diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-01-13 01:22:29 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-01-13 13:06:05 +0000 |
| commit | 91341fa0003befd097e190ec2a4bf63ad957c49a (patch) | |
| tree | 9a7ae534e177de1206e62ae6b9f61afdc45a40b5 /net | |
| parent | 3ba8c6258eb19a6212b066a383788174dd9779ab (diff) | |
| download | linux-91341fa0003befd097e190ec2a4bf63ad957c49a.tar.bz2 | |
inet: frags: annotate races around fqdir->dead and fqdir->high_thresh
Both fields can be read/written without synchronization,
add proper accessors and documentation.
Fixes: d5dd88794a13 ("inet: fix various use-after-free in defrags units")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/inet_fragment.c | 8 | ||||
| -rw-r--r-- | net/ipv4/ip_fragment.c | 3 |
2 files changed, 7 insertions, 4 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index 05cd198d7a6b..341096807100 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -235,9 +235,9 @@ void inet_frag_kill(struct inet_frag_queue *fq) /* The RCU read lock provides a memory barrier * guaranteeing that if fqdir->dead is false then * the hash table destruction will not start until - * after we unlock. Paired with inet_frags_exit_net(). + * after we unlock. Paired with fqdir_pre_exit(). */ - if (!fqdir->dead) { + if (!READ_ONCE(fqdir->dead)) { rhashtable_remove_fast(&fqdir->rhashtable, &fq->node, fqdir->f->rhash_params); refcount_dec(&fq->refcnt); @@ -352,9 +352,11 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, /* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) { + /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */ + long high_thresh = READ_ONCE(fqdir->high_thresh); struct inet_frag_queue *fq = NULL, *prev; - if (!fqdir->high_thresh || frag_mem_limit(fqdir) > fqdir->high_thresh) + if (!high_thresh || frag_mem_limit(fqdir) > high_thresh) return NULL; rcu_read_lock(); diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index cfeb8890f94e..fad803d2d711 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -144,7 +144,8 @@ static void ip_expire(struct timer_list *t) rcu_read_lock(); - if (qp->q.fqdir->dead) + /* Paired with WRITE_ONCE() in fqdir_pre_exit(). */ + if (READ_ONCE(qp->q.fqdir->dead)) goto out_rcu_unlock; spin_lock(&qp->q.lock); |