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 A467926159D for ; Tue, 8 Apr 2025 08:18:38 +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=1744100318; cv=none; b=JPsdv/DX3NZjSvq3jZon7PjaXoJ16a0kW2U8Ba6gsaG+xqkuQxGZuSQdRycPEjLmA64V4Gs9AEBy6AjPkuuek/apsEULrjxvSmvYp/+1SzEfkVB3Gic3kGGmXa4r4nMPO6BApu5pBAR4qM5AXb1tCtLUKu+4DIoRps5Ye8ozfLc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744100318; c=relaxed/simple; bh=ehpVwcauigD7aF74LbYSWg8JwXZ/9XjiUTzgoAR7VDI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Ldz6irrTEXc4qxlwQNO379I2qDxu2vaNWgLJBEfHDyOvnnfT6nPiSDPgq+COjiD7p3JZ9R0UYw8CU12+mR7n0s6RsktDLiis6qChNWiT2LAgCIYVR14dxHnJ5pJVv7b2TXmMbZIX8WdaMes3b/LVJmylu8zvKxByiEqFf5Sxqe0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Wc4/ct5s; 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="Wc4/ct5s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35CDEC4CEE5; Tue, 8 Apr 2025 08:18:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744100318; bh=ehpVwcauigD7aF74LbYSWg8JwXZ/9XjiUTzgoAR7VDI=; h=From:To:Cc:Subject:Date:Reply-to:From; b=Wc4/ct5sfs4hkAh46uLLqellw1RzHHs0Qu2URMZHY4B0jCsifTgk34OPTboJR+lkU EB89ucaqt6VoibRbAw1TeY71lbsQfdWkk5mgLbw8R6Fu9X82bfdD9hRBDZnszSVBCl 46atyRUTMmMdpeb0QMCGYS8B8e+3obUoXwuRKdpg= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2025-22015: mm/migrate: fix shmem xarray update during migration Date: Tue, 8 Apr 2025 10:16:49 +0200 Message-ID: <2025040843-CVE-2025-22015-3408@gregkh> X-Mailer: git-send-email 2.49.0 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=3737; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=ehpVwcauigD7aF74LbYSWg8JwXZ/9XjiUTzgoAR7VDI=; b=kA0DAAIRMUfUDdst+ykByyZiAGf022uhAttPgNSi7tMp+1YVbgte1xK5FXmMQjf+r8mUN8uZO 4hdBAARAgAdFiEE9LYMxb94wiFKMT3LMUfUDdst+ykFAmf022sACgkQMUfUDdst+ymkYQCdGc/7 XxJ+TlYO34vcau9TqDntrscAoMgTNWbc30wob58TJY4o+eWae22M 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/migrate: fix shmem xarray update during migration A shmem folio can be either in page cache or in swap cache, but not at the same time. Namely, once it is in swap cache, folio->mapping should be NULL, and the folio is no longer in a shmem mapping. In __folio_migrate_mapping(), to determine the number of xarray entries to update, folio_test_swapbacked() is used, but that conflates shmem in page cache case and shmem in swap cache case. It leads to xarray multi-index entry corruption, since it turns a sibling entry to a normal entry during xas_store() (see [1] for a userspace reproduction). Fix it by only using folio_test_swapcache() to determine whether xarray is storing swap cache entries or not to choose the right number of xarray entries to update. [1] https://lore.kernel.org/linux-mm/Z8idPCkaJW1IChjT@casper.infradead.org/ Note: In __split_huge_page(), folio_test_anon() && folio_test_swapcache() is used to get swap_cache address space, but that ignores the shmem folio in swap cache case. It could lead to NULL pointer dereferencing when a in-swap-cache shmem folio is split at __xa_store(), since !folio_test_anon() is true and folio->mapping is NULL. But fortunately, its caller split_huge_page_to_list_to_order() bails out early with EBUSY when folio->mapping is NULL. So no need to take care of it here. The Linux kernel CVE team has assigned CVE-2025-22015 to this issue. Affected and fixed versions =========================== Issue introduced in 6.1.71 with commit be72d197b2281e2ee3f28017fc9be1ab17e26d16 and fixed in 6.1.132 with commit 49100c0b070e900f87c8fac3be9b9ef8a30fa673 Issue introduced in 6.6.10 with commit 07550b1461d4d0499165e7d6f7718cfd0e440427 and fixed in 6.6.85 with commit 29124ae980e2860f0eec7355949d3d3292ee81da Issue introduced in 6.7 with commit fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c and fixed in 6.12.21 with commit c057ee03f751d6cecf7ee64f52f6545d94082aaa Issue introduced in 6.7 with commit fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c and fixed in 6.13.9 with commit 75cfb92eb63298d717b6b0118f91ba12c4fcfeb5 Issue introduced in 6.7 with commit fc346d0a70a13d52fe1c4bc49516d83a42cd7c4c and fixed in 6.14 with commit 60cf233b585cdf1f3c5e52d1225606b86acd08b0 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-2025-22015 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/migrate.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/49100c0b070e900f87c8fac3be9b9ef8a30fa673 https://git.kernel.org/stable/c/29124ae980e2860f0eec7355949d3d3292ee81da https://git.kernel.org/stable/c/c057ee03f751d6cecf7ee64f52f6545d94082aaa https://git.kernel.org/stable/c/75cfb92eb63298d717b6b0118f91ba12c4fcfeb5 https://git.kernel.org/stable/c/60cf233b585cdf1f3c5e52d1225606b86acd08b0