usb: potential integer overflow in usbg_make_tpg()

The variable tpgt in usbg_make_tpg() is defined as unsigned long and is
assigned to tpgt->tport_tpgt, which is defined as u16. This may cause an
integer overflow when tpgt is greater than USHRT_MAX (65535). I
haven't tried to trigger it myself, but it is possible to trigger it
by calling usbg_make_tpg() with a large value for tpgt.

I modified the type of tpgt to match tpgt->tport_tpgt and adjusted the
relevant code accordingly.

This patch is similar to commit 59c816c1f24d ("vhost/scsi: potential
memory corruption").

Signed-off-by: Chen Yufeng <chenyufeng@iie.ac.cn>
Link: https://lore.kernel.org/r/20250415065857.1619-1-chenyufeng@iie.ac.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_tcm.c b/drivers/usb/gadget/function/f_tcm.c
index 5a2e1237f85c3f4a6ac223c229b38706c8cffaa0..6e8804f04baa774f5e6bed548b64769e93f6eb1c 100644 (file)
--- a/drivers/usb/gadget/function/f_tcm.c
+++ b/drivers/usb/gadget/function/f_tcm.c
@@ -1641,14 +1641,14 @@ static struct se_portal_group *usbg_make_tpg(struct se_wwn *wwn,
        struct usbg_tport *tport = container_of(wwn, struct usbg_tport,
                        tport_wwn);
        struct usbg_tpg *tpg;
-       unsigned long tpgt;
+       u16 tpgt;
        int ret;
        struct f_tcm_opts *opts;
        unsigned i;
 
        if (strstr(name, "tpgt_") != name)
                return ERR_PTR(-EINVAL);
-       if (kstrtoul(name + 5, 0, &tpgt) || tpgt > UINT_MAX)
+       if (kstrtou16(name + 5, 0, &tpgt))
                return ERR_PTR(-EINVAL);
        ret = -ENODEV;
        mutex_lock(&tpg_instances_lock);