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Filename Latest commit message Latest commit date
David Howells e2a231454e vfs: Check the truncate maximum size in inode_newsize_ok()
commit e2ebff9c57fe4eb104ce4768f6ebcccf76bef849 upstream.

If something manages to set the maximum file size to MAX_OFFSET+1, this
can cause the xfs and ext4 filesystems at least to become corrupt.

Ordinarily, the kernel protects against userspace trying this by
checking the value early in the truncate() and ftruncate() system calls
calls - but there are at least two places that this check is bypassed:

 (1) Cachefiles will round up the EOF of the backing file to DIO block
     size so as to allow DIO on the final block - but this might push
     the offset negative. It then calls notify_change(), but this
     inadvertently bypasses the checking. This can be triggered if
     someone puts an 8EiB-1 file on a server for someone else to try and
     access by, say, nfs.

 (2) ksmbd doesn't check the value it is given in set_end_of_file_info()
     and then calls vfs_truncate() directly - which also bypasses the
     check.

In both cases, it is potentially possible for a network filesystem to
cause a disk filesystem to be corrupted: cachefiles in the client's
cache filesystem; ksmbd in the server's filesystem.

nfsd is okay as it checks the value, but we can then remove this check
too.

Fix this by adding a check to inode_newsize_ok(), as called from
setattr_prepare(), thereby catching the issue as filesystems set up to
perform the truncate with minimal opportunity for bypassing the new
check.

Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Fixes: f44158485826 ("cifsd: add file operations")
Signed-off-by: David Howells <dhowells@redhat.com>
Reported-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@kernel.org
Acked-by: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Steve French <sfrench@samba.org>
cc: Hyunchul Lee <hyc.lee@gmail.com>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25 11:17:21 +02:00
arch KVM: x86: Set error code to segment selector on LLDT/LTR non-canonical #GP 2022-08-25 11:17:20 +02:00
block block: fix bio_clone_blkg_association() to associate with proper blkcg_gq 2022-06-14 18:11:50 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: drbg - make reseeding from get_random_bytes() synchronous 2022-06-22 14:11:18 +02:00
Documentation x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
drivers tty: vt: initialize unicode screen buffer 2022-08-25 11:17:21 +02:00
fs vfs: Check the truncate maximum size in inode_newsize_ok() 2022-08-25 11:17:21 +02:00
include add barriers to buffer_uptodate and set_buffer_uptodate 2022-08-25 11:17:18 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-14 18:11:41 +02:00
kernel bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds() 2022-08-11 12:57:51 +02:00
lib locking/refcount: Consolidate implementations of refcount_t 2022-07-29 17:14:17 +02:00
LICENSES
mm mm/mremap: hold the rmap lock in write mode when moving page table entries. 2022-08-25 11:17:20 +02:00
net sctp: leave the err path free in sctp_stream_init to sctp_stream_free 2022-08-03 11:59:41 +02:00
samples
scripts modpost: fix section mismatch check for exported init/exit sections 2022-06-29 08:58:49 +02:00
security ima: remove the IMA_TEMPLATE Kconfig option 2022-07-29 17:14:16 +02:00
sound ALSA: hda/realtek: Add quirk for another Asus K42JZ model 2022-08-25 11:17:21 +02:00
tools x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
usr
virt KVM: Don't null dereference ops->destroy 2022-08-11 12:57:52 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: co-maintain random.c 2022-06-22 14:11:05 +02:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-25 11:17:17 +02:00
README

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.