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Sean Christopherson 5b66e335ea KVM: SEV: Reject non-positive effective lengths during LAUNCH_UPDATE
Check for an invalid length during LAUNCH_UPDATE at the start of
snp_launch_update() instead of subtly relying on kvm_gmem_populate() to
detect the bad state.  Code that directly handles userspace input
absolutely should sanitize those inputs; failure to do so is asking for
bugs where KVM consumes an invalid "npages".

Keep the check in gmem, but wrap it in a WARN to flag any bad usage by
the caller.

Note, this is technically an ABI change as KVM would previously allow a
length of '0'.  But allowing a length of '0' is nonsensical and creates
pointless conundrums in KVM.  E.g. an empty range is arguably neither
private nor shared, but LAUNCH_UPDATE will fail if the starting gpa can't
be made private.  In practice, no known or well-behaved VMM passes a
length of '0'.

Note #2, the PAGE_ALIGNED(params.len) check ensures that lengths between
1 and 4095 (inclusive) are also rejected, i.e. that KVM won't end up with
npages=0 when doing "npages = params.len / PAGE_SIZE".

Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20250919211649.1575654-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-09-23 08:55:20 -07:00
arch KVM: SEV: Reject non-positive effective lengths during LAUNCH_UPDATE 2025-09-23 08:55:20 -07:00
block block: restore default wbt enablement 2025-08-13 05:33:48 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
drivers - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
fs xfs: Fixes for 6.17-rc2 2025-08-15 12:50:12 -07:00
include - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring io_uring/io-wq: add check free worker before create new worker 2025-08-13 06:31:10 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
lib Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/mremap: avoid expensive folio lookup on mremap folio pte batch 2025-08-11 23:00:59 -07:00
net Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
rust rust: kbuild: clean output before running rustdoc 2025-08-12 21:10:50 +02:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/tas2781: Normalize the volume kcontrol name 2025-08-14 11:17:12 +02:00
tools Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt KVM: SEV: Reject non-positive effective lengths during LAUNCH_UPDATE 2025-09-23 08:55:20 -07:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.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 Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
Makefile Linux 6.17-rc2 2025-08-17 15:22:10 -07:00
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.