commit 919dc320956ea353a7fb2d84265195ad5ef525ac upstream.
If an fsverity builtin signature is given for a file but the
".fs-verity" keyring is empty, there's no real reason to run the PKCS#7
parser. Skip this to avoid the PKCS#7 attack surface when builtin
signature support is configured into the kernel but is not being used.
This is a hardening improvement, not a fix per se, but I've added
Fixes and Cc stable to get it out to more users.
Fixes: 432434c9f8 ("fs-verity: support builtin file signatures")
Cc: stable@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/r/20230820173237.2579-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix all kerneldoc warnings in fs/verity/ and include/linux/fsverity.h.
Most of these were due to missing documentation for function parameters.
Detected with:
scripts/kernel-doc -v -none fs/verity/*.{c,h} include/linux/fsverity.h
This cleanup makes it possible to check new patches for kerneldoc
warnings without having to filter out all the existing ones.
Link: https://lore.kernel.org/r/20200511192118.71427-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
To meet some users' needs, add optional support for having fs-verity
handle a portion of the authentication policy in the kernel. An
".fs-verity" keyring is created to which X.509 certificates can be
added; then a sysctl 'fs.verity.require_signatures' can be set to cause
the kernel to enforce that all fs-verity files contain a signature of
their file measurement by a key in this keyring.
See the "Built-in signature verification" section of
Documentation/filesystems/fsverity.rst for the full documentation.
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
