| Message ID | 20180904184740.11102-1-labbott@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [PATCHv3] iscsi-target: Don't use stack buffer for scatterlist | expand |
On 09/04/2018 01:47 PM, Laura Abbott wrote: > 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> > --- > v3: Switched to kcalloc to drop an extra memset call. I was asked > offline about kmalloc vs. kmalloc_array and ended up asking about this > at the security summit since I was there last week. The preferred style > is kmalloc_array for all arrays, even those of one byte characters. > I will also switch it if people feel really strongly about this or I've > misunderstood the array guidelines. > --- > drivers/target/iscsi/iscsi_target.c | 22 ++++++++++++++-------- > 1 file changed, 14 insertions(+), 8 deletions(-) > > diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c > index 94bad43c41ff..2a586b58a011 100644 > --- a/drivers/target/iscsi/iscsi_target.c > +++ b/drivers/target/iscsi/iscsi_target.c > @@ -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) > Ok. Reviewed-by: Mike Christie <mchristi@redhat.com>
Laura, > 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. Applied to 4.20/scsi-queue, thank you!
> Applied to 4.20/scsi-queue, thank you!
4.19/scsi-fixes, that is...
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 94bad43c41ff..2a586b58a011 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -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)
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> --- v3: Switched to kcalloc to drop an extra memset call. I was asked offline about kmalloc vs. kmalloc_array and ended up asking about this at the security summit since I was there last week. The preferred style is kmalloc_array for all arrays, even those of one byte characters. I will also switch it if people feel really strongly about this or I've misunderstood the array guidelines. --- drivers/target/iscsi/iscsi_target.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)