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Message-ID: <20250607005134.10488-5-casey@schaufler-ca.com>
Date: Fri, 6 Jun 2025 17:51:34 -0700
From: Casey Schaufler <casey@...aufler-ca.com>
To: casey@...aufler-ca.com,
paul@...l-moore.com,
eparis@...hat.com,
linux-security-module@...r.kernel.org,
audit@...r.kernel.org
Cc: jmorris@...ei.org,
serge@...lyn.com,
keescook@...omium.org,
john.johansen@...onical.com,
penguin-kernel@...ove.sakura.ne.jp,
stephen.smalley.work@...il.com,
linux-kernel@...r.kernel.org,
selinux@...r.kernel.org
Subject: [PATCH v4 4/4] Audit: Add record for multiple object contexts
Create a new audit record AUDIT_MAC_OBJ_CONTEXTS.
An example of the MAC_OBJ_CONTEXTS record is:
type=MAC_OBJ_CONTEXTS
msg=audit(1601152467.009:1050):
obj_selinux=unconfined_u:object_r:user_home_t:s0
When an audit event includes a AUDIT_MAC_OBJ_CONTEXTS record
the "obj=" field in other records in the event will be "obj=?".
An AUDIT_MAC_OBJ_CONTEXTS record is supplied when the system has
multiple security modules that may make access decisions based
on an object security context.
Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
---
include/linux/audit.h | 7 +++++
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 58 +++++++++++++++++++++++++++++++++++++-
kernel/auditsc.c | 45 ++++++++---------------------
security/selinux/hooks.c | 3 +-
security/smack/smack_lsm.c | 3 +-
6 files changed, 80 insertions(+), 37 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 5020939fb8bc..c507fdfcf534 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -151,6 +151,7 @@ extern unsigned compat_signal_class[];
/* bit values for audit_lsm_secctx */
#define AUDIT_SECCTX_SUBJECT BIT(0)
+#define AUDIT_SECCTX_OBJECT BIT(1)
struct filename;
@@ -191,6 +192,7 @@ extern void audit_log_path_denied(int type,
extern void audit_log_lost(const char *message);
extern int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop);
+extern int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop);
extern int audit_log_task_context(struct audit_buffer *ab);
extern void audit_log_task_info(struct audit_buffer *ab);
@@ -258,6 +260,11 @@ static inline int audit_log_subj_ctx(struct audit_buffer *ab,
{
return 0;
}
+static inline int audit_log_obj_ctx(struct audit_buffer *ab,
+ struct lsm_prop *prop)
+{
+ return 0;
+}
static inline int audit_log_task_context(struct audit_buffer *ab)
{
return 0;
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 8cad2f307719..14a1c1fe013a 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -149,6 +149,7 @@
#define AUDIT_LANDLOCK_ACCESS 1423 /* Landlock denial */
#define AUDIT_LANDLOCK_DOMAIN 1424 /* Landlock domain status */
#define AUDIT_MAC_TASK_CONTEXTS 1425 /* Multiple LSM task contexts */
+#define AUDIT_MAC_OBJ_CONTEXTS 1426 /* Multiple LSM objext contexts */
#define AUDIT_FIRST_KERN_ANOM_MSG 1700
#define AUDIT_LAST_KERN_ANOM_MSG 1799
diff --git a/kernel/audit.c b/kernel/audit.c
index 0987b2f391cc..451c36965889 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -85,7 +85,9 @@ static unsigned int audit_net_id;
/* Number of modules that provide a security context.
List of lsms that provide a security context */
static u32 audit_subj_secctx_cnt;
+static u32 audit_obj_secctx_cnt;
static const struct lsm_id *audit_subj_lsms[MAX_LSM_COUNT];
+static const struct lsm_id *audit_obj_lsms[MAX_LSM_COUNT];
/**
* struct audit_net - audit private network namespace data
@@ -305,6 +307,12 @@ void audit_lsm_secctx(const struct lsm_id *lsmid, int flags)
return;
audit_subj_lsms[audit_subj_secctx_cnt++] = lsmid;
}
+ if (flags & AUDIT_SECCTX_OBJECT) {
+ for (i = 0 ; i < audit_obj_secctx_cnt; i++)
+ if (audit_obj_lsms[i] == lsmid)
+ return;
+ audit_obj_lsms[audit_obj_secctx_cnt++] = lsmid;
+ }
}
/**
@@ -1142,7 +1150,6 @@ static int is_audit_feature_set(int i)
return af.features & AUDIT_FEATURE_TO_MASK(i);
}
-
static int audit_get_feature(struct sk_buff *skb)
{
u32 seq;
@@ -2337,6 +2344,55 @@ int audit_log_task_context(struct audit_buffer *ab)
}
EXPORT_SYMBOL(audit_log_task_context);
+int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop)
+{
+ int i;
+ int rc;
+ int error = 0;
+ char *space = "";
+ struct lsm_context ctx;
+
+ if (audit_obj_secctx_cnt < 2) {
+ error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF);
+ if (error < 0) {
+ if (error != -EINVAL)
+ goto error_path;
+ return error;
+ }
+ audit_log_format(ab, " obj=%s", ctx.context);
+ security_release_secctx(&ctx);
+ return 0;
+ }
+ audit_log_format(ab, " obj=?");
+ error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS);
+ if (error)
+ goto error_path;
+
+ for (i = 0; i < audit_obj_secctx_cnt; i++) {
+ rc = security_lsmprop_to_secctx(prop, &ctx,
+ audit_obj_lsms[i]->id);
+ if (rc < 0) {
+ audit_log_format(ab, "%sobj_%s=?", space,
+ audit_obj_lsms[i]->name);
+ if (rc != -EINVAL)
+ audit_panic("error in audit_log_obj_ctx");
+ error = rc;
+ } else {
+ audit_log_format(ab, "%sobj_%s=%s", space,
+ audit_obj_lsms[i]->name, ctx.context);
+ security_release_secctx(&ctx);
+ }
+ space = " ";
+ }
+
+ audit_buffer_aux_end(ab);
+ return error;
+
+error_path:
+ audit_panic("error in audit_log_obj_ctx");
+ return error;
+}
+
void audit_log_d_path_exe(struct audit_buffer *ab,
struct mm_struct *mm)
{
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 322d4e27f28e..0c28fa33d099 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1098,7 +1098,6 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
char *comm)
{
struct audit_buffer *ab;
- struct lsm_context ctx;
int rc = 0;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -1108,15 +1107,9 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
from_kuid(&init_user_ns, auid),
from_kuid(&init_user_ns, uid), sessionid);
- if (lsmprop_is_set(prop)) {
- if (security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF) < 0) {
- audit_log_format(ab, " obj=(none)");
- rc = 1;
- } else {
- audit_log_format(ab, " obj=%s", ctx.context);
- security_release_secctx(&ctx);
- }
- }
+ if (lsmprop_is_set(prop) && audit_log_obj_ctx(ab, prop))
+ rc = 1;
+
audit_log_format(ab, " ocomm=");
audit_log_untrustedstring(ab, comm);
audit_log_end(ab);
@@ -1392,16 +1385,8 @@ static void show_special(struct audit_context *context, int *call_panic)
from_kgid(&init_user_ns, context->ipc.gid),
context->ipc.mode);
if (lsmprop_is_set(&context->ipc.oprop)) {
- struct lsm_context lsmctx;
-
- if (security_lsmprop_to_secctx(&context->ipc.oprop,
- &lsmctx,
- LSM_ID_UNDEF) < 0) {
+ if (audit_log_obj_ctx(ab, &context->ipc.oprop))
*call_panic = 1;
- } else {
- audit_log_format(ab, " obj=%s", lsmctx.context);
- security_release_secctx(&lsmctx);
- }
}
if (context->ipc.has_perm) {
audit_log_end(ab);
@@ -1558,18 +1543,9 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
from_kgid(&init_user_ns, n->gid),
MAJOR(n->rdev),
MINOR(n->rdev));
- if (lsmprop_is_set(&n->oprop)) {
- struct lsm_context ctx;
-
- if (security_lsmprop_to_secctx(&n->oprop, &ctx,
- LSM_ID_UNDEF) < 0) {
- if (call_panic)
- *call_panic = 2;
- } else {
- audit_log_format(ab, " obj=%s", ctx.context);
- security_release_secctx(&ctx);
- }
- }
+ if (lsmprop_is_set(&n->oprop) &&
+ audit_log_obj_ctx(ab, &n->oprop))
+ *call_panic = 2;
/* log the audit_names record type */
switch (n->type) {
@@ -1780,15 +1756,16 @@ static void audit_log_exit(void)
axs->target_sessionid[i],
&axs->target_ref[i],
axs->target_comm[i]))
- call_panic = 1;
+ call_panic = 1;
}
if (context->target_pid &&
audit_log_pid_context(context, context->target_pid,
context->target_auid, context->target_uid,
context->target_sessionid,
- &context->target_ref, context->target_comm))
- call_panic = 1;
+ &context->target_ref,
+ context->target_comm))
+ call_panic = 1;
if (context->pwd.dentry && context->pwd.mnt) {
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a89561c1fdea..0ffe3a7cacf3 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7517,7 +7517,8 @@ static __init int selinux_init(void)
cred_init_security();
/* Inform the audit system that secctx is used */
- audit_lsm_secctx(&selinux_lsmid, AUDIT_SECCTX_SUBJECT);
+ audit_lsm_secctx(&selinux_lsmid,
+ AUDIT_SECCTX_SUBJECT | AUDIT_SECCTX_OBJECT);
default_noexec = !(VM_DATA_DEFAULT_FLAGS & VM_EXEC);
if (!default_noexec)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 06603c328079..b54d93d31600 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -5276,7 +5276,8 @@ static __init int smack_init(void)
init_smack_known_list();
/* Inform the audit system that secctx is used */
- audit_lsm_secctx(&smack_lsmid, AUDIT_SECCTX_SUBJECT);
+ audit_lsm_secctx(&smack_lsmid,
+ AUDIT_SECCTX_SUBJECT | AUDIT_SECCTX_OBJECT);
return 0;
}
--
2.47.0
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