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[2001:8b0:1d0::2]) by smtp.gmail.com with ESMTPSA id d5-20020adff2c5000000b0032da6f17ffdsm9752176wrp.38.2023.11.06.07.32.41 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Nov 2023 07:32:41 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Subject: [PULL 05/12] hw/i386/intel_iommu: vtd_slpte_nonzero_rsvd(): assert no overflow Date: Mon, 6 Nov 2023 15:32:31 +0000 Message-Id: <20231106153238.1426649-6-peter.maydell@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231106153238.1426649-1-peter.maydell@linaro.org> References: <20231106153238.1426649-1-peter.maydell@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::136; envelope-from=peter.maydell@linaro.org; helo=mail-lf1-x136.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Vladimir Sementsov-Ogievskiy We support only 3- and 4-level page-tables, which is firstly checked in vtd_decide_config(), then setup in vtd_init(). Than level fields are checked by vtd_is_level_supported(). So here we can't have level out from 1..4 inclusive range. Let's assert it. That also explains Coverity that we are not going to overflow the array. CID: 1487158, 1487186 Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Peter Maydell Reviewed-by: Maksim Davydov Message-id: 20231017125941.810461-2-vsementsov@yandex-team.ru Signed-off-by: Peter Maydell --- hw/i386/intel_iommu.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index 1c6c18622fd..1a44ef696c3 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -1045,18 +1045,35 @@ static dma_addr_t vtd_get_iova_pgtbl_base(IntelIOMMUState *s, * Rsvd field masks for spte: * vtd_spte_rsvd 4k pages * vtd_spte_rsvd_large large pages + * + * We support only 3-level and 4-level page tables (see vtd_init() which + * sets only VTD_CAP_SAGAW_39bit and maybe VTD_CAP_SAGAW_48bit bits in s->cap). */ -static uint64_t vtd_spte_rsvd[5]; -static uint64_t vtd_spte_rsvd_large[5]; +#define VTD_SPTE_RSVD_LEN 5 +static uint64_t vtd_spte_rsvd[VTD_SPTE_RSVD_LEN]; +static uint64_t vtd_spte_rsvd_large[VTD_SPTE_RSVD_LEN]; static bool vtd_slpte_nonzero_rsvd(uint64_t slpte, uint32_t level) { - uint64_t rsvd_mask = vtd_spte_rsvd[level]; + uint64_t rsvd_mask; + + /* + * We should have caught a guest-mis-programmed level earlier, + * via vtd_is_level_supported. + */ + assert(level < VTD_SPTE_RSVD_LEN); + /* + * Zero level doesn't exist. The smallest level is VTD_SL_PT_LEVEL=1 and + * checked by vtd_is_last_slpte(). + */ + assert(level); if ((level == VTD_SL_PD_LEVEL || level == VTD_SL_PDP_LEVEL) && (slpte & VTD_SL_PT_PAGE_SIZE_MASK)) { /* large page */ rsvd_mask = vtd_spte_rsvd_large[level]; + } else { + rsvd_mask = vtd_spte_rsvd[level]; } return slpte & rsvd_mask;