netdev - Re: [PATCH net-next v2] ipv6: Fix signed integer overflow in __ip6_append

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Message-ID: <1b6745e9-a5cc-86e4-b94c-0506ca781ee7@huawei.com>
Date:   Sat, 28 May 2022 09:58:22 +0800
From:   wangyufen <wangyufen@...wei.com>
To:     Paolo Abeni <pabeni@...hat.com>, <davem@...emloft.net>,
        <yoshfuji@...ux-ipv6.org>, <dsahern@...nel.org>,
        <edumazet@...gle.com>, <kuba@...nel.org>, <ast@...nel.org>,
        <daniel@...earbox.net>, <andrii@...nel.org>, <kafai@...com>,
        <songliubraving@...com>, <yhs@...com>, <john.fastabend@...il.com>,
        <kpsingh@...nel.org>
CC:     <netdev@...r.kernel.org>, <bpf@...r.kernel.org>
Subject: Re: [PATCH net-next v2] ipv6: Fix signed integer overflow in
 __ip6_append_data


在 2022/5/26 17:41, Paolo Abeni 写道:
> On Wed, 2022-05-25 at 10:08 +0800, Wang Yufen wrote:
>> Resurrect ubsan overflow checks and ubsan report this warning,
>> fix it by change the variable [length] type to size_t.
>>
>> UBSAN: signed-integer-overflow in net/ipv6/ip6_output.c:1489:19
>> 2147479552 + 8567 cannot be represented in type 'int'
>> CPU: 0 PID: 253 Comm: err Not tainted 5.16.0+ #1
>> Hardware name: linux,dummy-virt (DT)
>> Call trace:
>>    dump_backtrace+0x214/0x230
>>    show_stack+0x30/0x78
>>    dump_stack_lvl+0xf8/0x118
>>    dump_stack+0x18/0x30
>>    ubsan_epilogue+0x18/0x60
>>    handle_overflow+0xd0/0xf0
>>    __ubsan_handle_add_overflow+0x34/0x44
>>    __ip6_append_data.isra.48+0x1598/0x1688
>>    ip6_append_data+0x128/0x260
>>    udpv6_sendmsg+0x680/0xdd0
>>    inet6_sendmsg+0x54/0x90
>>    sock_sendmsg+0x70/0x88
>>    ____sys_sendmsg+0xe8/0x368
>>    ___sys_sendmsg+0x98/0xe0
>>    __sys_sendmmsg+0xf4/0x3b8
>>    __arm64_sys_sendmmsg+0x34/0x48
>>    invoke_syscall+0x64/0x160
>>    el0_svc_common.constprop.4+0x124/0x300
>>    do_el0_svc+0x44/0xc8
>>    el0_svc+0x3c/0x1e8
>>    el0t_64_sync_handler+0x88/0xb0
>>    el0t_64_sync+0x16c/0x170
>>
>> Changes since v1:
>> -Change the variable [length] type to unsigned, as Eric Dumazet suggested.
>>    
>> Reported-by: Hulk Robot <hulkci@...wei.com>
>> Signed-off-by: Wang Yufen <wangyufen@...wei.com>
>> ---
>>   include/net/ipv6.h    | 4 ++--
>>   net/ipv6/ip6_output.c | 8 ++++----
>>   net/ipv6/udp.c        | 2 +-
>>   net/l2tp/l2tp_ip6.c   | 2 +-
>>   4 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
>> index 5b38bf1a586b..de9dcc5652c4 100644
>> --- a/include/net/ipv6.h
>> +++ b/include/net/ipv6.h
>> @@ -1063,7 +1063,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr);
>>   int ip6_append_data(struct sock *sk,
>>   		    int getfrag(void *from, char *to, int offset, int len,
>>   				int odd, struct sk_buff *skb),
>> -		    void *from, int length, int transhdrlen,
>> +		    void *from, size_t length, int transhdrlen,
>>   		    struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
>>   		    struct rt6_info *rt, unsigned int flags);
>>   
>> @@ -1079,7 +1079,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk, struct sk_buff_head *queue,
>>   struct sk_buff *ip6_make_skb(struct sock *sk,
>>   			     int getfrag(void *from, char *to, int offset,
>>   					 int len, int odd, struct sk_buff *skb),
>> -			     void *from, int length, int transhdrlen,
>> +			     void *from, size_t length, int transhdrlen,
>>   			     struct ipcm6_cookie *ipc6,
>>   			     struct rt6_info *rt, unsigned int flags,
>>   			     struct inet_cork_full *cork);
>> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
>> index 4081b12a01ff..7d47ddd1e1f2 100644
>> --- a/net/ipv6/ip6_output.c
>> +++ b/net/ipv6/ip6_output.c
>> @@ -1450,7 +1450,7 @@ static int __ip6_append_data(struct sock *sk,
>>   			     struct page_frag *pfrag,
>>   			     int getfrag(void *from, char *to, int offset,
>>   					 int len, int odd, struct sk_buff *skb),
>> -			     void *from, int length, int transhdrlen,
>> +			     void *from, size_t length, int transhdrlen,
>>   			     unsigned int flags, struct ipcm6_cookie *ipc6)
>>   {
>>   	struct sk_buff *skb, *skb_prev = NULL;
>> @@ -1798,7 +1798,7 @@ static int __ip6_append_data(struct sock *sk,
>>   int ip6_append_data(struct sock *sk,
>>   		    int getfrag(void *from, char *to, int offset, int len,
>>   				int odd, struct sk_buff *skb),
>> -		    void *from, int length, int transhdrlen,
>> +		    void *from, size_t length, int transhdrlen,
>>   		    struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
>>   		    struct rt6_info *rt, unsigned int flags)
>>   {
>> @@ -1995,13 +1995,13 @@ EXPORT_SYMBOL_GPL(ip6_flush_pending_frames);
>>   struct sk_buff *ip6_make_skb(struct sock *sk,
>>   			     int getfrag(void *from, char *to, int offset,
>>   					 int len, int odd, struct sk_buff *skb),
>> -			     void *from, int length, int transhdrlen,
>> +			     void *from, size_t length, int transhdrlen,
>>   			     struct ipcm6_cookie *ipc6, struct rt6_info *rt,
>>   			     unsigned int flags, struct inet_cork_full *cork)
>>   {
>>   	struct inet6_cork v6_cork;
>>   	struct sk_buff_head queue;
>> -	int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
>> +	size_t exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
> Is this the above line change needed? Why?

No need， I'll change.

Thanks.

>
> Thanks!
>
> Paolo
>
> .