On Thu, 05 Jan 2023, Greg Kroah-Hartman wrote:
On Thu, Jan 05, 2023 at 12:18:18PM +0000, Lee Jones wrote:
On Wed, 28 Dec 2022, Greg Kroah-Hartman wrote:
From: John Keeping john@metanate.com
[ Upstream commit 89ff3dfac604614287ad5aad9370c3f984ea3f4b ]
The embedded struct cdev does not have its lifetime correctly tied to the enclosing struct f_hidg, so there is a use-after-free if /dev/hidgN is held open while the gadget is deleted.
This can readily be replicated with libusbgx's example programs (for conciseness - operating directly via configfs is equivalent):
gadget-hid exec 3<> /dev/hidg0 gadget-vid-pid-remove exec 3<&-
Pull the existing device up in to struct f_hidg and make use of the cdev_device_{add,del}() helpers. This changes the lifetime of the device object to match struct f_hidg, but note that it is still added and deleted at the same time.
Fixes: 71adf1189469 ("USB: gadget: add HID gadget driver") Tested-by: Lee Jones lee@kernel.org Reviewed-by: Andrzej Pietrasiewicz andrzej.p@collabora.com Reviewed-by: Lee Jones lee@kernel.org Signed-off-by: John Keeping john@metanate.com Link: https://lore.kernel.org/r/20221122123523.3068034-2-john@metanate.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org
drivers/usb/gadget/function/f_hid.c | 52 ++++++++++++++++------------- 1 file changed, 28 insertions(+), 24 deletions(-)
Dear Stable,
Would you be kind enough to take this back as far back as linux.4.14.y please? There is a trivial fix-up required for kernels older than v5.15, but it's the same fix-up back through v4.14.
This is already in the queue for 5.10, 5.4, and 4.19, but for some reason not in 4.14. Can you verify that the 4.19 version works there too?
That works. v4.19 isn't required. Thanks.