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1d6119baf0
This patch fixes following problems :
1) percpu_counter_init() can return an error, therefore
init_frag_mem_limit() must propagate this error so that
inet_frags_init_net() can do the same up to its callers.
2) If ip[46]_frags_ns_ctl_register() fail, we must unwind
properly and free the percpu_counter.
Without this fix, we leave freed object in percpu_counters
global list (if CONFIG_HOTPLUG_CPU) leading to crashes.
This bug was detected by KASAN and syzkaller tool
(http://github.com/google/syzkaller)
Fixes: 6d7b857d54
("net: use lib/percpu_counter API for fragmentation mem accounting")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
188 lines
5.0 KiB
C
188 lines
5.0 KiB
C
#ifndef __NET_FRAG_H__
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#define __NET_FRAG_H__
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#include <linux/percpu_counter.h>
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struct netns_frags {
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/* The percpu_counter "mem" need to be cacheline aligned.
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* mem.count must not share cacheline with other writers
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*/
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struct percpu_counter mem ____cacheline_aligned_in_smp;
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/* sysctls */
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int timeout;
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int high_thresh;
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int low_thresh;
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};
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/**
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* fragment queue flags
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*
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* @INET_FRAG_FIRST_IN: first fragment has arrived
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* @INET_FRAG_LAST_IN: final fragment has arrived
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* @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction
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*/
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enum {
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INET_FRAG_FIRST_IN = BIT(0),
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INET_FRAG_LAST_IN = BIT(1),
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INET_FRAG_COMPLETE = BIT(2),
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};
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/**
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* struct inet_frag_queue - fragment queue
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*
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* @lock: spinlock protecting the queue
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* @timer: queue expiration timer
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* @list: hash bucket list
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* @refcnt: reference count of the queue
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* @fragments: received fragments head
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* @fragments_tail: received fragments tail
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* @stamp: timestamp of the last received fragment
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* @len: total length of the original datagram
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* @meat: length of received fragments so far
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* @flags: fragment queue flags
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* @max_size: maximum received fragment size
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* @net: namespace that this frag belongs to
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* @list_evictor: list of queues to forcefully evict (e.g. due to low memory)
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*/
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struct inet_frag_queue {
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spinlock_t lock;
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struct timer_list timer;
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struct hlist_node list;
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atomic_t refcnt;
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struct sk_buff *fragments;
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struct sk_buff *fragments_tail;
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ktime_t stamp;
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int len;
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int meat;
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__u8 flags;
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u16 max_size;
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struct netns_frags *net;
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struct hlist_node list_evictor;
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};
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#define INETFRAGS_HASHSZ 1024
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/* averaged:
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* max_depth = default ipfrag_high_thresh / INETFRAGS_HASHSZ /
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* rounded up (SKB_TRUELEN(0) + sizeof(struct ipq or
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* struct frag_queue))
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*/
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#define INETFRAGS_MAXDEPTH 128
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struct inet_frag_bucket {
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struct hlist_head chain;
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spinlock_t chain_lock;
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};
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struct inet_frags {
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struct inet_frag_bucket hash[INETFRAGS_HASHSZ];
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struct work_struct frags_work;
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unsigned int next_bucket;
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unsigned long last_rebuild_jiffies;
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bool rebuild;
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/* The first call to hashfn is responsible to initialize
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* rnd. This is best done with net_get_random_once.
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*
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* rnd_seqlock is used to let hash insertion detect
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* when it needs to re-lookup the hash chain to use.
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*/
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u32 rnd;
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seqlock_t rnd_seqlock;
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int qsize;
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unsigned int (*hashfn)(const struct inet_frag_queue *);
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bool (*match)(const struct inet_frag_queue *q,
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const void *arg);
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void (*constructor)(struct inet_frag_queue *q,
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const void *arg);
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void (*destructor)(struct inet_frag_queue *);
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void (*skb_free)(struct sk_buff *);
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void (*frag_expire)(unsigned long data);
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struct kmem_cache *frags_cachep;
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const char *frags_cache_name;
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};
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int inet_frags_init(struct inet_frags *);
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void inet_frags_fini(struct inet_frags *);
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static inline int inet_frags_init_net(struct netns_frags *nf)
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{
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return percpu_counter_init(&nf->mem, 0, GFP_KERNEL);
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}
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static inline void inet_frags_uninit_net(struct netns_frags *nf)
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{
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percpu_counter_destroy(&nf->mem);
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}
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void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f);
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void inet_frag_kill(struct inet_frag_queue *q, struct inet_frags *f);
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void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f);
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struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
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struct inet_frags *f, void *key, unsigned int hash);
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void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
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const char *prefix);
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static inline void inet_frag_put(struct inet_frag_queue *q, struct inet_frags *f)
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{
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if (atomic_dec_and_test(&q->refcnt))
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inet_frag_destroy(q, f);
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}
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static inline bool inet_frag_evicting(struct inet_frag_queue *q)
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{
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return !hlist_unhashed(&q->list_evictor);
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}
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/* Memory Tracking Functions. */
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/* The default percpu_counter batch size is not big enough to scale to
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* fragmentation mem acct sizes.
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* The mem size of a 64K fragment is approx:
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* (44 fragments * 2944 truesize) + frag_queue struct(200) = 129736 bytes
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*/
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static unsigned int frag_percpu_counter_batch = 130000;
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static inline int frag_mem_limit(struct netns_frags *nf)
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{
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return percpu_counter_read(&nf->mem);
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}
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static inline void sub_frag_mem_limit(struct netns_frags *nf, int i)
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{
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__percpu_counter_add(&nf->mem, -i, frag_percpu_counter_batch);
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}
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static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
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{
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__percpu_counter_add(&nf->mem, i, frag_percpu_counter_batch);
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}
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static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
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{
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unsigned int res;
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local_bh_disable();
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res = percpu_counter_sum_positive(&nf->mem);
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local_bh_enable();
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return res;
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}
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/* RFC 3168 support :
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* We want to check ECN values of all fragments, do detect invalid combinations.
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* In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
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*/
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#define IPFRAG_ECN_NOT_ECT 0x01 /* one frag had ECN_NOT_ECT */
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#define IPFRAG_ECN_ECT_1 0x02 /* one frag had ECN_ECT_1 */
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#define IPFRAG_ECN_ECT_0 0x04 /* one frag had ECN_ECT_0 */
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#define IPFRAG_ECN_CE 0x08 /* one frag had ECN_CE */
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extern const u8 ip_frag_ecn_table[16];
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#endif
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