From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8D2F6FCF for ; Tue, 10 Jan 2023 18:13:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7CACC433F1; Tue, 10 Jan 2023 18:13:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673374401; bh=crB9Rdh0h9jCxbbNJhNtCqjf7ifM9NLkH7Fa0seJnfE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tWwazh+sd3RASvIz97Oyj4t7m/3fTfjf6e6y/djAPm5R9LjKw9pkDmuapPlBtKAbx mByelzUw6E78gnQJeath9BG3IItOA6s462eIOf6RHJIrHFKEdzgu9vcs9N1fUb4WD2 icBjOx1NstLrZfYvmvlTcI4dXdfwugnSiky0dNCk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sergey Senozhatsky , Namjae Jeon , Steve French , zdi-disclosures@trendmicro.com Subject: [PATCH 6.0 143/148] ksmbd: fix infinite loop in ksmbd_conn_handler_loop() Date: Tue, 10 Jan 2023 19:04:07 +0100 Message-Id: <20230110180021.715411224@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230110180017.145591678@linuxfoundation.org> References: <20230110180017.145591678@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Namjae Jeon commit 83dcedd5540d4ac61376ddff5362f7d9f866a6ec upstream. If kernel_recvmsg() return -EAGAIN in ksmbd_tcp_readv() and go round again, It will cause infinite loop issue. And all threads from next connections would be doing that. This patch add max retry count(2) to avoid it. kernel_recvmsg() will wait during 7sec timeout and try to retry two time if -EAGAIN is returned. And add flags of kvmalloc to __GFP_NOWARN and __GFP_NORETRY to disconnect immediately without retrying on memory alloation failure. Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers") Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-18259 Reviewed-by: Sergey Senozhatsky Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/ksmbd/connection.c | 7 +++++-- fs/ksmbd/transport_tcp.c | 5 ++++- 2 files changed, 9 insertions(+), 3 deletions(-) --- a/fs/ksmbd/connection.c +++ b/fs/ksmbd/connection.c @@ -310,9 +310,12 @@ int ksmbd_conn_handler_loop(void *p) /* 4 for rfc1002 length field */ size = pdu_size + 4; - conn->request_buf = kvmalloc(size, GFP_KERNEL); + conn->request_buf = kvmalloc(size, + GFP_KERNEL | + __GFP_NOWARN | + __GFP_NORETRY); if (!conn->request_buf) - continue; + break; memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf)); if (!ksmbd_smb_request(conn)) --- a/fs/ksmbd/transport_tcp.c +++ b/fs/ksmbd/transport_tcp.c @@ -295,6 +295,7 @@ static int ksmbd_tcp_readv(struct tcp_tr struct msghdr ksmbd_msg; struct kvec *iov; struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn; + int max_retry = 2; iov = get_conn_iovec(t, nr_segs); if (!iov) @@ -321,9 +322,11 @@ static int ksmbd_tcp_readv(struct tcp_tr } else if (conn->status == KSMBD_SESS_NEED_RECONNECT) { total_read = -EAGAIN; break; - } else if (length == -ERESTARTSYS || length == -EAGAIN) { + } else if ((length == -ERESTARTSYS || length == -EAGAIN) && + max_retry) { usleep_range(1000, 2000); length = 0; + max_retry--; continue; } else if (length <= 0) { total_read = -EAGAIN;