6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gopi Krishna Menon krishnagopi487@gmail.com
[ Upstream commit a5160af78be7fcf3ade6caab0a14e349560c96d7 ]
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 krishnagopi487@gmail.com Reviewed-by: Andrey Konovalov andreyknvl@gmail.com Link: https://patch.msgid.link/20251028165659.50962-1-krishnagopi487@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/legacy/raw_gadget.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c index 2deab4a6030d7..8aa1a8408ae33 100644 --- a/drivers/usb/gadget/legacy/raw_gadget.c +++ b/drivers/usb/gadget/legacy/raw_gadget.c @@ -39,6 +39,7 @@ 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
@@ -620,6 +621,8 @@ 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 {