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Subject[PATCH ghak90 V7 19/21] audit: check cont depth
Date
Set an arbitrary limit on the depth of audit container identifier
nesting to limit abuse.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
kernel/audit.c | 21 +++++++++++++++++++++
kernel/audit.h | 2 ++
2 files changed, 23 insertions(+)

diff --git a/kernel/audit.c b/kernel/audit.c
index 848fd1c8c579..a70c9184e5d9 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -2667,6 +2667,22 @@ int audit_signal_info(int sig, struct task_struct *t)
return audit_signal_info_syscall(t);
}

+static int audit_contid_depth(struct audit_cont *cont)
+{
+ struct audit_cont *parent;
+ int depth = 1;
+
+ if (!cont)
+ return 0;
+
+ parent = cont->parent;
+ while (parent) {
+ depth++;
+ parent = parent->parent;
+ }
+ return depth;
+}
+
struct audit_cont *audit_cont(struct task_struct *tsk)
{
if (!tsk->audit || !tsk->audit->cont)
@@ -2785,6 +2801,11 @@ int audit_set_contid(struct task_struct *task, u64 contid)
rc = -ENOSPC;
goto conterror;
}
+ /* Set max contid depth */
+ if (audit_contid_depth(audit_cont(current->real_parent)) >= AUDIT_CONTID_DEPTH) {
+ rc = -EMLINK;
+ goto conterror;
+ }
if (!newcont) {
newcont = kmalloc(sizeof(struct audit_cont), GFP_ATOMIC);
if (newcont) {
diff --git a/kernel/audit.h b/kernel/audit.h
index 89b7de323c13..cb25341c1a0f 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -231,6 +231,8 @@ struct audit_contid_status {
u64 id;
};

+#define AUDIT_CONTID_DEPTH 5
+
/* Indicates that audit should log the full pathname. */
#define AUDIT_NAME_FULL -1

--
1.8.3.1
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