Looks like net-snmp 5.4 has a memory leak

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Hi,

I am experiencing a memory leak and it looks like the cause is in net-snmp
5.4 lib used in my program. I checked net-snmp source code and found that a
buffer was not deleted after use:

File:
net-snmp-5.4\snmplib\snmpUDPDomain.c

Function:
netsnmp_transport *
netsnmp_udp_transport(struct sockaddr_in *addr, int local)

Line:
addr_pair = (netsnmp_udp_addr_pair *)
malloc(sizeof(netsnmp_udp_addr_pair));

The variable addr_pair was not deleted after use. See attached file for the
whole function.

Please advise if this is a bug and need to be fixed.

Thanks,

Luu

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name="snmpUDPDomain.c.txt"
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filename="snmpUDPDomain.c.txt"

netsnmp_transport *
netsnmp_udp_transport(struct sockaddr_in *addr, int local)
{
netsnmp_transport *t =3D NULL;
int rc =3D 0;
char *str =3D NULL;
char *client_socket =3D NULL;
netsnmp_udp_addr_pair *addr_pair =3D NULL;

if (addr =3D=3D NULL || addr->sin_family !=3D AF_INET) {
return NULL;
}

addr_pair =3D (netsnmp_udp_addr_pair *) =
malloc(sizeof(netsnmp_udp_addr_pair));
if (addr_pair =3D=3D NULL) {
return NULL;
}
memset(addr_pair, 0, sizeof(netsnmp_udp_addr_pair));
memcpy(&(addr_pair->remote_addr), addr, sizeof(struct sockaddr_in));

t =3D (netsnmp_transport *) malloc(sizeof(netsnmp_transport));
if (t =3D=3D NULL) {
return NULL;
}

str =3D netsnmp_udp_fmtaddr(NULL, (void *)addr_pair,=20
sizeof(netsnmp_udp_addr_pair));
DEBUGMSGTL(("netsnmp_udp", "open %s %s:%d\n", local ? "local" : =
"remote",
str,addr->sin_port));
free(str);

memset(t, 0, sizeof(netsnmp_transport));

t->domain =3D netsnmpUDPDomain;
t->domain_length =3D netsnmpUDPDomain_len;

t->sock =3D socket(PF_INET, SOCK_DGRAM, 0);
if (t->sock < 0) {
netsnmp_transport_free(t);
return NULL;
}

_netsnmp_udp_sockopt_set(t->sock, local);

if (local) {
/*
* This session is inteneded as a server, so we must bind on to =
the
* given IP address, which may include an interface address, or =
could
* be INADDR_ANY, but certainly includes a port number.
*/

t->local =3D (u_char *) malloc(6);
if (t->local =3D=3D NULL) {
netsnmp_transport_free(t);
return NULL;
}
memcpy(t->local, (u_char *) & (addr->sin_addr.s_addr), 4);
t->local[4] =3D (htons(addr->sin_port) & 0xff00) >> 8;
t->local[5] =3D (htons(addr->sin_port) & 0x00ff) >> 0;
t->local_length =3D 6;

#if defined(linux) && defined(IP_PKTINFO)
{=20
int sockopt =3D 1;
if (setsockopt(t->sock, SOL_IP, IP_PKTINFO, &sockopt, sizeof =
sockopt) =3D=3D -1) {
DEBUGMSGTL(("netsnmp_udp", "couldn't set IP_PKTINFO: =
%s\n",
strerror(errno)));
return NULL;
}
DEBUGMSGTL(("netsnmp_udp", "set IP_PKTINFO\n"));
}
#endif
rc =3D bind(t->sock, (struct sockaddr *) addr,
sizeof(struct sockaddr));
if (rc !=3D 0) {
netsnmp_udp_close(t);
netsnmp_transport_free(t);
return NULL;
}
t->data =3D NULL;
t->data_length =3D 0;
} else {
/*
* This is a client session. If we've been given a
* client address to send from, then bind to that.
* Otherwise the send will use "something sensible".
*/
client_socket =3D netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID,
=
NETSNMP_DS_LIB_CLIENT_ADDR);
if (client_socket) {
struct sockaddr_in client_addr;
netsnmp_sockaddr_in2(&client_addr, client_socket, NULL);
client_addr.sin_port =3D 0;
bind(t->sock, (struct sockaddr *)&client_addr,
sizeof(struct sockaddr));
}
/*
* Save the (remote) address in the
* transport-specific data pointer for later use by =
netsnmp_udp_send.
*/

t->data =3D malloc(sizeof(netsnmp_udp_addr_pair));
t->remote =3D (u_char *)malloc(6);
if (t->data =3D=3D NULL || t->remote =3D=3D NULL) {
netsnmp_transport_free(t);
return NULL;
}
memcpy(t->remote, (u_char *) & (addr->sin_addr.s_addr), 4);
t->remote[4] =3D (htons(addr->sin_port) & 0xff00) >> 8;
t->remote[5] =3D (htons(addr->sin_port) & 0x00ff) >> 0;
t->remote_length =3D 6;
memcpy(t->data, addr_pair, sizeof(netsnmp_udp_addr_pair));
t->data_length =3D sizeof(netsnmp_udp_addr_pair);
}

/*
* 16-bit length field, 8 byte UDP header, 20 byte IPv4 header =20
*/

t->msgMaxSize =3D 0xffff - 8 - 20;
t->f_recv =3D netsnmp_udp_recv;
t->f_send =3D netsnmp_udp_send;
t->f_close =3D netsnmp_udp_close;
t->f_accept =3D NULL;
t->f_fmtaddr =3D netsnmp_udp_fmtaddr;

return t;
}

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