From nobody Mon Feb 9 02:11:41 2026 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63823187F for ; Wed, 20 Mar 2024 00:15:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710893751; cv=none; b=AdD5hKrtFqloQ3It45Kc2Kw5grxtXoaA/2LSlQzajjXl65ngATrpwo5kIlS4voZNsj/5q4oSDqR1p3kBYFDcuOK7iIV8PukA5VyDcLSENPaOrK1cFuxt9CDhNAFQmRmTB1pLON3dYBs72bWeOcWcLCtg6gf77umEij/uxRSPx2g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710893751; c=relaxed/simple; bh=Yt+8bVzeNRVFwoSbiyyZuiajeFUG3KOlGSiF7ZwTVSQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=SQkH+faDjnDB9bdhuNT5RoUSmJatvnB50phc5bv2IP3SYwLJKRbOZ6teEluwitLM8FoPWqE+2D6PgnQfIdw8rV5XzQdGb7mc22r82Fpp5cI1ZcIWY6aB/7rGht3BsrHp8sRtDRFs/VQykdmRfqfCT8U0OSI8DHLHZ76ny/piHU4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=BmpNwsXd; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="BmpNwsXd" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-609fe93b5cfso106538507b3.0 for ; Tue, 19 Mar 2024 17:15:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1710893748; x=1711498548; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=UhfoJMqa7cgNDZOfpPVEAPEpiQKCx49jDxBa32QwPAM=; b=BmpNwsXdYI6/JGb+exXrYX/eFJL/C8wSN8tD3FEpjUVJmGxPQsCOOHhuj8HK0etjcA WnA97gjyzB7R1GJ2NXahJSTgl/FwTg0DevzGeMx3vCxAi0mYu/3VeexkbvGyoc1Kycup 3YtaDHwWYXnhWNcAxnaStR653PEejZGZe3uoKSsSBoBuMcJBTaO6Fe4ldta53WvyEPMU v+oEn9LBW1J0hQwPFfKKTcftEnFSj85COUO1NobnH3f/ZvVJummDldwjjVMDjlaBqE3A cwzJr8j5GJdaNJx2yhpJrC0l110BD2lYj9v5xaem4lwCq0ZD6KPVw8v7bnDRKZFpSvX3 O5GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710893748; x=1711498548; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=UhfoJMqa7cgNDZOfpPVEAPEpiQKCx49jDxBa32QwPAM=; b=TH9+2PYWl3TKpWyu5o/hsF1eFSYNvCEVRTVkL6lynS3Gga2dFo824senyBSOKipPKC h59yXwxux7bYE7KyEL/1ZKNNajF4tBUkYd6t6UACcgnF4m64JBfqvXjnnq3smhayyyms YZU6xZc4XMHKDHa223Ft/JeUXNxNN2gz4AAJX162CTzA/rYXOOjpE4rh5ymLOVplrkmg 80rqrRn2komKGpjFTrwJK9j1MuUeQQ/Ysggn8OQNwk97dYXCF6iTdVkjLO8LeoiNB9/G 9yGdzXbJZIQdhPRvlDK5J4Y4Mwp2uxzpMjYEmaqBv71yrdNjneAci12JBxYtOTA4zFce ZpYw== X-Forwarded-Encrypted: i=1; AJvYcCW8C/5zAYKvSka5ks6ar0mgz+Yi6RifvRWXiiNdS6D4jWBmol4wqXISiXAOroZVdR0mCNq8UtIBzmvLArHJ6UZWroBD33rofGDuVvKP X-Gm-Message-State: AOJu0Yx/3lpEcu/u98jhiEZeXHEsP1EoNiflBt28a0189l8jS1hwbsln yDq4bgU82OnxnWm7Ze/Mc5BZEpqv1Pl6lz7yJujqoJwm19PnnhIbXMwWeNpSyoSGqOJRyHhiewq iBA== X-Google-Smtp-Source: AGHT+IEEvlbSsccTqQ4jGgQQB1hc+eWbYdcXnNRWLJsFow/ZnDqIfy1THCaZsqq7Y5Q3P1IQWedbNpfgLH8= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:2181:b0:dc6:dd76:34cc with SMTP id dl1-20020a056902218100b00dc6dd7634ccmr887389ybb.1.1710893748542; Tue, 19 Mar 2024 17:15:48 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 19 Mar 2024 17:15:41 -0700 In-Reply-To: <20240320001542.3203871-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240320001542.3203871-1-seanjc@google.com> X-Mailer: git-send-email 2.44.0.291.gc1ea87d7ee-goog Message-ID: <20240320001542.3203871-3-seanjc@google.com> Subject: [PATCH 2/3] KVM: Check validity of offset+length of gfn_to_pfn_cache prior to activation From: Sean Christopherson To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Christopherson , syzbot+106a4f72b0474e1d1b33@syzkaller.appspotmail.com, David Woodhouse , Paul Durrant Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When activating a gfn_to_pfn_cache, verify that the offset+length is sane and usable before marking the cache active. Letting __kvm_gpc_refresh() detect the problem results in a cache being marked active without setting the GPA (or any other fields), which in turn results in KVM trying to refresh a cache with INVALID_GPA. Attempting to refresh a cache with INVALID_GPA isn't functionally problematic, but it runs afoul of the sanity check that exactly one of GPA or userspace HVA is valid, i.e. that a cache is either GPA-based or HVA-based. Reported-by: syzbot+106a4f72b0474e1d1b33@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/0000000000005fa5cc0613f1cebd@google.com Fixes: 721f5b0dda78 ("KVM: pfncache: allow a cache to be activated with a f= ixed (userspace) HVA") Cc: David Woodhouse Cc: Paul Durrant Signed-off-by: Sean Christopherson Reviewed-by: David Woodhouse Reviewed-by: Paul Durrant --- virt/kvm/pfncache.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 8f2121b5f2a0..91b0e329006b 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -245,8 +245,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cac= he *gpc) return -EFAULT; } =20 -static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsi= gned long uhva, - unsigned long len) +static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsi= gned long uhva) { unsigned long page_offset; bool unmap_old =3D false; @@ -260,9 +259,6 @@ static int __kvm_gpc_refresh(struct gfn_to_pfn_cache *g= pc, gpa_t gpa, unsigned l if (WARN_ON_ONCE(kvm_is_error_gpa(gpa) =3D=3D kvm_is_error_hva(uhva))) return -EINVAL; =20 - if (!kvm_gpc_is_valid_len(gpa, uhva, len)) - return -EINVAL; - lockdep_assert_held(&gpc->refresh_lock); =20 write_lock_irq(&gpc->lock); @@ -365,6 +361,9 @@ int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, unsig= ned long len) =20 guard(mutex)(&gpc->refresh_lock); =20 + if (!kvm_gpc_is_valid_len(gpc->gpa, gpc->uhva, len)) + return -EINVAL; + /* * If the GPA is valid then ignore the HVA, as a cache can be GPA-based * or HVA-based, not both. For GPA-based caches, the HVA will be @@ -372,7 +371,7 @@ int kvm_gpc_refresh(struct gfn_to_pfn_cache *gpc, unsig= ned long len) */ uhva =3D kvm_is_error_gpa(gpc->gpa) ? gpc->uhva : KVM_HVA_ERR_BAD; =20 - return __kvm_gpc_refresh(gpc, gpc->gpa, uhva, len); + return __kvm_gpc_refresh(gpc, gpc->gpa, uhva); } =20 void kvm_gpc_init(struct gfn_to_pfn_cache *gpc, struct kvm *kvm) @@ -392,6 +391,9 @@ static int __kvm_gpc_activate(struct gfn_to_pfn_cache *= gpc, gpa_t gpa, unsigned { struct kvm *kvm =3D gpc->kvm; =20 + if (!kvm_gpc_is_valid_len(gpa, uhva, len)) + return -EINVAL; + guard(mutex)(&gpc->refresh_lock); =20 if (!gpc->active) { @@ -411,7 +413,7 @@ static int __kvm_gpc_activate(struct gfn_to_pfn_cache *= gpc, gpa_t gpa, unsigned gpc->active =3D true; write_unlock_irq(&gpc->lock); } - return __kvm_gpc_refresh(gpc, gpa, uhva, len); + return __kvm_gpc_refresh(gpc, gpa, uhva); } =20 int kvm_gpc_activate(struct gfn_to_pfn_cache *gpc, gpa_t gpa, unsigned lon= g len) --=20 2.44.0.291.gc1ea87d7ee-goog