[PATCH 2/5] Add a general netlink socket parser
Fabien Siron
fabien.siron at epita.fr
Wed Jun 1 10:15:07 UTC 2016
This commit introduces a general socket netlink parser which prints
the header and a string for the remaining part of the buffer. It doesn't
handle all the netlink flags and types because the parser needs more
information. It will be done soon.
* net.c (get_family): New function.
(do_msghdr): Call decode_iov_netlink.
* netlink.c: New file.
(decode_netlink): New function.
(decode_iov_netlink): New function.
* defs.h (decode_iov_netlink): Add.
* Makefile.am (strace_SOURCES): Add netlink.c.
---
Makefile.am | 1 +
defs.h | 4 +++
net.c | 60 ++++++++++++++++++++++++++++-----
netlink.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++
util.c | 2 +-
xlat/netlink_flags.in | 6 ++++
xlat/netlink_types.in | 4 +++
7 files changed, 161 insertions(+), 9 deletions(-)
create mode 100644 netlink.c
create mode 100644 xlat/netlink_flags.in
create mode 100644 xlat/netlink_types.in
diff --git a/Makefile.am b/Makefile.am
index 77e0cc8..ab0e200 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -156,6 +156,7 @@ strace_SOURCES = \
mtd.c \
native_defs.h \
net.c \
+ netlink.c \
numa.c \
open.c \
or1k_atomic.c \
diff --git a/defs.h b/defs.h
index 594a292..134e0fe 100644
--- a/defs.h
+++ b/defs.h
@@ -542,6 +542,7 @@ extern const char *signame(const int);
extern void pathtrace_select(const char *);
extern int pathtrace_match(struct tcb *);
extern int getfdpath(struct tcb *, int, char *, unsigned);
+extern int getfdproto(struct tcb *, int);
extern const char *xlookup(const struct xlat *, const uint64_t);
extern const char *xlat_search(const struct xlat *, const size_t, const uint64_t);
@@ -651,6 +652,9 @@ extern const char *sprintsigmask_n(const char *, const void *, unsigned int);
extern void printsignal(int);
extern void tprint_iov(struct tcb *, unsigned long, unsigned long, int decode_iov);
extern void tprint_iov_upto(struct tcb *, unsigned long, unsigned long, int decode_iov, unsigned long);
+extern void decode_iov_netlink_or_printaddr(struct tcb *, unsigned long,
+ unsigned long, unsigned long);
+extern void decode_netlink_or_printaddr(struct tcb *, unsigned long, unsigned long);
extern void tprint_open_modes(unsigned int);
extern const char *sprint_open_modes(unsigned int);
extern void print_seccomp_filter(struct tcb *, unsigned long);
diff --git a/net.c b/net.c
index 3349758..f56ff1c 100644
--- a/net.c
+++ b/net.c
@@ -297,6 +297,39 @@ printsock(struct tcb *tcp, long addr, int addrlen)
print_sockaddr(tcp, &addrbuf, addrlen);
}
+#include "socketutils.h"
+
+static void
+printsockbuf(struct tcb *tcp, int fd, long addr, long addrlen)
+{
+ int proto = getfdproto(tcp, fd);
+
+ switch (proto) {
+ case NETLINK:
+ decode_netlink_or_printaddr(tcp, addr, addrlen);
+ break;
+ default:
+ printstr(tcp, addr, addrlen);
+ }
+}
+
+static int
+get_family(struct tcb *tcp, long addr, int addrlen)
+{
+ sockaddr_buf_t addrbuf;
+
+ if (addrlen < 2)
+ return -1;
+ if (addrlen > (int) sizeof(addrbuf))
+ addrlen = sizeof(addrbuf);
+
+ memset(&addrbuf, 0, sizeof(addrbuf));
+ if (umoven(tcp, addr, addrlen, addrbuf.pad) == -1)
+ return -1;
+
+ return addrbuf.sa.sa_family;
+}
+
#include "xlat/scmvals.h"
#include "xlat/ip_cmsg_types.h"
@@ -598,8 +631,16 @@ do_msghdr(struct tcb *tcp, struct msghdr *msg, unsigned long data_size)
printsock(tcp, (long)msg->msg_name, msg->msg_namelen);
tprintf(", msg_iov(%lu)=", (unsigned long)msg->msg_iovlen);
- tprint_iov_upto(tcp, (unsigned long)msg->msg_iovlen,
- (unsigned long)msg->msg_iov, 1, data_size);
+#ifdef AF_NETLINK
+ if (get_family(tcp, (long) msg->msg_name, msg->msg_namelen)
+ == AF_NETLINK)
+ decode_iov_netlink_or_printaddr(tcp,
+ (unsigned long) msg->msg_iovlen,
+ (unsigned long) msg->msg_iov, data_size);
+ else
+#endif
+ tprint_iov_upto(tcp, (unsigned long)msg->msg_iovlen,
+ (unsigned long)msg->msg_iov, 1, data_size);
#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
tprintf(", msg_controllen=%lu", (unsigned long)msg->msg_controllen);
@@ -886,7 +927,7 @@ SYS_FUNC(send)
{
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
- printstr(tcp, tcp->u_arg[1], tcp->u_arg[2]);
+ printsockbuf(tcp, tcp->u_arg[0], tcp->u_arg[1], tcp->u_arg[2]);
tprintf(", %lu, ", tcp->u_arg[2]);
/* flags */
printflags(msg_flags, tcp->u_arg[3], "MSG_???");
@@ -898,7 +939,7 @@ SYS_FUNC(sendto)
{
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
- printstr(tcp, tcp->u_arg[1], tcp->u_arg[2]);
+ printsockbuf(tcp, tcp->u_arg[0], tcp->u_arg[1], tcp->u_arg[2]);
tprintf(", %lu, ", tcp->u_arg[2]);
/* flags */
printflags(msg_flags, tcp->u_arg[3], "MSG_???");
@@ -947,10 +988,11 @@ SYS_FUNC(recv)
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
} else {
- if (syserror(tcp))
+ if (syserror(tcp)) {
printaddr(tcp->u_arg[1]);
- else
- printstr(tcp, tcp->u_arg[1], tcp->u_rval);
+ } else
+ printsockbuf(tcp, tcp->u_arg[0], tcp->u_arg[1],
+ tcp->u_rval);
tprintf(", %lu, ", tcp->u_arg[2]);
printflags(msg_flags, tcp->u_arg[3], "MSG_???");
@@ -966,11 +1008,13 @@ SYS_FUNC(recvfrom)
printfd(tcp, tcp->u_arg[0]);
tprints(", ");
} else {
+
/* buf */
if (syserror(tcp)) {
printaddr(tcp->u_arg[1]);
} else {
- printstr(tcp, tcp->u_arg[1], tcp->u_rval);
+ printsockbuf(tcp, tcp->u_arg[0], tcp->u_arg[1],
+ tcp->u_rval);
}
/* len */
tprintf(", %lu, ", tcp->u_arg[2]);
diff --git a/netlink.c b/netlink.c
new file mode 100644
index 0000000..738c639
--- /dev/null
+++ b/netlink.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2016 Fabien Siron <fabien.siron at epita.fr>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "defs.h"
+#include <sys/socket.h>
+#if defined(HAVE_LINUX_NETLINK_H)
+# include <linux/netlink.h>
+#endif
+#include "xlat/netlink_flags.h"
+#include "xlat/netlink_types.h"
+
+void
+decode_netlink_or_printaddr(struct tcb *tcp, unsigned long addr,
+ unsigned long size)
+{
+#ifdef AF_NETLINK
+ struct nlmsghdr nlmsghdr;
+ memset(&nlmsghdr, 0, sizeof(nlmsghdr));
+ if (umoven(tcp, addr, sizeof(nlmsghdr), &nlmsghdr) == -1)
+ return;
+
+ tprintf("{{len=%u, type=", nlmsghdr.nlmsg_len);
+ if (nlmsghdr.nlmsg_type < NLMSG_MIN_TYPE)
+ printxval(netlink_types, nlmsghdr.nlmsg_type, "NLMSG_???");
+ else
+ tprintf("%u", nlmsghdr.nlmsg_type);
+
+ tprints(", flags=");
+ printflags(netlink_flags, nlmsghdr.nlmsg_flags, "NLM_F_???");
+ /* manage get/new requests */
+
+ tprintf(", seq=%u, pid=%u}, ", nlmsghdr.nlmsg_seq,
+ nlmsghdr.nlmsg_pid);
+
+ if (size - sizeof(struct nlmsghdr) > 0)
+ printstr(tcp, addr + sizeof(struct nlmsghdr),
+ size - sizeof(struct nlmsghdr));
+
+ tprints("}");
+
+#else
+ printaddr(addr);
+#endif
+}
+
+void
+decode_iov_netlink_or_printaddr(struct tcb *tcp, unsigned long len,
+ unsigned long addr, unsigned long data_size)
+{
+ unsigned long iov[2];
+ unsigned int i;
+
+ if (!len) {
+ tprints("[]");
+ return;
+ }
+
+ for (i = 0; i < len; ++i) {
+ if(umove_or_printaddr(tcp, addr + i * sizeof(iov), iov))
+ return;
+
+ if (iov[1] < sizeof(struct nlmsghdr)) {
+ tprintf("len(%lu)", len);
+ printaddr(addr);
+ return;
+ }
+ decode_netlink_or_printaddr(tcp, iov[0], iov[1]);
+ }
+}
diff --git a/util.c b/util.c
index b810fd0..f1ca079 100644
--- a/util.c
+++ b/util.c
@@ -481,7 +481,7 @@ const char *socket_protocol_strings[] = {
"UNIX",
};
-static int
+int
getfdproto(struct tcb *tcp, int fd)
{
#ifdef HAVE_SYS_XATTR_H
diff --git a/xlat/netlink_flags.in b/xlat/netlink_flags.in
new file mode 100644
index 0000000..1354506
--- /dev/null
+++ b/xlat/netlink_flags.in
@@ -0,0 +1,6 @@
+NLM_F_REQUEST 0x1
+NLM_F_MULTI 0x2
+NLM_F_ACK 0x4
+NLM_F_ECHO 0x8
+NLM_F_DUMP_INTR 0x10
+NLM_F_DUMP_FILTERED 0x20
diff --git a/xlat/netlink_types.in b/xlat/netlink_types.in
new file mode 100644
index 0000000..813b3ad
--- /dev/null
+++ b/xlat/netlink_types.in
@@ -0,0 +1,4 @@
+NETLINK_NOOP 0x1
+NETLINK_ERROR 0x2
+NETLINK_DONE 0x3
+NETLINK_OVERRUN 0x4
--
2.8.0
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