netfilter: prefer nla_strlcpy for dealing with NLA_STRING attributes

fixes these warnings:
'nfnl_cthelper_create' at net/netfilter/nfnetlink_cthelper.c:237:2,
'nfnl_cthelper_new' at net/netfilter/nfnetlink_cthelper.c:450:9:
./include/linux/string.h:246:9: warning: '__builtin_strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Moreover, strncpy assumes null-terminated source buffers, but thats
not the case here.
Unlike strlcpy, nla_strlcpy *does* pad the destination buffer
while also considering nla attribute size.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2018-05-06 00:45:43 +02:00 committed by Pablo Neira Ayuso
parent 25fd386e0b
commit 4e09fc873d
2 changed files with 5 additions and 4 deletions

View File

@ -115,7 +115,7 @@ static int nfnl_acct_new(struct net *net, struct sock *nfnl,
nfacct->flags = flags;
}
strncpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
nla_strlcpy(nfacct->name, nla_data(tb[NFACCT_NAME]), NFACCT_NAME_MAX);
if (tb[NFACCT_BYTES]) {
atomic64_set(&nfacct->bytes,

View File

@ -149,8 +149,8 @@ nfnl_cthelper_expect_policy(struct nf_conntrack_expect_policy *expect_policy,
!tb[NFCTH_POLICY_EXPECT_TIMEOUT])
return -EINVAL;
strncpy(expect_policy->name,
nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
nla_strlcpy(expect_policy->name,
nla_data(tb[NFCTH_POLICY_NAME]), NF_CT_HELPER_NAME_LEN);
expect_policy->max_expected =
ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX]));
if (expect_policy->max_expected > NF_CT_EXPECT_MAX_CNT)
@ -234,7 +234,8 @@ nfnl_cthelper_create(const struct nlattr * const tb[],
if (ret < 0)
goto err1;
strncpy(helper->name, nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
nla_strlcpy(helper->name,
nla_data(tb[NFCTH_NAME]), NF_CT_HELPER_NAME_LEN);
size = ntohl(nla_get_be32(tb[NFCTH_PRIV_DATA_LEN]));
if (size > FIELD_SIZEOF(struct nf_conn_help, data)) {
ret = -ENOMEM;