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Subject[PATCH ghak90 V7 06/21] audit: contid limit of 32k imposed to avoid DoS
Date
Set an arbitrary limit on the number of audit container identifiers to
limit abuse.

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
---
kernel/audit.c | 8 ++++++++
kernel/audit.h | 4 ++++
2 files changed, 12 insertions(+)

diff --git a/kernel/audit.c b/kernel/audit.c
index 53d13d638c63..329916534dd2 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -139,6 +139,7 @@ struct audit_net {
struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
/* Hash for contid-based rules */
struct list_head audit_contid_hash[AUDIT_CONTID_BUCKETS];
+int audit_contid_count = 0;

static struct kmem_cache *audit_buffer_cache;

@@ -2384,6 +2385,7 @@ void audit_cont_put(struct audit_cont *cont)
put_task_struct(cont->owner);
list_del_rcu(&cont->list);
kfree_rcu(cont, rcu);
+ audit_contid_count--;
}
}

@@ -2456,6 +2458,11 @@ int audit_set_contid(struct task_struct *task, u64 contid)
goto conterror;
}
}
+ /* Set max contids */
+ if (audit_contid_count > AUDIT_CONTID_COUNT) {
+ rc = -ENOSPC;
+ goto conterror;
+ }
if (!newcont) {
newcont = kmalloc(sizeof(struct audit_cont), GFP_ATOMIC);
if (newcont) {
@@ -2465,6 +2472,7 @@ int audit_set_contid(struct task_struct *task, u64 contid)
newcont->owner = current;
refcount_set(&newcont->refcount, 1);
list_add_rcu(&newcont->list, &audit_contid_hash[h]);
+ audit_contid_count++;
} else {
rc = -ENOMEM;
goto conterror;
diff --git a/kernel/audit.h b/kernel/audit.h
index 162de8366b32..543f1334ba47 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -219,6 +219,10 @@ static inline int audit_hash_contid(u64 contid)
return (contid & (AUDIT_CONTID_BUCKETS-1));
}

+extern int audit_contid_count;
+
+#define AUDIT_CONTID_COUNT 1 << 16
+
/* Indicates that audit should log the full pathname. */
#define AUDIT_NAME_FULL -1

--
1.8.3.1
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