CVE-2024-26587

In the Linux kernel, the following vulnerability has been resolved:

net: netdevsim: dont try to destroy PHC on VFs

PHC gets initialized in nsim_init_netdevsim(), which is only called if (nsim_dev_port_is_pf()).

Create a counterpart of nsim_init_netdevsim() and move the mock_phc_destroy() there.

This fixes a crash trying to destroy netdevsim with VFs instantiated, as caught by running the devlink.sh test:

BUG: kernel NULL pointer dereference, address: 00000000000000b8
RIP: 0010:mock_phc_destroy+0xd/0x30
Call Trace:
 <TASK>
 nsim_destroy+0x4a/0x70 [netdevsim]
 __nsim_dev_port_del+0x47/0x70 [netdevsim]
 nsim_dev_reload_destroy+0x105/0x120 [netdevsim]
 nsim_drv_remove+0x2f/0xb0 [netdevsim]
 device_release_driver_internal+0x1a1/0x210
 bus_remove_device+0xd5/0x120
 device_del+0x159/0x490
 device_unregister+0x12/0x30
 del_device_store+0x11a/0x1a0 [netdevsim]
 kernfs_fop_write_iter+0x130/0x1d0
 vfs_write+0x30b/0x4b0
 ksys_write+0x69/0xf0
 do_syscall_64+0xcc/0x1e0
 entry_SYSCALL_64_after_hwframe+0x6f/0x77

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/08aca65997fb6f233066883b1f1e653bcb1f26ca
• https://git.kernel.org/stable/c/c5068e442eed063d2f1658e6b6d3c1c6fcf1e588
• https://git.kernel.org/stable/c/ea937f77208323d35ffe2f8d8fc81b00118bfcda