hwmon: (coretemp) Fix out-of-bounds memory access

Fix a bug that pdata->cpu_map[] is set before out-of-bounds check.
The problem might be triggered on systems with more than 128 cores per
package.

Fixes: 7108b80a542b ("hwmon/coretemp: Handle large core ID value")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240202092144.71180-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index ba82d1e79c131678c0c673bd5c0d9d77b09fdf1a..e78c769191118948c491c6c9e0c76afa51c16078 100644 (file)
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -509,18 +509,14 @@ static int create_core_data(struct platform_device *pdev, unsigned int cpu,
        if (pkg_flag) {
                attr_no = PKG_SYSFS_ATTR_NO;
        } else {
-               index = ida_alloc(&pdata->ida, GFP_KERNEL);
+               index = ida_alloc_max(&pdata->ida, NUM_REAL_CORES - 1, GFP_KERNEL);
                if (index < 0)
                        return index;
+
                pdata->cpu_map[index] = topology_core_id(cpu);
                attr_no = index + BASE_SYSFS_ATTR_NO;
        }
 
-       if (attr_no > MAX_CORE_DATA - 1) {
-               err = -ERANGE;
-               goto ida_free;
-       }
-
        tdata = init_temp_data(cpu, pkg_flag);
        if (!tdata) {
                err = -ENOMEM;