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libnetlink: back port a fix for nlattr_parse()

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The bug was fixed in libnl-3 3.2.24, but
rhel7 and the Trusty ubuntu don't update this packet yet

commit b50a36bf34e7452377ab9bbb4d1873b68c65bf72
Author: Samuel Gauthier <samuel.gauthier@6wind.com>
Date:   Fri Nov 29 09:28:44 2013 +0100

    The commit 6a8d90f5fec4 "attr: Allow attribute type 0" intended to
    allow the parsing of {netlink,packet,unix}_diag, even if they are
    using type 0 for valid attributes.

    It lacked this part in nla_parse.

    Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
    Signed-off-by: Samuel Gauthier <samuel.gauthier@6wind.com>
    Signed-off-by: Thomas Graf <tgraf@suug.ch>

Fixes #137

Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
This commit is contained in:
Andrew Vagin 2016-03-16 08:06:00 +03:00 • committed by Pavel Emelyanov
parent cabafae2e5
commit bb2f97e663
2 changed files with 76 additions and 0 deletions
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4
criu/Makefile
View file

@ -6,6 +6,10 @@ HOSTLD ?= ld
HOSTCFLAGS ?= $(CFLAGS)
CFLAGS += $(USERCFLAGS)
# here is a workaround for a bug in libnl-3:
# 6a8d90f5fec4 "attr: Allow attribute type 0"
LDFLAGS += -Wl,--wrap=nla_parse,--wrap=nlmsg_parse
export HOSTCC HOSTLD HOSTCFLAGS
ifeq ($(ARCH),x86)

72
criu/libnetlink.c
View file

@ -3,6 +3,7 @@
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <libnl3/netlink/attr.h>
#include <libnl3/netlink/msg.h>
#include <string.h>
#include <unistd.h>
@ -146,3 +147,74 @@ int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
return 0;
}
/*
* Here is a workaround for a bug in libnl-3:
* 6a8d90f5fec4 "attr: Allow attribute type 0
*/
/**
* Create attribute index based on a stream of attributes.
* @arg tb Index array to be filled (maxtype+1 elements).
* @arg maxtype Maximum attribute type expected and accepted.
* @arg head Head of attribute stream.
* @arg len Length of attribute stream.
* @arg policy Attribute validation policy.
*
* Iterates over the stream of attributes and stores a pointer to each
* attribute in the index array using the attribute type as index to
* the array. Attribute with a type greater than the maximum type
* specified will be silently ignored in order to maintain backwards
* compatibility. If \a policy is not NULL, the attribute will be
* validated using the specified policy.
*
* @see nla_validate
* @return 0 on success or a negative error code.
*/
int __wrap_nla_parse(struct nlattr *tb[], int maxtype, struct nlattr *head, int len,
struct nla_policy *policy)
{
struct nlattr *nla;
int rem;
memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1));
nla_for_each_attr(nla, head, len, rem) {
int type = nla_type(nla);
if (type > maxtype)
continue;
if (tb[type])
pr_warn("Attribute of type %#x found multiple times in message, "
"previous attribute is being ignored.\n", type);
tb[type] = nla;
}
if (rem > 0)
pr_warn("netlink: %d bytes leftover after parsing "
"attributes.\n", rem);
return 0;
}
/**
* parse attributes of a netlink message
* @arg nlh netlink message header
* @arg hdrlen length of family specific header
* @arg tb destination array with maxtype+1 elements
* @arg maxtype maximum attribute type to be expected
* @arg policy validation policy
*
* See nla_parse()
*/
int __wrap_nlmsg_parse(struct nlmsghdr *nlh, int hdrlen, struct nlattr *tb[],
int maxtype, struct nla_policy *policy)
{
if (!nlmsg_valid_hdr(nlh, hdrlen))
return -NLE_MSG_TOOSHORT;
return nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
nlmsg_attrlen(nlh, hdrlen), policy);
}