From nobody Sat Feb 7 17:19:53 2026 Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C81C219A8A for ; Sun, 4 Jan 2026 14:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.47 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767537705; cv=none; b=gurCp0cJI5SYOzY1Lof0F0U4xu9jJkIokLi7t3nZ7mL2K2Fwx0K2LEclYjUe6YshXj3Z1yAQoXH7jeJ0lFbfliGNgt+gAnAblEIkUL3ZCWo0KSwW0zKtOYe/n+oKESA9U8YeSdY9divev6DAnM5LL/WErWP1PYL8yOjtAjyRJoI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767537705; c=relaxed/simple; bh=meOYv8M9D+QBew1P8udBbWq6A0E2q8ga6P8zm7SuOPs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BJShIBlbqTSXzUV10DeWuMxL9UWdGJmOgE3EFgimhhWr0YptneIlVygJTQzT1XD97+bGrcEuDObF/KB0Wctks6ddqLh4AyKkA/p54kN6QmhJ3HxjsYFVuWKxr4WEOkROoNo2vGPjoxclrEbRrYh5DQTYAE6NPYHFSvhx1X/TSA8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=HEoi1iGH; arc=none smtp.client-ip=209.85.128.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HEoi1iGH" Received: by mail-wm1-f47.google.com with SMTP id 5b1f17b1804b1-47bdbc90dcaso84322335e9.1 for ; Sun, 04 Jan 2026 06:41:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1767537702; x=1768142502; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=N3YXJvLIDRUWf3cgaQOAf2LS/ocSn2ejGLrLl/dnxC4=; b=HEoi1iGHcmEUkS8i+HbvjxKPqzha8qNEL7QqAGOj3bLO/WStUSu6/DfSoA47a3qrIc 9KJVXlaRoYn+Iv1wEBHPuwCispLSiKfWEtZflMvRKRsiW7ZxNrqYw0rLD9s6VPaGfzcy +DYeAKVYl3N1sevAfzGngp/zGzItJ+pYv6Zej65Ax3B8qYBDp6QUpwC++ZOyVH7+IVET YFwROjHIbXXOnfnOIzN9SX8rTlZ9xDzbKkhQTXzbIyRkOSEPej0O5EXiMfITIydnDItY X08rXxrs1BiWbNcDcCNS6bGM7SKsJmgF2L0w6u8P2/xv4YxF5NlLdS+DQu2D6INuJv4R h2Qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767537702; x=1768142502; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=N3YXJvLIDRUWf3cgaQOAf2LS/ocSn2ejGLrLl/dnxC4=; b=Cefw6rVizSavJE73HxbxpyJhv/HtnsJ4pqqhgZ/wfKjjrBL2pmIVlMAmIRGxE0laPS SKHAzvLREVpW4RYm+KzsQiLXImstO8/4XT5xu2WwzRl4/SOsIwyY9PSGI7TMBywOXESM DvRKHogmirswu+28hD7ESX5xpBN5Ybq8b/KGduyzWXOnLXvqKIupLXapD8rrkF80lzZS HlSlBOiYP6JcwJdq12xBhsQxegM1WipFCFIYu2TZwhV5PG+vI3o1tBhd6H8ZPgytbLVl oGmJvChUlxlQ0etIzNH/G/Ggmo5szRIyn0hnSFcaS+LVgc52OeIACNrHc3gYpPXm2diz Kibw== X-Gm-Message-State: AOJu0YwwbwnCNql3njRRcxcU/u369DFIjQRBX6hDmTncSi1ZgYvLLaOG RwDvvFToGwWTlf93Vxd9/RZyqYTCrY6IJfOZp6+9OXjtMtjRPbSaGdU= X-Gm-Gg: AY/fxX798qv6WEQzsoaMXoCcUsGwsCmqLTHL2Nm70JooVemIdUpMfS5EVlgkos22cmZ wftS371GN2dkj1Y8msv9SFtOMS3ZyTrnV5ltvkCtw9aGEkjHyQ6vA5M/HfIu9VqiYjFlyBUWiBt 477xR3fzmfRLLkGOcbhgrsGw9N47K4LHyJwDCDbr2SvHaiTc3fDvQyXgSFKb4Hs0EeH3nhTbYIx h8VM23s6iqt1grfH0/SKItg4bhR/ws1jBZ+4FOkNMiFs0HBR7gDKfQkvAmJsi1/wcxgYwo/TdFG G+NmB3u4xtXbiyrEX/pnJvPlNZAA+qep2DSH6vEwftk6iw8+qbR0lJijZcbSoRdash7l0aneZxR OmQU+lzMgiAONAAwOdcz+0YLCxZreERri2a/+oqoJR3ZVFnhHRa8Et93OiR+5nRMxgHjNv2+uUh TAZsrGQGEJUkyw X-Google-Smtp-Source: AGHT+IHNH9I4h/OQn3xT8jSi3/+vgAB1zow/lHbx5TdYq+4Wcsp8TLEqW9YWWzIPsIXQURgDrr1Qng== X-Received: by 2002:a05:600c:3b1f:b0:477:bb0:751b with SMTP id 5b1f17b1804b1-47d20423ca4mr575221865e9.27.1767537701658; Sun, 04 Jan 2026 06:41:41 -0800 (PST) Received: from DESKTOP-BKIPFGN ([45.43.86.16]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47d73066fdbsm43931425e9.15.2026.01.04.06.41.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 04 Jan 2026 06:41:41 -0800 (PST) From: Kery Qi To: davem@davemloft.net Cc: linux-kernel@vger.kernel.org, Kery Qi Subject: [PATCH] ipv6: mcast: fix data race in mld_process_v1 Date: Sun, 4 Jan 2026 22:41:24 +0800 Message-ID: <20260104144125.1190-1-qikeyu2017@gmail.com> X-Mailer: git-send-email 2.50.1.windows.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" idev->mc_ifc_count can be overwritten without proper locking in mld_process_v1. This issue is similar to the one found in ipv6_mc_down / mld_ifc_work (CVE-2024-26631), where mld_ifc_stop_work() modifies shared state without holding idev->mc_lock. mld_process_v1() invokes mld_gq_stop_work() and mld_ifc_stop_work() to cancel MLDv2 report work and interface change work. However, unlike other paths, it performs these calls without acquiring the mc_lock, leading to potential data races if the work queue is running concurrently. Fix this by wrapping the calls to mld_gq_stop_work() and mld_ifc_stop_work() with mutex_lock() and mutex_unlock() accordingly. Signed-off-by: Kery Qi --- net/ipv6/mcast.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 016b572e7d6f..6708eb693f9d 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1377,10 +1377,12 @@ static int mld_process_v1(struct inet6_dev *idev, s= truct mld_msg *mld, if (v1_query) mld_set_v1_mode(idev); =20 + mutex_lock(&idev->mc_lock); /* cancel MLDv2 report work */ mld_gq_stop_work(idev); /* cancel the interface change work */ mld_ifc_stop_work(idev); + mutex_unlock(&idev->mc_lock); /* clear deleted report items */ mld_clear_delrec(idev); =20 --=20 2.34.1