On Aug 29, 2024 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>
> Replace the secid value stored in struct audit_context with a struct
> lsmblob. Change the code that uses this value to accommodate the
> change. security_audit_rule_match() expects a lsmblob, so existing
> scaffolding can be removed. A call to security_secid_to_secctx()
> is changed to security_lsmblob_to_secctx(). The call to
> security_ipc_getsecid() is scaffolded.
>
> A new function lsmblob_is_set() is introduced to identify whether
> an lsmblob contains a non-zero value.
>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> ---
> include/linux/security.h | 13 +++++++++++++
> kernel/audit.h | 3 ++-
> kernel/auditsc.c | 19 ++++++++-----------
> 3 files changed, 23 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 457fafc32fb0..a0b23b6e8734 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -277,6 +277,19 @@ static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)
> return kernel_load_data_str[id];
> }
>
> +/**
> + * lsmblob_is_set - report if there is a value in the lsmblob
> + * @blob: Pointer to the exported LSM data
> + *
> + * Returns true if there is a value set, false otherwise
> + */
> +static inline bool lsmblob_is_set(struct lsmblob *blob)
> +{
> + const struct lsmblob empty = {};
> +
> + return !!memcmp(blob, &empty, sizeof(*blob));
> +}
> +
> #ifdef CONFIG_SECURITY
We probably want a !CONFIG_SECURITY variant of this too.
> int call_blocking_lsm_notifier(enum lsm_event event, void *data);
> diff --git a/kernel/audit.h b/kernel/audit.h
> index a60d2840559e..b1f2de4d4f1e 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -11,6 +11,7 @@
>
> #include <linux/fs.h>
> #include <linux/audit.h>
> +#include <linux/security.h>
> #include <linux/skbuff.h>
> #include <uapi/linux/mqueue.h>
> #include <linux/tty.h>
> @@ -160,7 +161,7 @@ struct audit_context {
> kuid_t uid;
> kgid_t gid;
> umode_t mode;
> - u32 osid;
> + struct lsmblob oblob;
> int has_perm;
> uid_t perm_uid;
> gid_t perm_gid;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 23adb15cae43..84f6e9356b8f 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -724,9 +724,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> /* Find ipc objects that match */
> if (!ctx || ctx->type != AUDIT_IPC)
> break;
> - /* scaffolding */
> - blob.scaffold.secid = ctx->ipc.osid;
> - if (security_audit_rule_match(&blob,
> + if (security_audit_rule_match(&ctx->ipc.oblob,
> f->type, f->op,
> f->lsm_rule))
> ++result;
> @@ -1394,19 +1392,17 @@ static void show_special(struct audit_context *context, int *call_panic)
> audit_log_format(ab, " a%d=%lx", i,
> context->socketcall.args[i]);
> break; }
> - case AUDIT_IPC: {
> - u32 osid = context->ipc.osid;
> -
> + case AUDIT_IPC:
> audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
> from_kuid(&init_user_ns, context->ipc.uid),
> from_kgid(&init_user_ns, context->ipc.gid),
> context->ipc.mode);
> - if (osid) {
> + if (lsmblob_is_set(&context->ipc.oblob)) {
> char *ctx = NULL;
> u32 len;
>
> - if (security_secid_to_secctx(osid, &ctx, &len)) {
> - audit_log_format(ab, " osid=%u", osid);
> + if (security_lsmblob_to_secctx(&context->ipc.oblob,
> + &ctx, &len)) {
> *call_panic = 1;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> @@ -1426,7 +1422,7 @@ static void show_special(struct audit_context *context, int *call_panic)
> context->ipc.perm_gid,
> context->ipc.perm_mode);
> }
> - break; }
> + break;
> case AUDIT_MQ_OPEN:
> audit_log_format(ab,
> "oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
> @@ -2642,7 +2638,8 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
> context->ipc.gid = ipcp->gid;
> context->ipc.mode = ipcp->mode;
> context->ipc.has_perm = 0;
> - security_ipc_getsecid(ipcp, &context->ipc.osid);
> + /* scaffolding */
> + security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
> context->type = AUDIT_IPC;
> }
>
> --
> 2.46.0
--
paul-moore.com
