fdget(), trivial conversions

fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.

Reviewed-by: Christian Brauner <[email protected]>
Signed

fdget(), trivial conversions

fdget() is the first thing done in scope, all matching fdput() are
immediately followed by leaving the scope.

Reviewed-by: Christian Brauner <[email protected]>
Signed-off-by: Al Viro <[email protected]>

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introduce fd_file(), convert all accessors to it.

For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are ve

introduce fd_file(), convert all accessors to it.

For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are very few (3 in linux/file.h,
1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in
explicit initializers).
Those can be dealt with in the commit converting to
new layout; accesses to struct fd::file are too many for that.
This commit converts (almost) all of f.file to
fd_file(f). It's not entirely mechanical ('file' is used as
a member name more than just in struct fd) and it does not
even attempt to distinguish the uses in pointer context from
those in boolean context; the latter will be eventually turned
into a separate helper (fd_empty()).

NOTE: mass conversion to fd_empty(), tempting as it
might be, is a bad idea; better do that piecewise in commit
that convert from fdget...() to CLASS(...).

[conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c
caught by git; fs/stat.c one got caught by git grep]
[fs/xattr.c conflict]

Reviewed-by: Christian Brauner <[email protected]>
Signed-off-by: Al Viro <[email protected]>

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fs: Fix kernel-doc warnings

These have a variety of causes and a corresponding variety of solutions.

Signed-off-by: "Matthew Wilcox (Oracle)" <[email protected]>
Message-Id: <20230818200824.27200

fs: Fix kernel-doc warnings

These have a variety of causes and a corresponding variety of solutions.

Signed-off-by: "Matthew Wilcox (Oracle)" <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

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fs/kernel_read_file: allow to read files up-to ssize_t

Patch series "Allow to kexec with initramfs larger than 2G", v2.

Currently, the largest initramfs that is supported by kexec_file_load()
sysca

fs/kernel_read_file: allow to read files up-to ssize_t

Patch series "Allow to kexec with initramfs larger than 2G", v2.

Currently, the largest initramfs that is supported by kexec_file_load()
syscall is 2G.

This is because kernel_read_file() returns int, and is limited to INT_MAX
or 2G.

On the other hand, there are kexec based boot loaders (i.e. u-root), that
may need to boot netboot images that might be larger than 2G.

The first patch changes the return type from int to ssize_t in
kernel_read_file* functions.

The second patch increases the maximum initramfs file size to 4G.

Tested: verified that can kexec_file_load() works with 4G initramfs
on x86_64.


This patch (of 2):

Currently, the maximum file size that is supported is 2G. This may be too
small in some cases. For example, kexec_file_load() system call loads
initramfs. In some netboot cases initramfs can be rather large.

Allow to use up-to ssize_t bytes. The callers still can limit the maximum
file size via buf_size.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Pasha Tatashin <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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vfs: check fd has read access in kernel_read_file_from_fd()

If we open a file without read access and then pass the fd to a syscall
whose implementation calls kernel_read_file_from_fd(), we get a wa

vfs: check fd has read access in kernel_read_file_from_fd()

If we open a file without read access and then pass the fd to a syscall
whose implementation calls kernel_read_file_from_fd(), we get a warning
from __kernel_read():

if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))

This currently affects both finit_module() and kexec_file_load(), but it
could affect other syscalls in the future.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: b844f0ecbc56 ("vfs: define kernel_copy_file_from_fd()")
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reported-by: Hao Sun <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Mimi Zohar <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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switch file_open_root() to struct path

... and provide file_open_root_mnt(), using the root of given mount.

Signed-off-by: Al Viro <[email protected]>

fs/kernel_file_read: Add "offset" arg for partial reads

To perform partial reads, callers of kernel_read_file*() must have a
non-NULL file_size argument and a preallocated buffer. The new "offset"
a

fs/kernel_file_read: Add "offset" arg for partial reads

To perform partial reads, callers of kernel_read_file*() must have a
non-NULL file_size argument and a preallocated buffer. The new "offset"
argument can then be used to seek to specific locations in the file to
fill the buffer to, at most, "buf_size" per call.

Where possible, the LSM hooks can report whether a full file has been
read or not so that the contents can be reasoned about.

Signed-off-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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LSM: Add "contents" flag to kernel_read_file hook

As with the kernel_load_data LSM hook, add a "contents" flag to the
kernel_read_file LSM hook that indicates whether the LSM can expect
a matching c

LSM: Add "contents" flag to kernel_read_file hook

As with the kernel_load_data LSM hook, add a "contents" flag to the
kernel_read_file LSM hook that indicates whether the LSM can expect
a matching call to the kernel_post_read_file LSM hook with the full
contents of the file. With the coming addition of partial file read
support for kernel_read_file*() API, the LSM will no longer be able
to always see the entire contents of a file during the read calls.

For cases where the LSM must read examine the complete file contents,
it will need to do so on its own every time the kernel_read_file
hook is called with contents=false (or reject such cases). Adjust all
existing LSMs to retain existing behavior.

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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fs/kernel_read_file: Add file_size output argument

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can re

fs/kernel_read_file: Add file_size output argument

In preparation for adding partial read support, add an optional output
argument to kernel_read_file*() that reports the file size so callers
can reason more easily about their reading progress.

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: James Morris <[email protected]>
Acked-by: Scott Branden <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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fs/kernel_read_file: Switch buffer size arg to size_t

In preparation for further refactoring of kernel_read_file*(), rename
the "max_size" argument to the more accurate "buf_size", and correct
its t

fs/kernel_read_file: Switch buffer size arg to size_t

In preparation for further refactoring of kernel_read_file*(), rename
the "max_size" argument to the more accurate "buf_size", and correct
its type to size_t. Add kerndoc to explain the specifics of how the
arguments will be used. Note that with buf_size now size_t, it can no
longer be negative (and was never called with a negative value). Adjust
callers to use it as a "maximum size" when *buf is NULL.

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: James Morris <[email protected]>
Acked-by: Scott Branden <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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fs/kernel_read_file: Remove redundant size argument

In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
cod

fs/kernel_read_file: Remove redundant size argument

In preparation for refactoring kernel_read_file*(), remove the redundant
"size" argument which is not needed: it can be included in the return
code, with callers adjusted. (VFS reads already cannot be larger than
INT_MAX.)

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: James Morris <[email protected]>
Acked-by: Scott Branden <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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fs/kernel_read_file: Split into separate source file

These routines are used in places outside of exec(2), so in preparation
for refactoring them, move them into a separate source file,
fs/kernel_re

fs/kernel_read_file: Split into separate source file

These routines are used in places outside of exec(2), so in preparation
for refactoring them, move them into a separate source file,
fs/kernel_read_file.c.

Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Acked-by: Scott Branden <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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