linux-kernel - [PATCH] csiostor: Avoid content leaks and casts

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Date:   Tue, 9 May 2017 15:34:44 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org, Daniel Micay <danielmicay@...il.com>
Subject: [PATCH] csiostor: Avoid content leaks and casts

When copying attributes, the len argument was padded out and the resulting
memcpy() would copy beyond the end of the source buffer.  Avoid this,
and use size_t for val_len to avoid all the casts. Similarly, avoid source
buffer casts and use void *.

Additionally enforces val_len can be represented by u16 and that
the DMA buffer was not overflowed. Fixes the size of mfa, which is not
FC_FDMI_PORT_ATTR_MAXFRAMESIZE_LEN (but it will be padded up to 4). This
was noticed by the future CONFIG_FORTIFY_SOURCE checks.

Cc: Daniel Micay <danielmicay@...il.com>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 drivers/scsi/csiostor/csio_lnode.c | 43 +++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
index c00b2ff72b55..be5ee2d37815 100644
--- a/drivers/scsi/csiostor/csio_lnode.c
+++ b/drivers/scsi/csiostor/csio_lnode.c
@@ -238,14 +238,23 @@ csio_osname(uint8_t *buf, size_t buf_len)
 }
 
 static inline void
-csio_append_attrib(uint8_t **ptr, uint16_t type, uint8_t *val, uint16_t len)
+csio_append_attrib(uint8_t **ptr, uint16_t type, void *val, size_t val_len)
 {
+	uint16_t len;
 	struct fc_fdmi_attr_entry *ae = (struct fc_fdmi_attr_entry *)*ptr;
+
+	if (WARN_ON(val_len > U16_MAX))
+		return;
+
+	len = val_len;
+
 	ae->type = htons(type);
 	len += 4;		/* includes attribute type and length */
 	len = (len + 3) & ~3;	/* should be multiple of 4 bytes */
 	ae->len = htons(len);
-	memcpy(ae->value, val, len);
+	memcpy(ae->value, val, val_len);
+	if (len > val_len)
+		memset(ae->value + val_len, 0, len - val_len);
 	*ptr += len;
 }
 
@@ -335,7 +344,7 @@ csio_ln_fdmi_rhba_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
 	numattrs++;
 	val = htonl(FC_PORTSPEED_1GBIT | FC_PORTSPEED_10GBIT);
 	csio_append_attrib(&pld, FC_FDMI_PORT_ATTR_SUPPORTEDSPEED,
-			   (uint8_t *)&val,
+			   &val,
 			   FC_FDMI_PORT_ATTR_SUPPORTEDSPEED_LEN);
 	numattrs++;
 
@@ -346,23 +355,22 @@ csio_ln_fdmi_rhba_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
 	else
 		val = htonl(CSIO_HBA_PORTSPEED_UNKNOWN);
 	csio_append_attrib(&pld, FC_FDMI_PORT_ATTR_CURRENTPORTSPEED,
-			   (uint8_t *)&val,
-			   FC_FDMI_PORT_ATTR_CURRENTPORTSPEED_LEN);
+			   &val, FC_FDMI_PORT_ATTR_CURRENTPORTSPEED_LEN);
 	numattrs++;
 
 	mfs = ln->ln_sparm.csp.sp_bb_data;
 	csio_append_attrib(&pld, FC_FDMI_PORT_ATTR_MAXFRAMESIZE,
-			   (uint8_t *)&mfs, FC_FDMI_PORT_ATTR_MAXFRAMESIZE_LEN);
+			   &mfs, sizeof(mfs));
 	numattrs++;
 
 	strcpy(buf, "csiostor");
 	csio_append_attrib(&pld, FC_FDMI_PORT_ATTR_OSDEVICENAME, buf,
-			   (uint16_t)strlen(buf));
+			   strlen(buf));
 	numattrs++;
 
 	if (!csio_hostname(buf, sizeof(buf))) {
 		csio_append_attrib(&pld, FC_FDMI_PORT_ATTR_HOSTNAME,
-				   buf, (uint16_t)strlen(buf));
+				   buf, strlen(buf));
 		numattrs++;
 	}
 	attrib_blk->numattrs = htonl(numattrs);
@@ -444,33 +452,32 @@ csio_ln_fdmi_dprt_cbfn(struct csio_hw *hw, struct csio_ioreq *fdmi_req)
 
 	strcpy(buf, "Chelsio Communications");
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_MANUFACTURER, buf,
-			   (uint16_t)strlen(buf));
+			   strlen(buf));
 	numattrs++;
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_SERIALNUMBER,
-			   hw->vpd.sn, (uint16_t)sizeof(hw->vpd.sn));
+			   hw->vpd.sn, sizeof(hw->vpd.sn));
 	numattrs++;
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_MODEL, hw->vpd.id,
-			   (uint16_t)sizeof(hw->vpd.id));
+			   sizeof(hw->vpd.id));
 	numattrs++;
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_MODELDESCRIPTION,
-			   hw->model_desc, (uint16_t)strlen(hw->model_desc));
+			   hw->model_desc, strlen(hw->model_desc));
 	numattrs++;
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_HARDWAREVERSION,
-			   hw->hw_ver, (uint16_t)sizeof(hw->hw_ver));
+			   hw->hw_ver, sizeof(hw->hw_ver));
 	numattrs++;
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_FIRMWAREVERSION,
-			   hw->fwrev_str, (uint16_t)strlen(hw->fwrev_str));
+			   hw->fwrev_str, strlen(hw->fwrev_str));
 	numattrs++;
 
 	if (!csio_osname(buf, sizeof(buf))) {
 		csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_OSNAMEVERSION,
-				   buf, (uint16_t)strlen(buf));
+				   buf, strlen(buf));
 		numattrs++;
 	}
 
 	csio_append_attrib(&pld, FC_FDMI_HBA_ATTR_MAXCTPAYLOAD,
-			   (uint8_t *)&maxpayload,
-			   FC_FDMI_HBA_ATTR_MAXCTPAYLOAD_LEN);
+			   &maxpayload, FC_FDMI_HBA_ATTR_MAXCTPAYLOAD_LEN);
 	len = (uint32_t)(pld - (uint8_t *)cmd);
 	numattrs++;
 	attrib_blk->numattrs = htonl(numattrs);
@@ -1794,6 +1801,8 @@ csio_ln_mgmt_submit_req(struct csio_ioreq *io_req,
 	struct csio_mgmtm *mgmtm = csio_hw_to_mgmtm(hw);
 	int rv;
 
+	BUG_ON(pld_len > pld->len);
+
 	io_req->io_cbfn = io_cbfn;	/* Upper layer callback handler */
 	io_req->fw_handle = (uintptr_t) (io_req);
 	io_req->eq_idx = mgmtm->eq_idx;
-- 
2.7.4


-- 
Kees Cook
Pixel Security