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bh=Z0EMHQD95IGfuMsMhnXpEI94+P61EvU9qbslVrJfqhY=; b=YqI5ll7As8Na8l5NZEAVeBj+Sr3gJgm/I+u1usLS7EffN2chaLdrGL3jDuRoxlA8kYFBdQ VYixQ1JOoYcE4FwZhYJgH1TAE25s53IlDT1XCPul4PmdRC7XeLpunu8BEp/89WPSvoBYhq 54KKmk9C0534KJZ7BSERCFNF+zLf40Y= X-MC-Unique: tMqOqBv5PXClKw_2iPamuQ-1 Subject: [PATCH] vfio/common: Fix vfio_iommu_type1_info use after free From: Alex Williamson To: qemu-devel@nongnu.org Cc: alex.williamson@redhat.com, nicolinc@nvidia.com, cohuck@redhat.com Date: Thu, 15 Sep 2022 11:18:27 -0600 Message-ID: <166326219630.3388898.12882473157184946072.stgit@omen> User-Agent: StGit/1.5.dev2+g9ce680a52bd9 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1663262439855100001 On error, vfio_get_iommu_info() frees and clears *info, but vfio_connect_container() continues to use the pointer regardless of the return value. Restructure the code such that a failure of this function triggers an error and clean up the remainder of the function, including updating an outdated comment that had drifted from its relevant line of code and using host page size for a default for better compatibility on non-4KB systems. Reported-by: Nicolin Chen Link: https://lore.kernel.org/all/20220910004245.2878-1-nicolinc@nvidia.com/ Signed-off-by: Alex Williamson Reviewed-by: Nicolin Chen Reviewed-by: Philippe Mathieu-Daud=C3=A9 Tested-by: Nicolin Chen --- hw/vfio/common.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) Turns out I had the errno vs ret correct the first time from the thread in the above Link, vfio_get_iommu_info() returns -errno. diff --git a/hw/vfio/common.c b/hw/vfio/common.c index ace9562a9ba1..6b5d8c0bf694 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -2111,29 +2111,31 @@ static int vfio_connect_container(VFIOGroup *group,= AddressSpace *as, { struct vfio_iommu_type1_info *info; =20 - /* - * FIXME: This assumes that a Type1 IOMMU can map any 64-bit - * IOVA whatsoever. That's not actually true, but the current - * kernel interface doesn't tell us what it can map, and the - * existing Type1 IOMMUs generally support any IOVA we're - * going to actually try in practice. - */ ret =3D vfio_get_iommu_info(container, &info); + if (ret) { + error_setg_errno(errp, -ret, "Failed to get VFIO IOMMU info"); + goto enable_discards_exit; + } =20 - if (ret || !(info->flags & VFIO_IOMMU_INFO_PGSIZES)) { - /* Assume 4k IOVA page size */ - info->iova_pgsizes =3D 4096; + if (info->flags & VFIO_IOMMU_INFO_PGSIZES) { + container->pgsizes =3D info->iova_pgsizes; + } else { + container->pgsizes =3D qemu_real_host_page_size(); } - vfio_host_win_add(container, 0, (hwaddr)-1, info->iova_pgsizes); - container->pgsizes =3D info->iova_pgsizes; =20 - /* The default in the kernel ("dma_entry_limit") is 65535. */ - container->dma_max_mappings =3D 65535; - if (!ret) { - vfio_get_info_dma_avail(info, &container->dma_max_mappings); - vfio_get_iommu_info_migration(container, info); + if (!vfio_get_info_dma_avail(info, &container->dma_max_mappings)) { + container->dma_max_mappings =3D 65535; } + vfio_get_iommu_info_migration(container, info); g_free(info); + + /* + * FIXME: We should parse VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE + * information to get the actual window extent rather than assume + * a 64-bit IOVA address space. + */ + vfio_host_win_add(container, 0, (hwaddr)-1, container->pgsizes); + break; } case VFIO_SPAPR_TCE_v2_IOMMU: