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 C55902641E8 for ; Tue, 8 Apr 2025 08:18:33 +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=1744100313; cv=none; b=gRprYPIbxcgLSVMdxxsuZuS9inUw9j1F1Tc4juuf4pTIe4Rz3hAS1V8auUtZDE8RqCrEXAdDDL5I/XvuLvUrX6r36u52PfA5Xi1TDtFWcboyfZG98VwdR+9S5+bXIZoe/tHs89H++pd/ODAP2QVy8NPaLZeYCO2qH2RdRt2eVzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744100313; c=relaxed/simple; bh=GmhDcgXxlbI2GmivJDhUNbJjbnfPAMZ6YpTJenFR3CQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Jt0HLpcAgb5GlaycffCwbL0V3DYsFQYRIaRt/EQL0cmVTMaX8QOoc106o5nD5WwxRz7LucuOroIQEjGy8PGHMbvRuczQuL4Jqf0b/mkmftygZ+Zklxdn18+H9DJkaFzIpTU5zzxwgF7NWLoVhM+A4A5ADjlySNRFY9z1bUEEPGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N1VPsimL; 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="N1VPsimL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2869C4CEE5; Tue, 8 Apr 2025 08:18:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744100313; bh=GmhDcgXxlbI2GmivJDhUNbJjbnfPAMZ6YpTJenFR3CQ=; h=From:To:Cc:Subject:Date:Reply-to:From; b=N1VPsimLasHZvkpN9RDGvEpzuMdcB/120YHkj2IzOVE5NpQRH0ZZhha94ZQGsRxAD JKkPnekycQBsLM1zshXUQCWncPP9IQf8DId+RlVrf5uJWE/ATvujpMPPsI5kkigTZk PPtVVDvlIZ5bgkq1OvqyZvb9UEb5WVTXQkie1BVs= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2025-22013: KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state Date: Tue, 8 Apr 2025 10:16:47 +0200 Message-ID: <2025040843-CVE-2025-22013-c885@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=3826; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=GmhDcgXxlbI2GmivJDhUNbJjbnfPAMZ6YpTJenFR3CQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDOlfbmc/O/M9Yc2hM1eDzkid2Dh5rvD3BUejV1hVTejRC z6mcV7GviOWhUGQiUFWTJHlyzaeo/srDil6GdqehpnDygQyhIGLUwAm8smEYcHEjZsE/1862td3 IGnTt6zfUplt2x8xzI8U9XzfFL/wjczdyyeZhFfuNrVqWgkA 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: KVM: arm64: Unconditionally save+flush host FPSIMD/SVE/SME state There are several problems with the way hyp code lazily saves the host's FPSIMD/SVE state, including: * Host SVE being discarded unexpectedly due to inconsistent configuration of TIF_SVE and CPACR_ELx.ZEN. This has been seen to result in QEMU crashes where SVE is used by memmove(), as reported by Eric Auger: https://issues.redhat.com/browse/RHEL-68997 * Host SVE state is discarded *after* modification by ptrace, which was an unintentional ptrace ABI change introduced with lazy discarding of SVE state. * The host FPMR value can be discarded when running a non-protected VM, where FPMR support is not exposed to a VM, and that VM uses FPSIMD/SVE. In these cases the hyp code does not save the host's FPMR before unbinding the host's FPSIMD/SVE/SME state, leaving a stale value in memory. Avoid these by eagerly saving and "flushing" the host's FPSIMD/SVE/SME state when loading a vCPU such that KVM does not need to save any of the host's FPSIMD/SVE/SME state. For clarity, fpsimd_kvm_prepare() is removed and the necessary call to fpsimd_save_and_flush_cpu_state() is placed in kvm_arch_vcpu_load_fp(). As 'fpsimd_state' and 'fpmr_ptr' should not be used, they are set to NULL; all uses of these will be removed in subsequent patches. Historical problems go back at least as far as v5.17, e.g. erroneous assumptions about TIF_SVE being clear in commit: 8383741ab2e773a9 ("KVM: arm64: Get rid of host SVE tracking/saving") ... and so this eager save+flush probably needs to be backported to ALL stable trees. The Linux kernel CVE team has assigned CVE-2025-22013 to this issue. Affected and fixed versions =========================== Issue introduced in 6.2 with commit 8c845e2731041f0fdf9287dea80b039b26332c9f and fixed in 6.6.85 with commit 806d5c1e1d2e5502175a24bf70f251648d99c36a Issue introduced in 6.2 with commit 8c845e2731041f0fdf9287dea80b039b26332c9f and fixed in 6.12.21 with commit 79e140bba70bcacc5fe15bf8c0b958793fd7d56f Issue introduced in 6.2 with commit 8c845e2731041f0fdf9287dea80b039b26332c9f and fixed in 6.13.9 with commit 900b444be493b7f404898c785d6605b177a093d0 Issue introduced in 6.2 with commit 8c845e2731041f0fdf9287dea80b039b26332c9f and fixed in 6.14 with commit fbc7e61195e23f744814e78524b73b59faa54ab4 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-2025-22013 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: arch/arm64/kernel/fpsimd.c arch/arm64/kvm/fpsimd.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/806d5c1e1d2e5502175a24bf70f251648d99c36a https://git.kernel.org/stable/c/79e140bba70bcacc5fe15bf8c0b958793fd7d56f https://git.kernel.org/stable/c/900b444be493b7f404898c785d6605b177a093d0 https://git.kernel.org/stable/c/fbc7e61195e23f744814e78524b73b59faa54ab4