audit: add support for session ID user filter

Define AUDIT_SESSIONID in the uapi and add support for specifying user
filters based on the session ID.  Also add the new session ID filter
to the feature bitmap so userspace knows it is available.

https://github.com/linux-audit/audit-kernel/issues/4
RFE: add a session ID filter to the kernel's user filter

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: combine multiple patches from Richard into this one]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index 82e8aa5..c8dc97b 100644 (file)
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -254,6 +254,7 @@
 #define AUDIT_OBJ_LEV_LOW      22
 #define AUDIT_OBJ_LEV_HIGH     23
 #define AUDIT_LOGINUID_SET     24
+#define AUDIT_SESSIONID        25      /* Session ID */
 
                                /* These are ONLY useful when checking
                                 * at syscall exit time (AUDIT_AT_EXIT). */
@@ -329,9 +330,11 @@ enum {
 #define AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT     0x00000001
 #define AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME 0x00000002
 #define AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH   0x00000004
+#define AUDIT_FEATURE_BITMAP_SESSIONID_FILTER  0x00000010
 #define AUDIT_FEATURE_BITMAP_ALL (AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | \
                                  AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME | \
-                                 AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH)
+                                 AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH | \
+                                 AUDIT_FEATURE_BITMAP_SESSIONID_FILTER)
 
 /* deprecated: AUDIT_VERSION_* */
 #define AUDIT_VERSION_LATEST           AUDIT_FEATURE_BITMAP_ALL

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 632e90d..880519d 100644 (file)
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -363,6 +363,7 @@ static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
        case AUDIT_EXIT:
        case AUDIT_SUCCESS:
        case AUDIT_INODE:
+       case AUDIT_SESSIONID:
                /* bit ops are only useful on syscall args */
                if (f->op == Audit_bitmask || f->op == Audit_bittest)
                        return -EINVAL;
@@ -476,6 +477,7 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
                        if (!gid_valid(f->gid))
                                goto exit_free;
                        break;
+               case AUDIT_SESSIONID:
                case AUDIT_ARCH:
                        entry->rule.arch_f = f;
                        break;

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d161b17..f78cb1b 100644 (file)
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -446,6 +446,7 @@ static int audit_filter_rules(struct task_struct *tsk,
        const struct cred *cred;
        int i, need_sid = 1;
        u32 sid;
+       unsigned int sessionid;
 
        cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
 
@@ -508,6 +509,10 @@ static int audit_filter_rules(struct task_struct *tsk,
                case AUDIT_FSGID:
                        result = audit_gid_comparator(cred->fsgid, f->op, f->gid);
                        break;
+               case AUDIT_SESSIONID:
+                       sessionid = audit_get_sessionid(current);
+                       result = audit_comparator(sessionid, f->op, f->val);
+                       break;
                case AUDIT_PERS:
                        result = audit_comparator(tsk->personality, f->op, f->val);
                        break;