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    Subject[RFC PATCH 3/5] ima: mamespace audit status flags
    Date
    The iint cache stores whether the file is measured, appraised, audited
    etc. This patch moves the IMA_AUDITED flag into the per-namespace
    ns_status, enabling IMA audit mechanism to audit the same file each time
    it is accessed in a new namespace.

    The ns_status is not looked up if the CONFIG_IMA_NS is disabled or if
    none of the IMA_NS_STATUS_ACTIONS (currently only IMA_AUDIT) are enabled.

    Read and write operations on the iint flags is replaced with function
    calls. For reading, iint_flags() returns the bitwise AND of iint->flags
    and ns_status->flags. The ns_status flags are masked with
    IMA_NS_STATUS_FLAGS (currently only IMA_AUDITED). Similarly
    set_iint_flags() only writes the masked portion to the ns_status flags,
    while the iint flags is set as before. The ns_status parameter added to
    ima_audit_measurement() is used with the above functions to query and
    set the ns_status flags.

    Signed-off-by: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
    ---
    init/Kconfig | 4 +++-
    security/integrity/ima/ima.h | 24 +++++++++++++++++++++++-
    security/integrity/ima/ima_api.c | 8 +++++---
    security/integrity/ima/ima_main.c | 15 ++++++++++++---
    security/integrity/ima/ima_ns.c | 21 +++++++++++++++++++++
    5 files changed, 64 insertions(+), 8 deletions(-)

    diff --git a/init/Kconfig b/init/Kconfig
    index 339f84d..6bfc579 100644
    --- a/init/Kconfig
    +++ b/init/Kconfig
    @@ -1294,7 +1294,9 @@ config IMA_NS
    help
    Allow the creation of IMA namespaces for each mount namespace.
    Namespaced IMA data enables having IMA features work separately
    - for each mount namespace.
    + for each mount namespace. Currently, only the audit status flags
    + are stored in the namespace, which allows the same file to be
    + audited each time it is accessed in a new namespace.

    endif # NAMESPACES

    diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
    index 5ab769a..78921b7 100644
    --- a/security/integrity/ima/ima.h
    +++ b/security/integrity/ima/ima.h
    @@ -210,7 +210,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
    struct evm_ima_xattr_data *xattr_value,
    int xattr_len, int pcr);
    void ima_audit_measurement(struct integrity_iint_cache *iint,
    - const unsigned char *filename);
    + const unsigned char *filename,
    + struct ns_status *status);
    int ima_alloc_init_template(struct ima_event_data *event_data,
    struct ima_template_entry **entry);
    int ima_store_template(struct ima_template_entry *entry, int violation,
    @@ -299,10 +300,17 @@ static inline int ima_read_xattr(struct dentry *dentry,

    #endif /* CONFIG_IMA_APPRAISE */

    +#define IMA_NS_STATUS_ACTIONS IMA_AUDIT
    +#define IMA_NS_STATUS_FLAGS IMA_AUDITED
    +
    #ifdef CONFIG_IMA_NS
    int ima_ns_init(void);
    struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
    struct inode *inode);
    +unsigned long iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status);
    +unsigned long set_iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status, unsigned long flags);
    #else
    static inline int ima_ns_init(void)
    {
    @@ -314,6 +322,20 @@ static inline struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
    {
    return NULL;
    }
    +
    +static inline unsigned long iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status)
    +{
    + return iint->flags;
    +}
    +
    +static inline unsigned long set_iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status,
    + unsigned long flags)
    +{
    + iint->flags = flags;
    + return flags;
    +}
    #endif /* CONFIG_IMA_NS */

    /* LSM based policy rules require audit */
    diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
    index c2edba8..4a77072 100644
    --- a/security/integrity/ima/ima_api.c
    +++ b/security/integrity/ima/ima_api.c
    @@ -287,15 +287,17 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
    }

    void ima_audit_measurement(struct integrity_iint_cache *iint,
    - const unsigned char *filename)
    + const unsigned char *filename,
    + struct ns_status *status)
    {
    struct audit_buffer *ab;
    char hash[(iint->ima_hash->length * 2) + 1];
    const char *algo_name = hash_algo_name[iint->ima_hash->algo];
    char algo_hash[sizeof(hash) + strlen(algo_name) + 2];
    int i;
    + unsigned long flags = iint_flags(iint, status);

    - if (iint->flags & IMA_AUDITED)
    + if (flags & IMA_AUDITED)
    return;

    for (i = 0; i < iint->ima_hash->length; i++)
    @@ -316,7 +318,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
    audit_log_task_info(ab, current);
    audit_log_end(ab);

    - iint->flags |= IMA_AUDITED;
    + set_iint_flags(iint, status, flags | IMA_AUDITED);
    }

    /*
    diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
    index 2aebb79..fb002f2 100644
    --- a/security/integrity/ima/ima_main.c
    +++ b/security/integrity/ima/ima_main.c
    @@ -160,6 +160,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
    {
    struct inode *inode = file_inode(file);
    struct integrity_iint_cache *iint = NULL;
    + struct ns_status *status = NULL;
    struct ima_template_desc *template_desc;
    char *pathbuf = NULL;
    char filename[NAME_MAX];
    @@ -170,6 +171,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
    int xattr_len = 0;
    bool violation_check;
    enum hash_algo hash_algo;
    + unsigned long flags;

    if (!ima_policy_flag || !S_ISREG(inode->i_mode))
    return 0;
    @@ -196,6 +198,12 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
    iint = integrity_inode_get(inode);
    if (!iint)
    goto out;
    +
    + if (action & IMA_NS_STATUS_ACTIONS) {
    + status = ima_get_ns_status(get_current_ns(), inode);
    + if (IS_ERR(status))
    + goto out;
    + }
    }

    if (violation_check) {
    @@ -211,9 +219,10 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
    * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
    * IMA_AUDIT, IMA_AUDITED)
    */
    - iint->flags |= action;
    + flags = iint_flags(iint, status);
    + flags = set_iint_flags(iint, status, flags | action);
    action &= IMA_DO_MASK;
    - action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
    + action &= ~((flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);

    /* If target pcr is already measured, unset IMA_MEASURE action */
    if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
    @@ -251,7 +260,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
    rc = ima_appraise_measurement(func, iint, file, pathname,
    xattr_value, xattr_len, opened);
    if (action & IMA_AUDIT)
    - ima_audit_measurement(iint, pathname);
    + ima_audit_measurement(iint, pathname, status);

    out_digsig:
    if ((mask & MAY_WRITE) && (iint->flags & IMA_DIGSIG) &&
    diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
    index 5ec5a4b..562a0812 100644
    --- a/security/integrity/ima/ima_ns.c
    +++ b/security/integrity/ima/ima_ns.c
    @@ -301,3 +301,24 @@ struct ns_status *ima_get_ns_status(struct ima_namespace *ns,

    return status;
    }
    +
    +#define IMA_NS_STATUS_ACTIONS IMA_AUDIT
    +#define IMA_NS_STATUS_FLAGS IMA_AUDITED
    +
    +unsigned long iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status)
    +{
    + if (!status)
    + return iint->flags;
    +
    + return iint->flags & (status->flags & IMA_NS_STATUS_FLAGS);
    +}
    +
    +unsigned long set_iint_flags(struct integrity_iint_cache *iint,
    + struct ns_status *status, unsigned long flags)
    +{
    + iint->flags = flags;
    + if (status)
    + status->flags = flags & IMA_NS_STATUS_FLAGS;
    + return flags;
    +}
    --
    2.9.4
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