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Mon, 6 Jul 2026 09:40:24 +0000 (GMT) Received: from t83lp68.lnxne.boe (unknown [9.87.84.240]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 6 Jul 2026 09:40:24 +0000 (GMT) From: Hidayath Khan To: aswin@linux.ibm.com, wintera@linux.ibm.com, pasic@linux.ibm.com, nagamani@linux.ibm.com Cc: wenjia@linux.ibm.com, gbayer@linux.ibm.com, linux390-list@tuxmaker.boeblingen.de.ibm.com, mjambigi@linux.ibm.com, sidraya@linux.ibm.com, hidayath@linux.ibm.com, stable@vger.kernel.org Subject: [PATCH net] net/af_iucv: fix NULL deref in afiucv_hs_callback_syn() Date: Mon, 6 Jul 2026 11:40:19 +0200 Message-ID: <20260706094019.6600-1-hidayath@linux.ibm.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=M7J97Sws c=1 sm=1 tr=0 ts=6a4b780e cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=UNGD-gTXSZoCYQNaG48A:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzA2MDA5NCBTYWx0ZWRfX1STuqcWeXiZn UNprMtZk8RsAq2D1i/VxVaVMMjPSRg9jqwh3AvJ9dDvIU6787swdoa9dq1gweXIx8sNhBxdelc7 p8baSJDmTsbJdrZOIWth/k3XE41kkGNd7d2HlAEbyN+vPiMex5GCLYjs5LNcs9cg585jgj5RJyd 0CffBg5BC0Dy1sk7ksXmTqoRxy6ePDMmNalpYPdjhhm5e6Fk/+jb0JOF7tMyj5kQSyHsaLN24l9 wfJntZXJqTE4TtBOopQP3T9vXfa5h962RmzbGxg8pd/eEI+2fxPJIWbTQ7Jm2dIzlZrDqN8zB14 WTwImAHZ2RK8RjKy5JAX7IuppwNIAK4G6IDaZd38Ff79Q7aogJRXkLaGMBd6CZY2EwnUIzMQ7mm Hoc07YCaZQsYBtFyqVHpEBRnN8Q7hVBdCZs3Y4Xib09NyB1UHU2LSPszshT1RHe3C3PuhgPh2sP sSMHU9Nux7WV1heM0UQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzA2MDA5NCBTYWx0ZWRfXybB/rXMZ64iL IWBz3ZEqyorTeESoniMusUr6ddm06K1S2KFszhnHtxfBGNyA1pw5wQAnGhCHJu8PLNzg/HNRs45 SJ3nA7MTrhGV2ArRfleJJOc/XUJ5c+M= X-Proofpoint-GUID: ZsGGz6Kc7tKUBkkOtp9TI4yIxheVNw9a X-Proofpoint-ORIG-GUID: ZsGGz6Kc7tKUBkkOtp9TI4yIxheVNw9a X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-07-06_01,2026-07-03_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 adultscore=0 priorityscore=1501 bulkscore=0 spamscore=0 impostorscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607060094 afiucv_hs_callback_syn() allocates the child socket with GFP_ATOMIC, which can fail and return NULL. The connection-refused branch is entered when the listen state check fails, the accept backlog is full, or nsk is NULL - and unconditionally calls iucv_sock_kill(nsk). When entered due to allocation failure, iucv_sock_kill() dereferences the NULL pointer at the sock_flag(sk, SOCK_ZAPPED) check, causing a NULL pointer dereference in softirq context. Only kill the child socket if it was actually allocated. Fixes: 3881ac441f64 ("af_iucv: add HiperSockets transport") Cc: stable@vger.kernel.org Signed-off-by: Hidayath Khan --- net/iucv/af_iucv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c index 890d9df5ae36..a471fbe178e8 100644 --- a/net/iucv/af_iucv.c +++ b/net/iucv/af_iucv.c @@ -1875,7 +1875,8 @@ static int afiucv_hs_callback_syn(struct sock *sk, struct sk_buff *skb) afiucv_swap_src_dest(skb); trans_hdr->flags = AF_IUCV_FLAG_SYN | AF_IUCV_FLAG_FIN; err = dev_queue_xmit(skb); - iucv_sock_kill(nsk); + if (nsk) + iucv_sock_kill(nsk); bh_unlock_sock(sk); goto out; } -- 2.52.0