CVE-2026-98059: bpf: Mark sched_process_wait argument as nullable

CVE-2026-98059: bpf: Mark sched_process_wait argument as nullable

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

bpf: Mark sched_process_wait argument as nullable

do_wait() passes wo->wo_pid to the sched_process_wait tracepoint.
kernel_wait4() leaves wo_pid NULL for wait4(-1), and
kernel_waitid_prepare() does likewise for waitid(P_ALL).

btf_ctx_access() currently types argument 0 as PTR_TO_BTF_ID |
PTR_TRUSTED. Without PTR_MAYBE_NULL, the verifier accepts an unchecked
dereference. Trusted pointer loads have no fault protection, so a wait for
any child can then cause a NULL pointer dereference in JITed BPF code.

Add sched_process_wait to raw_tp_null_args[] with argument 0 marked
nullable. The verifier rejects an unchecked dereference while preserving
access after the program checks the pointer for NULL.

The Linux kernel CVE team has assigned CVE-2026-98059 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.12.6 with commit b2fc4b17fc13810ef440fb323fad3981cd174985 and fixed in 6.12.111 with commit bee862c79cb7e0e5c33b2df2e3a31d164705120d
	Issue introduced in 6.13 with commit 838a10bd2ebfe11a60dd67687533a7cfc220cc86 and fixed in 6.18.53 with commit 3c03a1b8ded858685a73c1ba4080adef99db4544
	Issue introduced in 6.13 with commit 838a10bd2ebfe11a60dd67687533a7cfc220cc86 and fixed in 7.2.7 with commit b9205e936dde9a94e93376c8de6195b740bcd5d2
	Issue introduced in 6.13 with commit 838a10bd2ebfe11a60dd67687533a7cfc220cc86 and fixed in 7.3-rc2 with commit a453d6e3b8e8e1a321c8744d6189d763af9287d0

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-98059
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	kernel/bpf/btf.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/bee862c79cb7e0e5c33b2df2e3a31d164705120d
	https://git.kernel.org/stable/c/3c03a1b8ded858685a73c1ba4080adef99db4544
	https://git.kernel.org/stable/c/b9205e936dde9a94e93376c8de6195b740bcd5d2
	https://git.kernel.org/stable/c/a453d6e3b8e8e1a321c8744d6189d763af9287d0