src: check if netlink parsing fails

We have to check if mnl_attr_parse() returns an error, which means that it
failed to validate and retrieve the attributes.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

6 files changed, 32 insertions, 11 deletions

diff --git a/examples/nft-compat-get.c b/examples/nft-compat-get.c
index 3294028..8f00cbf 100644
--- a/examples/nft-compat-get.c
+++ b/examples/nft-compat-get.c
@@ -51,7 +51,8 @@ static int cb(const struct nlmsghdr *nlh, void *data)
 	struct nlattr *tb[NFTA_COMPAT_MAX+1] = {};
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
 
-	mnl_attr_parse(nlh, sizeof(*nfg), data_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg), data_attr_cb, tb) < 0)
+		return MNL_CB_ERROR;
 
 	if (tb[NFTA_COMPAT_NAME])
 		printf("name=%s ", mnl_attr_get_str(tb[NFTA_COMPAT_NAME]));
diff --git a/src/chain.c b/src/chain.c
index 33540b1..ca71069 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -502,7 +502,9 @@ int nft_chain_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_chain *c)
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
 	int ret = 0;
 
-	mnl_attr_parse(nlh, sizeof(*nfg), nft_chain_parse_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg), nft_chain_parse_attr_cb, tb) < 0)
+		return -1;
+
 	if (tb[NFTA_CHAIN_NAME]) {
 		strncpy(c->name, mnl_attr_get_str(tb[NFTA_CHAIN_NAME]),
 			NFT_CHAIN_MAXNAMELEN);
@@ -512,8 +514,11 @@ int nft_chain_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_chain *c)
 		c->table = strdup(mnl_attr_get_str(tb[NFTA_CHAIN_TABLE]));
 		c->flags |= (1 << NFT_CHAIN_ATTR_TABLE);
 	}
-	if (tb[NFTA_CHAIN_HOOK])
+	if (tb[NFTA_CHAIN_HOOK]) {
 		ret = nft_chain_parse_hook(tb[NFTA_CHAIN_HOOK], c);
+		if (ret < 0)
+			return ret;
+	}
 	if (tb[NFTA_CHAIN_POLICY]) {
 		c->policy = ntohl(mnl_attr_get_u32(tb[NFTA_CHAIN_POLICY]));
 		c->flags |= (1 << NFT_CHAIN_ATTR_POLICY);
@@ -522,8 +527,11 @@ int nft_chain_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_chain *c)
 		c->use = ntohl(mnl_attr_get_u32(tb[NFTA_CHAIN_USE]));
 		c->flags |= (1 << NFT_CHAIN_ATTR_USE);
 	}
-	if (tb[NFTA_CHAIN_COUNTERS])
+	if (tb[NFTA_CHAIN_COUNTERS]) {
 		ret = nft_chain_parse_counters(tb[NFTA_CHAIN_COUNTERS], c);
+		if (ret < 0)
+			return ret;
+	}
 	if (tb[NFTA_CHAIN_HANDLE]) {
 		c->handle = be64toh(mnl_attr_get_u64(tb[NFTA_CHAIN_HANDLE]));
 		c->flags |= (1 << NFT_CHAIN_ATTR_HANDLE);
diff --git a/src/rule.c b/src/rule.c
index adb7426..eb9f41c 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -455,7 +455,9 @@ int nft_rule_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_rule *r)
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
 	int ret = 0;
 
-	mnl_attr_parse(nlh, sizeof(*nfg), nft_rule_parse_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg), nft_rule_parse_attr_cb, tb) < 0)
+		return -1;
+
 	if (tb[NFTA_RULE_TABLE]) {
 		r->table = strdup(mnl_attr_get_str(tb[NFTA_RULE_TABLE]));
 		r->flags |= (1 << NFT_RULE_ATTR_TABLE);
diff --git a/src/set.c b/src/set.c
index ef10af5..368d069 100644
--- a/src/set.c
+++ b/src/set.c
@@ -281,9 +281,10 @@ int nft_set_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_set *s)
 {
 	struct nlattr *tb[NFTA_SET_MAX+1] = {};
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
-	int ret = 0;
 
-	mnl_attr_parse(nlh, sizeof(*nfg), nft_set_parse_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg), nft_set_parse_attr_cb, tb) < 0)
+		return -1;
+
 	if (tb[NFTA_SET_TABLE]) {
 		s->table = strdup(mnl_attr_get_str(tb[NFTA_SET_TABLE]));
 		s->flags |= (1 << NFT_SET_ATTR_TABLE);
@@ -315,7 +316,7 @@ int nft_set_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_set *s)
 	s->family = nfg->nfgen_family;
 	s->flags |= (1 << NFT_SET_ATTR_FAMILY);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(nft_set_nlmsg_parse);
 
diff --git a/src/set_elem.c b/src/set_elem.c
index 79fc641..ff2c9d5 100644
--- a/src/set_elem.c
+++ b/src/set_elem.c
@@ -252,7 +252,11 @@ static int nft_set_elems_parse2(struct nft_set *s, const struct nlattr *nest)
 	if (e == NULL)
 		return -1;
 
-	mnl_attr_parse_nested(nest, nft_set_elem_parse_attr_cb, tb);
+	if (mnl_attr_parse_nested(nest, nft_set_elem_parse_attr_cb, tb) < 0) {
+		nft_set_elem_free(e);
+		return -1;
+	}
+
 	if (tb[NFTA_SET_ELEM_FLAGS]) {
 		e->set_elem_flags =
 			ntohl(mnl_attr_get_u32(tb[NFTA_SET_ELEM_FLAGS]));
@@ -338,7 +342,10 @@ int nft_set_elems_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_set *s)
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
 	int ret = 0;
 
-	mnl_attr_parse(nlh, sizeof(*nfg), nft_set_elem_list_parse_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg),
+			   nft_set_elem_list_parse_attr_cb, tb) < 0)
+		return -1;
+
 	if (tb[NFTA_SET_ELEM_LIST_TABLE]) {
 		s->table =
 			strdup(mnl_attr_get_str(tb[NFTA_SET_ELEM_LIST_TABLE]));
diff --git a/src/table.c b/src/table.c
index 0299209..7a85b9e 100644
--- a/src/table.c
+++ b/src/table.c
@@ -234,7 +234,9 @@ int nft_table_nlmsg_parse(const struct nlmsghdr *nlh, struct nft_table *t)
 	struct nlattr *tb[NFTA_TABLE_MAX+1] = {};
 	struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);
 
-	mnl_attr_parse(nlh, sizeof(*nfg), nft_table_parse_attr_cb, tb);
+	if (mnl_attr_parse(nlh, sizeof(*nfg), nft_table_parse_attr_cb, tb) < 0)
+		return -1;
+
 	if (tb[NFTA_TABLE_NAME]) {
 		t->name = strdup(mnl_attr_get_str(tb[NFTA_TABLE_NAME]));
 		t->flags |= (1 << NFT_TABLE_ATTR_NAME);