| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-38592: drm/mediatek: Init `ddp_comp` with devm_kcalloc() |
| |
| Description |
| =========== |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2024-38592 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.7 with commit 01389b324c97ff8f04e9c33b9ee246084f9f6dd2 and fixed in 6.8.12 with commit cf69d0af7db917b82aceaa44b7b1b9376609da22 |
| Issue introduced in 6.7 with commit 01389b324c97ff8f04e9c33b9ee246084f9f6dd2 and fixed in 6.9.3 with commit 9fe2cc3fa44f7ad7ba5f29c1a68b2b924c17b9b1 |
| Issue introduced in 6.7 with commit 01389b324c97ff8f04e9c33b9ee246084f9f6dd2 and fixed in 6.10 with commit 01a2c5123e27b3c4685bf2fc4c2e879f6e0c7b33 |
| |
| 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-2024-38592 |
| 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/gpu/drm/mediatek/mtk_drm_crtc.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/cf69d0af7db917b82aceaa44b7b1b9376609da22 |
| https://git.kernel.org/stable/c/9fe2cc3fa44f7ad7ba5f29c1a68b2b924c17b9b1 |
| https://git.kernel.org/stable/c/01a2c5123e27b3c4685bf2fc4c2e879f6e0c7b33 |
