ftrace: Synchronize the initialization of ftrace_opsgrafted

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 <rostedt@goodmis.org>

1 files changed, 342 insertions, 0 deletions

diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c
new file mode 100644
index 000000000..0ae54a880
--- /dev/null
+++ b/security/ipe/hooks.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2024 Microsoft Corporation. All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/types.h>
+#include <linux/binfmts.h>
+#include <linux/mman.h>
+#include <linux/blk_types.h>
+
+#include "ipe.h"
+#include "hooks.h"
+#include "eval.h"
+#include "digest.h"
+
+/**
+ * ipe_bprm_check_security() - ipe security hook function for bprm check.
+ * @bprm: Supplies a pointer to a linux_binprm structure to source the file
+ *	  being evaluated.
+ *
+ * This LSM hook is called when a binary is loaded through the exec
+ * family of system calls.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_bprm_check_security(struct linux_binprm *bprm)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+
+	ipe_build_eval_ctx(&ctx, bprm->file, IPE_OP_EXEC, IPE_HOOK_BPRM_CHECK);
+	return ipe_evaluate_event(&ctx);
+}
+
+/**
+ * ipe_bprm_creds_for_exec() - ipe security hook function for bprm creds check.
+ * @bprm: Supplies a pointer to a linux_binprm structure to source the file
+ *	  being evaluated.
+ *
+ * This LSM hook is called when userspace signals the kernel to check a file
+ * for execution through the execveat syscall with the AT_EXECVE_CHECK flag.
+ * The hook triggers IPE policy evaluation on the script file and returns
+ * the policy decision to userspace. The userspace program receives the
+ * return code and can decide whether to proceed with script execution.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_bprm_creds_for_exec(struct linux_binprm *bprm)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+
+	if (!bprm->is_check)
+		return 0;
+
+	ipe_build_eval_ctx(&ctx, bprm->file, IPE_OP_EXEC,
+			   IPE_HOOK_BPRM_CREDS_FOR_EXEC);
+	return ipe_evaluate_event(&ctx);
+}
+
+/**
+ * ipe_mmap_file() - ipe security hook function for mmap check.
+ * @f: File being mmap'd. Can be NULL in the case of anonymous memory.
+ * @reqprot: The requested protection on the mmap, passed from usermode.
+ * @prot: The effective protection on the mmap, resolved from reqprot and
+ *	  system configuration.
+ * @flags: Unused.
+ *
+ * This hook is called when a file is loaded through the mmap
+ * family of system calls.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_mmap_file(struct file *f, unsigned long reqprot __always_unused,
+		  unsigned long prot, unsigned long flags)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+
+	if (prot & PROT_EXEC) {
+		ipe_build_eval_ctx(&ctx, f, IPE_OP_EXEC, IPE_HOOK_MMAP);
+		return ipe_evaluate_event(&ctx);
+	}
+
+	return 0;
+}
+
+/**
+ * ipe_file_mprotect() - ipe security hook function for mprotect check.
+ * @vma: Existing virtual memory area created by mmap or similar.
+ * @reqprot: The requested protection on the mmap, passed from usermode.
+ * @prot: The effective protection on the mmap, resolved from reqprot and
+ *	  system configuration.
+ *
+ * This LSM hook is called when a mmap'd region of memory is changing
+ * its protections via mprotect.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_file_mprotect(struct vm_area_struct *vma,
+		      unsigned long reqprot __always_unused,
+		      unsigned long prot)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+
+	/* Already Executable */
+	if (vma->vm_flags & VM_EXEC)
+		return 0;
+
+	if (prot & PROT_EXEC) {
+		ipe_build_eval_ctx(&ctx, vma->vm_file, IPE_OP_EXEC, IPE_HOOK_MPROTECT);
+		return ipe_evaluate_event(&ctx);
+	}
+
+	return 0;
+}
+
+/**
+ * ipe_kernel_read_file() - ipe security hook function for kernel read.
+ * @file: Supplies a pointer to the file structure being read in from disk.
+ * @id: Supplies the enumeration identifying the purpose of the read.
+ * @contents: Unused.
+ *
+ * This LSM hook is called when a file is read from disk in the kernel.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_kernel_read_file(struct file *file, enum kernel_read_file_id id,
+			 bool contents)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+	enum ipe_op_type op;
+
+	switch (id) {
+	case READING_FIRMWARE:
+		op = IPE_OP_FIRMWARE;
+		break;
+	case READING_MODULE:
+	case READING_MODULE_COMPRESSED:
+		op = IPE_OP_KERNEL_MODULE;
+		break;
+	case READING_KEXEC_INITRAMFS:
+		op = IPE_OP_KEXEC_INITRAMFS;
+		break;
+	case READING_KEXEC_IMAGE:
+		op = IPE_OP_KEXEC_IMAGE;
+		break;
+	case READING_POLICY:
+		op = IPE_OP_POLICY;
+		break;
+	case READING_X509_CERTIFICATE:
+		op = IPE_OP_X509;
+		break;
+	default:
+		op = IPE_OP_INVALID;
+		WARN(1, "no rule setup for kernel_read_file enum %d", id);
+	}
+
+	ipe_build_eval_ctx(&ctx, file, op, IPE_HOOK_KERNEL_READ);
+	return ipe_evaluate_event(&ctx);
+}
+
+/**
+ * ipe_kernel_load_data() - ipe security hook function for kernel load data.
+ * @id: Supplies the enumeration identifying the purpose of the load.
+ * @contents: Unused.
+ *
+ * This LSM hook is called when a data buffer provided by userspace is loading
+ * into the kernel.
+ *
+ * Return:
+ * * %0		- Success
+ * * %-EACCES	- Did not pass IPE policy
+ */
+int ipe_kernel_load_data(enum kernel_load_data_id id, bool contents)
+{
+	struct ipe_eval_ctx ctx = IPE_EVAL_CTX_INIT;
+	enum ipe_op_type op;
+
+	switch (id) {
+	case LOADING_FIRMWARE:
+		op = IPE_OP_FIRMWARE;
+		break;
+	case LOADING_MODULE:
+		op = IPE_OP_KERNEL_MODULE;
+		break;
+	case LOADING_KEXEC_INITRAMFS:
+		op = IPE_OP_KEXEC_INITRAMFS;
+		break;
+	case LOADING_KEXEC_IMAGE:
+		op = IPE_OP_KEXEC_IMAGE;
+		break;
+	case LOADING_POLICY:
+		op = IPE_OP_POLICY;
+		break;
+	case LOADING_X509_CERTIFICATE:
+		op = IPE_OP_X509;
+		break;
+	default:
+		op = IPE_OP_INVALID;
+		WARN(1, "no rule setup for kernel_load_data enum %d", id);
+	}
+
+	ipe_build_eval_ctx(&ctx, NULL, op, IPE_HOOK_KERNEL_LOAD);
+	return ipe_evaluate_event(&ctx);
+}
+
+/**
+ * ipe_unpack_initramfs() - Mark the current rootfs as initramfs.
+ */
+void ipe_unpack_initramfs(void)
+{
+	ipe_sb(current->fs->root.mnt->mnt_sb)->initramfs = true;
+}
+
+#ifdef CONFIG_IPE_PROP_DM_VERITY
+/**
+ * ipe_bdev_free_security() - Free IPE's LSM blob of block_devices.
+ * @bdev: Supplies a pointer to a block_device that contains the structure
+ *	  to free.
+ */
+void ipe_bdev_free_security(struct block_device *bdev)
+{
+	struct ipe_bdev *blob = ipe_bdev(bdev);
+
+	ipe_digest_free(blob->root_hash);
+}
+
+#ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE
+static void ipe_set_dmverity_signature(struct ipe_bdev *blob,
+				       const void *value,
+				       size_t size)
+{
+	blob->dm_verity_signed = size > 0 && value;
+}
+#else
+static inline void ipe_set_dmverity_signature(struct ipe_bdev *blob,
+					      const void *value,
+					      size_t size)
+{
+}
+#endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */
+
+/**
+ * ipe_bdev_setintegrity() - Save integrity data from a bdev to IPE's LSM blob.
+ * @bdev: Supplies a pointer to a block_device that contains the LSM blob.
+ * @type: Supplies the integrity type.
+ * @value: Supplies the value to store.
+ * @size: The size of @value.
+ *
+ * This hook is currently used to save dm-verity's root hash or the existence
+ * of a validated signed dm-verity root hash into LSM blob.
+ *
+ * Return: %0 on success. If an error occurs, the function will return the
+ * -errno.
+ */
+int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type type,
+			  const void *value, size_t size)
+{
+	const struct dm_verity_digest *digest = NULL;
+	struct ipe_bdev *blob = ipe_bdev(bdev);
+	struct digest_info *info = NULL;
+
+	if (type == LSM_INT_DMVERITY_SIG_VALID) {
+		ipe_set_dmverity_signature(blob, value, size);
+
+		return 0;
+	}
+
+	if (type != LSM_INT_DMVERITY_ROOTHASH)
+		return -EINVAL;
+
+	if (!value) {
+		ipe_digest_free(blob->root_hash);
+		blob->root_hash = NULL;
+
+		return 0;
+	}
+	digest = value;
+
+	info = kzalloc_obj(*info);
+	if (!info)
+		return -ENOMEM;
+
+	info->digest = kmemdup(digest->digest, digest->digest_len, GFP_KERNEL);
+	if (!info->digest)
+		goto err;
+
+	info->alg = kstrdup(digest->alg, GFP_KERNEL);
+	if (!info->alg)
+		goto err;
+
+	info->digest_len = digest->digest_len;
+
+	ipe_digest_free(blob->root_hash);
+	blob->root_hash = info;
+
+	return 0;
+err:
+	ipe_digest_free(info);
+
+	return -ENOMEM;
+}
+#endif /* CONFIG_IPE_PROP_DM_VERITY */
+
+#ifdef CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG
+/**
+ * ipe_inode_setintegrity() - save integrity data from a inode to IPE's LSM blob.
+ * @inode: The inode to source the security blob from.
+ * @type: Supplies the integrity type.
+ * @value: The value to be stored.
+ * @size: The size of @value.
+ *
+ * This hook is currently used to save the existence of a validated fs-verity
+ * builtin signature into LSM blob.
+ *
+ * Return: %0 on success. If an error occurs, the function will return the
+ * -errno.
+ */
+int ipe_inode_setintegrity(const struct inode *inode,
+			   enum lsm_integrity_type type,
+			   const void *value, size_t size)
+{
+	struct ipe_inode *inode_sec = ipe_inode(inode);
+
+	if (type == LSM_INT_FSVERITY_BUILTINSIG_VALID) {
+		inode_sec->fs_verity_signed = size > 0 && value;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+#endif /* CONFIG_IPE_PROP_FS_VERITY_BUILTIN_SIG */