[PATCH v15 21/23] Audit: Include object data for all security modules

Casey Schaufler
2020-02-22T00:06:19Z

When there is more than one context displaying security
module extend what goes into the audit record by supplimenting
the "obj=" with an "obj_<lsm>=" for each such security
module.

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc:linux-audit@redhat.com
---
kernel/audit.h | 4 +-
kernel/auditsc.c | 106 ++++++++++++++++++++++++-----------------------
2 files changed, 56 insertions(+), 54 deletions(-)

diff --git a/kernel/audit.h b/kernel/audit.h
index f65f516913c6..9a26ba213f6a 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -78,7 +78,7 @@ struct audit_names {
kuid_t uid;
kgid_t gid;
dev_t rdev;
- u32 osid;
+ struct lsmblob oblob;
struct audit_cap_data fcap;
unsigned int fcap_ver;
unsigned char type; /* record type */
@@ -152,7 +152,7 @@ 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 68ae5fa843c1..7dab48661e31 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -659,7 +659,6 @@ static int audit_filter_rules(struct task_struct *tsk,
if (f->lsm_isset) {
/* Find files that match */
if (name) {
- lsmblob_init(&blob, name->osid);
result = security_audit_rule_match(
&blob,
f->type,
@@ -667,7 +666,6 @@ static int audit_filter_rules(struct task_struct *tsk,
f->lsm_rules);
} else if (ctx) {
list_for_each_entry(n, &ctx->names_list, list) {
- lsmblob_init(&blob, name->osid);
if (security_audit_rule_match(
&blob,
f->type,
@@ -681,8 +679,7 @@ static int audit_filter_rules(struct task_struct *tsk,
/* Find ipc objects that match */
if (!ctx || ctx->type != AUDIT_IPC)
break;
- lsmblob_init(&blob, ctx->ipc.osid);
- if (security_audit_rule_match(&blob,
+ if (security_audit_rule_match(&ctx->ipc.oblob,
f->type, f->op,
f->lsm_rules))
++result;
@@ -956,13 +953,57 @@ static inline void audit_free_context(struct audit_context *context)
kfree(context);
}

+static int audit_log_object_context(struct audit_buffer *ab,
+ struct lsmblob *blob)
+{
+ struct lsmcontext context;
+ const char *lsm;
+ int i;
+
+ /*
+ * None of the installed modules have object labels.
+ */
+ if (security_lsm_slot_name(0) == NULL)
+ return 0;
+
+ if (blob->secid[0] != 0) {
+ if (security_secid_to_secctx(blob, &context, 0)) {
+ audit_log_format(ab, " obj=?");
+ return 1;
+ }
+ audit_log_format(ab, " obj=%s", context.context);
+ security_release_secctx(&context);
+ }
+
+ /*
+ * Don't do anything more unless there is more than one LSM
+ * with a security context to report.
+ */
+ if (security_lsm_slot_name(1) == NULL)
+ return 0;
+
+ for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+ lsm = security_lsm_slot_name(i);
+ if (lsm == NULL)
+ break;
+ if (blob->secid[i] == 0)
+ continue;
+ if (security_secid_to_secctx(blob, &context, i)) {
+ audit_log_format(ab, " obj_%s=?", lsm);
+ continue;
+ }
+ audit_log_format(ab, " obj_%s=%s", lsm, context.context);
+ security_release_secctx(&context);
+ }
+ return 0;
+}
+
static int audit_log_pid_context(struct audit_context *context, pid_t pid,
kuid_t auid, kuid_t uid,
unsigned int sessionid,
struct lsmblob *blob, char *comm)
{
struct audit_buffer *ab;
- struct lsmcontext lsmctx;
int rc = 0;

ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
@@ -972,15 +1013,7 @@ 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 (lsmblob_is_set(blob)) {
- if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) {
- audit_log_format(ab, " obj=(none)");
- rc = 1;
- } else {
- audit_log_format(ab, " obj=%s", lsmctx.context);
- security_release_secctx(&lsmctx);
- }
- }
+ rc = audit_log_object_context(ab, blob);
audit_log_format(ab, " ocomm=");
audit_log_untrustedstring(ab, comm);
audit_log_end(ab);
@@ -1207,26 +1240,14 @@ static void show_special(struct audit_context *context, int *call_panic)
context->socketcall.args[i]);
break; }
case AUDIT_IPC: {
- u32 osid = context->ipc.osid;
+ struct lsmblob *oblob = & context->ipc.oblob;

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) {
- struct lsmcontext lsmcxt;
- struct lsmblob blob;
-
- lsmblob_init(&blob, osid);
- if (security_secid_to_secctx(&blob, &lsmcxt,
- LSMBLOB_FIRST)) {
- audit_log_format(ab, " osid=%u", osid);
- *call_panic = 1;
- } else {
- audit_log_format(ab, " obj=%s", lsmcxt.context);
- security_release_secctx(&lsmcxt);
- }
- }
+ if (audit_log_object_context(ab, oblob))
+ *call_panic = 1;
if (context->ipc.has_perm) {
audit_log_end(ab);
ab = audit_log_start(context, GFP_KERNEL,
@@ -1366,20 +1387,8 @@ 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 (n->osid != 0) {
- struct lsmblob blob;
- struct lsmcontext lsmctx;
-
- lsmblob_init(&blob, n->osid);
- if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) {
- audit_log_format(ab, " osid=%u", n->osid);
- if (call_panic)
- *call_panic = 2;
- } else {
- audit_log_format(ab, " obj=%s", lsmctx.context);
- security_release_secctx(&lsmctx);
- }
- }
+ if (audit_log_object_context(ab, &n->oblob) && call_panic)
+ *call_panic = 2;

/* log the audit_names record type */
switch (n->type) {
@@ -1929,17 +1938,13 @@ static void audit_copy_inode(struct audit_names *name,
const struct dentry *dentry,
struct inode *inode, unsigned int flags)
{
- struct lsmblob blob;
-
name->ino = inode->i_ino;
name->dev = inode->i_sb->s_dev;
name->mode = inode->i_mode;
name->uid = inode->i_uid;
name->gid = inode->i_gid;
name->rdev = inode->i_rdev;
- security_inode_getsecid(inode, &blob);
- /* scaffolding until osid is updated */
- name->osid = blob.secid[0];
+ security_inode_getsecid(inode, &name->oblob);
if (flags & AUDIT_INODE_NOEVAL) {
name->fcap_ver = -1;
return;
@@ -2285,14 +2290,11 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
{
struct audit_context *context = audit_context();
- struct lsmblob blob;
context->ipc.uid = ipcp->uid;
context->ipc.gid = ipcp->gid;
context->ipc.mode = ipcp->mode;
context->ipc.has_perm = 0;
- security_ipc_getsecid(ipcp, &blob);
- /* scaffolding on the [0] - change "osid" to a lsmblob */
- context->ipc.osid = blob.secid[0];
+ security_ipc_getsecid(ipcp, &context->ipc.oblob);
context->type = AUDIT_IPC;
}

--
2.24.1