A vulnerability (CVE-2024-56752) was recently discovered in the Linux kernel, specifically within the drm/nouveau/gr/gf100 component. The vulnerability could lead to potential flaws within the Linux system, and this article aims to provide an overview of the vulnerability, code snippets showcasing the issue and fix, as well as links to original references and a brief explanation of the exploit details. The Linux kernel developers have already addressed this issue, which previously resulted in an inconsistent return of '&gr->fecs.mutex'.
Code Snippet Highlighting the Issue
The code snippet below demonstrates the original issue in the Linux kernel, where the gf100_gr_chan_new() function failed to unlock gr->fecs.mutex when the call to gf100_grctx_generate() failed.
static int
gf100_gr_chan_new(struct nvkm_gr *base, struct nvkm_fifo_chan *fchan,
const struct nvkm_oclass *oclass, struct nvkm_object **pobject)
{
struct gf100_gr *gr = gf100_gr(base);
struct gf100_gr_chan *chan;
int ret;
if (!(chan = kzalloc(sizeof(*chan), GFP_KERNEL)))
return -ENOMEM;
nvkm_object_ctor(&gf100_gr_chan_sclass, oclass, &chan->object);
chan->object.engine = nvkm_engine(base);
chan->fence = fchan->fifo->func->fence.context_new(fchan-fifo);
if (IS_ERR(chan->fence)) {
ret = PTR_ERR(chan->fence);
goto out_free;
}
mutex_lock(&gr->fecs.mutex);
// Initialization code
if ((ret = gf100_grctx_generate(gr, &chan->grctx)))
return ret; // <-- here is the missing unlock of gr->fecs.mutex
// Rest of the code
The following code snippet showcases the proposed fix for the above vulnerability
if ((ret = gf100_grctx_generate(gr, &chan->grctx))) {
mutex_unlock(&gr->fecs.mutex); // <-- added unlock here
return ret;
}
This added line of code ensures that gr->fecs.mutex is unlocked before returning an error, resolving the original vulnerability (CVE-2024-56752).
Original References
To provide a reliable understanding of the issue, here is a link to the original commit where the vulnerability was fixed:
Fixed in commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=682d366c7d41061cb40570fb420d79c4be002d7f
Exploit Details
The primary issue with this vulnerability lies in its potential to cause inconsistencies in the return values within the Linux kernel, which could potentially lead to unexpected behavior in a Linux system. However, if exploited, the impact of this vulnerability is comparatively low due to the fact that it only affects a specific graphics component of the Linux kernel – drm/nouveau/gr/gf100.
In conclusion, the Linux kernel developers successfully identified and patched a vulnerability (CVE-2024-56752) within the drm/nouveau/gr/gf100 component. The provided code snippets and references should aid in understanding the nature of the vulnerability and the fix implemented to address it. Users of affected systems are advised to update their Linux kernel to a version containing the relevant patch to ensure their systems are secure.
Timeline
Published on: 12/29/2024 12:15:08 UTC
Last modified on: 01/06/2025 19:11:42 UTC