strace/netlink.c
Dmitry V. Levin 28e478a6eb netlink: move NLMSG_ERROR payload length check to nlmsgerr decoder
Move decoder specific check to the decoder.

* netlink.c (decode_payload): Move NLMSG_ERROR payload length check ...
(decode_nlmsgerr): ... here.
2017-06-02 22:22:22 +00:00

192 lines
5.0 KiB
C

/*
* Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
* Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
* Copyright (c) 2016-2017 The strace developers.
* 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>
#include <linux/netlink.h>
#include "xlat/netlink_flags.h"
#include "xlat/netlink_types.h"
#undef NLMSG_HDRLEN
#define NLMSG_HDRLEN NLMSG_ALIGN(sizeof(struct nlmsghdr))
/*
* Fetch a struct nlmsghdr from the given address.
*/
static bool
fetch_nlmsghdr(struct tcb *const tcp, struct nlmsghdr *const nlmsghdr,
const kernel_ulong_t addr, const kernel_ulong_t len)
{
if (len < sizeof(struct nlmsghdr)) {
printstrn(tcp, addr, len);
return false;
}
if (umove_or_printaddr(tcp, addr, nlmsghdr))
return false;
return true;
}
static void
print_nlmsghdr(struct tcb *tcp, const struct nlmsghdr *const nlmsghdr)
{
/* print the whole structure regardless of its nlmsg_len */
tprintf("{len=%u, type=", nlmsghdr->nlmsg_len);
printxval(netlink_types, nlmsghdr->nlmsg_type, "NLMSG_???");
tprints(", flags=");
printflags(netlink_flags, nlmsghdr->nlmsg_flags, "NLM_F_???");
tprintf(", seq=%u, pid=%u}", nlmsghdr->nlmsg_seq,
nlmsghdr->nlmsg_pid);
}
static void
decode_nlmsghdr_with_payload(struct tcb *const tcp,
const struct nlmsghdr *const nlmsghdr,
const kernel_ulong_t addr,
const kernel_ulong_t len);
static void
decode_nlmsgerr(struct tcb *const tcp,
kernel_ulong_t addr,
kernel_ulong_t len)
{
struct nlmsgerr err;
if (len < sizeof(err.error)) {
printstrn(tcp, addr, len);
return;
}
if (umove_or_printaddr(tcp, addr, &err.error))
return;
tprints("{error=");
if (err.error < 0 && (unsigned) -err.error < nerrnos) {
tprintf("-%s", errnoent[-err.error]);
} else {
tprintf("%d", err.error);
}
addr += offsetof(struct nlmsgerr, msg);
len -= offsetof(struct nlmsgerr, msg);
if (len) {
tprints(", msg=");
if (fetch_nlmsghdr(tcp, &err.msg, addr, len)) {
decode_nlmsghdr_with_payload(tcp, &err.msg, addr, len);
}
}
tprints("}");
}
static void
decode_payload(struct tcb *const tcp,
const struct nlmsghdr *const nlmsghdr,
const kernel_ulong_t addr,
const kernel_ulong_t len)
{
if (nlmsghdr->nlmsg_type == NLMSG_ERROR) {
decode_nlmsgerr(tcp, addr, len);
return;
}
printstrn(tcp, addr, len);
}
static void
decode_nlmsghdr_with_payload(struct tcb *const tcp,
const struct nlmsghdr *const nlmsghdr,
const kernel_ulong_t addr,
const kernel_ulong_t len)
{
tprints("{");
print_nlmsghdr(tcp, nlmsghdr);
unsigned int nlmsg_len =
nlmsghdr->nlmsg_len > len ? len : nlmsghdr->nlmsg_len;
if (nlmsg_len > NLMSG_HDRLEN) {
tprints(", ");
decode_payload(tcp, nlmsghdr, addr + NLMSG_HDRLEN,
nlmsg_len - NLMSG_HDRLEN);
}
tprints("}");
}
void
decode_netlink(struct tcb *const tcp, kernel_ulong_t addr, kernel_ulong_t len)
{
struct nlmsghdr nlmsghdr;
bool print_array = false;
unsigned int elt;
for (elt = 0; fetch_nlmsghdr(tcp, &nlmsghdr, addr, len); elt++) {
if (abbrev(tcp) && elt == max_strlen) {
tprints("...");
break;
}
unsigned int nlmsg_len = NLMSG_ALIGN(nlmsghdr.nlmsg_len);
kernel_ulong_t next_addr = 0;
kernel_ulong_t next_len = 0;
if (nlmsghdr.nlmsg_len >= NLMSG_HDRLEN) {
next_len = (len >= nlmsg_len) ? len - nlmsg_len : 0;
if (next_len && addr + nlmsg_len > addr)
next_addr = addr + nlmsg_len;
}
if (!print_array && next_addr) {
tprints("[");
print_array = true;
}
decode_nlmsghdr_with_payload(tcp, &nlmsghdr, addr, len);
if (!next_addr)
break;
tprints(", ");
addr = next_addr;
len = next_len;
}
if (print_array) {
tprints("]");
}
}