ghsa-9mq7-fm24-r296
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
drm/mediatek: Init ddp_comp with devm_kcalloc()
In the case where conn_routes is true we allocate an extra slot in
the ddp_comp array but mtk_drm_crtc_create() never seemed to
initialize it in the test case I ran. For me, this caused a later
crash when we looped through the array in mtk_drm_crtc_mode_valid().
This showed up for me when I booted with slub_debug=FZPUA which
poisons the memory initially. Without slub_debug I couldn't
reproduce, presumably because the later code handles the value being
NULL and in most cases (not guaranteed in all cases) the memory the
allocator returned started out as 0.
It really doesn't hurt to initialize the array with devm_kcalloc() since the array is small and the overhead of initting a handful of elements to 0 is small. In general initting memory to zero is a safer practice and usually it's suggested to only use the non-initting alloc functions if you really need to.
Let's switch the function to use an allocation function that zeros the memory. For me, this avoids the crash.
{
"affected": [],
"aliases": [
"CVE-2024-38592"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-06-19T14:15:19Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/mediatek: Init `ddp_comp` with devm_kcalloc()\n\nIn the case where `conn_routes` is true we allocate an extra slot in\nthe `ddp_comp` array but mtk_drm_crtc_create() never seemed to\ninitialize it in the test case I ran. For me, this caused a later\ncrash when we looped through the array in mtk_drm_crtc_mode_valid().\nThis showed up for me when I booted with `slub_debug=FZPUA` which\npoisons the memory initially. Without `slub_debug` I couldn\u0027t\nreproduce, presumably because the later code handles the value being\nNULL and in most cases (not guaranteed in all cases) the memory the\nallocator returned started out as 0.\n\nIt really doesn\u0027t hurt to initialize the array with devm_kcalloc()\nsince the array is small and the overhead of initting a handful of\nelements to 0 is small. In general initting memory to zero is a safer\npractice and usually it\u0027s suggested to only use the non-initting alloc\nfunctions if you really need to.\n\nLet\u0027s switch the function to use an allocation function that zeros the\nmemory. For me, this avoids the crash.",
"id": "GHSA-9mq7-fm24-r296",
"modified": "2024-06-19T15:30:54Z",
"published": "2024-06-19T15:30:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38592"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01a2c5123e27b3c4685bf2fc4c2e879f6e0c7b33"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9fe2cc3fa44f7ad7ba5f29c1a68b2b924c17b9b1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/cf69d0af7db917b82aceaa44b7b1b9376609da22"
}
],
"schema_version": "1.4.0",
"severity": []
}