From: Dan Carpenter dan.carpenter@oracle.com
[ Upstream commit f57004b9d96755cd6a243b51c267be4016b4563c ]
This from static analysis. The vla_item() takes a size and adds it to the total. It has a built in integer overflow check so if it encounters an integer overflow anywhere then it records the total as SIZE_MAX.
However there is an issue here because the "lang_count*(needed_count+1)" multiplication can overflow. Technically the "lang_count + 1" addition could overflow too, but that would be detected and is harmless. Fix both using the new size_add() and size_mul() functions.
Fixes: e6f3862fa1ec ("usb: gadget: FunctionFS: Remove VLAIS usage from gadget code") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Link: https://lore.kernel.org/r/YxDI3lMYomE7WCjn@kili Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_fs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index e0fa4b186ec6..36184a762527 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -2645,10 +2645,10 @@ static int __ffs_data_got_strings(struct ffs_data *ffs, unsigned i = 0; vla_group(d); vla_item(d, struct usb_gadget_strings *, stringtabs, - lang_count + 1); + size_add(lang_count, 1)); vla_item(d, struct usb_gadget_strings, stringtab, lang_count); vla_item(d, struct usb_string, strings, - lang_count*(needed_count+1)); + size_mul(lang_count, (needed_count + 1)));
char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);