[PATCH ghak90 V7 18/21] audit: track container nesting

From: Richard Guy Briggs
Date: Wed Sep 18 2019 - 21:27:21 EST

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Track the parent container of a container to be able to filter and
report nesting.

Now that we have a way to track and check the parent container of a
container, fixup other patches, or squash all nesting fixes together.

fixup! audit: add container id
fixup! audit: log drop of contid on exit of last task
fixup! audit: log container info of syscalls
fixup! audit: add containerid filtering
fixup! audit: NETFILTER_PKT: record each container ID associated with a netNS
fixup! audit: convert to contid list to check for orch/engine ownership softirq (for netfilter) audit: protect contid list lock from softirq

Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
---
include/linux/audit.h | 1 +
kernel/audit.c | 67 ++++++++++++++++++++++++++++++++++++++++++---------
kernel/audit.h | 3 +++
kernel/auditfilter.c | 20 ++++++++++++++-
kernel/auditsc.c | 2 +-
5 files changed, 79 insertions(+), 14 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index dcd92f964120..1ce27af686ea 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -110,6 +110,7 @@ struct audit_cont {
struct task_struct *owner;
refcount_t refcount;
struct rcu_head rcu;
+ struct audit_cont *parent;
};

struct audit_task_info {
diff --git a/kernel/audit.c b/kernel/audit.c
index 9e82de13d2eb..848fd1c8c579 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -213,7 +213,7 @@ struct audit_reply {

static struct kmem_cache *audit_task_cache;

-static DEFINE_SPINLOCK(audit_contid_list_lock);
+DEFINE_SPINLOCK(audit_contid_list_lock);

void __init audit_task_init(void)
{
@@ -275,6 +275,7 @@ void audit_free(struct task_struct *tsk)
{
struct audit_task_info *info = tsk->audit;
struct nsproxy *ns = tsk->nsproxy;
+ unsigned long flags;

audit_free_syscall(tsk);
if (ns)
@@ -282,9 +283,9 @@ void audit_free(struct task_struct *tsk)
/* Freeing the audit_task_info struct must be performed after
* audit_log_exit() due to need for loginuid and sessionid.
*/
- spin_lock(&audit_contid_list_lock);
+ spin_lock_irqsave(&audit_contid_list_lock, flags);
audit_cont_put(tsk->audit->cont);
- spin_unlock(&audit_contid_list_lock);
+ spin_unlock_irqrestore(&audit_contid_list_lock, flags);
info = tsk->audit;
tsk->audit = NULL;
kmem_cache_free(audit_task_cache, info);
@@ -450,6 +451,7 @@ void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p)
audit_netns_contid_add(new->net_ns, contid);
}

+void audit_log_contid(struct audit_buffer *ab, u64 contid);
/**
* audit_log_netns_contid_list - List contids for the given network namespace
* @net: the network namespace of interest
@@ -481,7 +483,7 @@ void audit_log_netns_contid_list(struct net *net, struct audit_context *context)
audit_log_format(ab, "contid=");
} else
audit_log_format(ab, ",");
- audit_log_format(ab, "%llu", cont->id);
+ audit_log_contid(ab, cont->id);
}
audit_log_end(ab);
out:
@@ -2371,6 +2373,36 @@ void audit_log_session_info(struct audit_buffer *ab)
audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
}

+void audit_log_contid(struct audit_buffer *ab, u64 contid)
+{
+ struct audit_cont *cont = NULL;
+ struct audit_cont *prcont = NULL;
+ int h;
+ unsigned long flags;
+
+ if (!audit_contid_valid(contid)) {
+ audit_log_format(ab, "%llu", contid);
+ return;
+ }
+ h = audit_hash_contid(contid);
+ spin_lock_irqsave(&audit_contid_list_lock, flags);
+ list_for_each_entry_rcu(cont, &audit_contid_hash[h], list)
+ if (cont->id == contid)
+ prcont = cont;
+ if (!prcont) {
+ audit_log_format(ab, "%llu", contid);
+ goto out;
+ }
+ while (prcont) {
+ audit_log_format(ab, "%llu", prcont->id);
+ prcont = prcont->parent;
+ if (prcont)
+ audit_log_format(ab, "^");
+ }
+out:
+ spin_unlock_irqrestore(&audit_contid_list_lock, flags);
+}
+
/*
* audit_log_container_id - report container info
* @context: task or local context for record
@@ -2386,7 +2418,8 @@ void audit_log_container_id(struct audit_context *context, u64 contid)
ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONTAINER_ID);
if (!ab)
return;
- audit_log_format(ab, "contid=%llu", contid);
+ audit_log_format(ab, "contid=");
+ audit_log_contid(ab, contid);
audit_log_end(ab);
}
EXPORT_SYMBOL(audit_log_container_id);
@@ -2648,6 +2681,7 @@ void audit_cont_put(struct audit_cont *cont)
return;
if (refcount_dec_and_test(&cont->refcount)) {
put_task_struct(cont->owner);
+ audit_cont_put(cont->parent);
list_del_rcu(&cont->list);
kfree_rcu(cont, rcu);
audit_contid_count--;
@@ -2732,8 +2766,9 @@ int audit_set_contid(struct task_struct *task, u64 contid)
struct audit_cont *cont = NULL;
struct audit_cont *newcont = NULL;
int h = audit_hash_contid(contid);
+ unsigned long flags;

- spin_lock(&audit_contid_list_lock);
+ spin_lock_irqsave(&audit_contid_list_lock, flags);
list_for_each_entry_rcu(cont, &audit_contid_hash[h], list)
if (cont->id == contid) {
/* task injection to existing container */
@@ -2757,6 +2792,9 @@ int audit_set_contid(struct task_struct *task, u64 contid)
newcont->id = contid;
get_task_struct(current);
newcont->owner = current;
+ newcont->parent = audit_cont(newcont->owner);
+ if (newcont->parent)
+ refcount_inc(&newcont->parent->refcount);
refcount_set(&newcont->refcount, 1);
list_add_rcu(&newcont->list, &audit_contid_hash[h]);
audit_contid_count++;
@@ -2768,7 +2806,7 @@ int audit_set_contid(struct task_struct *task, u64 contid)
task->audit->cont = newcont;
audit_cont_put(oldcont);
conterror:
- spin_unlock(&audit_contid_list_lock);
+ spin_unlock_irqrestore(&audit_contid_list_lock, flags);
}
if (!rc) {
if (audit_contid_valid(oldcontid))
@@ -2786,9 +2824,12 @@ int audit_set_contid(struct task_struct *task, u64 contid)

uid = from_kuid(&init_user_ns, task_uid(current));
tty = audit_get_tty();
+ audit_log_format(ab, "op=set opid=%d contid=", task_tgid_nr(task));
+ audit_log_contid(ab, contid);
+ audit_log_format(ab, " old-contid=");
+ audit_log_contid(ab, oldcontid);
audit_log_format(ab,
- "op=set opid=%d contid=%llu old-contid=%llu pid=%d uid=%u auid=%u tty=%s ses=%u",
- task_tgid_nr(task), contid, oldcontid,
+ " pid=%d uid=%u auid=%u tty=%s ses=%u",
task_tgid_nr(current), uid,
from_kuid(&init_user_ns, audit_get_loginuid(current)),
tty ? tty_name(tty) : "(none)",
@@ -2819,10 +2860,12 @@ void audit_log_container_drop(void)

uid = from_kuid(&init_user_ns, task_uid(current));
tty = audit_get_tty();
+ audit_log_format(ab, "op=drop opid=%d contid=%llu old-contid=",
+ task_tgid_nr(current), AUDIT_CID_UNSET);
+ audit_log_contid(ab, audit_get_contid(current));
audit_log_format(ab,
- "op=drop opid=%d contid=%llu old-contid=%llu pid=%d uid=%u auid=%u tty=%s ses=%u",
- task_tgid_nr(current), audit_get_contid(current),
- audit_get_contid(current), task_tgid_nr(current), uid,
+ " pid=%d uid=%u auid=%u tty=%s ses=%u",
+ task_tgid_nr(current), uid,
from_kuid(&init_user_ns, audit_get_loginuid(current)),
tty ? tty_name(tty) : "(none)",
audit_get_sessionid(current));
diff --git a/kernel/audit.h b/kernel/audit.h
index 25732fbc47a4..89b7de323c13 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -220,6 +220,8 @@ static inline int audit_hash_contid(u64 contid)
return (contid & (AUDIT_CONTID_BUCKETS-1));
}

+extern spinlock_t audit_contid_list_lock;
+
extern int audit_contid_count;

#define AUDIT_CONTID_COUNT 1 << 16
@@ -235,6 +237,7 @@ struct audit_contid_status {
extern int audit_match_class(int class, unsigned syscall);
extern int audit_comparator(const u32 left, const u32 op, const u32 right);
extern int audit_comparator64(const u64 left, const u32 op, const u64 right);
+extern int audit_contid_comparator(const u64 left, const u32 op, const u64 right);
extern int audit_uid_comparator(kuid_t left, u32 op, kuid_t right);
extern int audit_gid_comparator(kgid_t left, u32 op, kgid_t right);
extern int parent_len(const char *path);
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 9606f973fe33..513d57d03637 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1297,6 +1297,24 @@ int audit_gid_comparator(kgid_t left, u32 op, kgid_t right)
}
}

+int audit_contid_comparator(u64 left, u32 op, u64 right)
+{
+ struct audit_cont *cont = NULL;
+ int h;
+ int result = 0;
+ unsigned long flags;
+
+ h = audit_hash_contid(left);
+ spin_lock_irqsave(&audit_contid_list_lock, flags);
+ list_for_each_entry_rcu(cont, &audit_contid_hash[h], list) {
+ result = audit_comparator64(cont->id, op, right);
+ if (result)
+ break;
+ }
+ spin_unlock_irqrestore(&audit_contid_list_lock, flags);
+ return result;
+}
+
/**
* parent_len - find the length of the parent portion of a pathname
* @path: pathname of which to determine length
@@ -1388,7 +1406,7 @@ int audit_filter(int msgtype, unsigned int listtype)
f->op, f->val);
break;
case AUDIT_CONTID:
- result = audit_comparator64(audit_get_contid(current),
+ result = audit_contid_comparator(audit_get_contid(current),
f->op, f->val64);
break;
case AUDIT_MSGTYPE:
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index a658fe775b86..6bf6d8b9dfd1 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -630,7 +630,7 @@ static int audit_filter_rules(struct task_struct *tsk,
f->op, f->val);
break;
case AUDIT_CONTID:
- result = audit_comparator64(audit_get_contid(tsk),
+ result = audit_contid_comparator(audit_get_contid(tsk),
f->op, f->val64);
break;
case AUDIT_SUBJ_USER:
--
1.8.3.1

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