kernel/linux.git/drivers/gpu/drm/drm_edid.c, branch v5.10.264

drm/edid: fix OOB read in drm_parse_tiled_block()

2026-07-24T13:49:04+00:00

[ Upstream commit faaa1e1155833e7d4ce7e3cfaf64c0d636b190db ] drm_parse_tiled_block() casts the DisplayID block to a struct displayid_tiled_block and reads the full fixed layout up to tile->topology_id[7] without checking block->num_bytes. The DisplayID iterator only validates the declared payload length, so a crafted EDID can advertise a tiled-display block (tag DATA_BLOCK_TILED_DISPLAY, or DATA_BLOCK_2_TILED_DISPLAY_TOPOLOGY for v2.0) with a small num_bytes at the end of a DisplayID extension. The read then runs past the end of the exact-sized kmemdup()'d EDID allocation, a heap out-of-bounds read. Reject blocks shorter than the spec's 22-byte tiled payload before reading the fixed struct, as drm_parse_vesa_mso_data() already does. BUG: KASAN: slab-out-of-bounds in drm_edid_connector_update Read of size 2 at addr ffff888010077700 by task exploit/147 dump_stack_lvl (lib/dump_stack.c:94 ...) print_report (mm/kasan/report.c:378 ...) kasan_report (mm/kasan/report.c:595) drm_edid_connector_update (drivers/gpu/drm/drm_edid.c:7581) bochs_connector_helper_get_modes (drivers/gpu/drm/tiny/bochs.c:574) drm_helper_probe_single_connector_modes (drivers/gpu/drm/drm_probe_helper.c:426) status_store (drivers/gpu/drm/drm_sysfs.c:219) ... vfs_write (fs/read_write.c:595 fs/read_write.c:688) ksys_write (fs/read_write.c:740) Fixes: 40d9b043a89e ("drm/connector: store tile information from displayid (v3)") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Reviewed-by: Jani Nikula Link: https://patch.msgid.link/20260615184737.899892-1-xmei5@asu.edu Signed-off-by: Jani Nikula Signed-off-by: Sasha Levin

drm/edid: fixed the bug that hdr metadata was not reset

2025-06-04T12:37:07+00:00

commit 6692dbc15e5ed40a3aa037aced65d7b8826c58cd upstream. When DP connected to a device with HDR capability, the hdr structure was filled.Then connected to another sink device without hdr capability, but the hdr info still exist. Fixes: e85959d6cbe0 ("drm: Parse HDR metadata info from EDID") Cc: # v5.3+ Signed-off-by: "feijuan.li" Reviewed-by: Jani Nikula Link: https://lore.kernel.org/r/20250514063511.4151780-1-feijuan.li@samsung.com Signed-off-by: Jani Nikula Signed-off-by: Greg Kroah-Hartman

drm/edid: fix AVI infoframe aspect ratio handling

2023-03-11T15:40:07+00:00

commit 1cbc1f0d324ba6c4d1b10ac6362b5e0b029f63d5 upstream. We try to avoid sending VICs defined in the later specs in AVI infoframes to sinks that conform to the earlier specs, to not upset them, and use 0 for the VIC instead. However, we do this detection and conversion to 0 too early, as we'll need the actual VIC to figure out the aspect ratio. In particular, for a mode with 64:27 aspect ratio, 0 for VIC fails the AVI infoframe generation altogether with -EINVAL. Separate the VIC lookup from the "filtering", and postpone the filtering, to use the proper VIC for aspect ratio handling, and the 0 VIC for the infoframe video code as needed. Reported-by: William Tseng Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6153 References: https://lore.kernel.org/r/20220920062316.43162-1-william.tseng@intel.com Cc: Cc: Ville Syrjälä Signed-off-by: Jani Nikula Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/c3e78cc6d01ed237f71ad0038826b08d83d75eef.1672826282.git.jani.nikula@intel.com Signed-off-by: Greg Kroah-Hartman

drm/edid: fix invalid EDID extension block filtering

2022-06-09T08:20:59+00:00

[ Upstream commit 3aefc722ff52076407203b6af9713de567993adf ] The invalid EDID block filtering uses the number of valid EDID extensions instead of all EDID extensions for looping the extensions in the copy. This is fine, by coincidence, if all the invalid blocks are at the end of the EDID. However, it's completely broken if there are invalid extensions in the middle; the invalid blocks are included and valid blocks are excluded. Fix it by modifying the base block after, not before, the copy. Fixes: 14544d0937bf ("drm/edid: Only print the bad edid when aborting") Reported-by: Ville Syrjälä Signed-off-by: Jani Nikula Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220330170426.349248-1-jani.nikula@intel.com Signed-off-by: Sasha Levin

drm/edid: Don't clear formats if using deep color

2022-04-08T12:40:13+00:00

[ Upstream commit 75478b3b393bcbdca4e6da76fe3a9f1a4133ec5d ] The current code, when parsing the EDID Deep Color depths, that the YUV422 cannot be used, referring to the HDMI 1.3 Specification. This specification, in its section 6.2.4, indeed states: For each supported Deep Color mode, RGB 4:4:4 shall be supported and optionally YCBCR 4:4:4 may be supported. YCBCR 4:2:2 is not permitted for any Deep Color mode. This indeed can be interpreted like the code does, but the HDMI 1.4 specification further clarifies that statement in its section 6.2.4: For each supported Deep Color mode, RGB 4:4:4 shall be supported and optionally YCBCR 4:4:4 may be supported. YCBCR 4:2:2 is also 36-bit mode but does not require the further use of the Deep Color modes described in section 6.5.2 and 6.5.3. This means that, even though YUV422 can be used with 12 bit per color, it shouldn't be treated as a deep color mode. This is also broken with YUV444 if it's supported by the display, but DRM_EDID_HDMI_DC_Y444 isn't set. In such a case, the code will clear color_formats of the YUV444 support set previously in drm_parse_cea_ext(), but will not set it back. Since the formats supported are already setup properly in drm_parse_cea_ext(), let's just remove the code modifying the formats in drm_parse_hdmi_deep_color_info() Fixes: d0c94692e0a3 ("drm/edid: Parse and handle HDMI deep color modes.") Signed-off-by: Maxime Ripard Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-3-maxime@cerno.tech Signed-off-by: Sasha Levin

drm/edid: check basic audio support on CEA extension block

2022-04-08T12:39:55+00:00

commit 5662abf6e21338be6d085d6375d3732ac6147fd2 upstream. Tag code stored in bit7:5 for CTA block byte[3] is not the same as CEA extension block definition. Only check CEA block has basic audio support. v3: update commit message. Cc: stable@vger.kernel.org Cc: Jani Nikula Cc: Shawn C Lee Cc: intel-gfx Signed-off-by: Cooper Chiou Signed-off-by: Lee Shawn C Fixes: e28ad544f462 ("drm/edid: parse CEA blocks embedded in DisplayID") Reviewed-by: Jani Nikula Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20220324061218.32739-1-shawn.c.lee@intel.com Signed-off-by: Greg Kroah-Hartman

drm/edid: Always set RGB444

2022-03-02T10:42:50+00:00

commit ecbd4912a693b862e25cba0a6990a8c95b00721e upstream. In order to fill the drm_display_info structure each time an EDID is read, the code currently will call drm_add_display_info with the parsed EDID. drm_add_display_info will then call drm_reset_display_info to reset all the fields to 0, and then set them to the proper value depending on the EDID. In the color_formats case, we will thus report that we don't support any color format, and then fill it back with RGB444 plus the additional formats described in the EDID Feature Support byte. However, since that byte only contains format-related bits since the 1.4 specification, this doesn't happen if the EDID is following an earlier specification. In turn, it means that for one of these EDID, we end up with color_formats set to 0. The EDID 1.3 specification never really specifies what it means by RGB exactly, but since both HDMI and DVI will use RGB444, it's fairly safe to assume it's supposed to be RGB444. Let's move the addition of RGB444 to color_formats earlier in drm_add_display_info() so that it's always set for a digital display. Fixes: da05a5a71ad8 ("drm: parse color format support for digital displays") Cc: Ville Syrjälä Reported-by: Matthias Reichl Signed-off-by: Maxime Ripard Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220203115416.1137308-1-maxime@cerno.tech Signed-off-by: Greg Kroah-Hartman

drm/edid: In connector_bad_edid() cap num_of_ext by num_blocks read

2021-10-20T09:45:05+00:00

commit 97794170b696856483f74b47bfb6049780d2d3a0 upstream. 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]`. Fixes: e11f5bd8228f ("drm: Add support for DP 1.4 Compliance edid corruption test") Reported-by: Ville Syrjälä Signed-off-by: Douglas Anderson Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20211005192905.v2.1.Ib059f9c23c2611cb5a9d760e7d0a700c1295928d@changeid Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman

drm/edid: fix objtool warning in drm_cvt_modes()

2020-12-30T10:54:29+00:00

commit d652d5f1eeeb06046009f4fcb9b4542249526916 upstream. Commit 991fcb77f490 ("drm/edid: Fix uninitialized variable in drm_cvt_modes()") just replaced one warning with another. The original warning about a possibly uninitialized variable was due to the compiler not being smart enough to see that the case statement actually enumerated all possible cases. And the initial fix was just to add a "default" case that had a single "unreachable()", just to tell the compiler that that situation cannot happen. However, that doesn't actually fix the fundamental reason for the problem: the compiler still doesn't see that the existing case statements enumerate all possibilities, so the compiler will still generate code to jump to that unreachable case statement. It just won't complain about an uninitialized variable any more. So now the compiler generates code to our inline asm marker that we told it would not fall through, and end end result is basically random. We have created a bridge to nowhere. And then, depending on the random details of just exactly what the compiler ends up doing, 'objtool' might end up complaining about the conditional branches (for conditions that cannot happen, and that thus will never be taken - but if the compiler was not smart enough to figure that out, we can't expect objtool to do so) going off in the weeds. So depending on how the compiler has laid out the result, you might see something like this: drivers/gpu/drm/drm_edid.o: warning: objtool: do_cvt_mode() falls through to next function drm_mode_detailed.isra.0() and now you have a truly inscrutable warning that makes no sense at all unless you start looking at whatever random code the compiler happened to generate for our bare "unreachable()" statement. IOW, don't use "unreachable()" unless you have an _active_ operation that generates code that actually makes it obvious that something is not reachable (ie an UD instruction or similar). Solve the "compiler isn't smart enough" problem by just marking one of the cases as "default", so that even when the compiler doesn't otherwise see that we've enumerated all cases, the compiler will feel happy and safe about there always being a valid case that initializes the 'width' variable. This also generates better code, since now the compiler doesn't generate comparisons for five different possibilities (the four real ones and the one that can't happen), but just for the three real ones and "the rest" (which is that last one). A smart enough compiler that sees that we cover all the cases won't care. Cc: Lyude Paul Cc: Ilia Mirkin Cc: Josh Poimboeuf Cc: Peter Zijlstra Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

drm/edid: Fix uninitialized variable in drm_cvt_modes()

2020-12-30T10:53:03+00:00

[ Upstream commit 991fcb77f490390bcad89fa67d95763c58cdc04c ] Noticed this when trying to compile with -Wall on a kernel fork. We potentially don't set width here, which causes the compiler to complain about width potentially being uninitialized in drm_cvt_modes(). So, let's fix that. Changes since v1: * Don't emit an error as this code isn't reachable, just mark it as such Changes since v2: * Remove now unused variable Fixes: 3f649ab728cd ("treewide: Remove uninitialized_var() usage") Signed-off-by: Lyude Paul Reviewed-by: Ilia Mirkin Link: https://patchwork.freedesktop.org/patch/msgid/20201105235703.1328115-1-lyude@redhat.com Signed-off-by: Sasha Levin