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Avihai Horon 1ef195178f vfio/pci: Properly hide first-in-list PCIe extended capability
[ Upstream commit fe4bf8d0b6 ]

There are cases where a PCIe extended capability should be hidden from
the user. For example, an unknown capability (i.e., capability with ID
greater than PCI_EXT_CAP_ID_MAX) or a capability that is intentionally
chosen to be hidden from the user.

Hiding a capability is done by virtualizing and modifying the 'Next
Capability Offset' field of the previous capability so it points to the
capability after the one that should be hidden.

The special case where the first capability in the list should be hidden
is handled differently because there is no previous capability that can
be modified. In this case, the capability ID and version are zeroed
while leaving the next pointer intact. This hides the capability and
leaves an anchor for the rest of the capability list.

However, today, hiding the first capability in the list is not done
properly if the capability is unknown, as struct
vfio_pci_core_device->pci_config_map is set to the capability ID during
initialization but the capability ID is not properly checked later when
used in vfio_config_do_rw(). This leads to the following warning [1] and
to an out-of-bounds access to ecap_perms array.

Fix it by checking cap_id in vfio_config_do_rw(), and if it is greater
than PCI_EXT_CAP_ID_MAX, use an alternative struct perm_bits for direct
read only access instead of the ecap_perms array.

Note that this is safe since the above is the only case where cap_id can
exceed PCI_EXT_CAP_ID_MAX (except for the special capabilities, which
are already checked before).

[1]

WARNING: CPU: 118 PID: 5329 at drivers/vfio/pci/vfio_pci_config.c:1900 vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
CPU: 118 UID: 0 PID: 5329 Comm: simx-qemu-syste Not tainted 6.12.0+ #1
(snip)
Call Trace:
 <TASK>
 ? show_regs+0x69/0x80
 ? __warn+0x8d/0x140
 ? vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
 ? report_bug+0x18f/0x1a0
 ? handle_bug+0x63/0xa0
 ? exc_invalid_op+0x19/0x70
 ? asm_exc_invalid_op+0x1b/0x20
 ? vfio_pci_config_rw+0x395/0x430 [vfio_pci_core]
 ? vfio_pci_config_rw+0x244/0x430 [vfio_pci_core]
 vfio_pci_rw+0x101/0x1b0 [vfio_pci_core]
 vfio_pci_core_read+0x1d/0x30 [vfio_pci_core]
 vfio_device_fops_read+0x27/0x40 [vfio]
 vfs_read+0xbd/0x340
 ? vfio_device_fops_unl_ioctl+0xbb/0x740 [vfio]
 ? __rseq_handle_notify_resume+0xa4/0x4b0
 __x64_sys_pread64+0x96/0xc0
 x64_sys_call+0x1c3d/0x20d0
 do_syscall_64+0x4d/0x120
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fixes: 89e1f7d4c6 ("vfio: Add PCI device driver")
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20241124142739.21698-1-avihaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-12-05 14:02:29 +01:00
arch m68k: coldfire/device.c: only build FEC when HW macros are defined 2024-12-05 14:02:24 +01:00
block block: fix bio_split_rw_at to take zone_write_granularity into account 2024-12-05 14:01:14 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-05 14:01:18 +01:00
Documentation f2fs: fix to avoid use GC_AT when setting gc_mode as GC_URGENT_LOW or GC_URGENT_MID 2024-12-05 14:02:22 +01:00
drivers vfio/pci: Properly hide first-in-list PCIe extended capability 2024-12-05 14:02:29 +01:00
fs f2fs: fix to do cast in F2FS_{BLK_TO_BYTES, BTYES_TO_BLK} to avoid overflow 2024-12-05 14:02:27 +01:00
include f2fs: fix to do cast in F2FS_{BLK_TO_BYTES, BTYES_TO_BLK} to avoid overflow 2024-12-05 14:02:27 +01:00
init initramfs: avoid filename buffer overrun 2024-12-05 14:01:12 +01:00
io_uring io_uring/rw: fix missing NOWAIT check for O_DIRECT start write 2024-10-31 08:21:02 -06:00
ipc struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
kernel trace/trace_event_perf: remove duplicate samples on the first tracepoint event 2024-12-05 14:02:02 +01:00
lib kasan: move checks to do_strncpy_from_user 2024-12-05 14:02:12 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/mmap: fix __mmap_region() error handling in rare merge failure case 2024-11-22 15:30:26 +01:00
net svcrdma: fix miss destroy percpu_counter in svc_rdma_proc_init() 2024-12-05 14:02:26 +01:00
rust rust: block: fix formatting of kernel::block::mq::request module 2024-12-05 14:02:21 +01:00
samples bpf: Fix the xdp_adjust_tail sample prog issue 2024-12-05 14:01:42 +01:00
scripts checkpatch: always parse orig_commit in fixes tag 2024-12-05 14:02:09 +01:00
security integrity-v6.12 2024-11-12 13:06:31 -08:00
sound ALSA: 6fire: Release resources at card release 2024-12-05 14:01:58 +01:00
tools selftests/mount_setattr: Fix failures on 64K PAGE_SIZE kernels 2024-12-05 14:02:28 +01:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt ARM64: 2024-10-21 11:22:04 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: appoint myself the XFS maintainer for 6.12 LTS 2024-12-05 14:01:10 +01:00
Makefile Linux 6.12.1 2024-11-22 15:30:26 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText markup notation.

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.