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 /include/net | |
| parent | 3ba8c6258eb19a6212b066a383788174dd9779ab (diff) | |
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 'include/net')
| -rw-r--r-- | include/net/inet_frag.h | 11 | ||||
| -rw-r--r-- | include/net/ipv6_frag.h | 3 |
2 files changed, 11 insertions, 3 deletions
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h index 48cc5795ceda..63540be0fc34 100644 --- a/include/net/inet_frag.h +++ b/include/net/inet_frag.h @@ -117,8 +117,15 @@ int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net); static inline void fqdir_pre_exit(struct fqdir *fqdir) { - fqdir->high_thresh = 0; /* prevent creation of new frags */ - fqdir->dead = true; + /* Prevent creation of new frags. + * Pairs with READ_ONCE() in inet_frag_find(). + */ + WRITE_ONCE(fqdir->high_thresh, 0); + + /* Pairs with READ_ONCE() in inet_frag_kill(), ip_expire() + * and ip6frag_expire_frag_queue(). + */ + WRITE_ONCE(fqdir->dead, true); } void fqdir_exit(struct fqdir *fqdir); diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h index 851029ecff13..0a4779175a52 100644 --- a/include/net/ipv6_frag.h +++ b/include/net/ipv6_frag.h @@ -67,7 +67,8 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq) struct sk_buff *head; rcu_read_lock(); - if (fq->q.fqdir->dead) + /* Paired with the WRITE_ONCE() in fqdir_pre_exit(). */ + if (READ_ONCE(fq->q.fqdir->dead)) goto out_rcu_unlock; spin_lock(&fq->q.lock); |