From patchwork Wed Aug 12 07:28:35 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junjie Cao X-Patchwork-Id: 94982 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id D94FCC5AD5A for ; Wed, 12 Aug 2026 05:31:10 +0000 (UTC) Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) by mx.groups.io with SMTP id smtpd.msgproc02-g2.1484.1786512667785297652 for ; Tue, 11 Aug 2026 22:31:08 -0700 Authentication-Results: mx.groups.io; dkim=fail reason="dkim: body hash did not verify" header.i=@linux.dev header.s=key1 header.b=ki1S7Bsn; spf=pass (domain: linux.dev, ip: 91.218.175.182, mailfrom: junjie.cao@linux.dev) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1786512664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uXm2Zfq1jroUKOSU13LxSSr7kqd4FwK3NEbkH7bvMas=; b=ki1S7BsnmKFmzcPYX7Oz0QTG/TCPI2Put00yPwJaBd1pf9pewfj2ImluzS3qTPsJOK17fP RANbbqlZlw7QVR70ZCIZSgLDfAXRZMA0VEAshvUevx/JGDWSQdWxDfyo1O/AYoxWcSu0Ad 5D4TM8ayyNfZMPyqMU8onY7YXQ3HKM0= From: Junjie Cao To: openembedded-core@lists.openembedded.org Cc: paul@pbarker.dev Subject: [OE-core][PATCH v3 2/9] cve-exclusions: set status for CVE-2021-3714 Date: Wed, 12 Aug 2026 02:28:35 -0500 Message-ID: <20260812072842.1176341-3-junjie.cao@linux.dev> In-Reply-To: <20260812072842.1176341-1-junjie.cao@linux.dev> References: <20260812072842.1176341-1-junjie.cao@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT List-Id: X-Webhook-Received: from 45-33-107-173.ip.linodeusercontent.com [45.33.107.173] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 12 Aug 2026 05:31:10 -0000 X-Groupsio-URL: https://lists.openembedded.org/g/openembedded-core/message/243227 KSM merges identical anonymous pages across processes. An attacker who can place chosen page-sized content in a victim's memory can detect the merge through the timing of the resulting copy-on-write fault, and so leak memory contents. There is no upstream fix; removing the side channel means removing deduplication. Distribution trackers describe it the same way - Debian marks src:linux unfixed with "Inherent design limitation, can be avoided by not using KSM", Red Hat closed its bug WONTFIX, and Ubuntu records no upstream fix as of 2024-06-17: https://security-tracker.debian.org/tracker/CVE-2021-3714 https://bugzilla.redhat.com/show_bug.cgi?id=1931327 https://ubuntu.com/security/CVE-2021-3714 Exposure requires two runtime opt-ins: ksmd must be started by the administrator (ksm_run defaults to KSM_RUN_STOP in mm/ksm.c) and memory is only eligible when a process asks with madvise(MADV_MERGEABLE) or prctl(PR_SET_MEMORY_MERGE). CONFIG_KSM=y is set in yocto-kernel-cache (bsp/intel-x86 and the paravirt_kvm fragments), so this is not a configuration exclusion. CC: Paul Barker AI-Generated: Uses Claude (claude-opus-5) Signed-off-by: Junjie Cao --- v3: - use "unpatched" instead of "upstream-wontfix": the WONTFIX is a distribution position, not an upstream one v2: https://lore.kernel.org/openembedded-core/20260803084827.1348810-1-junjie.cao@linux.dev/ meta/recipes-kernel/linux/cve-exclusion.inc | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/meta/recipes-kernel/linux/cve-exclusion.inc b/meta/recipes-kernel/linux/cve-exclusion.inc index 5ed4a00..af3576d 100644 --- a/meta/recipes-kernel/linux/cve-exclusion.inc +++ b/meta/recipes-kernel/linux/cve-exclusion.inc @@ -199,3 +199,10 @@ CVE_STATUS[CVE-2025-71145] = "cpe-stable-backport: Fixed from v6.18.3" # https://ubuntu.com/security/CVE-2019-14899 CVE_STATUS[CVE-2019-14899] = "unpatched: consequence of the default weak \ host model, no upstream kernel fix, mitigated by firewall configuration" + +# Timing side channel inherent to KSM page deduplication. Reachable only +# when ksmd is started (/sys/kernel/mm/ksm/run defaults to 0) and the +# workload opts in via MADV_MERGEABLE or prctl(PR_SET_MEMORY_MERGE). +# https://security-tracker.debian.org/tracker/CVE-2021-3714 +CVE_STATUS[CVE-2021-3714] = "unpatched: timing side channel inherent to \ +KSM page deduplication, only reachable when KSM is enabled and opted into"