[PATCH 3.13 110/163] [SCSI] libiscsi: fix potential buffer overrun in __iscsi_conn_send_pdu

From: Kamal Mostafa
Date: Thu Oct 09 2014 - 17:09:45 EST -stable review patch. If anyone has any objections, please let me know.


From: Mike Christie <michaelc@xxxxxxxxxxx>

commit db9bfd64b14a3a8f1868d2164518fdeab1b26ad1 upstream.

This patches fixes a potential buffer overrun in __iscsi_conn_send_pdu.
This function is used by iscsi drivers and userspace to send iscsi PDUs/
commands. For login commands, we have a set buffer size. For all other
commands we do not support data buffers.

This was reported by Dan Carpenter here:

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
Reviewed-by: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/scsi/libiscsi.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index e399561..b69b233 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -717,11 +717,21 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
return NULL;

+ if (data_size > ISCSI_DEF_MAX_RECV_SEG_LEN) {
+ iscsi_conn_printk(KERN_ERR, conn, "Invalid buffer len of %u for login task. Max len is %u\n", data_size, ISCSI_DEF_MAX_RECV_SEG_LEN);
+ return NULL;
+ }
task = conn->login_task;
} else {
if (session->state != ISCSI_STATE_LOGGED_IN)
return NULL;

+ if (data_size != 0) {
+ iscsi_conn_printk(KERN_ERR, conn, "Can not send data buffer of len %u for op 0x%x\n", data_size, opcode);
+ return NULL;
+ }
BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);


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