From: Alan Stern stern@rowland.harvard.edu
stable inclusion from stable-v4.19.193 commit 2ab21d6e1411999b5fb43434f421f00bf50002eb category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9BHQL CVE: CVE-2021-47170
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 4f2629ea67e7225c3fd292c7fe4f5b3c9d6392de upstream.
Syzbot found that the kernel generates a WARNing if the user tries to submit a bulk transfer through usbfs with a buffer that is way too large. This isn't a bug in the kernel; it's merely an invalid request from the user and the usbfs code does handle it correctly.
In theory the same thing can happen with async transfers, or with the packet descriptor table for isochronous transfers.
To prevent the MM subsystem from complaining about these bad allocation requests, add the __GFP_NOWARN flag to the kmalloc calls for these buffers.
CC: Andrew Morton akpm@linux-foundation.org CC: stable@vger.kernel.org Reported-and-tested-by: syzbot+882a85c0c8ec4a3e2281@syzkaller.appspotmail.com Signed-off-by: Alan Stern stern@rowland.harvard.edu Link: https://lore.kernel.org/r/20210518201835.GA1140918@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yu Liao liaoyu15@huawei.com --- drivers/usb/core/devio.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 35eee2d05ba5..b3b88c08be8a 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1189,7 +1189,12 @@ static int proc_bulk(struct usb_dev_state *ps, void __user *arg) ret = usbfs_increase_memory_usage(len1 + sizeof(struct urb)); if (ret) return ret; - tbuf = kmalloc(len1, GFP_KERNEL); + + /* + * len1 can be almost arbitrarily large. Don't WARN if it's + * too big, just fail the request. + */ + tbuf = kmalloc(len1, GFP_KERNEL | __GFP_NOWARN); if (!tbuf) { ret = -ENOMEM; goto done; @@ -1630,7 +1635,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb if (num_sgs) { as->urb->sg = kmalloc_array(num_sgs, sizeof(struct scatterlist), - GFP_KERNEL); + GFP_KERNEL | __GFP_NOWARN); if (!as->urb->sg) { ret = -ENOMEM; goto error; @@ -1665,7 +1670,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb (uurb_start - as->usbm->vm_start); } else { as->urb->transfer_buffer = kmalloc(uurb->buffer_length, - GFP_KERNEL); + GFP_KERNEL | __GFP_NOWARN); if (!as->urb->transfer_buffer) { ret = -ENOMEM; goto error;