[Patch] Possible dereference in fs/nfsd/nfs4callback.c

[Eric Sesterhenn]

hi,

the following commit introduced a possible NULL pointer dereference
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=ae5c79476f36512d1100e162606bb5691f2cce5a

we set cb->cb_client to NULL and pass it to rpc_shutdown_client() which dereferences it.
The easy fix below.

Signed-off-by: Eric Sesterhenn <snakebyte@xxxxxx>

--- linux-2.6.18-git5/fs/nfsd/nfs4callback.c.orig	2006-09-26 12:24:23.000000000 +0200
+++ linux-2.6.18-git5/fs/nfsd/nfs4callback.c	2006-09-26 12:24:40.000000000 +0200
@@ -450,7 +450,8 @@ out_rpciod:
 	rpciod_down();
 	cb->cb_client = NULL;
 out_clnt:
-	rpc_shutdown_client(cb->cb_client);
+	if (cb->cb_client)
+		rpc_shutdown_client(cb->cb_client);
 out_err:
 	dprintk("NFSD: warning: no callback path to client %.*s\n",
 		(int)clp->cl_name.len, clp->cl_name.data);


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