[PATCH] [2/139] fuse: verify ioctl retries

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Miklos Szeredi <mszeredi@xxxxxxx>

commit 7572777eef78ebdee1ecb7c258c0ef94d35bad16 upstream.

Verify that the total length of the iovec returned in FUSE_IOCTL_RETRY
doesn't overflow iov_length().

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
CC: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/fuse/file.c |   22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Index: linux-2.6.35.y/fs/fuse/file.c
===================================================================
--- linux-2.6.35.y.orig/fs/fuse/file.c
+++ linux-2.6.35.y/fs/fuse/file.c
@@ -1627,6 +1627,20 @@ static int fuse_ioctl_copy_user(struct p
 	return 0;
 }
 
+/* Make sure iov_length() won't overflow */
+static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
+{
+	size_t n;
+	u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
+
+	for (n = 0; n < count; n++) {
+		if (iov->iov_len > (size_t) max)
+			return -ENOMEM;
+		max -= iov->iov_len;
+	}
+	return 0;
+}
+
 /*
  * For ioctls, there is no generic way to determine how much memory
  * needs to be read and/or written.  Furthermore, ioctls are allowed
@@ -1820,6 +1834,14 @@ long fuse_do_ioctl(struct file *file, un
 		in_iov = page_address(iov_page);
 		out_iov = in_iov + in_iovs;
 
+		err = fuse_verify_ioctl_iov(in_iov, in_iovs);
+		if (err)
+			goto out;
+
+		err = fuse_verify_ioctl_iov(out_iov, out_iovs);
+		if (err)
+			goto out;
+
 		goto retry;
 	}
 
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