From 7b175a4fc9f81fe3f721d9a7ebb5b954a4fd7606 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Sun, 19 Mar 2017 22:01:10 +0800 Subject: [PATCH] examples: fix double free in nftc-helper-add After inputting the following test command, core dump happened: # ./examples/nfct-helper-add test 1 *** Error in `.../libnetfilter_cthelper/examples/.libs/lt-nfct-helper-add': double free or corruption (fasttop): 0x0000000001f3c070 *** ======= Backtrace: ========= /lib64/libc.so.6(+0x77de5)[0x7fd9ebe88de5] /lib64/libc.so.6(+0x8022a)[0x7fd9ebe9122a] /lib64/libc.so.6(cfree+0x4c)[0x7fd9ebe9478c] [...] Because "struct nfct_helper_policy *p" had been freed by nfct_helper_free, so there's no need to invoke nfct_helper_policy_free again, otherwise double free error will happen. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso (cherry picked from commit 9f223e612d3b0be6e4dca84e1db8042dbec64e93) --- examples/nfct-helper-add.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/examples/nfct-helper-add.c b/examples/nfct-helper-add.c index 6c476261b75e8..cb7291e8ec4b0 100644 --- a/examples/nfct-helper-add.c +++ b/examples/nfct-helper-add.c @@ -32,6 +32,7 @@ int main(int argc, char *argv[]) nfct_helper_attr_set_u16(nfct_helper, NFCTH_ATTR_PROTO_L3NUM, AF_INET); nfct_helper_attr_set_u8(nfct_helper, NFCTH_ATTR_PROTO_L4NUM, IPPROTO_TCP); + /* Will be freed by nfct_helper_free. */ p = nfct_helper_policy_alloc(); if (p == NULL) { perror("OOM"); @@ -49,7 +50,6 @@ int main(int argc, char *argv[]) nfct_helper_nlmsg_build_payload(nlh, nfct_helper); nfct_helper_free(nfct_helper); - nfct_helper_policy_free(p); nl = mnl_socket_open(NETLINK_NETFILTER); if (nl == NULL) { -- 2.21.0