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authorEyal Birger <eyal.birger@gmail.com>2021-01-01 11:02:26 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2021-01-03 20:03:54 +0100
commitd05e9515b84074b0a0a49a2b49da31bd057bad7b (patch)
tree26df9ec48df9f9fa0e4987becc7cdc8dc37f1775 /examples/nfct-mnl-get.c
parentf20393c27802449d9b9c4e52540c716f1fc1ecc2 (diff)
examples: check return value of nfct_nlmsg_build()
nfct_nlmsg_build() may fail for different reasons, for example if insufficient parameters exist in the ct object. The resulting nlh would not contain any of the ct attributes. Some conntrack operations would still operate in such case, for example an IPCTNL_MSG_CT_DELETE message would just delete all existing conntrack entries. While the example as it is does supply correct parameters, it's safer as reference to validate the return value. Signed-off-by: Eyal Birger <eyal.birger@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'examples/nfct-mnl-get.c')
-rw-r--r--examples/nfct-mnl-get.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/examples/nfct-mnl-get.c b/examples/nfct-mnl-get.c
index 4858acf..5be3331 100644
--- a/examples/nfct-mnl-get.c
+++ b/examples/nfct-mnl-get.c
@@ -74,7 +74,11 @@ int main(void)
nfct_set_attr_u16(ct, ATTR_PORT_SRC, htons(20));
nfct_set_attr_u16(ct, ATTR_PORT_DST, htons(10));
- nfct_nlmsg_build(nlh, ct);
+ ret = nfct_nlmsg_build(nlh, ct);
+ if (ret == -1) {
+ perror("nfct_nlmsg_build");
+ exit(EXIT_FAILURE);
+ }
ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len);
if (ret == -1) {