Hi Casey,
On Fri, 2020-11-20 at 12:14 -0800, Casey Schaufler wrote:
> When more than one security module is exporting data to
> audit and networking sub-systems a single 32 bit integer
> is no longer sufficient to represent the data. Add a
> structure to be used instead.
>
> The lsmblob structure is currently an array of
> u32 "secids". There is an entry for each of the
> security modules built into the system that would
> use secids if active. The system assigns the module
> a "slot" when it registers hooks. If modules are
> compiled in but not registered there will be unused
> slots.
>
> A new lsm_id structure, which contains the name
> of the LSM and its slot number, is created. There
> is an instance for each LSM, which assigns the name
> and passes it to the infrastructure to set the slot.
>
> The audit rules data is expanded to use an array of
> security module data rather than a single instance.
> Because IMA uses the audit rule functions it is
> affected as well.
This patch is quite large, even without the audit rule change. I would
limit this patch to the new lsm_id structure changes. The audit rule
change should be broken out as a separate patch so that the audit
changes aren't hidden.
In addition, here are a few high level nits:
- The (patch description) body of the explanation, line wrapped at 75
columns, which will be copied to the permanent changelog to describe
this patch. (Refer Documentation/process/submitting-patches.rst.)
- The brief kernel-doc descriptions should not have a trailing period.
Nor should kernel-doc variable definitions have a trailing period.
Example(s) inline below. (The existing kernel-doc is mostly correct.)
- For some reason existing comments that span multiple lines aren't
formatted properly. In those cases, where there is another change,
please fix the comment and function description.
thanks,
Mimi
>
> Acked-by: Stephen Smalley <sds@xxxxxxxxxxxxx>
> Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
> Acked-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> Cc: <bpf@xxxxxxxxxxxxxxx>
> Cc: linux-audit@xxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> Cc: selinux@xxxxxxxxxxxxxxx
> ---
> diff --git a/include/linux/security.h b/include/linux/security.h
> index bc2725491560..fdb6e95c98e8 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -132,6 +132,65 @@ enum lockdown_reason {
>
> extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
>
> +/*
> + * Data exported by the security modules
> + *
> + * Any LSM that provides secid or secctx based hooks must be included.
> + */
> +#define LSMBLOB_ENTRIES ( \
> + (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
> + (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
> + (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0) + \
> + (IS_ENABLED(CONFIG_BPF_LSM) ? 1 : 0))
> +
> +struct lsmblob {
> + u32 secid[LSMBLOB_ENTRIES];
> +};
> +
> +#define LSMBLOB_INVALID -1 /* Not a valid LSM slot number */
> +#define LSMBLOB_NEEDED -2 /* Slot requested on initialization */
> +#define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */
> +
> +/**
> + * lsmblob_init - initialize an lsmblob structure.
Only this kernel-doc brief description is suffixed with a period.
Please remove.
> + * @blob: Pointer to the data to initialize
> + * @secid: The initial secid value
> + *
> + * Set all secid for all modules to the specified value.
> + */
> +static inline void lsmblob_init(struct lsmblob *blob, u32 secid)
> +{
> + int i;
> +
> + for (i = 0; i < LSMBLOB_ENTRIES; i++)
> + blob->secid[i] = secid;
> +}
> +
> +/**
> + * lsmblob_is_set - report if there is an value in the lsmblob
> + * @blob: Pointer to the exported LSM data
> + *
> + * Returns true if there is a secid set, false otherwise
> + */
> +static inline bool lsmblob_is_set(struct lsmblob *blob)
> +{
> + struct lsmblob empty = {};
> +
> + return !!memcmp(blob, &empty, sizeof(*blob));
> +}
> +
> +/**
> + * lsmblob_equal - report if the two lsmblob's are equal
> + * @bloba: Pointer to one LSM data
> + * @blobb: Pointer to the other LSM data
> + *
> + * Returns true if all entries in the two are equal, false otherwise
> + */
> +static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
> +{
> + return !memcmp(bloba, blobb, sizeof(*bloba));
> +}
> +
> /* These functions are in security/commoncap.c */
> extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 9b5adeaa47fc..cd393aaa17d5 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> } lsm[MAX_LSM_RULES];
> @@ -88,6 +88,22 @@ struct ima_rule_entry {
> struct ima_template_desc *template;
> };
>
> +/**
> + * ima_lsm_isset - Is a rule set for any of the active security modules
> + * @rules: The set of IMA rules to check.
Nor do kernel-doc variable definitions have a trailing period.
> + *
> + * If a rule is set for any LSM return true, otherwise return false.
> + */
> +static inline bool ima_lsm_isset(void *rules[])
> +{
> + int i;
> +
> + for (i = 0; i < LSMBLOB_ENTRIES; i++)
> + if (rules[i])
> + return true;
> + return false;
> +}
> +
> /*
> * Without LSM specific knowledge, the default policy can only be
> * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
