Created attachment 234461 [details] a possible patch In ib_device_register_sysfs, on the error path, device_unregister is called. device_register deletes the device, which will cause use after free. device_del should be called which undose device_add but not delete the device.
I need to check with the LinuxKPI if this is correct or not.
A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=55d183367104e3efcdaa936f65e4f82303871271 commit 55d183367104e3efcdaa936f65e4f82303871271 Author: Hans Petter Selasky <hselasky@FreeBSD.org> AuthorDate: 2022-06-21 09:07:06 +0000 Commit: Hans Petter Selasky <hselasky@FreeBSD.org> CommitDate: 2022-06-21 09:33:27 +0000 ibcore: Fix sysfs registration error flow The kernel commit cited below restructured ib device management so that the device kobject is initialized in ib_alloc_device. As part of the restructuring, the kobject is now initialized in procedure ib_alloc_device, and is later added to the device hierarchy in the ib_register_device call stack, in procedure ib_device_register_sysfs (which calls device_add). However, in the ib_device_register_sysfs error flow, if an error occurs following the call to device_add, the cleanup procedure device_unregister is called. This call results in the device object being deleted -- which results in various use-after-free crashes. The correct cleanup call is device_del -- which undoes device_add without deleting the device object. The device object will then (correctly) be deleted in the ib_register_device caller's error cleanup flow, when the caller invokes ib_dealloc_device. Linux commit: b312be3d87e4c80872cbea869e569175c5eb0f9a PR: 264472 MFC after: 3 days Sponsored by: NVIDIA Networking sys/ofed/drivers/infiniband/core/ib_sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Thank you!
A commit in branch stable/13 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=1ecd211915ff0dd1989db9e8052794f1ea872772 commit 1ecd211915ff0dd1989db9e8052794f1ea872772 Author: Hans Petter Selasky <hselasky@FreeBSD.org> AuthorDate: 2022-06-21 09:07:06 +0000 Commit: Hans Petter Selasky <hselasky@FreeBSD.org> CommitDate: 2022-06-27 08:14:49 +0000 ibcore: Fix sysfs registration error flow The kernel commit cited below restructured ib device management so that the device kobject is initialized in ib_alloc_device. As part of the restructuring, the kobject is now initialized in procedure ib_alloc_device, and is later added to the device hierarchy in the ib_register_device call stack, in procedure ib_device_register_sysfs (which calls device_add). However, in the ib_device_register_sysfs error flow, if an error occurs following the call to device_add, the cleanup procedure device_unregister is called. This call results in the device object being deleted -- which results in various use-after-free crashes. The correct cleanup call is device_del -- which undoes device_add without deleting the device object. The device object will then (correctly) be deleted in the ib_register_device caller's error cleanup flow, when the caller invokes ib_dealloc_device. Linux commit: b312be3d87e4c80872cbea869e569175c5eb0f9a PR: 264472 Sponsored by: NVIDIA Networking (cherry picked from commit 55d183367104e3efcdaa936f65e4f82303871271) sys/ofed/drivers/infiniband/core/ib_sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)