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scsi: iscsi: target: Don't use stack buffer for scatterlist

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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>
This commit is contained in:
Laura Abbott 2018-09-04 11:47:40 -07:00 committed by Martin K. Petersen
parent c77a2fa3ff
commit 679fcae46c
1 changed files with 14 additions and 8 deletions
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22
drivers/target/iscsi/iscsi_target.c
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@ -1416,7 +1416,8 @@ static void iscsit_do_crypto_hash_buf(struct ahash_request *hash,
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);
@ -3910,10 +3911,14 @@ static bool iscsi_target_check_conn_state(struct iscsi_conn *conn)
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
@ -3921,7 +3926,6 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
*/
iscsit_thread_check_cpumask(conn, current, 0);
memset(buffer, 0, ISCSI_HDR_LEN);
memset(&iov, 0, sizeof(struct kvec));
iov.iov_base = buffer;
@ -3930,7 +3934,7 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
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) {
@ -3940,7 +3944,7 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
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,
@ -3964,7 +3968,7 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
}
if (conn->conn_state == TARG_CONN_STATE_IN_LOGOUT)
return;
break;
opcode = buffer[0] & ISCSI_OPCODE_MASK;
@ -3975,13 +3979,15 @@ static void iscsit_get_rx_pdu(struct iscsi_conn *conn)
" 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)