| 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-2022-49218: drm/dp: Fix OOB read when handling Post Cursor2 register |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| drm/dp: Fix OOB read when handling Post Cursor2 register |
| |
| The link_status array was not large enough to read the Adjust Request |
| Post Cursor2 register, so remove the common helper function to avoid |
| an OOB read, found with a -Warray-bounds build: |
| |
| drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': |
| drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] |
| 59 | return link_status[r - DP_LANE0_1_STATUS]; |
| | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ |
| drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' |
| 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], |
| | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| Replace the only user of the helper with an open-coded fetch and decode, |
| similar to drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49218 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit 79465e0ffeb9e4866939ea562bc55367be91e595 and fixed in 5.17.2 with commit aeaed9a9fe694f8b1462fb81e2d33298c929180b |
| Issue introduced in 5.5 with commit 79465e0ffeb9e4866939ea562bc55367be91e595 and fixed in 5.18 with commit a2151490cc6c57b368d7974ffd447a8b36ade639 |
| |
| 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-2022-49218 |
| 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/dp/drm_dp.c |
| drivers/gpu/drm/tegra/dp.c |
| include/drm/dp/drm_dp_helper.h |
| |
| |
| 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/aeaed9a9fe694f8b1462fb81e2d33298c929180b |
| https://git.kernel.org/stable/c/a2151490cc6c57b368d7974ffd447a8b36ade639 |
