audit: comparison on interprocess fields

This allows audit to specify rules in which we compare two fields of a
process.  Such as is the running process uid != to the running process
euid?

Signed-off-by: Peter Moody <pmoody@google.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

2 files changed, 62 insertions, 1 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 67113cb4bc15..9ff7a2c48b50 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -193,7 +193,29 @@
 #define AUDIT_COMPARE_FSUID_TO_OBJ_UID  8
 #define AUDIT_COMPARE_FSGID_TO_OBJ_GID  9
 
-#define AUDIT_MAX_FIELD_COMPARE         AUDIT_COMPARE_FSGID_TO_OBJ_GID
+#define AUDIT_COMPARE_UID_TO_AUID       10
+#define AUDIT_COMPARE_UID_TO_EUID       11
+#define AUDIT_COMPARE_UID_TO_FSUID      12
+#define AUDIT_COMPARE_UID_TO_SUID       13
+
+#define AUDIT_COMPARE_AUID_TO_FSUID     14
+#define AUDIT_COMPARE_AUID_TO_SUID      15
+#define AUDIT_COMPARE_AUID_TO_EUID      16
+
+#define AUDIT_COMPARE_EUID_TO_SUID      17
+#define AUDIT_COMPARE_EUID_TO_FSUID     18
+
+#define AUDIT_COMPARE_SUID_TO_FSUID     19
+
+#define AUDIT_COMPARE_GID_TO_EGID       20
+#define AUDIT_COMPARE_GID_TO_FSGID      21
+#define AUDIT_COMPARE_GID_TO_SGID       22
+
+#define AUDIT_COMPARE_EGID_TO_FSGID     23
+#define AUDIT_COMPARE_EGID_TO_SGID      24
+#define AUDIT_COMPARE_SGID_TO_FSGID     25
+
+#define AUDIT_MAX_FIELD_COMPARE         AUDIT_COMPARE_SGID_TO_FSGID
 
 /* Rule fields */
                                 /* These are useful when checking the
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b8cee462b99e..593237e3654d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -545,6 +545,45 @@ static int audit_field_compare(struct task_struct *tsk,
                 return audit_compare_id(cred->fsgid,
                                         name, offsetof(struct audit_names, gid),
                                         f, ctx);
+        /* uid comparisons */
+        case AUDIT_COMPARE_UID_TO_AUID:
+                return audit_comparator(cred->uid, f->op, tsk->loginuid);
+        case AUDIT_COMPARE_UID_TO_EUID:
+                return audit_comparator(cred->uid, f->op, cred->euid);
+        case AUDIT_COMPARE_UID_TO_SUID:
+                return audit_comparator(cred->uid, f->op, cred->suid);
+        case AUDIT_COMPARE_UID_TO_FSUID:
+                return audit_comparator(cred->uid, f->op, cred->fsuid);
+        /* auid comparisons */
+        case AUDIT_COMPARE_AUID_TO_EUID:
+                return audit_comparator(tsk->loginuid, f->op, cred->euid);
+        case AUDIT_COMPARE_AUID_TO_SUID:
+                return audit_comparator(tsk->loginuid, f->op, cred->suid);
+        case AUDIT_COMPARE_AUID_TO_FSUID:
+                return audit_comparator(tsk->loginuid, f->op, cred->fsuid);
+        /* euid comparisons */
+        case AUDIT_COMPARE_EUID_TO_SUID:
+                return audit_comparator(cred->euid, f->op, cred->suid);
+        case AUDIT_COMPARE_EUID_TO_FSUID:
+                return audit_comparator(cred->euid, f->op, cred->fsuid);
+        /* suid comparisons */
+        case AUDIT_COMPARE_SUID_TO_FSUID:
+                return audit_comparator(cred->suid, f->op, cred->fsuid);
+        /* gid comparisons */
+        case AUDIT_COMPARE_GID_TO_EGID:
+                return audit_comparator(cred->gid, f->op, cred->egid);
+        case AUDIT_COMPARE_GID_TO_SGID:
+                return audit_comparator(cred->gid, f->op, cred->sgid);
+        case AUDIT_COMPARE_GID_TO_FSGID:
+                return audit_comparator(cred->gid, f->op, cred->fsgid);
+        /* egid comparisons */
+        case AUDIT_COMPARE_EGID_TO_SGID:
+                return audit_comparator(cred->egid, f->op, cred->sgid);
+        case AUDIT_COMPARE_EGID_TO_FSGID:
+                return audit_comparator(cred->egid, f->op, cred->fsgid);
+        /* sgid comparison */
+        case AUDIT_COMPARE_SGID_TO_FSGID:
+                return audit_comparator(cred->sgid, f->op, cred->fsgid);
         default:
                 WARN(1, "Missing AUDIT_COMPARE define.  Report as a bug\n");
                 return 0;