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Sean Christopherson cf25855e9f vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn() commit `5cbf3264bc` upstream. Use follow_pfn() to get the PFN of a PFNMAP VMA instead of assuming that vma->vm_pgoff holds the base PFN of the VMA. This fixes a bug where attempting to do VFIO_IOMMU_MAP_DMA on an arbitrary PFNMAP'd region of memory calculates garbage for the PFN. Hilariously, this only got detected because the first "PFN" calculated by vaddr_get_pfn() is PFN 0 (vma->vm_pgoff==0), and iommu_iova_to_phys() uses PA==0 as an error, which triggers a WARN in vfio_unmap_unpin() because the translation "failed". PFN 0 is now unconditionally reserved on x86 in order to mitigate L1TF, which causes is_invalid_reserved_pfn() to return true and in turns results in vaddr_get_pfn() returning success for PFN 0. Eventually the bogus calculation runs into PFNs that aren't reserved and leads to failure in vfio_pin_map_dma(). The subsequent call to vfio_remove_dma() attempts to unmap PFN 0 and WARNs. WARNING: CPU: 8 PID: 5130 at drivers/vfio/vfio_iommu_type1.c:750 vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1] Modules linked in: vfio_pci vfio_virqfd vfio_iommu_type1 vfio ... CPU: 8 PID: 5130 Comm: sgx Tainted: G W 5.6.0-rc5-705d787c7fee-vfio+ #3 Hardware name: Intel Corporation Mehlow UP Server Platform/Moss Beach Server, BIOS CNLSE2R1.D00.X119.B49.1803010910 03/01/2018 RIP: 0010:vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1] Code: <0f> 0b 49 81 c5 00 10 00 00 e9 c5 fe ff ff bb 00 10 00 00 e9 3d fe RSP: 0018:ffffbeb5039ebda8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff9a55cbf8d480 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9a52b771c200 RBP: 0000000000000000 R08: 0000000000000040 R09: 00000000fffffff2 R10: 0000000000000001 R11: ffff9a51fa896000 R12: 0000000184010000 R13: 0000000184000000 R14: 0000000000010000 R15: ffff9a55cb66ea08 FS: 00007f15d3830b40(0000) GS:ffff9a55d5600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561cf39429e0 CR3: 000000084f75f005 CR4: 00000000003626e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vfio_remove_dma+0x17/0x70 [vfio_iommu_type1] vfio_iommu_type1_ioctl+0x9e3/0xa7b [vfio_iommu_type1] ksys_ioctl+0x92/0xb0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x4c/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f15d04c75d7 Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48 Fixes: `73fa0d10d0` ("vfio: Type1 IOMMU implementation") Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-05-06 08:13:31 +02:00
arch	bpf, x86_32: Fix clobbering of dst for BPF_JSET	2020-05-02 17:26:00 +02:00
block	block, bfq: fix use-after-free in bfq_idle_slice_timer_body	2020-04-17 10:48:42 +02:00
certs	export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()	2018-08-22 23:21:44 +09:00
crypto	crypto: api - Fix race condition in crypto_spawn_alg	2020-02-11 04:34:05 -08:00
Documentation	arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419	2020-04-29 16:31:08 +02:00
drivers	vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn()	2020-05-06 08:13:31 +02:00
firmware	Fix built-in early-load Intel microcode alignment	2020-01-23 08:21:29 +01:00
fs	btrfs: fix block group leak when removing fails	2020-05-06 08:13:27 +02:00
include	qed: Fix use after free in qed_chain_free	2020-05-02 17:26:00 +02:00
init	fork: fix some -Wmissing-prototypes warnings	2019-12-05 09:21:04 +01:00
ipc	ipc/util.c: sysvipc_find_ipc() should increase position index	2020-04-29 16:31:13 +02:00
kernel	PM: hibernate: Freeze kernel threads in software_resume()	2020-05-06 08:13:28 +02:00
lib	lib/raid6: use vdupq_n_u8 to avoid endianness warnings	2020-04-23 10:30:15 +02:00
LICENSES	LICENSES: Remove CC-BY-SA-4.0 license text	2018-10-18 11:28:50 +02:00
mm	mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy path	2020-05-02 17:25:54 +02:00
net	svcrdma: Fix leak of svc_rdma_recv_ctxt objects	2020-05-02 17:25:52 +02:00
samples	vmalloc: fix remap_vmalloc_range() bounds checks	2020-04-29 16:31:27 +02:00
scripts	kconfig: qconf: Fix a few alignment issues	2020-04-29 16:31:13 +02:00
security	KEYS: Avoid false positive ENOMEM error on key read	2020-04-29 16:31:23 +02:00
sound	ALSA: pcm: oss: Place the plugin buffer overflow checks correctly	2020-05-06 08:13:28 +02:00
tools	objtool: Support Clang non-section symbols in ORC dump	2020-05-02 17:25:57 +02:00
usr	initramfs: restore default compression behavior	2020-04-13 10:44:59 +02:00
virt	x86/kvm: Cache gfn to pfn translation	2020-04-29 16:31:19 +02:00
.clang-format	clang-format: Set IndentWrappedFunctionNames false	2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	Kbuild updates for v4.17 (2nd)	2018-04-15 17:21:30 -07:00
.mailmap	libnvdimm-for-4.19_misc	2018-08-25 18:13:10 -07:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	9p: remove Ron Minnich from MAINTAINERS	2018-08-17 16:20:26 -07:00
Kbuild	Kbuild updates for v4.15	2017-11-17 17:45:29 -08:00
Kconfig	kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt	2018-08-02 08:06:55 +09:00
MAINTAINERS	MAINTAINERS: Update drm/i915 bug filing URL	2020-02-28 16:38:49 +01:00
Makefile	Linux 4.19.120	2020-05-02 17:26:01 +02:00
README	Docs: Added a pointer to the formatted docs to README	2018-03-21 09:02:53 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.