This is a note to let you know that I've just added the patch titled
scsi: target: iscsi: Fix a race condition between login_work and the login thread
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-target-iscsi-fix-a-race-condition-between-login.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5209e626d5f2411c820e4d6aa152452c8abfe9f7
Author: Maurizio Lombardi <mlombard@xxxxxxxxxx>
Date: Tue Nov 15 13:56:38 2022 +0100
scsi: target: iscsi: Fix a race condition between login_work and the login thread
[ Upstream commit fec1b2fa62c162d03f5dcd7b03e3c89d3116d49f ]
In case a malicious initiator sends some random data immediately after a
login PDU; the iscsi_target_sk_data_ready() callback will schedule the
login_work and, at the same time, the negotiation may end without clearing
the LOGIN_FLAGS_INITIAL_PDU flag (because no additional PDU exchanges are
required to complete the login).
The login has been completed but the login_work function will find the
LOGIN_FLAGS_INITIAL_PDU flag set and will never stop from rescheduling
itself; at this point, if the initiator drops the connection, the
iscsit_conn structure will be freed, login_work will dereference a released
socket structure and the kernel crashes.
BUG: kernel NULL pointer dereference, address: 0000000000000230
PF: supervisor write access in kernel mode
PF: error_code(0x0002) - not-present page
Workqueue: events iscsi_target_do_login_rx [iscsi_target_mod]
RIP: 0010:_raw_read_lock_bh+0x15/0x30
Call trace:
iscsi_target_do_login_rx+0x75/0x3f0 [iscsi_target_mod]
process_one_work+0x1e8/0x3c0
Fix this bug by forcing login_work to stop after the login has been
completed and the socket callbacks have been restored.
Add a comment to clearify the return values of iscsi_target_do_login()
Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221115125638.102517-1-mlombard@xxxxxxxxxx
Reviewed-by: Mike Christie <michael.christie@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index f2919319ad38..ff49c8f3fe24 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -1018,6 +1018,13 @@ static int iscsi_target_handle_csg_one(struct iscsit_conn *conn, struct iscsi_lo
return 0;
}
+/*
+ * RETURN VALUE:
+ *
+ * 1 = Login successful
+ * -1 = Login failed
+ * 0 = More PDU exchanges required
+ */
static int iscsi_target_do_login(struct iscsit_conn *conn, struct iscsi_login *login)
{
int pdu_count = 0;
@@ -1363,12 +1370,13 @@ int iscsi_target_start_negotiation(
ret = -1;
if (ret < 0) {
- cancel_delayed_work_sync(&conn->login_work);
iscsi_target_restore_sock_callbacks(conn);
iscsi_remove_failed_auth_entry(conn);
}
- if (ret != 0)
+ if (ret != 0) {
+ cancel_delayed_work_sync(&conn->login_work);
iscsi_target_nego_release(conn);
+ }
return ret;
}
