raw/ifpga: terminate string filled by readlink with null

[ upstream commit 5a90690 ]

readlink() does not terminate string, add a null character at the end
of the string if readlink() succeeds.

Coverity issue: 362820
Fixes: 9c006c4 ("raw/ifpga: scan PCIe BDF device tree")

Signed-off-by: Wei Huang <wei.huang@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>

drivers/raw/ifpga/ifpga_rawdev.c

@@ -237,8 +237,9 @@ static int ifpga_rawdev_fill_info(struct ifpga_rawdev *ifpga_dev,
 	memset(link, 0, sizeof(link));
 	memset(link1, 0, sizeof(link1));
 	ret = readlink(path, link, (sizeof(link)-1));
-	if (ret == -1)
+	if ((ret < 0) || ((unsigned int)ret > (sizeof(link)-1)))
 		return -1;
+	link[ret] = 0;   /* terminate string with null character */
 	strlcpy(link1, link, sizeof(link1));
 	memset(ifpga_dev->parent_bdf, 0, 16);
 	point = strlen(link);