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 B6D06C8E5 for ; Mon, 26 Jun 2023 18:36:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C658C433CA; Mon, 26 Jun 2023 18:36:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687804616; bh=VvcDlxUQaRiX2ruxjT8DhrhgUh+QPAZStuGAHH2eEFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GYl1aWTf5j6pNo+W5XTHZ89ft6wHcuWOXiBlme5Dr5HOeJlNJ36tgPPVRRrWdWRg8 EhaPJnnk/JQ/mivTY/MeTg7RI1oDYMvIRD0lIMfbzlS0lF8IMOWILsCcB+ma/6ioCr GfBRdFr4NdA+FpMrABNRFMPS5R2mY8L6klIIc+ts= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Maurizio Lombardi , Mike Christie , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 5.4 44/60] scsi: target: iscsi: Prevent login threads from racing between each other Date: Mon, 26 Jun 2023 20:12:23 +0200 Message-ID: <20230626180741.385793935@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230626180739.558575012@linuxfoundation.org> References: <20230626180739.558575012@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: Maurizio Lombardi [ Upstream commit 2a737d3b8c792400118d6cf94958f559de9c5e59 ] The tpg->np_login_sem is a semaphore that is used to serialize the login process when multiple login threads run concurrently against the same target portal group. The iscsi_target_locate_portal() function finds the tpg, calls iscsit_access_np() against the np_login_sem semaphore and saves the tpg pointer in conn->tpg; If iscsi_target_locate_portal() fails, the caller will check for the conn->tpg pointer and, if it's not NULL, then it will assume that iscsi_target_locate_portal() called iscsit_access_np() on the semaphore. Make sure that conn->tpg gets initialized only if iscsit_access_np() was successful, otherwise iscsit_deaccess_np() may end up being called against a semaphore we never took, allowing more than one thread to access the same tpg. Signed-off-by: Maurizio Lombardi Link: https://lore.kernel.org/r/20230508162219.1731964-4-mlombard@redhat.com Reviewed-by: Mike Christie Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/iscsi/iscsi_target_nego.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index e32d93b927428..4017464a5909b 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -1053,6 +1053,7 @@ int iscsi_target_locate_portal( iscsi_target_set_sock_callbacks(conn); login->np = np; + conn->tpg = NULL; login_req = (struct iscsi_login_req *) login->req; payload_length = ntoh24(login_req->dlength); @@ -1122,7 +1123,6 @@ int iscsi_target_locate_portal( */ sessiontype = strncmp(s_buf, DISCOVERY, 9); if (!sessiontype) { - conn->tpg = iscsit_global->discovery_tpg; if (!login->leading_connection) goto get_target; @@ -1139,9 +1139,11 @@ int iscsi_target_locate_portal( * Serialize access across the discovery struct iscsi_portal_group to * process login attempt. */ + conn->tpg = iscsit_global->discovery_tpg; if (iscsit_access_np(np, conn->tpg) < 0) { iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR, ISCSI_LOGIN_STATUS_SVC_UNAVAILABLE); + conn->tpg = NULL; ret = -1; goto out; } -- 2.39.2