Re: [PATCH net 1/6] net/diag: Do not race on dumping MD5 keys with adding new MD5 keys

Re: [PATCH net 1/6] net/diag: Do not race on dumping MD5 keys with adding new MD5 keys

[kernel test robot]

Hi Dmitry,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 2e1b3cc9d7f790145a80cb705b168f05dab65df2]

url:    https://github.com/intel-lab-lkp/linux/commits/Dmitry-Safonov-via-B4-Relay/net-diag-Do-not-race-on-dumping-MD5-keys-with-adding-new-MD5-keys/20241107-025054
base:   2e1b3cc9d7f790145a80cb705b168f05dab65df2
patch link:    https://lore.kernel.org/r/20241106-tcp-md5-diag-prep-v1-1-d62debf3dded%40gmail.com
patch subject: [PATCH net 1/6] net/diag: Do not race on dumping MD5 keys with adding new MD5 keys
config: arm64-randconfig-003-20241107 (https://download.01.org/0day-ci/archive/20241107/202411071218.G7g6a8JG-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 592c0fe55f6d9a811028b5f3507be91458ab2713)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241107/202411071218.G7g6a8JG-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411071218.G7g6a8JG-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from net/ipv4/tcp_diag.c:9:
   In file included from include/linux/net.h:24:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:504:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     504 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     505 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:511:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     511 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     512 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:524:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     524 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     525 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
>> net/ipv4/tcp_diag.c:70:3: warning: variable 'md5sig_count' is uninitialized when used here [-Wuninitialized]
      70 |                 md5sig_count++;
         |                 ^~~~~~~~~~~~
   net/ipv4/tcp_diag.c:60:36: note: initialize the variable 'md5sig_count' to silence this warning
      60 |         unsigned int attrlen, md5sig_count;
         |                                           ^
         |                                            = 0
   5 warnings generated.


vim +/md5sig_count +70 net/ipv4/tcp_diag.c

c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  54  
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  55  static int tcp_diag_put_md5sig(struct sk_buff *skb,
4a6144fbc706b3c Dmitry Safonov 2024-11-06  56  			       const struct tcp_md5sig_info *md5sig,
4a6144fbc706b3c Dmitry Safonov 2024-11-06  57  			       struct nlmsghdr *nlh)
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  58  {
4a6144fbc706b3c Dmitry Safonov 2024-11-06  59  	size_t key_size = sizeof(struct tcp_diag_md5sig);
4a6144fbc706b3c Dmitry Safonov 2024-11-06  60  	unsigned int attrlen, md5sig_count;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  61  	const struct tcp_md5sig_key *key;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  62  	struct tcp_diag_md5sig *info;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  63  	struct nlattr *attr;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  64  
4a6144fbc706b3c Dmitry Safonov 2024-11-06  65  	/*
4a6144fbc706b3c Dmitry Safonov 2024-11-06  66  	 * Userspace doesn't like to see zero-filled key-values, so
4a6144fbc706b3c Dmitry Safonov 2024-11-06  67  	 * allocating too large attribute is bad.
4a6144fbc706b3c Dmitry Safonov 2024-11-06  68  	 */
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  69  	hlist_for_each_entry_rcu(key, &md5sig->head, node)
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31 @70  		md5sig_count++;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  71  	if (md5sig_count == 0)
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  72  		return 0;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  73  
4a6144fbc706b3c Dmitry Safonov 2024-11-06  74  	attrlen = skb_availroom(skb) - NLA_HDRLEN;
4a6144fbc706b3c Dmitry Safonov 2024-11-06  75  	md5sig_count = min(md5sig_count, attrlen / key_size);
4a6144fbc706b3c Dmitry Safonov 2024-11-06  76  	attr = nla_reserve(skb, INET_DIAG_MD5SIG, md5sig_count * key_size);
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  77  	if (!attr)
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  78  		return -EMSGSIZE;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  79  
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  80  	info = nla_data(attr);
4a6144fbc706b3c Dmitry Safonov 2024-11-06  81  	memset(info, 0, md5sig_count * key_size);
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  82  	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
4a6144fbc706b3c Dmitry Safonov 2024-11-06  83  		/* More keys on a socket than pre-allocated space available */
4a6144fbc706b3c Dmitry Safonov 2024-11-06  84  		if (md5sig_count-- == 0) {
4a6144fbc706b3c Dmitry Safonov 2024-11-06  85  			nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  86  			break;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  87  		}
4a6144fbc706b3c Dmitry Safonov 2024-11-06  88  		tcp_diag_md5sig_fill(info++, key);
4a6144fbc706b3c Dmitry Safonov 2024-11-06  89  	}
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  90  
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  91  	return 0;
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  92  }
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  93  #endif
c03fa9bcacd9ac0 Ivan Delalande 2017-08-31  94  

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