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Message-ID: <97b85c74-55e9-4607-8f30-3a938638a309@linux.alibaba.com>
Date: Wed, 14 Aug 2024 10:25:27 +0800
From: "D. Wythe" <alibuda@...ux.alibaba.com>
To: Jeongjun Park <aha310510@...il.com>
Cc: wenjia@...ux.ibm.com, jaka@...ux.ibm.com, gbayer@...ux.ibm.com,
tonylu@...ux.alibaba.com, guwen@...ux.alibaba.com, davem@...emloft.net,
dust.li@...ux.alibaba.com, edumazet@...gle.com, pabeni@...hat.com,
kuba@...nel.org, linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org,
netdev@...r.kernel.org, syzbot+f69bfae0a4eb29976e44@...kaller.appspotmail.com
Subject: Re: [PATCH net,v3] net/smc: prevent NULL pointer dereference in
txopt_get
On 8/13/24 7:48 PM, Jeongjun Park wrote:
> D. Wythe wrote:
>>
>>
>> On 8/13/24 6:07 PM, Jeongjun Park wrote:
>>> Since smc_inet6_prot does not initialize ipv6_pinfo_offset, inet6_create()
>>> copies an incorrect address value, sk + 0 (offset), to inet_sk(sk)->pinet6.
>>>
>>> In addition, since inet_sk(sk)->pinet6 and smc_sk(sk)->clcsock practically
>>> point to the same address, when smc_create_clcsk() stores the newly
>>> created clcsock in smc_sk(sk)->clcsock, inet_sk(sk)->pinet6 is corrupted
>>> into clcsock. This causes NULL pointer dereference and various other
>>> memory corruptions.
>>>
>>> To solve this, we need to add a smc6_sock structure for ipv6_pinfo_offset
>>> initialization and modify the smc_sock structure.
>>>
>>> Reported-by: syzbot+f69bfae0a4eb29976e44@...kaller.appspotmail.com
>>> Tested-by: syzbot+f69bfae0a4eb29976e44@...kaller.appspotmail.com
>>> Fixes: d25a92ccae6b ("net/smc: Introduce IPPROTO_SMC")
>>> Signed-off-by: Jeongjun Park <aha310510@...il.com>
>>> ---
>>> net/smc/smc.h | 19 ++++++++++---------
>>> net/smc/smc_inet.c | 24 +++++++++++++++---------
>>> 2 files changed, 25 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/net/smc/smc.h b/net/smc/smc.h
>>> index 34b781e463c4..f4d9338b5ed5 100644
>>> --- a/net/smc/smc.h
>>> +++ b/net/smc/smc.h
>>> @@ -284,15 +284,6 @@ struct smc_connection {
>>>
>>> struct smc_sock { /* smc sock container */
>>> struct sock sk;
>>> - struct socket *clcsock; /* internal tcp socket */
>>> - void (*clcsk_state_change)(struct sock *sk);
>>> - /* original stat_change fct. */
>>> - void (*clcsk_data_ready)(struct sock *sk);
>>> - /* original data_ready fct. */
>>> - void (*clcsk_write_space)(struct sock *sk);
>>> - /* original write_space fct. */
>>> - void (*clcsk_error_report)(struct sock *sk);
>>> - /* original error_report fct. */
>>> struct smc_connection conn; /* smc connection */
>>> struct smc_sock *listen_smc; /* listen parent */
>>> struct work_struct connect_work; /* handle non-blocking connect*/
>>> @@ -325,6 +316,16 @@ struct smc_sock { /* smc sock container */
>>> /* protects clcsock of a listen
>>> * socket
>>> * */
>>> + struct socket *clcsock; /* internal tcp socket */
>>> + void (*clcsk_state_change)(struct sock *sk);
>>> + /* original stat_change fct. */
>>> + void (*clcsk_data_ready)(struct sock *sk);
>>> + /* original data_ready fct. */
>>> + void (*clcsk_write_space)(struct sock *sk);
>>> + /* original write_space fct. */
>>> + void (*clcsk_error_report)(struct sock *sk);
>>> + /* original error_report fct. */
>>> +
>>> };
>>>
>>> #define smc_sk(ptr) container_of_const(ptr, struct smc_sock, sk)
>>> diff --git a/net/smc/smc_inet.c b/net/smc/smc_inet.c
>>> index bece346dd8e9..25f34fd65e8d 100644
>>> --- a/net/smc/smc_inet.c
>>> +++ b/net/smc/smc_inet.c
>>> @@ -60,16 +60,22 @@ static struct inet_protosw smc_inet_protosw = {
>>> };
>>>
>>> #if IS_ENABLED(CONFIG_IPV6)
>>> +struct smc6_sock {
>>> + struct smc_sock smc;
>>> + struct ipv6_pinfo np;
>>> +};
>> I prefer to:
>>
>> struct ipv6_pinfo inet6;
> Okay, I'll write a v4 patch and send it to you tomorrow.
>
> Regards,
> Jeongjun Park
Before you issue the v4, I still don't know why you move clcsk_xxx from
smc_connection
to smc_sock, can you explain it ?
Also, regarding alignment, it's okay for me whether it's aligned or
not,But I checked the styles of other types of
structures and did not strictly require alignment, so I now feel that
there is no need to
modify so much to do alignment.
D. Wythe
>
>>> +
>>> static struct proto smc_inet6_prot = {
>>> - .name = "INET6_SMC",
>>> - .owner = THIS_MODULE,
>>> - .init = smc_inet_init_sock,
>>> - .hash = smc_hash_sk,
>>> - .unhash = smc_unhash_sk,
>>> - .release_cb = smc_release_cb,
>>> - .obj_size = sizeof(struct smc_sock),
>>> - .h.smc_hash = &smc_v6_hashinfo,
>>> - .slab_flags = SLAB_TYPESAFE_BY_RCU,
>>> + .name = "INET6_SMC",
>>> + .owner = THIS_MODULE,
>>> + .init = smc_inet_init_sock,
>>> + .hash = smc_hash_sk,
>>> + .unhash = smc_unhash_sk,
>>> + .release_cb = smc_release_cb,
>>> + .obj_size = sizeof(struct smc6_sock),
>>> + .h.smc_hash = &smc_v6_hashinfo,
>>> + .slab_flags = SLAB_TYPESAFE_BY_RCU,
>>> + .ipv6_pinfo_offset = offsetof(struct smc6_sock, np),
>>> };
>>>
>>> static const struct proto_ops smc_inet6_stream_ops = {
>>> --
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