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platform_system_core
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Extend to receive NFLOG packets. 

Packets captured and logged by the NFLOG target are unicast, so
extend to catch and decode them.  To avoid escaping issues, the raw
contents are passed around as hex strings.

Bug: 18335678
Change-Id: Ib7299500baa00080a1f000f9da843eb527363353
This commit is contained in:
Jeff Sharkey 2014-10-30 14:51:59 -07:00
parent 4503a1450c
commit 9a20e67fa6
8 changed files with 86 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
CleanSpec.mk
View File

@ -54,3 +54,4 @@ $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/bin/reboot)
$(call add-clean-step, rm -rf $(PRODUCT_OUT)/root/default.prop)
$(call add-clean-step, rm -rf $(PRODUCT_OUT)/recovery/root/default.prop)
$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/EXECUTABLES/lmkd_intermediates/import_includes)
$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/SHARED_LIBRARIES/libsysutils_intermediates/import_includes)

1
include/cutils/uevent.h
View File

@ -27,6 +27,7 @@ extern "C" {
int uevent_open_socket(int buf_sz, bool passcred);
ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length);
ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer, size_t length, uid_t *uid);
ssize_t uevent_kernel_recv(int socket, void *buffer, size_t length, bool require_group, uid_t *uid);
#ifdef __cplusplus
}

1
include/sysutils/NetlinkEvent.h
View File

@ -57,6 +57,7 @@ public:
bool parseIfInfoMessage(const struct nlmsghdr *nh);
bool parseIfAddrMessage(const struct nlmsghdr *nh);
bool parseUlogPacketMessage(const struct nlmsghdr *nh);
bool parseNfPacketMessage(struct nlmsghdr *nh);
bool parseRtMessage(const struct nlmsghdr *nh);
bool parseNdUserOptMessage(const struct nlmsghdr *nh);
};

1
include/sysutils/NetlinkListener.h
View File

@ -27,6 +27,7 @@ class NetlinkListener : public SocketListener {
public:
static const int NETLINK_FORMAT_ASCII = 0;
static const int NETLINK_FORMAT_BINARY = 1;
static const int NETLINK_FORMAT_BINARY_UNICAST = 2;
#if 1
/* temporary version until we can get Motorola to update their

26
libcutils/uevent.c
View File

@ -31,12 +31,12 @@
*/
ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length)
{
uid_t user = -1;
return uevent_kernel_multicast_uid_recv(socket, buffer, length, &user);
uid_t uid = -1;
return uevent_kernel_multicast_uid_recv(socket, buffer, length, &uid);
}
/**
* Like the above, but passes a uid_t in by reference. In the event that this
* Like the above, but passes a uid_t in by pointer. In the event that this
* fails due to a bad uid check, the uid_t will be set to the uid of the
* socket's peer.
*
@ -44,8 +44,12 @@ ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length)
* returns -1, sets errno to EIO, and sets "user" to the UID associated with the
* message. If the peer UID cannot be determined, "user" is set to -1."
*/
ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
size_t length, uid_t *user)
ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer, size_t length, uid_t *uid)
{
return uevent_kernel_recv(socket, buffer, length, true, uid);
}
ssize_t uevent_kernel_recv(int socket, void *buffer, size_t length, bool require_group, uid_t *uid)
{
struct iovec iov = { buffer, length };
struct sockaddr_nl addr;
@ -60,7 +64,7 @@ ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
0,
};
*user = -1;
*uid = -1;
ssize_t n = recvmsg(socket, &hdr, 0);
if (n <= 0) {
return n;
@ -73,14 +77,18 @@ ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
}
struct ucred *cred = (struct ucred *)CMSG_DATA(cmsg);
*user = cred->uid;
*uid = cred->uid;
if (cred->uid != 0) {
/* ignoring netlink message from non-root user */
goto out;
}
if (addr.nl_groups == 0 || addr.nl_pid != 0) {
/* ignoring non-kernel or unicast netlink message */
if (addr.nl_pid != 0) {
/* ignore non-kernel */
goto out;
}
if (require_group && addr.nl_groups == 0) {
/* ignore unicast messages when requested */
goto out;
}

7
libsysutils/Android.mk
View File

@ -16,11 +16,12 @@ LOCAL_SRC_FILES:= \
LOCAL_MODULE:= libsysutils
LOCAL_C_INCLUDES :=
LOCAL_CFLAGS := -Werror
LOCAL_SHARED_LIBRARIES := libcutils liblog
LOCAL_SHARED_LIBRARIES := \
libcutils \
liblog \
libnl
include $(BUILD_SHARED_LIBRARY)

59
libsysutils/src/NetlinkEvent.cpp
View File

@ -32,13 +32,21 @@
#include <linux/if_addr.h>
#include <linux/if_link.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_log.h>
#include <linux/netfilter_ipv4/ipt_ULOG.h>
/* From kernel's net/netfilter/xt_quota2.c */
const int QLOG_NL_EVENT = 112;
const int LOCAL_QLOG_NL_EVENT = 112;
const int LOCAL_NFLOG_PACKET = NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET;
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <netlink/attr.h>
#include <netlink/genl/genl.h>
#include <netlink/handlers.h>
#include <netlink/msg.h>
const int NetlinkEvent::NlActionUnknown = 0;
const int NetlinkEvent::NlActionAdd = 1;
const int NetlinkEvent::NlActionRemove = 2;
@ -95,7 +103,8 @@ static const char *rtMessageName(int type) {
NL_EVENT_RTM_NAME(RTM_NEWROUTE);
NL_EVENT_RTM_NAME(RTM_DELROUTE);
NL_EVENT_RTM_NAME(RTM_NEWNDUSEROPT);
NL_EVENT_RTM_NAME(QLOG_NL_EVENT);
NL_EVENT_RTM_NAME(LOCAL_QLOG_NL_EVENT);
NL_EVENT_RTM_NAME(LOCAL_NFLOG_PACKET);
default:
return NULL;
}
@ -271,6 +280,41 @@ bool NetlinkEvent::parseUlogPacketMessage(const struct nlmsghdr *nh) {
return true;
}
/*
* Parse a LOCAL_NFLOG_PACKET message.
*/
bool NetlinkEvent::parseNfPacketMessage(struct nlmsghdr *nh) {
int uid = -1;
int len = 0;
char* raw = NULL;
struct nlattr *uid_attr = nlmsg_find_attr(nh, sizeof(struct genlmsghdr), NFULA_UID);
if (uid_attr) {
uid = ntohl(nla_get_u32(uid_attr));
}
struct nlattr *payload = nlmsg_find_attr(nh, sizeof(struct genlmsghdr), NFULA_PAYLOAD);
if (payload) {
/* First 256 bytes is plenty */
len = nla_len(payload);
if (len > 256) len = 256;
raw = (char*) nla_data(payload);
}
char* hex = (char*) calloc(1, 5 + (len * 2));
strcpy(hex, "HEX=");
for (int i = 0; i < len; i++) {
hex[4 + (i * 2)] = "0123456789abcdef"[(raw[i] >> 4) & 0xf];
hex[5 + (i * 2)] = "0123456789abcdef"[raw[i] & 0xf];
}
asprintf(&mParams[0], "UID=%d", uid);
mParams[1] = hex;
mSubsystem = strdup("strict");
mAction = NlActionChange;
return true;
}
/*
* Parse a RTM_NEWROUTE or RTM_DELROUTE message.
*/
@ -478,7 +522,7 @@ bool NetlinkEvent::parseNdUserOptMessage(const struct nlmsghdr *nh) {
* TODO: consider only ever looking at the first message.
*/
bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
const struct nlmsghdr *nh;
struct nlmsghdr *nh;
for (nh = (struct nlmsghdr *) buffer;
NLMSG_OK(nh, (unsigned) size) && (nh->nlmsg_type != NLMSG_DONE);
@ -493,7 +537,7 @@ bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
if (parseIfInfoMessage(nh))
return true;
} else if (nh->nlmsg_type == QLOG_NL_EVENT) {
} else if (nh->nlmsg_type == LOCAL_QLOG_NL_EVENT) {
if (parseUlogPacketMessage(nh))
return true;
@ -511,6 +555,10 @@ bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
if (parseNdUserOptMessage(nh))
return true;
} else if (nh->nlmsg_type == LOCAL_NFLOG_PACKET) {
if (parseNfPacketMessage(nh))
return true;
}
}
@ -588,7 +636,8 @@ bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) {
}
bool NetlinkEvent::decode(char *buffer, int size, int format) {
if (format == NetlinkListener::NETLINK_FORMAT_BINARY) {
if (format == NetlinkListener::NETLINK_FORMAT_BINARY
|| format == NetlinkListener::NETLINK_FORMAT_BINARY_UNICAST) {
return parseBinaryNetlinkMessage(buffer, size);
} else {
return parseAsciiNetlinkMessage(buffer, size);

9
libsysutils/src/NetlinkListener.cpp
View File

@ -47,8 +47,13 @@ bool NetlinkListener::onDataAvailable(SocketClient *cli)
ssize_t count;
uid_t uid = -1;
count = TEMP_FAILURE_RETRY(uevent_kernel_multicast_uid_recv(
socket, mBuffer, sizeof(mBuffer), &uid));
bool require_group = true;
if (mFormat == NETLINK_FORMAT_BINARY_UNICAST) {
require_group = false;
}
count = TEMP_FAILURE_RETRY(uevent_kernel_recv(socket,
mBuffer, sizeof(mBuffer), require_group, &uid));
if (count < 0) {
if (uid > 0)
LOG_EVENT_INT(65537, uid);