Commit ad3d2eed authored Jan 17, 2011 by Jesper Juhl Committed by Trond Myklebust Jan 25, 2011

NFS4: Avoid potential NULL pointer dereference in decode_and_add_ds().



On Mon, 17 Jan 2011, Mi Jinlong wrote:

>
>
> Jesper Juhl:
> > strrchr() can return NULL if nothing is found. If this happens we'll
> > dereference a NULL pointer in
> > fs/nfs/nfs4filelayoutdev.c::decode_and_add_ds().
> >
> > I tried to find some other code that guarantees that this can never
> > happen but I was unsuccessful. So, unless someone else can point to some
> > code that ensures this can never be a problem, I believe this patch is
> > needed.
> >
> > While I was changing this code I also noticed that all the dprintk()
> > statements, except one, start with "%s:". The one missing the ":" I added
> > it to.
>
>   Maybe another one also should be changed at decode_and_add_ds() at line 243:
>
>    243  printk("%s Decoded address and port %s\n", __func__, buf);
>
Missed that one. Thanks.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

parent 0da2a4ac

fs/nfs/nfs4filelayoutdev.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -214,7 +214,7 @@ decode_and_add_ds(__be32 *pp, struct inode inode)

		/* ipv6 length plus port is legal */
		if (rlen > INET6_ADDRSTRLEN + 8) {
		dprintk("%s Invalid address, length %d\n", __func__,
		dprintk("%s: Invalid address, length %d\n", __func__,
		rlen);
		goto out_err;
		}
		@@ -225,6 +225,11 @@ decode_and_add_ds(__be32 *pp, struct inode inode)
		/* replace the port dots with dashes for the in4_pton() delimiter*/
		for (i = 0; i < 2; i++) {
		char *res = strrchr(buf, '.');
		if (!res) {
		dprintk("%s: Failed finding expected dots in port\n",
		__func__);
		goto out_free;
		}
		*res = '-';
		}

		@@ -240,7 +245,7 @@ decode_and_add_ds(__be32 *pp, struct inode inode)
		port = htons((tmp[0] << 8) \| (tmp[1]));

		ds = nfs4_pnfs_ds_add(inode, ip_addr, port);
		dprintk("%s Decoded address and port %s\n", __func__, buf);
		dprintk("%s: Decoded address and port %s\n", __func__, buf);
		out_free:
		kfree(buf);
		out_err: