| 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-2021-47444: drm/edid: In connector_bad_edid() cap num_of_ext by num_blocks read |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| drm/edid: In connector_bad_edid() cap num_of_ext by num_blocks read |
| |
| In commit e11f5bd8228f ("drm: Add support for DP 1.4 Compliance edid |
| corruption test") the function connector_bad_edid() started assuming |
| that the memory for the EDID passed to it was big enough to hold |
| `edid[0x7e] + 1` blocks of data (1 extra for the base block). It |
| completely ignored the fact that the function was passed `num_blocks` |
| which indicated how much memory had been allocated for the EDID. |
| |
| Let's fix this by adding a bounds check. |
| |
| This is important for handling the case where there's an error in the |
| first block of the EDID. In that case we will call |
| connector_bad_edid() without having re-allocated memory based on |
| `edid[0x7e]`. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47444 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.7 with commit e11f5bd8228fc3760c221f940b9f6365dbf3e7ed and fixed in 5.10.75 with commit a7b45024f66f9ec769e8dbb1a51ae83cd05929c7 |
| Issue introduced in 5.7 with commit e11f5bd8228fc3760c221f940b9f6365dbf3e7ed and fixed in 5.14.14 with commit 09f3946bb452918dbfb1982add56f9ffaae393dc |
| Issue introduced in 5.7 with commit e11f5bd8228fc3760c221f940b9f6365dbf3e7ed and fixed in 5.15 with commit 97794170b696856483f74b47bfb6049780d2d3a0 |
| |
| 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-2021-47444 |
| 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/drm_edid.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/a7b45024f66f9ec769e8dbb1a51ae83cd05929c7 |
| https://git.kernel.org/stable/c/09f3946bb452918dbfb1982add56f9ffaae393dc |
| https://git.kernel.org/stable/c/97794170b696856483f74b47bfb6049780d2d3a0 |
