreqprot_get()); + + for (i = 0; i < __POLICYDB_CAP_MAX; i++) + seq_buf_printf(&s, "%s=%d;", selinux_policycap_names[i], + selinux_state.policycap[i]); + + WARN_ON(seq_buf_has_overflowed(&s)); + + return buf; +} + +/* + * selinux_ima_measure_state_locked - Measure SELinux state and hash of policy + */ +void selinux_ima_measure_state_locked(void) +{ + char *state_str = NULL; + void *policy = NULL; + size_t policy_len; + int rc = 0; + + lockdep_assert_held(&selinux_state.policy_mutex); + + state_str = selinux_ima_collect_state(); + if (!state_str) { + pr_err("SELinux: %s: failed to read state.\n", __func__); + return; + } + + ima_measure_critical_data("selinux", "selinux-state", + state_str, strlen(state_str), false, + NULL, 0); + + kfree(state_str); + + /* + * Measure SELinux policy only after initialization is completed. + */ + if (!selinux_initialized()) + return; + + rc = security_read_state_kernel(&policy, &policy_len); + if (rc) { + pr_err("SELinux: %s: failed to read policy %d.\n", __func__, rc); + return; + } + + ima_measure_critical_data("selinux", "selinux-policy-hash", + policy, policy_len, true, + NULL, 0); + + vfree(policy); +} + +/* + * selinux_ima_measure_state - Measure SELinux state and hash of policy + */ +void selinux_ima_measure_state(void) +{ + lockdep_assert_not_held(&selinux_state.policy_mutex); + + mutex_lock(&selinux_state.policy_mutex); + selinux_ima_measure_state_locked(); + mutex_unlock(&selinux_state.policy_mutex); +} -- cgit v1.3.1