Re: [PATCH] Fix for possible null pointer dereference in auth.c

Hi

I do not know, I'm not an expert on this code.
But since there before was a if (cred) someone must have thought this
could happen.

Best regards
Rickard Strandqvist


2014-05-16 0:07 GMT+02:00 Trond Myklebust [off-list ref]:

On Thu, May 15, 2014 at 5:56 PM, Rickard Strandqvist
[off-list ref] wrote:

quoted

There is otherwise a risk of a possible null pointer dereference.

Was largely found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <redacted>
---
 net/sunrpc/auth.c |   10 +++++++---
 1 fil ändrad, 7 tillägg(+), 3 borttagningar(-)

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 5285ead..3a55698 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c

@@ -801,10 +801,14 @@ rpcauth_invalcred(struct rpc_task *task)
 {
        struct rpc_cred *cred = task->tk_rqstp->rq_cred;

-       dprintk("RPC: %5u invalidating %s cred %p\n",
-               task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
-       if (cred)
+       if (cred) {
+               dprintk("RPC: %5u invalidating %s cred %p\n",
+                       task->tk_pid, cred->cr_auth->au_ops->au_name, cred);
+
                clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
+       }
+       else
+               dprintk("RPC: %5u invalidating is NULL\n", task->tk_pid);
 }

Can you please explain how we can get to rpcauth_invalcred() without a
valid cred pointer? I'm not seeing it...

Cheers
  Trond