[GIT PULL] fsverity updates for 5.12

[Eric Biggers]

The following changes since commit 6ee1d745b7c9fd573fba142a2efdad76a9f1cb04:

  Linux 5.11-rc5 (2021-01-24 16:47:14 -0800)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/fs/fscrypt/fscrypt.git tags/fsverity-for-linus

for you to fetch changes up to 07c99001312cbf90a357d4877a358f796eede65b:

  fs-verity: support reading signature with ioctl (2021-02-07 14:51:19 -0800)

----------------------------------------------------------------

Add an ioctl which allows reading fs-verity metadata from a file.

This is useful when a file with fs-verity enabled needs to be served
somewhere, and the other end wants to do its own fs-verity compatible
verification of the file.  See the commit messages for details.

This new ioctl has been tested using new xfstests I've written for it.

----------------------------------------------------------------
Eric Biggers (6):
      fs-verity: factor out fsverity_get_descriptor()
      fs-verity: don't pass whole descriptor to fsverity_verify_signature()
      fs-verity: add FS_IOC_READ_VERITY_METADATA ioctl
      fs-verity: support reading Merkle tree with ioctl
      fs-verity: support reading descriptor with ioctl
      fs-verity: support reading signature with ioctl

 Documentation/filesystems/fsverity.rst |  76 +++++++++++++
 fs/ext4/ioctl.c                        |   7 ++
 fs/f2fs/file.c                         |  11 ++
 fs/verity/Makefile                     |   1 +
 fs/verity/fsverity_private.h           |  13 ++-
 fs/verity/open.c                       | 133 ++++++++++++++--------
 fs/verity/read_metadata.c              | 195 +++++++++++++++++++++++++++++++++
 fs/verity/signature.c                  |  20 +---
 include/linux/fsverity.h               |  12 ++
 include/uapi/linux/fsverity.h          |  14 +++
 10 files changed, 417 insertions(+), 65 deletions(-)
 create mode 100644 fs/verity/read_metadata.c