fuse: initialize the flock flag in fuse_file on allocation
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: 37fb3a30b462 ("fuse: fix flock")
Cc: <stable@vger.kernel.org> # v3.1+
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3ee4fdc..76eac2a 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -46,7 +46,7 @@
{
struct fuse_file *ff;
- ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
+ ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
if (unlikely(!ff))
return NULL;