From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8B43F28505E; Thu, 16 Jul 2026 14:14:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211260; cv=none; b=hGT2Ok0HWoKKeEhcwTUUlQdMCUQqWuagV2zzkg6tk6y0qK0nazoB6aS6O+ML8dkgi0Dr/HrqAemE+zoG0mAoYuun6SHuzjua2Pz5syUNXBzh4+cIC2Q3MX4/yzgmrhUXKUessSxLXI+XZyXzpFdZSmk0CmLpeehR4ZXkMfz7Xms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211260; c=relaxed/simple; bh=10NBPBr+MGLmJEW7ys7D4URQsIW40SG7R7Wdp+DPDT8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UzXM4pLjLzF9NAkndkUaq5M9K+zwwo90520A63uxdOJIbKI/eJ8Rb7OyD6q3HNqpgoUcheVXrWAU3T7OoRLNPXODl/O7JFy5YXe6U39L9PxHBNtPTyxRc84F4ZrGTrLHqyrM1wmlTR5cReBwkjkrL2B8x319MrlPo+gj+RmmCN8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=khHek6zE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="khHek6zE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFBAB1F000E9; Thu, 16 Jul 2026 14:14:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784211259; bh=9xRnUJO0ZIcA1PrAy3J+DdptGQThmU/Fm9XCfxkPNXE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=khHek6zEcCQcHcUtaP6Q4Aek6CYcZSmBsRQz7oMIOTGQHoNuG//M0PknUZROaN9VN lOI2bZN/Ru+/8kV97bliyqEQEzLLKymkzq+qBTZEuqyUpzoZOLzymP79CS4A2d0nWf 1F8qEDTvxbw3rrByZX9PPnIquTMnn+GBkBX0KVGU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Tycho Andersen (AMD)" , Tom Lendacky , Herbert Xu Subject: [PATCH 6.18 359/480] crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) Date: Thu, 16 Jul 2026 15:31:46 +0200 Message-ID: <20260716133052.569904572@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133044.672218725@linuxfoundation.org> References: <20260716133044.672218725@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tycho Andersen (AMD) commit 08f0e65e784c4b20e6e620dd4f68d8636073a3d2 upstream. Sashiko notes: > if SEV initialization fails and KVM is actively running normal VMs, could a > userspace process trigger this code path via /dev/sev ioctls (e.g., > SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN > execution for an active VM trigger a general protection fault and crash the > host? Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG. This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options: * do something like symbol_get() for kvm and refuse to initialize if KVM is loaded * check each cpu's HSAVE_PA for non-zero data before re-initializing * once initialization has failed, continue to refuse to initialize until the ccp module is unloaded Fixes: ceac7fb89e8d ("crypto: ccp - Ensure implicit SEV/SNP init and shutdown in ioctls") Reported-by: Sashiko Assisted-by: Gemini:gemini-3.1-pro-preview Link: https://sashiko.dev/#/patchset/20260324161301.1353976-1-tycho%40kernel.org CC: Signed-off-by: Tycho Andersen (AMD) Reviewed-by: Tom Lendacky Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/crypto/ccp/sev-dev.c | 33 ++++----------------------------- 1 file changed, 4 insertions(+), 29 deletions(-) --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1700,21 +1700,6 @@ static int sev_move_to_init_state(struct return 0; } -static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_required) -{ - int error, rc; - - rc = __sev_snp_init_locked(&error, 0); - if (rc) { - argp->error = SEV_RET_INVALID_PLATFORM_STATE; - return rc; - } - - *shutdown_required = true; - - return 0; -} - static int sev_ioctl_do_reset(struct sev_issue_cmd *argp, bool writable) { int state, rc; @@ -2425,8 +2410,6 @@ static int sev_ioctl_do_snp_set_config(s { struct sev_device *sev = psp_master->sev_data; struct sev_user_data_snp_config config; - bool shutdown_required = false; - int ret, error; if (!argp->data) return -EINVAL; @@ -2434,21 +2417,13 @@ static int sev_ioctl_do_snp_set_config(s if (!writable) return -EPERM; + if (!sev->snp_initialized) + return -ENODEV; + if (copy_from_user(&config, (void __user *)argp->data, sizeof(config))) return -EFAULT; - if (!sev->snp_initialized) { - ret = snp_move_to_init_state(argp, &shutdown_required); - if (ret) - return ret; - } - - ret = __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error); - - if (shutdown_required) - __sev_snp_shutdown_locked(&error, false); - - return ret; + return __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error); } static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable)