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commit 6f1a1d103b48b1533a9c804e7a069e2c8e937ce7 upstream. boot_aggregate is the first entry of IMA measurement list. Its purpose is to link pre-boot measurements to IMA measurements. As IMA was designed to work with a TPM 1.2, the SHA1 PCR bank was always selected even if a TPM 2.0 with support for stronger hash algorithms is available. This patch first tries to find a PCR bank with the IMA default hash algorithm. If it does not find it, it selects the SHA256 PCR bank for TPM 2.0 and SHA1 for TPM 1.2. Ultimately, it selects SHA1 also for TPM 2.0 if the SHA256 PCR bank is not found. If none of the PCR banks above can be found, boot_aggregate file digest is filled with zeros, as for TPM bypass, making it impossible to perform a remote attestation of the system. Cc: stable@vger.kernel.org # 5.1.x Fixes: 879b589210a9 ("tpm: retrieve digest size of unknown algorithms with PCR read") Reported-by: Jerry Snitselaar <jsnitsel@redhat.com> Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.
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.