From: Xin Long Date: Fri, 30 Nov 2018 17:36:59 +0000 (+0800) Subject: sctp: kfree_rcu asoc X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fb6df5a6234c38a9c551559506a49a677ac6f07a;p=linux.git sctp: kfree_rcu asoc In sctp_hash_transport/sctp_epaddr_lookup_transport, it dereferences a transport's asoc under rcu_read_lock while asoc is freed not after a grace period, which leads to a use-after-free panic. This patch fixes it by calling kfree_rcu to make asoc be freed after a grace period. Note that only the asoc's memory is delayed to free in the patch, it won't cause sk to linger longer. Thanks Neil and Marcelo to make this clear. Fixes: 7fda702f9315 ("sctp: use new rhlist interface on sctp transport rhashtable") Fixes: cd2b70875058 ("sctp: check duplicate node before inserting a new transport") Reported-by: syzbot+0b05d8aa7cb185107483@syzkaller.appspotmail.com Reported-by: syzbot+aad231d51b1923158444@syzkaller.appspotmail.com Suggested-by: Neil Horman Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Signed-off-by: David S. Miller --- diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index a11f937904769..feada358d872f 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -2075,6 +2075,8 @@ struct sctp_association { __u64 abandoned_unsent[SCTP_PR_INDEX(MAX) + 1]; __u64 abandoned_sent[SCTP_PR_INDEX(MAX) + 1]; + + struct rcu_head rcu; }; diff --git a/net/sctp/associola.c b/net/sctp/associola.c index dd77ec3892b6a..914750b819b26 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -435,7 +435,7 @@ static void sctp_association_destroy(struct sctp_association *asoc) WARN_ON(atomic_read(&asoc->rmem_alloc)); - kfree(asoc); + kfree_rcu(asoc, rcu); SCTP_DBG_OBJCNT_DEC(assoc); }