On 30/10/23 14:29, Eric Dumazet wrote:
On Sat, Oct 28, 2023 at 4:41 PM Bragatheswaran Manickavel
<bragathemanick0908@xxxxxxxxx> wrote:
ccid_hc_tx_send_packet might be called with a NULL ccid pointer
leading to a NULL pointer dereference
Below mentioned commit has similarly changes
commit 276bdb82dedb ("dccp: check ccid before dereferencing")
Reported-by: syzbot+c71bc336c5061153b502@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=c71bc336c5061153b502
Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@xxxxxxxxx>
---
net/dccp/ccid.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index 105f3734dadb..1015dc2b9392 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -163,7 +163,7 @@ static inline int ccid_packet_dequeue_eval(const int return_code)
static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
struct sk_buff *skb)
{
- if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
+ if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
return CCID_PACKET_SEND_AT_ONCE;
}
--
2.34.1
If you are willing to fix dccp, I would make sure that some of
lockless accesses to dccps_hc_tx_ccid
are also double checked and fixed.
do_dccp_getsockopt() and dccp_get_info()
Hi Eric,
In both do_dccp_getsockopt() and dccp_get_info(), dccps_hc_rx_ccid are
checked properly before access.
Thanks,
Bragathe
