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 F3F773537DF; Fri, 24 Apr 2026 13:44:26 +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=1777038267; cv=none; b=h/VlhLisbS5zwRfg2W4XHDQr2V4fmRVQAM4Eth1q4zjMTcaJ2/MpuPp1tPQaBMDCarkfmdNc9FcYF7Zrup2P54E/Sny0Zu6Lyiib0Clz25kVVt2HPL8t6b5ppdtojhHCTxKgvu9Venvero0iSjGL2hN/N4FcqALH1BFmey16OR4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777038267; c=relaxed/simple; bh=tcXUIxXKvZg/B9y24aorLS/Fgw0foX+57uZfF7PUv7g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WmbzxnQJ1+lWx9mODBGcucR2E/eV69NEuw2gzAC5Mz7KQPZ9f4g2fRamZhaGegjGt9ddv3liVt+u9Jsy6osAowKTi422DrJnAGKPVV1GEfpYoekRDzSdUFJTiypIY9746sh0jfx+IWToccapKwGnoWiFfNtElFEwwDuNOJpBnU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=adCzJ8m0; 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="adCzJ8m0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52E25C19425; Fri, 24 Apr 2026 13:44:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777038266; bh=tcXUIxXKvZg/B9y24aorLS/Fgw0foX+57uZfF7PUv7g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=adCzJ8m0V1qTg3qO8ofJxhPkmveTzX3c9BnnXBfkK72QVLPftQPcQrxXOPblfqiL7 wADtooj1VqMOK1kG4A8K8mMSs4cPK4PYZ/3vkFr3Al/oepnnGj9TFCr4Ep8cF3FXRu xvKNSg3vu8jExe2Cg2nfGzf8fI0mVhz1oNDd374k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexander Potapenko , Sebastian Alba Vives , Sean Christopherson , Herbert Xu Subject: [PATCH 6.12 32/35] crypto: ccp: Dont attempt to copy CSR to userspace if PSP command failed Date: Fri, 24 Apr 2026 15:31:39 +0200 Message-ID: <20260424132418.538758211@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260424132411.427029259@linuxfoundation.org> References: <20260424132411.427029259@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit abe4a6d6f606113251868c2c4a06ba904bb41eed upstream. When retrieving the PEK CSR, don't attempt to copy the blob to userspace if the firmware command failed. If the failure was due to an invalid length, i.e. the userspace buffer+length was too small, copying the number of bytes _firmware_ requires will overflow the kernel-allocated buffer and leak data to userspace. BUG: KASAN: slab-out-of-bounds in instrument_copy_to_user ../include/linux/instrumented.h:129 [inline] BUG: KASAN: slab-out-of-bounds in _inline_copy_to_user ../include/linux/uaccess.h:205 [inline] BUG: KASAN: slab-out-of-bounds in _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26 Read of size 2084 at addr ffff898144612e20 by task syz.9.219/21405 CPU: 14 UID: 0 PID: 21405 Comm: syz.9.219 Tainted: G U O 7.0.0-smp-DEV #28 PREEMPTLAZY Tainted: [U]=USER, [O]=OOT_MODULE Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 12.62.0-0 11/19/2025 Call Trace: dump_stack_lvl+0xc5/0x110 ../lib/dump_stack.c:120 print_address_description ../mm/kasan/report.c:378 [inline] print_report+0xbc/0x260 ../mm/kasan/report.c:482 kasan_report+0xa2/0xe0 ../mm/kasan/report.c:595 check_region_inline ../mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 ../mm/kasan/generic.c:200 instrument_copy_to_user ../include/linux/instrumented.h:129 [inline] _inline_copy_to_user ../include/linux/uaccess.h:205 [inline] _copy_to_user+0x66/0xa0 ../lib/usercopy.c:26 copy_to_user ../include/linux/uaccess.h:236 [inline] sev_ioctl_do_pek_csr+0x31f/0x590 ../drivers/crypto/ccp/sev-dev.c:1872 sev_ioctl+0x3a4/0x490 ../drivers/crypto/ccp/sev-dev.c:2562 vfs_ioctl ../fs/ioctl.c:51 [inline] __do_sys_ioctl ../fs/ioctl.c:597 [inline] __se_sys_ioctl+0x11d/0x1b0 ../fs/ioctl.c:583 do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe0/0x800 ../arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e WARN if the driver says the command succeeded, but the firmware error code says otherwise, as __sev_do_cmd_locked() is expected to return -EIO on any firwmware error. Reported-by: Alexander Potapenko Reported-by: Sebastian Alba Vives Fixes: e799035609e1 ("crypto: ccp: Implement SEV_PEK_CSR ioctl command") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/crypto/ccp/sev-dev.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1541,7 +1541,10 @@ cmd: ret = __sev_do_cmd_locked(SEV_CMD_PEK_CSR, &data, &argp->error); - /* If we query the CSR length, FW responded with expected data. */ + /* + * Firmware will returns the length of the CSR blob (either the minimum + * required length or the actual length written), return it to the user. + */ input.length = data.len; if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) { @@ -1549,6 +1552,9 @@ cmd: goto e_free_blob; } + if (ret || WARN_ON_ONCE(argp->error)) + goto e_free_blob; + if (blob) { if (copy_to_user(input_address, blob, input.length)) ret = -EFAULT;