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authorXin Long <lucien.xin@gmail.com>2018-11-30 20:36:59 +0300
committerDavid S. Miller <davem@davemloft.net>2018-12-04 02:54:41 +0300
commitfb6df5a6234c38a9c551559506a49a677ac6f07a (patch)
tree7411e479d478cf378f65a2b23fbf8bb81747ed37
parent986103e7920cabc0b910749e77ae5589d3934d52 (diff)
downloadlinux-fb6df5a6234c38a9c551559506a49a677ac6f07a.tar.xz
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 <nhorman@tuxdriver.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/sctp/structs.h2
-rw-r--r--net/sctp/associola.c2
2 files changed, 3 insertions, 1 deletions
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index a11f93790476..feada358d872 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 dd77ec3892b6..914750b819b2 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);
}