From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 67B4E31619C for ; Thu, 28 May 2026 09:43:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779961403; cv=none; b=m37j6DIXeZZFDiA1KztS0r7+kMRqPwcvRArCQ9ukCNJ8I28Ns6h+B87IiLEklx3E0et1QIUOZDVrUOqycf1wIoYBSerebfane/aggDe1sIM9Cxizyexy9bqSPrJvmgifT24850XBduQbuN3xFjJ9d1TLUDXjhnmiMNI5toavZAE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779961403; c=relaxed/simple; bh=FcRABAtEH+ZGV+BmBYtvmnnLnwgPzZai3DJUqXQuQvw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=EtM4QbQaHrm9Fbg4q7dLTkfDse/fI4CY2OeVV4LKRRgCB2USVwkZZGghCOQeEprrnmOejKgD8P9ajr8G/SpHx1v9poWrubVnM0KOLp6svrVbY5sYvD/qDLUsJvBtjAqNrxxuQ80AR4iJiwu1duO5LmE6L06DG4Q/V/EoQ5IvkPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BDP24ZrG; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BDP24ZrG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCBC01F000E9; Thu, 28 May 2026 09:43:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779961402; bh=ErsSPRznc7xF7Qb/wVP/PsgOHtNztKNoAAUlA0LrOEE=; h=From:To:Cc:Subject:Date:Reply-To; b=BDP24ZrGh1zNXp4DOAkljz8s9DuA6lWN/IyeuKxc0GxZ7gmU96OST0hY2uFS93PV/ zfkrH8Vkuwl6r5my0hY9SDpwNrJHUWuf6pczDqH3GOFypvFshzSW2/N58hIlzG4mH+ VRGHhsNB5rNYEjjgRZLpho4p61+RQR+qO+Ptuw5w= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-46209: drm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs() Date: Thu, 28 May 2026 11:40:44 +0200 Message-ID: <2026052834-CVE-2026-46209-e4e9@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3636; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=lemEmObNi+s5Rffli6gkSwIvwe4gAfLQcaGirMSTDnY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkSvJP8eDZa7vM7U5SRNVPE91XNzUMNr3+wXFB1FYhwj l9xpHxJRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEzk+x+G+Y5K/7c3rGYQYOZ3 s8isfn7xEuOfDQzz60zd1fcanXz6+U/whTfR6TOSfd+xAQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: drm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs() drm_gem_fb_init_with_funcs() computes sub-sampled plane dimensions using plain integer division: unsigned int width = mode_cmd->width / (i ? info->hsub : 1); unsigned int height = mode_cmd->height / (i ? info->vsub : 1); However, the ioctl-level framebuffer_check() in drm_framebuffer.c uses drm_format_info_plane_width/height() which round up dimensions via DIV_ROUND_UP(). This inconsistency corrupts the subsequent GEM object size check for certain pixel format and dimension combinations. For example, with NV12 (vsub=2) and a 1-pixel-tall framebuffer the GEM size validation path sees height=0 instead of height=1. The expression (height - 1) then wraps to UINT_MAX as an unsigned int, causing min_size to overflow and wrap back to a small value. A tiny GEM object therefore passes the size guard, yet when the GPU accesses the chroma plane it will read or write memory beyond the object's bounds. Fix by replacing the open-coded divisions with drm_format_info_plane_width() and drm_format_info_plane_height(), which use DIV_ROUND_UP() and match the calculation already used in framebuffer_check(). The Linux kernel CVE team has assigned CVE-2026-46209 to this issue. Affected and fixed versions =========================== Issue introduced in 4.14 with commit 4c3dbb2c312c9fafbac30d98c523b8b1f3455d78 and fixed in 6.6.140 with commit 6b992591e04f2cce813bcf239b354f375bbf84d3 Issue introduced in 4.14 with commit 4c3dbb2c312c9fafbac30d98c523b8b1f3455d78 and fixed in 6.12.90 with commit 1da4ab7189f1064b3b712b388772c008b4d82580 Issue introduced in 4.14 with commit 4c3dbb2c312c9fafbac30d98c523b8b1f3455d78 and fixed in 6.18.32 with commit 1a17ea9861e89585361caa8bc231bd22dc6dbe7d Issue introduced in 4.14 with commit 4c3dbb2c312c9fafbac30d98c523b8b1f3455d78 and fixed in 7.0.9 with commit c5fc49d8470c5ebf3b41607600f277158f159950 Issue introduced in 4.14 with commit 4c3dbb2c312c9fafbac30d98c523b8b1f3455d78 and fixed in 7.1-rc2 with commit 3d4c2268bd7243c3780fe32bf24ff876da272acf 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-2026-46209 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_gem_framebuffer_helper.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/6b992591e04f2cce813bcf239b354f375bbf84d3 https://git.kernel.org/stable/c/1da4ab7189f1064b3b712b388772c008b4d82580 https://git.kernel.org/stable/c/1a17ea9861e89585361caa8bc231bd22dc6dbe7d https://git.kernel.org/stable/c/c5fc49d8470c5ebf3b41607600f277158f159950 https://git.kernel.org/stable/c/3d4c2268bd7243c3780fe32bf24ff876da272acf