From 70a9c0352e219fc87ccdeb54793e457abbef81e3 Mon Sep 17 00:00:00 2001 From: Zeng Tao Date: Fri, 4 Sep 2020 14:37:44 +0800 Subject: [PATCH] usb: core: fix slab-out-of-bounds Read in read_descriptors commit a18cd6c9b6bc73dc17e8b7e9bd07decaa8833c97 upstream. The USB device descriptor may get changed between two consecutive enumerations on the same device for some reason, such as DFU or malicius device. In that case, we may access the changing descriptor if we don't take the device lock here. The issue is reported: https://syzkaller.appspot.com/bug?id=901a0d9e6519ef8dc7acab25344bd287dd3c7be9 Cc: stable Cc: Alan Stern Reported-by: syzbot+256e56ddde8b8957eabd@syzkaller.appspotmail.com Fixes: 217a9081d8e6 ("USB: add all configs to the "descriptors" attribute") Signed-off-by: Zeng Tao Link: https://lore.kernel.org/r/1599201467-11000-1-git-send-email-prime.zeng@hisilicon.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/sysfs.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index f19694e69f5c..2f594c88d905 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -889,7 +889,11 @@ read_descriptors(struct file *filp, struct kobject *kobj, size_t srclen, n; int cfgno; void *src; + int retval; + retval = usb_lock_device_interruptible(udev); + if (retval < 0) + return -EINTR; /* The binary attribute begins with the device descriptor. * Following that are the raw descriptor entries for all the * configurations (config plus subsidiary descriptors). @@ -914,6 +918,7 @@ read_descriptors(struct file *filp, struct kobject *kobj, off -= srclen; } } + usb_unlock_device(udev); return count - nleft; }