CVE-2021-47444

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]`.

• linux linux kernel (>= 5.7 < 5.10.75) • linux linux kernel (>= 5.11 < 5.14.14) • linux linux kernel 5.15