CVE-2026-89592: accel/rocket: fix NULL dereference and integer overflow in rocket_job_push()

CVE-2026-89592: accel/rocket: fix NULL dereference and integer overflow in rocket_job_push()

[Greg Kroah-Hartman]

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

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

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

accel/rocket: fix NULL dereference and integer overflow in rocket_job_push()

rocket_job_push() allocates a temporary array to hold all input and
output GEM object pointers:

    bos = kvmalloc_array(job->in_bo_count + job->out_bo_count,
                         sizeof(void *), GFP_KERNEL);
    memcpy(bos, job->in_bos, job->in_bo_count * sizeof(void *));
    memcpy(&bos[job->in_bo_count], job->out_bos, ...);

Two bugs exist:

1. Missing NULL check: if kvmalloc_array() fails, bos is NULL and
   the subsequent memcpy() dereferences it, causing a kernel NULL
   pointer dereference.

2. Integer overflow: in_bo_count and out_bo_count are both u32, set
   directly from userspace-supplied in_bo_handle_count and
   out_bo_handle_count with no prior validation. Their sum is computed
   in u32 arithmetic and can wrap to a smaller value, causing the
   allocation count passed to kvmalloc_array() to be smaller than
   intended. Subsequent uses still operate on the original counts when
   copying and locking objects, which may lead to out-of-bounds accesses
   on the temporary array.

Fix by using check_add_overflow() to detect count overflow before the
allocation, and adding a NULL check on the allocation result.

The Linux kernel CVE team has assigned CVE-2026-89592 to this issue.


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

	Issue introduced in 6.18 with commit 0810d5ad88a18f1e6d549853a388ad0316f74e36 and fixed in 6.18.50 with commit c1a5bf1b6e1d5944183dcef3844a18c17219af4d
	Issue introduced in 6.18 with commit 0810d5ad88a18f1e6d549853a388ad0316f74e36 and fixed in 7.2.4 with commit dfff90a6eb2258e3b867994ae17af4a7ba3504d2
	Issue introduced in 6.18 with commit 0810d5ad88a18f1e6d549853a388ad0316f74e36 and fixed in 7.3-rc1 with commit a85402bff218f2b8f0d806e46c16c2f3d49cdda7

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-2026-89592
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:
	drivers/accel/rocket/rocket_job.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/c1a5bf1b6e1d5944183dcef3844a18c17219af4d
	https://git.kernel.org/stable/c/dfff90a6eb2258e3b867994ae17af4a7ba3504d2
	https://git.kernel.org/stable/c/a85402bff218f2b8f0d806e46c16c2f3d49cdda7