From: Gopi Krishna Menon Date: Tue, 28 Oct 2025 16:56:57 +0000 (+0530) Subject: usb: raw-gadget: cap raw_io transfer length to KMALLOC_MAX_SIZE X-Git-Tag: v6.19-rc1~63^2~14 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a5160af78be7fcf3ade6caab0a14e349560c96d7;p=thirdparty%2Fkernel%2Flinux.git usb: raw-gadget: cap raw_io transfer length to KMALLOC_MAX_SIZE The previous commit removed the PAGE_SIZE limit on transfer length of raw_io buffer in order to avoid any problems with emulating USB devices whose full configuration descriptor exceeds PAGE_SIZE in length. However this also removes the upperbound on user supplied length, allowing very large values to be passed to the allocator. syzbot on fuzzing the transfer length with very large value (1.81GB) results in kmalloc() to fall back to the page allocator, which triggers a kernel warning as the page allocator cannot handle allocations more than MAX_PAGE_ORDER/KMALLOC_MAX_SIZE. Since there is no limit imposed on the size of buffer for both control and non control transfers, cap the raw_io transfer length to KMALLOC_MAX_SIZE and return -EINVAL for larger transfer length to prevent any warnings from the page allocator. Fixes: 37b9dd0d114a ("usb: raw-gadget: do not limit transfer length") Tested-by: syzbot+d8fd35fa6177afa8c92b@syzkaller.appspotmail.com Reported-by: syzbot+d8fd35fa6177afa8c92b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68fc07a0.a70a0220.3bf6c6.01ab.GAE@google.com/ Signed-off-by: Gopi Krishna Menon Reviewed-by: Andrey Konovalov Link: https://patch.msgid.link/20251028165659.50962-1-krishnagopi487@gmail.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c index b71680c58de6c..46f343ba48b3d 100644 --- a/drivers/usb/gadget/legacy/raw_gadget.c +++ b/drivers/usb/gadget/legacy/raw_gadget.c @@ -40,6 +40,7 @@ MODULE_LICENSE("GPL"); static DEFINE_IDA(driver_id_numbers); #define DRIVER_DRIVER_NAME_LENGTH_MAX 32 +#define USB_RAW_IO_LENGTH_MAX KMALLOC_MAX_SIZE #define RAW_EVENT_QUEUE_SIZE 16 @@ -667,6 +668,8 @@ static void *raw_alloc_io_data(struct usb_raw_ep_io *io, void __user *ptr, return ERR_PTR(-EINVAL); if (!usb_raw_io_flags_valid(io->flags)) return ERR_PTR(-EINVAL); + if (io->length > USB_RAW_IO_LENGTH_MAX) + return ERR_PTR(-EINVAL); if (get_from_user) data = memdup_user(ptr + sizeof(*io), io->length); else {