Jann Horn 8314335277 fuse: Initialize beyond-EOF page contents before setting uptodate ...

commit 3c0da3d163 upstream.

fuse_notify_store(), unlike fuse_do_readpage(), does not enable page
zeroing (because it can be used to change partial page contents).

So fuse_notify_store() must be more careful to fully initialize page
contents (including parts of the page that are beyond end-of-file)
before marking the page uptodate.

The current code can leave beyond-EOF page contents uninitialized, which
makes these uninitialized page contents visible to userspace via mmap().

This is an information leak, but only affects systems which do not
enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the
corresponding kernel command line parameter).

Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2574
Cc: stable@kernel.org
Fixes: a1d75f2582 ("fuse: add store request")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2024-08-29 17:30:12 +02:00

..

acl.c

…

control.c

…

cuse.c

…

dax.c

fuse: dax: set fc->dax to NULL in fuse_dax_conn_free()

2023-12-20 17:00:20 +01:00

dev.c

fuse: Initialize beyond-EOF page contents before setting uptodate

2024-08-29 17:30:12 +02:00

dir.c

fuse: fix root lookup with nonzero generation

2024-04-03 15:19:30 +02:00

file.c

…

fuse_i.h

fuse: don't unhash root

2024-04-03 15:19:30 +02:00

inode.c

fuse: verify {g,u}id mount options correctly

2024-08-03 08:49:31 +02:00

ioctl.c

…

Kconfig

…

Makefile

…

readdir.c

fuse: nlookup missing decrement in fuse_direntplus_link

2023-09-19 12:28:05 +02:00

virtio_fs.c

…

xattr.c

…