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    Subject[PATCH v10 17/27] ima: Add functions for creating and freeing of an ima_namespace
    Date
    Implement create_ima_ns() to create an empty ima_namespace. Defer its
    initialization to a later point outside this function. Implement
    free_ima_ns() to free it.

    Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
    Acked-by: Christian Brauner <brauner@kernel.org>

    ---
    v9:
    - Set user_ns->ims_ns = NULL in free_ima_ns()
    - Refactored create_ima_ns() to defer initialization
    - Removed pr_debug functions
    ---
    include/linux/ima.h | 13 ++++++
    security/integrity/ima/Makefile | 1 +
    security/integrity/ima/ima.h | 15 +++++++
    security/integrity/ima/ima_init_ima_ns.c | 2 +-
    security/integrity/ima/ima_ns.c | 53 ++++++++++++++++++++++++
    5 files changed, 83 insertions(+), 1 deletion(-)
    create mode 100644 security/integrity/ima/ima_ns.c

    diff --git a/include/linux/ima.h b/include/linux/ima.h
    index 0cf2a80c8b35..964a08702573 100644
    --- a/include/linux/ima.h
    +++ b/include/linux/ima.h
    @@ -220,4 +220,17 @@ static inline bool ima_appraise_signature(enum kernel_read_file_id func)
    return false;
    }
    #endif /* CONFIG_IMA_APPRAISE && CONFIG_INTEGRITY_TRUSTED_KEYRING */
    +
    +#ifdef CONFIG_IMA_NS
    +
    +void free_ima_ns(struct user_namespace *ns);
    +
    +#else
    +
    +static inline void free_ima_ns(struct user_namespace *user_ns)
    +{
    +}
    +
    +#endif /* CONFIG_IMA_NS */
    +
    #endif /* _LINUX_IMA_H */
    diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
    index f8a5e5f3975d..b86a35fbed60 100644
    --- a/security/integrity/ima/Makefile
    +++ b/security/integrity/ima/Makefile
    @@ -14,6 +14,7 @@ ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
    ima-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
    ima-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o
    ima-$(CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS) += ima_queue_keys.o
    +ima-$(CONFIG_IMA_NS) += ima_ns.o

    ifeq ($(CONFIG_EFI),y)
    ima-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT) += ima_efi.o
    diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
    index 8c757223d549..751e936a6311 100644
    --- a/security/integrity/ima/ima.h
    +++ b/security/integrity/ima/ima.h
    @@ -167,6 +167,7 @@ extern bool ima_canonical_fmt;
    int ima_init(void);
    int ima_fs_init(void);
    int ima_ns_init(void);
    +int ima_init_namespace(struct ima_namespace *ns);
    int ima_add_template_entry(struct ima_namespace *ns,
    struct ima_template_entry *entry, int violation,
    const char *op, struct inode *inode,
    @@ -502,4 +503,18 @@ static inline struct ima_namespace
    return NULL;
    }

    +#ifdef CONFIG_IMA_NS
    +
    +struct ima_namespace *create_ima_ns(void);
    +
    +#else
    +
    +static inline struct ima_namespace *create_ima_ns(void)
    +{
    + WARN(1, "Cannot create an IMA namespace\n");
    + return ERR_PTR(-EFAULT);
    +}
    +
    +#endif /* CONFIG_IMA_NS */
    +
    #endif /* __LINUX_IMA_H */
    diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
    index 1cba545ae477..166dab4a3126 100644
    --- a/security/integrity/ima/ima_init_ima_ns.c
    +++ b/security/integrity/ima/ima_init_ima_ns.c
    @@ -8,7 +8,7 @@

    #include "ima.h"

    -static int ima_init_namespace(struct ima_namespace *ns)
    +int ima_init_namespace(struct ima_namespace *ns)
    {
    int rc;

    diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
    new file mode 100644
    index 000000000000..b3b81a1e313e
    --- /dev/null
    +++ b/security/integrity/ima/ima_ns.c
    @@ -0,0 +1,53 @@
    +// SPDX-License-Identifier: GPL-2.0-only
    +/*
    + * Copyright (C) 2016-2021 IBM Corporation
    + * Author:
    + * Yuqiong Sun <suny@us.ibm.com>
    + * Stefan Berger <stefanb@linux.vnet.ibm.com>
    + */
    +
    +#include <linux/ima.h>
    +
    +#include "ima.h"
    +
    +static struct kmem_cache *imans_cachep;
    +
    +struct ima_namespace *create_ima_ns(void)
    +{
    + struct ima_namespace *ns;
    +
    + ns = kmem_cache_zalloc(imans_cachep, GFP_KERNEL);
    + if (!ns)
    + return ERR_PTR(-ENOMEM);
    +
    + return ns;
    +}
    +
    +/* destroy_ima_ns() must only be called after ima_init_namespace() was called */
    +static void destroy_ima_ns(struct ima_namespace *ns)
    +{
    + unregister_blocking_lsm_notifier(&ns->ima_lsm_policy_notifier);
    + kfree(ns->arch_policy_entry);
    + ima_free_policy_rules(ns);
    +}
    +
    +void free_ima_ns(struct user_namespace *user_ns)
    +{
    + struct ima_namespace *ns = user_ns->ima_ns;
    +
    + if (!ns || WARN_ON(ns == &init_ima_ns))
    + return;
    +
    + destroy_ima_ns(ns);
    +
    + kmem_cache_free(imans_cachep, ns);
    +
    + user_ns->ima_ns = NULL;
    +}
    +
    +static int __init imans_cache_init(void)
    +{
    + imans_cachep = KMEM_CACHE(ima_namespace, SLAB_PANIC);
    + return 0;
    +}
    +subsys_initcall(imans_cache_init)
    --
    2.31.1
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