@@ -47,12 +47,14 @@ struct security_hook_heads {
* struct lsm_id - Identify a Linux Security Module.
* @lsm: name of the LSM, must be approved by the LSM maintainers
* @id: LSM ID number from uapi/linux/lsm.h
+ * @lsmblob: indicates the LSM has an entry in struct lsmblob
*
* Contains the information that identifies the LSM.
*/
struct lsm_id {
const char *name;
u64 id;
+ bool lsmblob;
};
/*
@@ -192,6 +192,7 @@ struct lsmblob {
extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
extern u32 lsm_active_cnt;
+extern u32 lsm_blob_cnt;
extern const struct lsm_id *lsm_idlist[];
/* These functions are in security/commoncap.c */
@@ -143,6 +143,7 @@
#define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */
#define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */
#define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */
+#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM task contexts */
#define AUDIT_FIRST_KERN_ANOM_MSG 1700
#define AUDIT_LAST_KERN_ANOM_MSG 1799
@@ -54,6 +54,7 @@
#include <net/netlink.h>
#include <linux/skbuff.h>
#include <linux/security.h>
+#include <linux/lsm_hooks.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
@@ -2228,21 +2229,51 @@ int audit_log_task_context(struct audit_buffer *ab)
{
struct lsmcontext ctx;
struct lsmblob blob;
+ bool space = false;
int error;
+ int i;
security_current_getlsmblob_subj(&blob);
if (!lsmblob_is_set(&blob))
return 0;
- error = security_lsmblob_to_secctx(&blob, &ctx, LSM_ID_UNDEF);
- if (error < 0) {
- if (error != -EINVAL)
- goto error_path;
+ if (lsm_blob_cnt < 2) {
+ error = security_lsmblob_to_secctx(&blob, &ctx, LSM_ID_UNDEF);
+ if (error < 0) {
+ if (error != -EINVAL)
+ goto error_path;
+ return 0;
+ }
+ audit_log_format(ab, " subj=%s", ctx.context);
+ security_release_secctx(&ctx);
return 0;
}
-
- audit_log_format(ab, " subj=%s", ctx.context);
- security_release_secctx(&ctx);
+ /* Multiple LSMs provide contexts. Include an aux record. */
+ audit_log_format(ab, " subj=?");
+ error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS);
+ if (error)
+ goto error_path;
+
+ for (i = 0; i < lsm_active_cnt; i++) {
+ if (!lsm_idlist[i]->lsmblob)
+ continue;
+ error = security_lsmblob_to_secctx(&blob, &ctx,
+ lsm_idlist[i]->id);
+ if (error < 0) {
+ if (error == -EOPNOTSUPP)
+ continue;
+ audit_log_format(ab, "%ssubj_%s=?", space ? " " : "",
+ lsm_idlist[i]->name);
+ if (error != -EINVAL)
+ audit_panic("error in audit_log_task_context");
+ } else {
+ audit_log_format(ab, "%ssubj_%s=%s", space ? " " : "",
+ lsm_idlist[i]->name, ctx.context);
+ security_release_secctx(&ctx);
+ }
+ space = true;
+ }
+ audit_buffer_aux_end(ab);
return 0;
error_path:
@@ -1447,6 +1447,7 @@ struct lsm_blob_sizes apparmor_blob_sizes __ro_after_init = {
static const struct lsm_id apparmor_lsmid = {
.name = "apparmor",
.id = LSM_ID_APPARMOR,
+ .lsmblob = true,
};
static struct security_hook_list apparmor_hooks[] __ro_after_init = {
@@ -19,6 +19,7 @@ static struct security_hook_list bpf_lsm_hooks[] __ro_after_init = {
static const struct lsm_id bpf_lsmid = {
.name = "bpf",
.id = LSM_ID_BPF,
+ .lsmblob = true,
};
static int __init bpf_lsm_init(void)
@@ -269,6 +269,7 @@ static void __init initialize_lsm(struct lsm_info *lsm)
* Current index to use while initializing the lsm id list.
*/
u32 lsm_active_cnt __ro_after_init;
+u32 lsm_blob_cnt __ro_after_init;
const struct lsm_id *lsm_idlist[LSM_CONFIG_COUNT];
/**
@@ -599,6 +600,8 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
if (lsm_active_cnt >= LSM_CONFIG_COUNT)
panic("%s Too many LSMs registered.\n", __func__);
lsm_idlist[lsm_active_cnt++] = lsmid;
+ if (lsmid->lsmblob)
+ lsm_blob_cnt++;
}
for (i = 0; i < count; i++) {
@@ -7092,6 +7092,7 @@ static int selinux_uring_cmd(struct io_uring_cmd *ioucmd)
static const struct lsm_id selinux_lsmid = {
.name = "selinux",
.id = LSM_ID_SELINUX,
+ .lsmblob = true,
};
/*
@@ -5069,6 +5069,7 @@ struct lsm_blob_sizes smack_blob_sizes __ro_after_init = {
static const struct lsm_id smack_lsmid = {
.name = "smack",
.id = LSM_ID_SMACK,
+ .lsmblob = true,
};
static struct security_hook_list smack_hooks[] __ro_after_init = {
Create a new audit record AUDIT_MAC_TASK_CONTEXTS. An example of the MAC_TASK_CONTEXTS (1420) record is: type=MAC_TASK_CONTEXTS[1420] msg=audit(1600880931.832:113) subj_apparmor=unconfined subj_smack=_ When an audit event includes a AUDIT_MAC_TASK_CONTEXTS record the "subj=" field in other records in the event will be "subj=?". An AUDIT_MAC_TASK_CONTEXTS record is supplied when the system has multiple security modules that may make access decisions based on a subject security context. Acked-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/linux/lsm_hooks.h | 2 ++ include/linux/security.h | 1 + include/uapi/linux/audit.h | 1 + kernel/audit.c | 45 ++++++++++++++++++++++++++++++++------ security/apparmor/lsm.c | 1 + security/bpf/hooks.c | 1 + security/security.c | 3 +++ security/selinux/hooks.c | 1 + security/smack/smack_lsm.c | 1 + 9 files changed, 49 insertions(+), 7 deletions(-)