From 0ca650c13ba2f53cd3592d1a1d054adcd4164ca4 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 2 Apr 2019 12:58:13 -0700 Subject: [PATCH] scsi: target/iscsi: Handle too large immediate data buffers correctly Since target_alloc_sgl() and iscsit_allocate_iovecs() allocate buffer space for se_cmd.data_length bytes and since that number can be smaller than the iSCSI Expected Data Transfer Length (EDTL), ensure that the iSCSI target driver does not attempt to receive more bytes than what fits in the receive buffer. Always receive the full immediate data buffer such that the iSCSI target driver does not attempt to parse immediate data as an iSCSI PDU. Note: the current code base only calls iscsit_get_dataout() if the size of the immediate data buffer does not exceed the buffer size derived from the SCSI CDB. See also target_cmd_size_check(). Cc: Mike Christie Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Nicholas Bellinger Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/target/iscsi/iscsi_target.c | 27 +++++++++++++++++++++--- drivers/target/iscsi/iscsi_target_util.c | 1 + include/target/iscsi/iscsi_target_core.h | 1 + 3 files changed, 26 insertions(+), 3 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 828697015759..8cdea25f1377 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -1568,9 +1568,11 @@ iscsit_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd, { struct kvec *iov; u32 checksum, iov_count = 0, padding = 0, rx_got = 0, rx_size = 0; - u32 payload_length = ntoh24(hdr->dlength); + u32 payload_length; int iov_ret, data_crc_failed = 0; + payload_length = min_t(u32, cmd->se_cmd.data_length, + ntoh24(hdr->dlength)); rx_size += payload_length; iov = &cmd->iov_data[0]; @@ -2575,14 +2577,33 @@ static int iscsit_handle_immediate_data( u32 checksum, iov_count = 0, padding = 0; struct iscsi_conn *conn = cmd->conn; struct kvec *iov; + void *overflow_buf = NULL; - iov_ret = iscsit_map_iovec(cmd, cmd->iov_data, cmd->write_data_done, length); + BUG_ON(cmd->write_data_done > cmd->se_cmd.data_length); + rx_size = min(cmd->se_cmd.data_length - cmd->write_data_done, length); + iov_ret = iscsit_map_iovec(cmd, cmd->iov_data, cmd->write_data_done, + rx_size); if (iov_ret < 0) return IMMEDIATE_DATA_CANNOT_RECOVER; - rx_size = length; iov_count = iov_ret; iov = &cmd->iov_data[0]; + if (rx_size < length) { + /* + * Special case: length of immediate data exceeds the data + * buffer size derived from the CDB. + */ + overflow_buf = kmalloc(length - rx_size, GFP_KERNEL); + if (!overflow_buf) { + iscsit_unmap_iovec(cmd); + return IMMEDIATE_DATA_CANNOT_RECOVER; + } + cmd->overflow_buf = overflow_buf; + iov[iov_count].iov_base = overflow_buf; + iov[iov_count].iov_len = length - rx_size; + iov_count++; + rx_size = length; + } padding = ((-length) & 3); if (padding != 0) { diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index 5b26bc23016a..fae85bfd790e 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -737,6 +737,7 @@ void iscsit_release_cmd(struct iscsi_cmd *cmd) kfree(cmd->pdu_list); kfree(cmd->seq_list); kfree(cmd->tmr_req); + kfree(cmd->overflow_buf); kfree(cmd->iov_data); kfree(cmd->text_in_ptr); diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h index 24c398f4a68f..a49d37140a64 100644 --- a/include/target/iscsi/iscsi_target_core.h +++ b/include/target/iscsi/iscsi_target_core.h @@ -473,6 +473,7 @@ struct iscsi_cmd { struct timer_list dataout_timer; /* Iovecs for SCSI data payload RX/TX w/ kernel level sockets */ struct kvec *iov_data; + void *overflow_buf; /* Iovecs for miscellaneous purposes */ #define ISCSI_MISC_IOVECS 5 struct kvec iov_misc[ISCSI_MISC_IOVECS];