This Linux kernel change "usb: xhci: Fix a potential null pointer dereference in xhci_debugfs_create_endpoint()" is included in the Linux 5.2 release. This change is authored by Jia-Ju Bai <baijiaju1990 [at] gmail.com> on Wed May 22 14:33:58 2019 +0300. The commit for this change in Linux stable tree is 5bce256 (patch).
usb: xhci: Fix a potential null pointer dereference in xhci_debugfs_create_endpoint() In xhci_debugfs_create_slot(), kzalloc() can fail and dev->debugfs_private will be NULL. In xhci_debugfs_create_endpoint(), dev->debugfs_private is used without any null-pointer check, and can cause a null pointer dereference. To fix this bug, a null-pointer check is added in xhci_debugfs_create_endpoint(). This bug is found by a runtime fuzzing tool named FIZZER written by us. [subjet line change change, add potential -Mathais] Signed-off-by: Jia-Ju Bai <firstname.lastname@example.org> Reviewed-by: Greg Kroah-Hartman <email@example.com> Signed-off-by: Mathias Nyman <firstname.lastname@example.org> Signed-off-by: Greg Kroah-Hartman <email@example.com>
There are 3 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
drivers/usb/host/xhci-debugfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/host/xhci-debugfs.c b/drivers/usb/host/xhci-debugfs.c index cadc013..7ba6afc 100644 --- a/drivers/usb/host/xhci-debugfs.c +++ b/drivers/usb/host/xhci-debugfs.c @@ -440,6 +440,9 @@ void xhci_debugfs_create_endpoint(struct xhci_hcd *xhci, struct xhci_ep_priv *epriv; struct xhci_slot_priv *spriv = dev->debugfs_private; + if (!spriv) + return; + if (spriv->eps[ep_index]) return;