From patchwork Fri Feb 16 08:58:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: WANG Xuerui X-Patchwork-Id: 13559706 Received: from mailbox.box.xen0n.name (mail.xen0n.name [115.28.160.31]) (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 BB6571B95D; Fri, 16 Feb 2024 08:58:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.28.160.31 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708073917; cv=none; b=QjcESJ9GvFtq9h1QwuyCODzJz1MyLKUO26X4twDixOTbZwJPdv8fkT4qDRgyWFPB0S0vdrcyeaMPY5SoDLPBi1LlU1AKDDZbp9zr4rXlPFu9z7lc4xvxsUvUUjRu3308rHESriz1Kn0+XhcDBOWiUUssPpzeNfMFR+QbzpdkzrE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708073917; c=relaxed/simple; bh=NcJCcfqi8ekicRsCx7lcKlZxsG+ADiWoan5/EkMI1NU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SXhUAfPp98vVdw/1QA/6CmOJe/PuJs6mtx40CnqDJ+oM3JUCQmKE996vcuKKJUhOf1ciZZwIKpIOtN9OLpMQJzAYAj22mt5FZZjI5QA8+Vq4uPCI4t+X2+SUNR2jMPBXejf93ZPja+Gv389hajSIWUjubncDmVBUc9A7fm5CYUk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xen0n.name; spf=pass smtp.mailfrom=xen0n.name; dkim=pass (1024-bit key) header.d=xen0n.name header.i=@xen0n.name header.b=mO76rEvU; arc=none smtp.client-ip=115.28.160.31 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=xen0n.name Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xen0n.name Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=xen0n.name header.i=@xen0n.name header.b="mO76rEvU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=xen0n.name; s=mail; t=1708073910; bh=NcJCcfqi8ekicRsCx7lcKlZxsG+ADiWoan5/EkMI1NU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mO76rEvUz/01p234o2SAAs2to05wG3+DNg3sb00mT0knnk5q422OQL/bhqv+NbnSe I5Kd9N/o4VZ4UPQQ6BlhBp+z9TWsXqViVMaQxsB7VxmdZBpH04C5P9qfhtiHmz3rjk vBcMsrblEov56rBFalDCYfWXXLysYyfeeUvL7QvI= Received: from ld50.lan (unknown [IPv6:240e:388:8d00:6500:cda4:aa27:b0f6:1748]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mailbox.box.xen0n.name (Postfix) with ESMTPSA id 21BF760187; Fri, 16 Feb 2024 16:58:30 +0800 (CST) From: WANG Xuerui To: Paolo Bonzini , Huacai Chen Cc: Tianrui Zhao , Bibo Mao , kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, WANG Xuerui Subject: [PATCH for-6.8 v3 1/3] LoongArch: KVM: Fix input validation of _kvm_get_cpucfg and kvm_check_cpucfg Date: Fri, 16 Feb 2024 16:58:20 +0800 Message-ID: <20240216085822.3032984-2-kernel@xen0n.name> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240216085822.3032984-1-kernel@xen0n.name> References: <20240216085822.3032984-1-kernel@xen0n.name> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: WANG Xuerui The range check for the CPUCFG ID is wrong (should have been a || instead of &&); it is conceptually simpler to just express the check as another case of the switch statement on the ID. As it turns out to be the case, the userland (currently only the QEMU/KVM target code) expects to set CPUCFG IDs 0 to 20 inclusive, but only CPUCFG2 values are being validated. Furthermore, the juggling of the temp return value is unnecessary, because it is semantically equivalent and more readable to just return at every switch case's end. This is done too to avoid potential bugs in the future related to the unwanted complexity. Also, the return value of _kvm_get_cpucfg is meant to be checked, but this was not done, so bad CPUCFG IDs wrongly fall back to the default case and 0 is incorrectly returned; check the return value to fix the UAPI behavior. While at it, also remove the redundant range check in kvm_check_cpucfg, because out-of-range CPUCFG IDs are already rejected by the -EINVAL as returned by _kvm_get_cpucfg. Fixes: db1ecca22edf ("LoongArch: KVM: Add LSX (128bit SIMD) support") Signed-off-by: WANG Xuerui --- arch/loongarch/kvm/vcpu.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index 27701991886d..56da0881fc94 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -300,11 +300,6 @@ static int _kvm_setcsr(struct kvm_vcpu *vcpu, unsigned int id, u64 val) static int _kvm_get_cpucfg(int id, u64 *v) { - int ret = 0; - - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) - return -EINVAL; - switch (id) { case 2: /* Return CPUCFG2 features which have been supported by KVM */ @@ -324,31 +319,33 @@ static int _kvm_get_cpucfg(int id, u64 *v) if (cpu_has_lasx) *v |= CPUCFG2_LASX; - break; + return 0; + case 0 ... 1: + case 3 ... KVM_MAX_CPUCFG_REGS - 1: + /* no restrictions on other CPUCFG IDs' values */ + *v = U64_MAX; + return 0; default: - ret = -EINVAL; - break; + return -EINVAL; } - return ret; } static int kvm_check_cpucfg(int id, u64 val) { - u64 mask; - int ret = 0; - - if (id < 0 && id >= KVM_MAX_CPUCFG_REGS) - return -EINVAL; + u64 mask = 0; + int ret; - if (_kvm_get_cpucfg(id, &mask)) + ret = _kvm_get_cpucfg(id, &mask); + if (ret) return ret; + if (val & ~mask) + /* Unsupported features should not be set */ + return -EINVAL; + switch (id) { case 2: /* CPUCFG2 features checking */ - if (val & ~mask) - /* The unsupported features should not be set */ - ret = -EINVAL; else if (!(val & CPUCFG2_LLFTP)) /* The LLFTP must be set, as guest must has a constant timer */ ret = -EINVAL;