From: Mateusz Jurczyk <mjurczyk@google.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] fuse: Initialize the flock flag in the fuse_file structure upon allocation
Date: Wed, 7 Jun 2017 12:26:49 +0200 [thread overview]
Message-ID: <20170607102649.14713-1-mjurczyk@google.com> (raw)
Add initialization of the flock flag in the fuse_file structure after it
is allocated.
Before the patch, the flock flag could remain uninitialized for the
lifespan of the fuse_file allocation: it was not pre-set by kmalloc() or
later in the fuse_file_alloc() function. 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>
---
fs/fuse/file.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3ee4fdc3da9e..c9a86a748ceb 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -66,6 +66,8 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
ff->kh = ++fc->khctr;
spin_unlock(&fc->lock);
+ ff->flock = false;
+
return ff;
}
--
2.13.1.508.gb3defc5cc-goog
next reply other threads:[~2017-06-07 10:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-07 10:26 Mateusz Jurczyk [this message]
2017-06-09 9:20 ` [PATCH] fuse: Initialize the flock flag in the fuse_file structure upon allocation Miklos Szeredi
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