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

On Sat, May 17, 2014 at 12:36 PM, Rickard Strandqvist
[off-list ref] wrote:

Hi

I have made a new patch according Sergei specification.

I'll be happy to apply this patch once someone explains to me why we
can't just remove that check for cred != NULL, however I'm not
applying a patch purely in order to silence a warning from cppcheck.

Cheers,
   Trond

But there remains Tronds question though.

Best regards
Rickard Strandqvist


2014-05-16 14:19 GMT+02:00 Sergei Shtylyov [off-list ref]:

quoted

Hello.


On 16-05-2014 1:56, Rickard Strandqvist wrote:

quoted

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

quoted

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

quoted

Signed-off-by: Rickard Strandqvist
[off-list ref]
---
  net/sunrpc/auth.c |   10 +++++++---
  1 fil ändrad, 7 tillägg(+), 3 borttagningar(-)

quoted

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

   } and *else* should be on the same line, and there should be {} in the
*else* arm since there's {} in the *if* arm already, according to
Documentation/CodingStyle.

quoted

+               dprintk("RPC: %5u invalidating is NULL\n", task->tk_pid);

   That's not a proper English, I'm afraid.

quoted

  }

WBR, Sergei

-- 
Trond Myklebust

Linux NFS client maintainer, PrimaryData

trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org
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