[PATCH v36 27/33] Audit: Add record for multiple task security contexts
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.
Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com>
---
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 42 +++++++++++++++++++++++++++++++-------
2 files changed, 36 insertions(+), 7 deletions(-)
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 7c1dc818b1d5..7a5966b46f38 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -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
diff --git a/kernel/audit.c b/kernel/audit.c
index 987740374dfa..2333d7f59285 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2228,6 +2228,7 @@ static void audit_buffer_aux_end(struct audit_buffer *ab)
int audit_log_task_context(struct audit_buffer *ab)
{
+ int i;
int error;
struct lsmblob blob;
struct lsmcontext context;
@@ -2236,16 +2237,43 @@ int audit_log_task_context(struct audit_buffer *ab)
if (!lsmblob_is_set(&blob))
return 0;
- error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST);
-
- if (error) {
- if (error != -EINVAL)
+ if (!lsm_multiple_contexts()) {
+ error = security_secid_to_secctx(&blob, &context,
+ LSMBLOB_FIRST);
+ if (error) {
+ if (error != -EINVAL)
+ goto error_path;
+ return 0;
+ }
+ audit_log_format(ab, " subj=%s", context.context);
+ security_release_secctx(&context);
+ } else {
+ /* 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;
- return 0;
+ for (i = 0; i < LSMBLOB_ENTRIES; i++) {
+ if (blob.secid[i] == 0)
+ continue;
+ error = security_secid_to_secctx(&blob, &context, i);
+ if (error) {
+ audit_log_format(ab, "%ssubj_%s=?",
+ i ? " " : "",
+ lsm_slot_to_name(i));
+ if (error != -EINVAL)
+ audit_panic("error in audit_log_task_context");
+ } else {
+ audit_log_format(ab, "%ssubj_%s=%s",
+ i ? " " : "",
+ lsm_slot_to_name(i),
+ context.context);
+ security_release_secctx(&context);
+ }
+ }
+ audit_buffer_aux_end(ab);
}
- audit_log_format(ab, " subj=%s", context.context);
- security_release_secctx(&context);
return 0;
error_path:
--
2.35.1