Description

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

netlink: Fix kernel-infoleak-after-free in __skb_datagram_iter

syzbot reported the following uninit-value access issue [1]:

netlink_to_full_skb() creates a new `skb` and puts the `skb->data`
passed as a 1st arg of netlink_to_full_skb() onto new `skb`. The data
size is specified as `len` and passed to skb_put_data(). This `len`
is based on `skb->end` that is not data offset but buffer offset. The
`skb->end` contains data and tailroom. Since the tailroom is not
initialized when the new `skb` created, KMSAN detects uninitialized
memory area when copying the data.

This patch resolved this issue by correct the len from `skb->end` to
`skb->len`, which is the actual data offset.

BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_ubuf include/linux/iov_iter.h:29 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:271 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0x364/0x2520 lib/iov_iter.c:186
instrument_copy_to_user include/linux/instrumented.h:114 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
it...

Classification

CVE ID: CVE-2024-26805

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/ec343a55b687a452f5e87f3b52bf9f155864df65
https://git.kernel.org/stable/c/9ae51361da43270f4ba0eb924427a07e87e48777
https://git.kernel.org/stable/c/f19d1f98e60e68b11fc60839105dd02a30ec0d77
https://git.kernel.org/stable/c/c71ed29d15b1a1ed6c464f8c3536996963046285
https://git.kernel.org/stable/c/0b27bf4c494d61e5663baa34c3edd7ccebf0ea44
https://git.kernel.org/stable/c/d3ada42e534a83b618bbc1e490d23bf0fdae4736
https://git.kernel.org/stable/c/59fc3e3d049e39e7d0d271f20dd5fb47c57faf1d
https://git.kernel.org/stable/c/661779e1fcafe1b74b3f3fe8e980c1e207fea1fd

Timeline