netfilter: nft_log: fix possible memory leak if log expr init fail

Suppose that we specify the NFTA_LOG_PREFIX, then NFTA_LOG_LEVEL
and NFTA_LOG_GROUP are specified together or nf_logger_find_get
call returns fail, i.e. expr init fail, memory leak will happen.

Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nft_log.c b/net/netfilter/nft_log.c
index 713d668..e1b34ff 100644 (file)
--- a/net/netfilter/nft_log.c
+++ b/net/netfilter/nft_log.c
@@ -52,6 +52,14 @@ static int nft_log_init(const struct nft_ctx *ctx,
        struct nft_log *priv = nft_expr_priv(expr);
        struct nf_loginfo *li = &priv->loginfo;
        const struct nlattr *nla;
+       int err;
+
+       li->type = NF_LOG_TYPE_LOG;
+       if (tb[NFTA_LOG_LEVEL] != NULL &&
+           tb[NFTA_LOG_GROUP] != NULL)
+               return -EINVAL;
+       if (tb[NFTA_LOG_GROUP] != NULL)
+               li->type = NF_LOG_TYPE_ULOG;
 
        nla = tb[NFTA_LOG_PREFIX];
        if (nla != NULL) {
@@ -63,13 +71,6 @@ static int nft_log_init(const struct nft_ctx *ctx,
                priv->prefix = (char *)nft_log_null_prefix;
        }
 
-       li->type = NF_LOG_TYPE_LOG;
-       if (tb[NFTA_LOG_LEVEL] != NULL &&
-           tb[NFTA_LOG_GROUP] != NULL)
-               return -EINVAL;
-       if (tb[NFTA_LOG_GROUP] != NULL)
-               li->type = NF_LOG_TYPE_ULOG;
-
        switch (li->type) {
        case NF_LOG_TYPE_LOG:
                if (tb[NFTA_LOG_LEVEL] != NULL) {
@@ -96,7 +97,16 @@ static int nft_log_init(const struct nft_ctx *ctx,
                break;
        }
 
-       return nf_logger_find_get(ctx->afi->family, li->type);
+       err = nf_logger_find_get(ctx->afi->family, li->type);
+       if (err < 0)
+               goto err1;
+
+       return 0;
+
+err1:
+       if (priv->prefix != nft_log_null_prefix)
+               kfree(priv->prefix);
+       return err;
 }
 
 static void nft_log_destroy(const struct nft_ctx *ctx,