linux-kernel - [PATCH AUTOSEL 6.1 03/16] scsi: target: iscsi: Prevent login threads from racing between each other

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230615113816.649135-3-sashal@kernel.org>
Date:   Thu, 15 Jun 2023 07:38:03 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Maurizio Lombardi <mlombard@...hat.com>,
        Mike Christie <michael.christie@...cle.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>, d.bogdanov@...ro.com,
        davem@...emloft.net, peilin.ye@...edance.com,
        yang.lee@...ux.alibaba.com, linux-scsi@...r.kernel.org,
        target-devel@...r.kernel.org
Subject: [PATCH AUTOSEL 6.1 03/16] scsi: target: iscsi: Prevent login threads from racing between each other

From: Maurizio Lombardi <mlombard@...hat.com>

[ 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 <mlombard@...hat.com>
Link: https://lore.kernel.org/r/20230508162219.1731964-4-mlombard@redhat.com
Reviewed-by: Mike Christie <michael.christie@...cle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 ff49c8f3fe241..62b2d0dcfda86 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -1128,6 +1128,7 @@ 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);
@@ -1195,7 +1196,6 @@ 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;
 
@@ -1212,9 +1212,11 @@ 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