From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 602EA14A097 for ; Wed, 3 Apr 2024 14:58:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712156318; cv=none; b=gKCZN/arG6uYWsI8ametBQrPU0GyImqA4OhlDMr+HN1ktaWBcLQUf/iGcAKZANf5qA+MeHTZVj0sJvFIxTiXrMBIlCV6EKmsABErEGmHZmd1kTxTyvlVVssGiQDtpZH8fGQz+F1/HIhqXDq9puFmppMVdvkW3BEVXk66G03j/dM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712156318; c=relaxed/simple; bh=UnuHVE5gwKuFFV32oqZnhQt37OH4Zj47T+mVs9fMQzc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=QN7yO+7KYP9nZ0Al4SdxS4meNrGeUGZG3jdAC91+uyyUDuhtcjynHV3u7A4nRx6HIrVWz9AjFGZSjjHvC/i4a7eMYl0+1/3KCgJsPvYSlDPIoCeilnECEorKOipLrJZvlAGIxLynoqIbcU6A4eiLY8aTPVJjvDVKZP3NIQ5cELM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fhvZk4Tn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fhvZk4Tn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D523BC43390; Wed, 3 Apr 2024 14:58:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712156318; bh=UnuHVE5gwKuFFV32oqZnhQt37OH4Zj47T+mVs9fMQzc=; h=From:To:Cc:Subject:Date:Reply-to:From; b=fhvZk4TnmtlPsfoe1AK7bIy348YaFZu5Fp4cOfwC4MpMDh/3Ln/Lq/ubpitqWUZR9 qhx9x99uODoAqpibpBhQb0aQrhEuOLTbAs4db9O8VH0zn8TTOJ7J/nUrQZJ5V46QYH Swoc6qZCQ5E9thlbEuwPU5RvDIEq2fPMFgo5Akw4= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-26720: mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again Date: Wed, 3 Apr 2024 16:56:11 +0200 Message-ID: <2024040344-CVE-2024-26720-06fa@gregkh> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=3581; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=UnuHVE5gwKuFFV32oqZnhQt37OH4Zj47T+mVs9fMQzc=; b=owGbwMvMwCRo6H6F97bub03G02pJDGm8uR8KfYOesXDEL++6m/XkVr5uuZT8+cpPU+Vnhj1O3 RAdevpORywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAEzkMxPDXNmwjwvWKViIxsq0 Td/K07b0jPWGhwzzay6ZV+b78WvcvhSVp/Pab9mCivcRAA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again (struct dirty_throttle_control *)->thresh is an unsigned long, but is passed as the u32 divisor argument to div_u64(). On architectures where unsigned long is 64 bytes, the argument will be implicitly truncated. Use div64_u64() instead of div_u64() so that the value used in the "is this a safe division" check is the same as the divisor. Also, remove redundant cast of the numerator to u64, as that should happen implicitly. This would be difficult to exploit in memcg domain, given the ratio-based arithmetic domain_drity_limits() uses, but is much easier in global writeback domain with a BDI_CAP_STRICTLIMIT-backing device, using e.g. vm.dirty_bytes=(1<<32)*PAGE_SIZE so that dtc->thresh == (1<<32) The Linux kernel CVE team has assigned CVE-2024-26720 to this issue. Affected and fixed versions =========================== Issue introduced in 3.16 with commit f6789593d5ce and fixed in 4.19.307 with commit c593d26fb5d5 Issue introduced in 3.16 with commit f6789593d5ce and fixed in 5.4.269 with commit 1f12e4b3284d Issue introduced in 3.16 with commit f6789593d5ce and fixed in 5.10.210 with commit 81e7d2530d45 Issue introduced in 3.16 with commit f6789593d5ce and fixed in 5.15.149 with commit 5099871b3703 Issue introduced in 3.16 with commit f6789593d5ce and fixed in 6.1.79 with commit 16b1025eaa8f Issue introduced in 3.16 with commit f6789593d5ce and fixed in 6.6.18 with commit ec18ec230301 Issue introduced in 3.16 with commit f6789593d5ce and fixed in 6.7.6 with commit 65977bed167a Issue introduced in 3.16 with commit f6789593d5ce and fixed in 6.8 with commit 9319b647902c Issue introduced in 3.12.27 with commit c5fec566bef6 Issue introduced in 3.14.16 with commit c05d1fe6c19f Issue introduced in 3.15.9 with commit 3f7d325fbbe1 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-2024-26720 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: mm/page-writeback.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/c593d26fb5d577ef31b6e49a31e08ae3ebc1bc1e https://git.kernel.org/stable/c/1f12e4b3284d6c863f272eb2de0d4248ed211cf4 https://git.kernel.org/stable/c/81e7d2530d458548b90a5c5e76b77ad5e5d1c0df https://git.kernel.org/stable/c/5099871b370335809c0fd1abad74d9c7c205d43f https://git.kernel.org/stable/c/16b1025eaa8fc223ab4273ece20d1c3a4211a95d https://git.kernel.org/stable/c/ec18ec230301583395576915d274b407743d8f6c https://git.kernel.org/stable/c/65977bed167a92e87085e757fffa5798f7314c9f https://git.kernel.org/stable/c/9319b647902cbd5cc884ac08a8a6d54ce111fc78