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usb: atm: Use size_add() in call to struct_size()

PATCH Applied Gustavo A. R. Silva 2 participants 3 messages Sep 15, 2023 – Sep 29, 2023

Subsystems (3)
USB ATM Alcatel speedtouch USB driver
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 usb: atm: Use size_add() in call to struct_size()

If, for any reason, the open-coded arithmetic causes a wraparound, the protection that struct_size() adds against potential integer overflows is defeated. Fix this by hardening call to struct_size() with size_add().

Fixes b626871a7cda ("usb: atm: Use struct_size() helper")
Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/usb/atm/usbatm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
drivers/usb/atm/usbatm.c +2 -1
index 1cdb8758ae01..2da6615fbb6f 100644
@@ -1018,7 +1018,8 @@ int usbatm_usb_probe(struct usb_interface *intf, const struct usb_device_id *id,
 	size_t size;
 
 	/* instance init */
-	size = struct_size(instance, urbs, num_rcv_urbs + num_snd_urbs);
+	size = struct_size(instance, urbs,
+			   size_add(num_rcv_urbs, num_snd_urbs));
 	instance = kzalloc(size, GFP_KERNEL);
 	if (!instance)
 		return -ENOMEM;
Signature · 1 line
2.34.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 7 lines · Gustavo A. R. Silva

If, for any reason, the open-coded arithmetic causes a wraparound, the protection that struct_size() adds against potential integer overflows is defeated. Fix this by hardening call to struct_size() with size_add().

Fixes b626871a7cda ("usb: atm: Use struct_size() helper")
Signed-off-by Gustavo A. R. Silva <[email protected]>
Reviewed-by Kees Cook <[email protected]>
Signature · 1 line
Kees Cook
Applied
#2 lore raw
In reply to Gustavo A. R. Silva
Quoted 6 lines · Gustavo A. R. Silva

If, for any reason, the open-coded arithmetic causes a wraparound, the protection that struct_size() adds against potential integer overflows is defeated. Fix this by hardening call to struct_size() with size_add().

Applied to for-next/hardening, thanks!

[1/1] usb: atm: Use size_add() in call to struct_size()

      https://git.kernel.org/kees/c/13f1a60fe04f

Take care,

Signature · 1 line
Kees Cook