4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Laura Abbott labbott@redhat.com
[ Upstream commit 679fcae46c8b2352bba3485d521da070cfbe68e6 ]
Fedora got a bug report of a crash with iSCSI:
kernel BUG at include/linux/scatterlist.h:143! ... RIP: 0010:iscsit_do_crypto_hash_buf+0x154/0x180 [iscsi_target_mod] ... Call Trace: ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod] iscsit_get_rx_pdu+0x4cd/0xa90 [iscsi_target_mod] ? native_sched_clock+0x3e/0xa0 ? iscsi_target_tx_thread+0x200/0x200 [iscsi_target_mod] iscsi_target_rx_thread+0x81/0xf0 [iscsi_target_mod] kthread+0x120/0x140 ? kthread_create_worker_on_cpu+0x70/0x70 ret_from_fork+0x3a/0x50
This is a BUG_ON for using a stack buffer with a scatterlist. There are two cases that trigger this bug. Switch to using a dynamically allocated buffer for one case and do not assign a NULL buffer in another case.
Signed-off-by: Laura Abbott labbott@redhat.com Reviewed-by: Mike Christie mchristi@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/target/iscsi/iscsi_target.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)
--- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -1419,7 +1419,8 @@ static void iscsit_do_crypto_hash_buf(st
sg_init_table(sg, ARRAY_SIZE(sg)); sg_set_buf(sg, buf, payload_length); - sg_set_buf(sg + 1, pad_bytes, padding); + if (padding) + sg_set_buf(sg + 1, pad_bytes, padding);
ahash_request_set_crypt(hash, sg, data_crc, payload_length + padding);
@@ -3913,10 +3914,14 @@ static bool iscsi_target_check_conn_stat static void iscsit_get_rx_pdu(struct iscsi_conn *conn) { int ret; - u8 buffer[ISCSI_HDR_LEN], opcode; + u8 *buffer, opcode; u32 checksum = 0, digest = 0; struct kvec iov;
+ buffer = kcalloc(ISCSI_HDR_LEN, sizeof(*buffer), GFP_KERNEL); + if (!buffer) + return; + while (!kthread_should_stop()) { /* * Ensure that both TX and RX per connection kthreads @@ -3924,7 +3929,6 @@ static void iscsit_get_rx_pdu(struct isc */ iscsit_thread_check_cpumask(conn, current, 0);
- memset(buffer, 0, ISCSI_HDR_LEN); memset(&iov, 0, sizeof(struct kvec));
iov.iov_base = buffer; @@ -3933,7 +3937,7 @@ static void iscsit_get_rx_pdu(struct isc ret = rx_data(conn, &iov, 1, ISCSI_HDR_LEN); if (ret != ISCSI_HDR_LEN) { iscsit_rx_thread_wait_for_tcp(conn); - return; + break; }
if (conn->conn_ops->HeaderDigest) { @@ -3943,7 +3947,7 @@ static void iscsit_get_rx_pdu(struct isc ret = rx_data(conn, &iov, 1, ISCSI_CRC_LEN); if (ret != ISCSI_CRC_LEN) { iscsit_rx_thread_wait_for_tcp(conn); - return; + break; }
iscsit_do_crypto_hash_buf(conn->conn_rx_hash, buffer, @@ -3967,7 +3971,7 @@ static void iscsit_get_rx_pdu(struct isc }
if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT) - return; + break;
opcode = buffer[0] & ISCSI_OPCODE_MASK;
@@ -3978,13 +3982,15 @@ static void iscsit_get_rx_pdu(struct isc " while in Discovery Session, rejecting.\n", opcode); iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR, buffer); - return; + break; }
ret = iscsi_target_rx_opcode(conn, buffer); if (ret < 0) - return; + break; } + + kfree(buffer); }
int iscsi_target_rx_thread(void *arg)