Simplify and fix overlayfs layer parsing so the maximum of 500 layers
can be used.

* patches from https://lore.kernel.org/r/20240705011510.794025-1-chengzhihao1@huawei.com:
  ovl: ovl_parse_param_lowerdir: Add missed '\n' for pr_err
  ovl: fix wrong lowerdir number check for parameter Opt_lowerdir
  ovl: pass string to ovl_parse_layer()

Link: https://lore.kernel.org/r/20240705011510.794025-1-chengzhihao1@huawei.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Add '\n' for pr_err in function ovl_parse_param_lowerdir(), which
ensures that error message is displayed at once.

Fixes: b36a5780cb44 ("ovl: modify layer parameter parsing")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20240705011510.794025-4-chengzhihao1@huawei.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

The max count of lowerdir is OVL_MAX_STACK[500], which is broken by
commit 37f32f526438("ovl: fix memory leak in ovl_parse_param()") for
parameter Opt_lowerdir. Since commit 819829f0319a("ovl: refactor layer
parsing helpers") and commit 24e16e385f22("ovl: add support for
appending lowerdirs one by one") added check ovl_mount_dir_check() in
function ovl_parse_param_lowerdir(), the 'ctx->nr' should be smaller
than OVL_MAX_STACK, after commit 37f32f526438("ovl: fix memory leak in
ovl_parse_param()") is applied, the 'ctx->nr' is updated before the
check ovl_mount_dir_check(), which leads the max count of lowerdir
to become 499 for parameter Opt_lowerdir.
Fix it by replacing lower layers parsing code with the existing helper
function ovl_parse_layer().

Fixes: 37f32f526438 ("ovl: fix memory leak in ovl_parse_param()")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20240705011510.794025-3-chengzhihao1@huawei.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

So it can be used for parsing the Opt_lowerdir.

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20240705011510.794025-2-chengzhihao1@huawei.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

ovl_check_encode_origin() should return a positive number if the lower
dentry is to be encoded, zero otherwise.  If there's no upper layer at all
(read-only overlay), then it obviously needs to return positive.

This was broken by commit 16aac5ad1fa9 ("ovl: support encoding
non-decodable file handles"), which didn't take the lower-only
configuration into account.

Fix by checking the no-upper-layer case up-front.

Reported-and-tested-by: Youzhong Yang <youzhong@gmail.com>
Closes: https://lore.kernel.org/all/CADpNCvaBimi+zCYfRJHvCOhMih8OU0rmZkwLuh24MKKroRuT8Q@mail.gmail.com/
Fixes: 16aac5ad1fa9 ("ovl: support encoding non-decodable file handles")
Cc: <stable@vger.kernel.org> # v6.6
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Move ovl_copy_up() call outside of ovl_want_write()/ovl_drop_write()
region, since copy up may also call ovl_want_write() resulting in recursive
locking on sb->s_writers.

Reported-and-tested-by: syzbot+85e58cdf5b3136471d4b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000f6865106191c3e58@google.com/
Fixes: 9a87907de359 ("ovl: implement tmpfile")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

Pull overlayfs updates from Miklos Szeredi:

 - Add tmpfile support

 - Clean up include

* tag 'ovl-update-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
  ovl: remove duplicate included header
  ovl: remove upper umask handling from ovl_create_upper()
  ovl: implement tmpfile

Pull misc vfs updates from Al Viro:
 "Assorted commits that had missed the last merge window..."

* tag 'pull-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  remove call_{read,write}_iter() functions
  do_dentry_open(): kill inode argument
  kernel_file_open(): get rid of inode argument
  get_file_rcu(): no need to check for NULL separately
  fd_is_open(): move to fs/file.c
  close_on_exec(): pass files_struct instead of fdtable

Pull integrity updates from Mimi Zohar:
 "Two IMA changes, one EVM change, a use after free bug fix, and a code
  cleanup to address "-Wflex-array-member-not-at-end" warnings:

   - The existing IMA {ascii, binary}_runtime_measurements lists include
     a hard coded SHA1 hash. To address this limitation, define per TPM
     enabled hash algorithm {ascii, binary}_runtime_measurements lists

   - Close an IMA integrity init_module syscall measurement gap by
     defining a new critical-data record

   - Enable (partial) EVM support on stacked filesystems (overlayfs).
     Only EVM portable & immutable file signatures are copied up, since
     they do not contain filesystem specific metadata"

* tag 'integrity-v6.10' of ssh://ra.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
  ima: add crypto agility support for template-hash algorithm
  evm: Rename is_unsupported_fs to is_unsupported_hmac_fs
  fs: Rename SB_I_EVM_UNSUPPORTED to SB_I_EVM_HMAC_UNSUPPORTED
  evm: Enforce signatures on unsupported filesystem for EVM_INIT_X509
  ima: re-evaluate file integrity on file metadata change
  evm: Store and detect metadata inode attributes changes
  ima: Move file-change detection variables into new structure
  evm: Use the metadata inode to calculate metadata hash
  evm: Implement per signature type decision in security_inode_copy_up_xattr
  security: allow finer granularity in permitting copy-up of security xattrs
  ima: Rename backing_inode to real_inode
  integrity: Avoid -Wflex-array-member-not-at-end warnings
  ima: define an init_module critical data record
  ima: Fix use-after-free on a dentry's dname.name

Remove duplicate included header file linux/posix_acl.h

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>