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authorEric Wong <normalperson@yhbt.net>2013-02-04 13:04:44 +0000
committerMiklos Szeredi <mszeredi@suse.cz>2013-02-04 15:22:23 +0100
commit6a4e922c3db06f7da27e072729e047185c2fba66 (patch)
tree26d92e82ab982b25b3f115e52a9bf9956003889b /fs/fuse/dev.c
parent23c153e54197171f30b889d9654929d74b6599d5 (diff)
downloadlinux-6a4e922c3db06f7da27e072729e047185c2fba66.tar.gz
fuse: avoid out-of-scope stack access
The all pointers within fuse_req must point to valid memory once
fuse_force_forget() returns.

This bug appeared in "fuse: implement NFS-like readdirplus support"
and was never in any official Linux release.

I tested the fuse_force_forget() code path by injecting to fake -ENOMEM and
verified the FORGET operation was called properly in userspace.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse/dev.c')
-rw-r--r--fs/fuse/dev.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index cbae09e5a491..e9bdec0b16d9 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -440,9 +440,8 @@ __acquires(fc->lock)
 	}
 }
 
-void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
+static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 {
-	req->isreply = 1;
 	spin_lock(&fc->lock);
 	if (!fc->connected)
 		req->out.h.error = -ENOTCONN;
@@ -459,6 +458,12 @@ void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 	}
 	spin_unlock(&fc->lock);
 }
+
+void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
+{
+	req->isreply = 1;
+	__fuse_request_send(fc, req);
+}
 EXPORT_SYMBOL_GPL(fuse_request_send);
 
 static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
@@ -541,7 +546,9 @@ void fuse_force_forget(struct file *file, u64 nodeid)
 	req->in.args[0].size = sizeof(inarg);
 	req->in.args[0].value = &inarg;
 	req->isreply = 0;
-	fuse_request_send_nowait(fc, req);
+	__fuse_request_send(fc, req);
+	/* ignore errors */
+	fuse_put_request(fc, req);
 }
 
 /*