Thread (6 messages) flat view 6 messages, 4 authors, 2017-09-27

Re: [PATCH net v2] sctp: Fix a big endian bug in sctp_diag_dump()

From: Xin Long <lucien.xin@gmail.com>
Date: 2017-09-25 15:00:26
Also in: kernel-janitors, linux-sctp

On Mon, Sep 25, 2017 at 6:19 PM, Dan Carpenter [off-list ref] wrote:
quoted hunk ↗ jump to hunk
The sctp_for_each_transport() function takes an pointer to int.  The
cb->args[] array holds longs so it's only using the high 32 bits.  It
works on little endian system but will break on big endian 64 bit
machines.

Fixes: d25adbeb0cdb ("sctp: fix an use-after-free issue in sctp_sock_dump")
Signed-off-by: Dan Carpenter <redacted>
---
v2: The v1 patch changed the function to take a long pointer, but v2
    just changes the caller.
diff --git a/net/sctp/sctp_diag.c b/net/sctp/sctp_diag.c
index 22ed01a76b19..a72a7d925d46 100644
--- a/net/sctp/sctp_diag.c
+++ b/net/sctp/sctp_diag.c
@@ -463,6 +463,7 @@ static void sctp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
                .r = r,
                .net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN),
        };
+       int pos = cb->args[2];

        /* eps hashtable dumps
         * args:
@@ -493,7 +494,8 @@ static void sctp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
                goto done;

        sctp_for_each_transport(sctp_sock_filter, sctp_sock_dump,
-                               net, (int *)&cb->args[2], &commp);
+                               net, &pos, &commp);
+       cb->args[2] = pos;

 done:
        cb->args[1] = cb->args[4];
Reviewed-by: Xin Long <lucien.xin@gmail.com>
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