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 F1D9B20AF89 for ; Wed, 12 Feb 2025 13:53:11 +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=1739368392; cv=none; b=q7ABzwFOniT6fE3Usq9z8PMJ7kWHggN3L3yNA2OEB8naA2lxGEQRr3EFF3QeaAdmkw68DW8faoZvETtRrDlWestG6nYZkuZF33O2s9nhmkbj5iV4EP2Vplkg0roImVrhgtu8xdf8SKa5HgRRuItmyEA5DNkbeO8lFHhycAwBi40= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739368392; c=relaxed/simple; bh=Uz326uMLIIsplvUQK4vGUcSEMmFqtF8yfHRR148PFEE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=OX+CjsAXdce92dFPZj+vYKIqBb6U5sbGTJfmrkQYa1TQE/wVCrN5i4jVZsUbIIn2g/81UOmDdETE6KvUfLGWBbP1nDs0fDm1qLGe1OVZEEqhzCdeBVPI0iW5DkBb9VB27M9FH0cZgR+R3a8Qf/JJZ/vEJSu9cKDJl04jcGSivrM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kY9zPEuY; 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="kY9zPEuY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 111B0C4CEE7; Wed, 12 Feb 2025 13:53:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739368391; bh=Uz326uMLIIsplvUQK4vGUcSEMmFqtF8yfHRR148PFEE=; h=From:To:Cc:Subject:Date:Reply-to:From; b=kY9zPEuYUtOZZqbUQKy0mzthV+CohQ8tnnmxlLvhDiKn12zyfacMTSM7SQwzvZFo4 DZJCX2L7PC6UDQpyXNPhQ4jRMBY9YPC6OENWpkQLo8z0Yp8dN84bTtuP/aRL2RVTa3 BGY4RsJw14g11zJIZBi2CBhIYsQUL2Pm8NspnRu8= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-57952: Revert "libfs: fix infinite directory reads for offset dir" Date: Wed, 12 Feb 2025 14:52:00 +0100 Message-ID: <2025021259-CVE-2024-57952-c0fe@gregkh> X-Mailer: git-send-email 2.48.1 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=3287; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Uz326uMLIIsplvUQK4vGUcSEMmFqtF8yfHRR148PFEE=; b=owGbwMvMwCRo6H6F97bub03G02pJDOlrltcre/6VenN5ucjDM+veBLfdOLa6tTpy0/2jQZPfv uRjTzrE1RHLwiDIxCArpsjyZRvP0f0VhxS9DG1Pw8xhZQIZwsDFKQATMX3CME9n96zy8vlBr6vb Fs7Y7OF1cflfyyyG+e5HRFf9TTMsTCuJ6d61dpHKsXdvEwE= 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: Revert "libfs: fix infinite directory reads for offset dir" The current directory offset allocator (based on mtree_alloc_cyclic) stores the next offset value to return in octx->next_offset. This mechanism typically returns values that increase monotonically over time. Eventually, though, the newly allocated offset value wraps back to a low number (say, 2) which is smaller than other already- allocated offset values. Yu Kuai reports that, after commit 64a7ce76fb90 ("libfs: fix infinite directory reads for offset dir"), if a directory's offset allocator wraps, existing entries are no longer visible via readdir/getdents because offset_readdir() stops listing entries once an entry's offset is larger than octx->next_offset. These entries vanish persistently -- they can be looked up, but will never again appear in readdir(3) output. The reason for this is that the commit treats directory offsets as monotonically increasing integer values rather than opaque cookies, and introduces this comparison: if (dentry2offset(dentry) >= last_index) { On 64-bit platforms, the directory offset value upper bound is 2^63 - 1. Directory offsets will monotonically increase for millions of years without wrapping. On 32-bit platforms, however, LONG_MAX is 2^31 - 1. The allocator can wrap after only a few weeks (at worst). Revert commit 64a7ce76fb90 ("libfs: fix infinite directory reads for offset dir") to prepare for a fix that can work properly on 32-bit systems and might apply to recent LTS kernels where shmem employs the simple_offset mechanism. The Linux kernel CVE team has assigned CVE-2024-57952 to this issue. Affected and fixed versions =========================== Fixed in 6.12.12 with commit 9e9e710f68bac49bd9b587823c077d06363440e0 Fixed in 6.13.1 with commit 3f250b82040a72b0059ae00855a74d8570ad2147 Fixed in 6.14-rc1 with commit b662d858131da9a8a14e68661656989b14dbf113 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-2024-57952 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: fs/libfs.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/9e9e710f68bac49bd9b587823c077d06363440e0 https://git.kernel.org/stable/c/3f250b82040a72b0059ae00855a74d8570ad2147 https://git.kernel.org/stable/c/b662d858131da9a8a14e68661656989b14dbf113