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Filename Latest commit message Latest commit date
Eric Biggers e9116299ff f2fs: fix race conditions in ->d_compare() and ->d_hash()
commit 80f2388afa6ef985f9c5c228e36705c4d4db4756 upstream.

Since ->d_compare() and ->d_hash() can be called in RCU-walk mode,
->d_parent and ->d_inode can be concurrently modified, and in
particular, ->d_inode may be changed to NULL.  For f2fs_d_hash() this
resulted in a reproducible NULL dereference if a lookup is done in a
directory being deleted, e.g. with:

	int main()
	{
		if (fork()) {
			for (;;) {
				mkdir("subdir", 0700);
				rmdir("subdir");
			}
		} else {
			for (;;)
				access("subdir/file", 0);
		}
	}

... or by running the 't_encrypted_d_revalidate' program from xfstests.
Both repros work in any directory on a filesystem with the encoding
feature, even if the directory doesn't actually have the casefold flag.

I couldn't reproduce a crash in f2fs_d_compare(), but it appears that a
similar crash is possible there.

Fix these bugs by reading ->d_parent and ->d_inode using READ_ONCE() and
falling back to the case sensitive behavior if the inode is NULL.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 2c2eb7a300 ("f2fs: Support case-insensitive file name lookups")
Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11 04:35:25 -08:00
arch powerpc/32s: Fix CPU wake-up from sleep mode 2020-02-11 04:35:18 -08:00
block
certs
crypto crypto: api - Check spawn->alg under lock in crypto_drop_spawn 2020-02-11 04:35:22 -08:00
Documentation
drivers power: supply: ltc2941-battery-gauge: fix use-after-free 2020-02-11 04:35:24 -08:00
fs f2fs: fix race conditions in ->d_compare() and ->d_hash() 2020-02-11 04:35:25 -08:00
include ALSA: hda: Apply aligned MMIO access only conditionally 2020-02-11 04:35:15 -08:00
init
ipc ipc/msg.c: consolidate all xxxctl_down() functions 2020-02-11 04:35:07 -08:00
kernel padata: Remove broken queue flushing 2020-02-11 04:35:22 -08:00
lib lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() 2020-02-11 04:35:14 -08:00
LICENSES
mm mm: move_pages: report the number of non-attempted pages 2020-02-11 04:35:13 -08:00
net netfilter: ipset: fix suspicious RCU usage in find_set_and_id 2020-02-11 04:35:07 -08:00
samples
scripts scripts/find-unused-docs: Fix massive false positives 2020-02-11 04:35:23 -08:00
security
sound ASoC: SOF: core: free trace on errors 2020-02-11 04:35:21 -08:00
tools cpupower: Revert library ABI changes from commit ae2917093f 2020-02-11 04:35:24 -08:00
usr
virt KVM: arm64: Only sign-extend MMIO up to register width 2020-02-11 04:35:16 -08:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: correct entries for ISDN/mISDN section 2020-02-11 04:35:06 -08:00
Makefile
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.