[PATCH V2 1/2] qedi: Fix truncation of CHAP name and secret

[Nilesh Javali]

From: Andrew Vasquez <andrew.vasq...@cavium.com>

The data in NVRAM is not guaranteed to be NUL terminated.
Copy the data upto the element size or to the first NUL
in the byte-stream and then append a NUL.

Signed-off-by: Andrew Vasquez <andrew.vasq...@cavium.com>
Signed-off-by: Nilesh Javali <nilesh.jav...@cavium.com>
---
 drivers/scsi/qedi/qedi_main.c | 45 +++++++++++++++++++++++++++++++------------
 1 file changed, 33 insertions(+), 12 deletions(-)

diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/qedi_main.c
index 8808f0d..f3dd438 100644
--- a/drivers/scsi/qedi/qedi_main.c
+++ b/drivers/scsi/qedi/qedi_main.c
@@ -1705,6 +1705,27 @@ void qedi_reset_host_mtu(struct qedi_ctx *qedi, u16 mtu)
        qedi_ops->ll2->start(qedi->cdev, &params);
 }
 
+static ssize_t
+qedi_show_copy_data(char *buf, size_t size, u8 *data)
+{
+       size_t i;
+
+       if (!data)
+               return sprintf(buf, "\n");
+
+       /*
+        * Data not guaranteed to be NUL terminated. Copy until NUL found or
+        * complete copy done.
+        */
+       for (i = 0; i < size && data[i]; i++)
+               buf[i] = data[i];
+
+       /* Data copy complete, append NEWLINE and NUL terminator. */
+       buf[i] = '\n';
+       buf[i + 1] = '\0';
+       return strlen(buf);
+}
+
 /**
  * qedi_get_nvram_block: - Scan through the iSCSI NVRAM block (while accounting
  * for gaps) for the matching absolute-pf-id of the QEDI device.
@@ -1842,8 +1863,8 @@ static ssize_t qedi_show_boot_ini_info(void *data, int 
type, char *buf)
 
        switch (type) {
        case ISCSI_BOOT_INI_INITIATOR_NAME:
-               rc = snprintf(str, NVM_ISCSI_CFG_ISCSI_NAME_MAX_LEN, "%s\n",
-                             initiator->initiator_name.byte);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_ISCSI_NAME_MAX_LEN,
+                                        initiator->initiator_name.byte);
                break;
        default:
                rc = 0;
@@ -1910,8 +1931,8 @@ static umode_t qedi_ini_get_attr_visibility(void *data, 
int type)
 
        switch (type) {
        case ISCSI_BOOT_TGT_NAME:
-               rc = snprintf(str, NVM_ISCSI_CFG_ISCSI_NAME_MAX_LEN, "%s\n",
-                             block->target[idx].target_name.byte);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_ISCSI_NAME_MAX_LEN,
+                                        block->target[idx].target_name.byte);
                break;
        case ISCSI_BOOT_TGT_IP_ADDR:
                if (ipv6_en)
@@ -1932,20 +1953,20 @@ static umode_t qedi_ini_get_attr_visibility(void *data, 
int type)
                              block->target[idx].lun.value[0]);
                break;
        case ISCSI_BOOT_TGT_CHAP_NAME:
-               rc = snprintf(str, NVM_ISCSI_CFG_CHAP_NAME_MAX_LEN, "%s\n",
-                             chap_name);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_CHAP_NAME_MAX_LEN,
+                                        chap_name);
                break;
        case ISCSI_BOOT_TGT_CHAP_SECRET:
-               rc = snprintf(str, NVM_ISCSI_CFG_CHAP_PWD_MAX_LEN, "%s\n",
-                             chap_secret);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_CHAP_PWD_MAX_LEN,
+                                        chap_secret);
                break;
        case ISCSI_BOOT_TGT_REV_CHAP_NAME:
-               rc = snprintf(str, NVM_ISCSI_CFG_CHAP_NAME_MAX_LEN, "%s\n",
-                             mchap_name);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_CHAP_NAME_MAX_LEN,
+                                        mchap_name);
                break;
        case ISCSI_BOOT_TGT_REV_CHAP_SECRET:
-               rc = snprintf(str, NVM_ISCSI_CFG_CHAP_PWD_MAX_LEN, "%s\n",
-                             mchap_secret);
+               rc = qedi_show_copy_data(str, NVM_ISCSI_CFG_CHAP_PWD_MAX_LEN,
+                                        mchap_secret);
                break;
        case ISCSI_BOOT_TGT_FLAGS:
                rc = snprintf(str, 3, "%hhd\n", SYSFS_FLAG_FW_SEL_BOOT);
-- 
1.8.3.1