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 A9FF727A477; Sat, 30 May 2026 17:42:34 +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=1780162955; cv=none; b=OTNTXSzzlgXW1Cvkdd2pELw9WXRDz3104Nd7SPOxURWtbuvbFOhrUdWQXmFWVtp86usO9qBc9yQCWwavYgHBiDgqQCaulgOU/SVOSlyDdkgWJVxsYn3oizDt0oaXzYKGOekRxWnMqt+BtkZPQRCYwcWZqP4E8Z1KmDHO9olucw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162955; c=relaxed/simple; bh=F6UyGpqu+mkWZFA5EKJUeB29xbAGJP1yzfntLpPiRPw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IL6+Wxgewz5lZ3EBj1Oj54wcRCu8eDhHfEH80+t809NrZfzrhkRKirD5imy3012aVLeI76N0Ew/RzYOJTXtu2teM4oRBFQVvtRo6DoqOCMP0MaN+rnkQQyJOwdE4kY/dqNYvxPU/gjJI/a/E+SJiDds7PcyFGdjnZHGjBzjeSHs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ouqYztQF; 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="ouqYztQF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEF361F00893; Sat, 30 May 2026 17:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780162954; bh=jsmQv2+GUNWUUova6MTn0k9w9ZfeMt40alU8QEOq3Q0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ouqYztQFe0V5+7ptLg+fj0h8DIDRQsAL8GN1Pe8EzLzsukk9J5Q6JMYa3DWtKhKCB pNPj4xwkh2gH3jMgak4FygLjXYgkp15aIWkUAapGKksYyT9Voob+Dc9NyiTnMdPM7s rvUXrQ8p3UPZmCV3ir/nLXQvj9d807hiLjQN+bmY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Liam Merwick , Sean Christopherson Subject: [PATCH 5.15 074/776] KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION Date: Sat, 30 May 2026 17:56:28 +0200 Message-ID: <20260530160242.236768463@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit 8acffeef5ef720c35e513e322ab08e32683f32f2 upstream. Drop the WARN in sev_pin_memory() on npages overflowing an int, as the WARN is comically trivially to trigger from userspace, e.g. by doing: struct kvm_enc_region range = { .addr = 0, .size = -1ul, }; __vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range); Note, the checks in sev_mem_enc_register_region() that presumably exist to verify the incoming address+size are completely worthless, as both "addr" and "size" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater than ULONG_MAX. That wart will be cleaned up in the near future. if (range->addr > ULONG_MAX || range->size > ULONG_MAX) return -EINVAL; Opportunistically add a comment to explain why the code calculates the number of pages the "hard" way, e.g. instead of just shifting @ulen. Fixes: 78824fabc72e ("KVM: SVM: fix svn_pin_memory()'s use of get_user_pages_fast()") Cc: stable@vger.kernel.org Reviewed-by: Liam Merwick Tested-by: Liam Merwick Link: https://patch.msgid.link/20260313003302.3136111-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/sev.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -388,10 +388,16 @@ static struct page **sev_pin_memory(stru if (ulen == 0 || uaddr + ulen < uaddr) return ERR_PTR(-EINVAL); - /* Calculate number of pages. */ + /* + * Calculate the number of pages that need to be pinned to cover the + * entire range. Note! This isn't simply ulen >> PAGE_SHIFT, as KVM + * doesn't require the incoming address+size to be page aligned! + */ first = (uaddr & PAGE_MASK) >> PAGE_SHIFT; last = ((uaddr + ulen - 1) & PAGE_MASK) >> PAGE_SHIFT; npages = (last - first + 1); + if (npages > INT_MAX) + return ERR_PTR(-EINVAL); locked = sev->pages_locked + npages; lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; @@ -400,9 +406,6 @@ static struct page **sev_pin_memory(stru return ERR_PTR(-ENOMEM); } - if (WARN_ON_ONCE(npages > INT_MAX)) - return ERR_PTR(-EINVAL); - /* Avoid using vmalloc for smaller buffers. */ size = npages * sizeof(struct page *); if (size > PAGE_SIZE)