Hi Ivan, On Mon, Feb 03, 2014 at 10:54:23AM +0100, Ivan Homoliak wrote: > Uninitialized values in libnetfilter.log.c which were discovered by > valgrind and ulogd. > > Signed-off-by: Ivan Homoliak <xhomol11@xxxxxxxxx> > --- > > Valgrinds output: > [...] > ==13821== Syscall param socketcall.sendto(msg) points to uninitialised byte(s) > ==13821== at 0x3E93AF6E83: __sendto_nocancel (in /usr/lib64/libc-2.17.so) > ==13821== by 0x5433E81: nfnl_send (libnfnetlink.c:391) > ==13821== by 0x5435C0E: nfnl_query (libnfnetlink.c:1569) > ==13821== by 0x522E9A0: nflog_set_mode (libnetfilter_log.c:481) > ==13821== by 0x5029FA2: start (ulogd_inppkt_NFLOG.c:581) > ==13821== by 0x403E5D: create_stack_start_instances (ulogd.c:918) > ==13821== by 0x4041B4: create_stack (ulogd.c:1010) > ==13821== by 0x4078D6: config_parse_file (conffile.c:225) > ==13821== by 0x404411: parse_conffile (ulogd.c:1088) > ==13821== by 0x405478: main (ulogd.c:1573) > ==13821== Address 0x7feffff9d is on thread 1's stack > ==13821== Uninitialised value was created by a stack allocation > ==13821== at 0x50293D0: ??? (in /usr/lib/ulogd/ulogd_inppkt_NFLOG.so) I found some time to looking into this. I think this patch for *libnfnetlink* should fix this for all the libraries. Better do this in a generic way so we skip similar reports in other libnetfilter_* libraries. Valgrind does not report any warning anymore here. If you can give a try to this libnfnetlink patch to confirm you see no more valgrind warnings, I'd appreciate. Thanks.
>From 7633f0c1679988ad18e4de9afc8a277510298139 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Date: Mon, 3 Feb 2014 12:09:29 +0100 Subject: [PATCH] libnfnetlink: initialize attribute padding to resolve valgrind warnings ==12195== Syscall param socketcall.sendto(msg) points to uninitialised byte(s) ==12195== at 0x51209C3: __sendto_nocancel (syscall-template.S:81) ==12195== by 0x53E4D12: nfnl_send (libnfnetlink.c:391) ==12195== by 0x53E6952: nfnl_query (libnfnetlink.c:1569) ==12195== by 0x4E344AF: __build_send_cfg_msg.isra.1 (libnetfilter_log.c:143) ==12195== by 0x4E34710: nflog_bind_group (libnetfilter_log.c:413) ==12195== by 0x400CB1: main (nfulnl_test.c:77) ==12195== Address 0x7fefff3e9 is on thread 1's stack This patch sets to zero the padding that is included to align the attribute payload. Reported-by: Ivan Homoliak <xhomol11@xxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> --- src/libnfnetlink.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/libnfnetlink.c b/src/libnfnetlink.c index 4b2bcd0..398b7d7 100644 --- a/src/libnfnetlink.c +++ b/src/libnfnetlink.c @@ -809,6 +809,7 @@ int nfnl_addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data, nfa->nfa_type = type; nfa->nfa_len = len; memcpy(NFA_DATA(nfa), data, alen); + memset((uint8_t *)nfa + nfa->nfa_len, 0, NFA_ALIGN(alen) - alen); n->nlmsg_len = (NLMSG_ALIGN(n->nlmsg_len) + NFA_ALIGN(len)); return 0; } -- 1.7.10.4
