CVE-2024-26935 Affecting kernel-modules-internal package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-CENTOS8-KERNELMODULESINTERNAL-6776692
- published2 May 2024
- disclosed1 May 2024
Introduced: 1 May 2024
CVE-2024-26935 (opens in a new tab)How to fix?
There is no fixed version for Centos:8 kernel-modules-internal.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-modules-internal package and not the kernel-modules-internal package as distributed by Centos.
See How to fix? for Centos:8 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Fix unremoved procfs host directory regression
Commit fc663711b944 ("scsi: core: Remove the /proc/scsi/${proc_name} directory earlier") fixed a bug related to modules loading/unloading, by adding a call to scsi_proc_hostdir_rm() on scsi_remove_host(). But that led to a potential duplicate call to the hostdir_rm() routine, since it's also called from scsi_host_dev_release(). That triggered a regression report, which was then fixed by commit be03df3d4bfe ("scsi: core: Fix a procfs host directory removal regression"). The fix just dropped the hostdir_rm() call from dev_release().
But it happens that this proc directory is created on scsi_host_alloc(), and that function "pairs" with scsi_host_dev_release(), while scsi_remove_host() pairs with scsi_add_host(). In other words, it seems the reason for removing the proc directory on dev_release() was meant to cover cases in which a SCSI host structure was allocated, but the call to scsi_add_host() didn't happen. And that pattern happens to exist in some error paths, for example.
Syzkaller causes that by using USB raw gadget device, error'ing on usb-storage driver, at usb_stor_probe2(). By checking that path, we can see that the BadDevice label leads to a scsi_host_put() after a SCSI host allocation, but there's no call to scsi_add_host() in such path. That leads to messages like this in dmesg (and a leak of the SCSI host proc structure):
usb-storage 4-1:87.51: USB Mass Storage device detected proc_dir_entry 'scsi/usb-storage' already registered WARNING: CPU: 1 PID: 3519 at fs/proc/generic.c:377 proc_register+0x347/0x4e0 fs/proc/generic.c:376
The proper fix seems to still call scsi_proc_hostdir_rm() on dev_release(), but guard that with the state check for SHOST_CREATED; there is even a comment in scsi_host_dev_release() detailing that: such conditional is meant for cases where the SCSI host was allocated but there was no calls to {add,remove}_host(), like the usb-storage case.
This is what we propose here and with that, the error path of usb-storage does not trigger the warning anymore.
References
- https://access.redhat.com/security/cve/CVE-2024-26935
- https://git.kernel.org/stable/c/0053f15d50d50c9312d8ab9c11e2e405812dfcac
- https://git.kernel.org/stable/c/3678cf67ff7136db1dd3bf63c361650db5d92889
- https://git.kernel.org/stable/c/5c2386ba80e779a92ec3bb64ccadbedd88f779b1
- https://git.kernel.org/stable/c/cea234bb214b17d004dfdccce4491e6ff57c96ee
- https://git.kernel.org/stable/c/d4c34782b6d7b1e68d18d9549451b19433bd4c6c
- https://git.kernel.org/stable/c/e293c773c13b830cdc251f155df2254981abc320
- https://git.kernel.org/stable/c/f23a4d6e07570826fe95023ca1aa96a011fa9f84
- https://git.kernel.org/stable/c/f4ff08fab66eb5c0b97e1a24edac052fb40bf5d7
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html