From: Rémi Denis-Courmont remi@remlab.net

stable inclusion from stable-v4.19.222 commit 982b6ba1ce626ef87e5c29f26f2401897554f235 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I95RE9 CVE: CVE-2021-47086

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 75a2f31520095600f650597c0ac41f48b5ba0068 upstream.

This ioctl() implicitly assumed that the socket was already bound to a valid local socket name, i.e. Phonet object. If the socket was not bound, two separate problems would occur:

1) We'd send an pipe enablement request with an invalid source object. 2) Later socket calls could BUG on the socket unexpectedly being connected yet not bound to a valid object.

Reported-by: syzbot+2dc91e7fc3dea88b1e8a@syzkaller.appspotmail.com Signed-off-by: Rémi Denis-Courmont remi@remlab.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Dong Chenchen dongchenchen2@huawei.com --- net/phonet/pep.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/net/phonet/pep.c b/net/phonet/pep.c index 63d34e702df5..fe01cc788448 100644 --- a/net/phonet/pep.c +++ b/net/phonet/pep.c @@ -960,6 +960,8 @@ static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg) ret = -EBUSY; else if (sk->sk_state == TCP_ESTABLISHED) ret = -EISCONN; + else if (!pn->pn_sk.sobject) + ret = -EADDRNOTAVAIL; else ret = pep_sock_enable(sk, NULL, 0); release_sock(sk);