Commit 9bba1b1b authored Jun 07, 2017 by Mateusz Jurczyk Committed by Greg Kroah-Hartman Aug 16, 2017

fuse: initialize the flock flag in fuse_file on allocation



commit 68227c03cba84a24faf8a7277d2b1a03c8959c2c upstream.

Before the patch, the flock flag could remain uninitialized for the
lifespan of the fuse_file allocation. Unless set to true in
fuse_file_flock(), it would remain in an indeterminate state until read in
an if statement in fuse_release_common(). This could consequently lead to
taking an unexpected branch in the code.

The bug was discovered by a runtime instrumentation designed to detect use
of uninitialized memory in the kernel.

Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
Fixes: 37fb3a30 ("fuse: fix flock")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 805348a0

fs/fuse/file.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -54,7 +54,7 @@ struct fuse_file fuse_file_alloc(struct fuse_conn fc)
	{		{
	struct fuse_file *ff;		struct fuse_file *ff;

	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);		ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
	if (unlikely(!ff))		if (unlikely(!ff))
	return NULL;		return NULL;