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From f1199636f29579f39bbf7e4ac1c378bb71f6ba8a Mon Sep 17 00:00:00 2001
From: Asias He <asias@redhat.com>
Date: Wed, 9 Oct 2013 15:41:03 +0800
Subject: [PATCH] scsi: Allocate SCSITargetReq r->buf dynamically [CVE-2013-4344]
Bug-Debian: http://bugs.debian.org/725944
r->buf is hardcoded to 2056 which is (256 + 1) * 8, allowing 256 luns at
most. If more than 256 luns are specified by user, we have buffer
overflow in scsi_target_emulate_report_luns.
To fix, we allocate the buffer dynamically.
Signed-off-by: Asias He <asias@redhat.com>
Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 846424350b292f16b732b573273a5c1f195cd7a3)
---
hw/scsi-bus.c | 45 ++++++++++++++++++++++++++++++++++-----------
hw/scsi.h | 2 ++
2 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index f10f3ec..5d589e1 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -11,6 +11,8 @@ static char *scsibus_get_dev_path(DeviceState *dev);
static char *scsibus_get_fw_dev_path(DeviceState *dev);
static int scsi_req_parse(SCSICommand *cmd, SCSIDevice *dev, uint8_t *buf);
static void scsi_req_dequeue(SCSIRequest *req);
+static uint8_t *scsi_target_alloc_buf(SCSIRequest *req, size_t len);
+static void scsi_target_free_buf(SCSIRequest *req);
static struct BusInfo scsi_bus_info = {
.name = "SCSI",
@@ -291,7 +293,8 @@ typedef struct SCSITargetReq SCSITargetReq;
struct SCSITargetReq {
SCSIRequest req;
int len;
- uint8_t buf[2056];
+ uint8_t *buf;
+ int buf_len;
};
static void store_lun(uint8_t *outbuf, int lun)
@@ -334,14 +337,12 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
if (!found_lun0) {
n += 8;
}
- len = MIN(n + 8, r->req.cmd.xfer & ~7);
- if (len > sizeof(r->buf)) {
- /* TODO: > 256 LUNs? */
- return false;
- }
+ scsi_target_alloc_buf(&r->req, n + 8);
+
+ len = MIN(n + 8, r->req.cmd.xfer & ~7);
memset(r->buf, 0, len);
- stl_be_p(&r->buf, n);
+ stl_be_p(&r->buf[0], n);
i = found_lun0 ? 8 : 16;
QTAILQ_FOREACH(qdev, &r->req.bus->qbus.children, sibling) {
SCSIDevice *dev = SCSI_DEVICE(qdev);
@@ -359,6 +360,9 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
static bool scsi_target_emulate_inquiry(SCSITargetReq *r)
{
assert(r->req.dev->lun != r->req.lun);
+
+ scsi_target_alloc_buf(&r->req, SCSI_INQUIRY_LEN);
+
if (r->req.cmd.buf[1] & 0x2) {
/* Command support data - optional, not implemented */
return false;
@@ -383,7 +387,7 @@ static bool scsi_target_emulate_inquiry(SCSITargetReq *r)
return false;
}
/* done with EVPD */
- assert(r->len < sizeof(r->buf));
+ assert(r->len < r->buf_len);
r->len = MIN(r->req.cmd.xfer, r->len);
return true;
}
@@ -394,7 +398,7 @@ static bool scsi_target_emulate_inquiry(SCSITargetReq *r)
}
/* PAGE CODE == 0 */
- r->len = MIN(r->req.cmd.xfer, 36);
+ r->len = MIN(r->req.cmd.xfer, SCSI_INQUIRY_LEN);
memset(r->buf, 0, r->len);
if (r->req.lun != 0) {
r->buf[0] = TYPE_NO_LUN;
@@ -427,8 +431,9 @@ static int32_t scsi_target_send_command(SCSIRequest *req, uint8_t *buf)
}
break;
case REQUEST_SENSE:
+ scsi_target_alloc_buf(&r->req, SCSI_SENSE_LEN);
r->len = scsi_device_get_sense(r->req.dev, r->buf,
- MIN(req->cmd.xfer, sizeof r->buf),
+ MIN(req->cmd.xfer, r->buf_len),
(req->cmd.buf[1] & 1) == 0);
if (r->req.dev->sense_is_ua) {
scsi_device_unit_attention_reported(req->dev);
@@ -473,11 +478,29 @@ static uint8_t *scsi_target_get_buf(SCSIRequest *req)
return r->buf;
}
+static uint8_t *scsi_target_alloc_buf(SCSIRequest *req, size_t len)
+{
+ SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
+
+ r->buf = g_malloc(len);
+ r->buf_len = len;
+
+ return r->buf;
+}
+
+static void scsi_target_free_buf(SCSIRequest *req)
+{
+ SCSITargetReq *r = DO_UPCAST(SCSITargetReq, req, req);
+
+ g_free(r->buf);
+}
+
static const struct SCSIReqOps reqops_target_command = {
.size = sizeof(SCSITargetReq),
.send_command = scsi_target_send_command,
.read_data = scsi_target_read_data,
.get_buf = scsi_target_get_buf,
+ .free_req = scsi_target_free_buf,
};
@@ -1153,7 +1176,7 @@ int scsi_build_sense(uint8_t *in_buf, int in_len,
buf[7] = 10;
buf[12] = sense.asc;
buf[13] = sense.ascq;
- return MIN(len, 18);
+ return MIN(len, SCSI_SENSE_LEN);
} else {
/* Return descriptor format sense buffer */
buf[0] = 0x72;
diff --git a/hw/scsi.h b/hw/scsi.h
index 2eb66f7..49b7157 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -8,6 +8,8 @@
#define MAX_SCSI_DEVS 255
#define SCSI_CMD_BUF_SIZE 16
+#define SCSI_SENSE_LEN 18
+#define SCSI_INQUIRY_LEN 36
typedef struct SCSIBus SCSIBus;
typedef struct SCSIBusInfo SCSIBusInfo;
--
1.7.10.4
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