Auditd initial commit (dfa24649) · Commits · e / os / android_system_core

auditd/Android.mk

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		# Copyright 2005 The Android Open Source Project

		LOCAL_PATH:= $(call my-dir)
		include $(CLEAR_VARS)

		LOCAL_SRC_FILES:= \
		auditd.c \
		netlink.c \
		libaudit.c \
		audit_log.c

		LOCAL_SHARED_LIBRARIES := \
		libcutils \
		libc

		LOCAL_MODULE_TAGS:=optional
		LOCAL_MODULE:=auditd

		include $(BUILD_EXECUTABLE)

auditd/NOTICE

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		Copyright 2012, Samsung Telecommunications of America

		Licensed under the Apache License, Version 2.0 (the "License");
		you may not use this file except in compliance with the License.

		Unless required by applicable law or agreed to in writing, software
		distributed under the License is distributed on an "AS IS" BASIS,
		WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		See the License for the specific language governing permissions and
		limitations under the License.


		Apache License
		Version 2.0, January 2004
		http://www.apache.org/licenses/

		TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

		1. Definitions.

		"License" shall mean the terms and conditions for use, reproduction,
		and distribution as defined by Sections 1 through 9 of this document.

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		"Work" shall mean the work of authorship, whether in Source or
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		copyright notice that is included in or attached to the work
		(an example is provided in the Appendix below).

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		form, that is based on (or derived from) the Work and for which the
		editorial revisions, annotations, elaborations, or other modifications
		represent, as a whole, an original work of authorship. For the purposes
		of this License, Derivative Works shall not include works that remain
		separable from, or merely link (or bind by name) to the interfaces of,
		the Work and Derivative Works thereof.

		"Contribution" shall mean any work of authorship, including
		the original version of the Work and any modifications or additions
		to that Work or Derivative Works thereof, that is intentionally
		submitted to Licensor for inclusion in the Work by the copyright owner
		or by an individual or Legal Entity authorized to submit on behalf of
		the copyright owner. For the purposes of this definition, "submitted"
		means any form of electronic, verbal, or written communication sent
		to the Licensor or its representatives, including but not limited to
		communication on electronic mailing lists, source code control systems,
		and issue tracking systems that are managed by, or on behalf of, the
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		excluding communication that is conspicuously marked or otherwise
		designated in writing by the copyright owner as "Not a Contribution."

		"Contributor" shall mean Licensor and any individual or Legal Entity
		on behalf of whom a Contribution has been received by Licensor and
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		2. Grant of Copyright License. Subject to the terms and conditions of
		this License, each Contributor hereby grants to You a perpetual,
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		3. Grant of Patent License. Subject to the terms and conditions of
		this License, each Contributor hereby grants to You a perpetual,
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		(except as stated in this section) patent license to make, have made,
		use, offer to sell, sell, import, and otherwise transfer the Work,
		where such license applies only to those patent claims licensable
		by such Contributor that are necessarily infringed by their
		Contribution(s) alone or by combination of their Contribution(s)
		with the Work to which such Contribution(s) was submitted. If You
		institute patent litigation against any entity (including a
		cross-claim or counterclaim in a lawsuit) alleging that the Work
		or a Contribution incorporated within the Work constitutes direct
		or contributory patent infringement, then any patent licenses
		granted to You under this License for that Work shall terminate
		as of the date such litigation is filed.

		4. Redistribution. You may reproduce and distribute copies of the
		Work or Derivative Works thereof in any medium, with or without
		modifications, and in Source or Object form, provided that You
		meet the following conditions:

		(a) You must give any other recipients of the Work or
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		(b) You must cause any modified files to carry prominent notices
		stating that You changed the files; and

		(c) You must retain, in the Source form of any Derivative Works
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		of the NOTICE file are for informational purposes only and
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		or as an addendum to the NOTICE text from the Work, provided
		that such additional attribution notices cannot be construed
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		You may add Your own copyright statement to Your modifications and
		may provide additional or different license terms and conditions
		for use, reproduction, or distribution of Your modifications, or
		for any such Derivative Works as a whole, provided Your use,
		reproduction, and distribution of the Work otherwise complies with
		the conditions stated in this License.

		5. Submission of Contributions. Unless You explicitly state otherwise,
		any Contribution intentionally submitted for inclusion in the Work
		by You to the Licensor shall be under the terms and conditions of
		this License, without any additional terms or conditions.
		Notwithstanding the above, nothing herein shall supersede or modify
		the terms of any separate license agreement you may have executed
		with Licensor regarding such Contributions.

		6. Trademarks. This License does not grant permission to use the trade
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		unless required by applicable law (such as deliberate and grossly
		negligent acts) or agreed to in writing, shall any Contributor be
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		END OF TERMS AND CONDITIONS

auditd/audit_log.c

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		#include <errno.h>
		#include <fcntl.h>
		#include <stdio.h>
		#include <string.h>
		#include <unistd.h>
		#include <stdint.h>

		#include <sys/klog.h>
		#include <sys/types.h>
		#include <sys/stat.h>

		#include "libaudit.h"
		#include "audit_log.h"
		#include "auditd.h"

		#define AUDIT_LOG_MODE (S_IRUSR \| S_IWUSR \| S_IRGRP)
		#define AUDIT_LOG_FLAGS (O_RDWR \| O_CREAT \| O_SYNC)

		struct audit_log {
		int fd;
		size_t total_bytes;
		size_t threshold;
		char *rotatefile;
		char *logfile;
		};

		/**
		* Writes data pointed by buf to audit log, appends a trailing newline.
		* @param l
		* The log to write
		* @param buf
		* The data to write
		* @param len
		* The length of the data
		* @return
		*/
		static int write_log(audit_log l, const void buf, size_t len) {

		int rc = 0;
		ssize_t bytes = 0;

		/*
		* Ensure that the pointer offset and
		* number of bytes written are the same
		* size. Avoid char *, as on esoteric
		* systems that are not byte addressable
		* it could be defined as something else.
		*/
		const uint8_t b = (uint8_t )buf;

		if(!l) {
		rc = EINVAL;
		goto err;
		}

		do {
		bytes = write(l->fd, b, len);
		if(bytes < 0 && errno != EINTR) {
		rc = errno;
		goto err;
		}
		b += bytes;
		len -= bytes;
		l->total_bytes += bytes;
		} while (len > 0);


		out:
		/*
		* Always attempt to write a newline, but ignore
		* any errors as it could be a cascading effect
		* from above.
		*/
		bytes = write(l->fd, "\n", 1);
		l->total_bytes += (bytes > 0) ? bytes : 0;

		/*
		* Always attempt to rotate, even in the
		* face of errors above
		*/
		if(l->total_bytes > l->threshold) {
		rc = audit_log_rotate(l);
		}

		return rc;

		err:
		ERROR("Error in function: %s, line: %d, error: %s\n",
		__FUNCTION__, __LINE__, strerror(rc));
		goto out;
		}

		audit_log audit_log_open(const char logfile, const char *rotatefile, size_t threshold) {

		int fd = -1;
		audit_log *l = NULL;
		struct stat log_file_stats;

		if (stat(logfile, &log_file_stats) < 0) {
		if (errno != ENOENT) {
		ERROR("Could not stat %s: %s\n",
		logfile, strerror(errno));
		goto err;
		}
		}
		/* The existing log had data */
		else if (log_file_stats.st_size != 0){
		if (rename(logfile, rotatefile) < 0) {
		ERROR("Could not rename %s to %s: %s\n",
		logfile, rotatefile, strerror(errno));
		goto err;
		}
		}

		/* Open the output logfile */
		fd = open(logfile, AUDIT_LOG_FLAGS, AUDIT_LOG_MODE);
		if (fd < 0) {
		ERROR("Could not open %s: %s\n",
		logfile, strerror(errno));
		goto err;
		}
		fchmod(fd, AUDIT_LOG_MODE);

		l = calloc(sizeof(struct audit_log), 1);
		if (!l) {
		goto err;
		}
		l->rotatefile = strdup(rotatefile);
		if (!l->rotatefile) {
		goto err;
		}

		l->logfile = strdup(logfile);
		if (!l->logfile) {
		goto err;
		}
		l->fd = fd;
		l->threshold = threshold;

		out:
		return l;

		err:
		audit_log_close(l);
		l = NULL;
		goto out;
		}

		int audit_log_write_str(audit_log l, const char str) {
		return write_log(l, str, strlen(str));
		}

		int audit_log_write(audit_log l, const struct audit_reply reply) {
		return write_log(l, reply->msg.data, reply->len);
		}

		int audit_log_rotate(audit_log *l) {
		int rc = 0;
		if(!l) {
		rc = EINVAL;
		goto err;
		}

		rc = rename(l->logfile, l->rotatefile);
		if (rc < 0) {
		rc = errno;
		goto err;
		}

		close(l->fd);
		l->total_bytes = 0;

		l->fd = open(l->logfile, AUDIT_LOG_FLAGS, AUDIT_LOG_MODE);
		if(l->fd < 0) {
		rc = errno;
		goto err;
		}
		fchmod(l->fd, AUDIT_LOG_MODE);

		out:
		return rc;
		err:
		goto out;
		}

		void audit_log_close(audit_log *l) {
		if(l) {
		if(l->logfile) {
		free(l->logfile);
		}
		if(l->rotatefile) {
		free(l->rotatefile);
		}
		if(l->fd >= 0) {
		close(l->fd);
		}
		free(l);
		l = NULL;
		}
		return;
		}

		int audit_log_put_kmsg(audit_log *l) {

		char *tok;

		int rc = 0;
		char *buf = NULL;
		int len = klogctl(KLOG_SIZE_BUFFER, NULL, 0);

		if (len > 0) {
		len++;
		buf = malloc(len * sizeof(*buf));
		if (!buf) {
		ERROR("Out of memory\n");
		rc = ENOMEM;
		goto err;
		}
		}
		else if(len < 0) {
		ERROR("Could not read logs: %s\n",
		strerror(errno));
		rc = errno;
		goto err;
		}

		rc = klogctl(KLOG_READ_ALL, buf, len);
		if(rc < 0) {
		ERROR("Could not read logs: %s\n",
		strerror(errno));
		rc = errno;
		goto err;
		}

		buf[len-1] = '\0';
		tok = buf;

		while((tok = strtok(tok, "\r\n"))) {
		if(strstr(tok, " audit(")) {
		audit_log_write_str(l, tok);
		}
		tok = NULL;
		}

		err:
		if (buf) {
		free(buf);
		}

		return 0;
		}

auditd/audit_log.h

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		/*
		* Copyright 2012, Samsung Telecommunications of America
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*
		* Written by William Roberts <w.roberts@sta.samsung.com>
		*/

		#ifndef _AUDIT_LOG_H_
		#define _AUDIT_LOG_H_

		#include <unistd.h>
		#include "libaudit.h"

		typedef struct audit_log audit_log;

		/**
		* Opens an audit logfile for writing
		* @param logfile
		* The logfile name to use
		* @param rotatefile
		* The logfile to rotate to when threshold is encountered
		* @param threshold
		* The threshold, in bytes, the log file should grow to
		* until rotation.
		* @return
		* A valid handle to the audit_log.
		*/
		extern audit_log audit_log_open(const char logfile, const char *rotatefile, size_t threshold);

		/**
		* Appends an audit reposnse to the audit log, and rotates the log if threshold is
		* passed. Note, it always finishes a message even if it is past threshold. Also
		* always appends a newline to the end of the message.
		* @param l
		* The audit log to use
		* @param reply
		* The response to write
		* @return
		* 0 on success
		*/
		extern int audit_log_write(audit_log l, const struct audit_reply reply);

		/**
		* Appends a string to the audit log, appending a newline, and rotating
		* the logs if needed.
		* @param l
		* The audit log to append too.
		* @param str
		* The string to append to the log.
		* @return
		* 0 on success
		*/
		extern int audit_log_write_str(audit_log l, const char str);

		/**
		* Forces a rotation of the audit log.
		* @param l
		* The log file to use
		* @return
		* 0 on success
		*/
		extern int audit_log_rotate(audit_log *l);

		/**
		* Closes the audit log file.
		* @param l
		* The log file to close, NULL's the pointer.
		*/
		extern void audit_log_close(audit_log *l);

		/**
		* Searches once through kmesg for type=1400
		* kernel messages and logs them to the audit log
		* @param l
		* The log to append too
		* @return
		* 0 on success
		*/
		extern int audit_log_put_kmsg(audit_log *l);

		#endif

auditd/auditd.c

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		/*
		* Copyright 2012, Samsung Telecommunications of America
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*
		* Written by William Roberts <w.roberts@sta.samsung.com>
		*/

		#include <stdio.h>
		#include <stdlib.h>

		#include <errno.h>
		#include <fcntl.h>
		#include <poll.h>
		#include <stdarg.h>
		#include <stdint.h>
		#include <string.h>
		#include <syslog.h>
		#include <unistd.h>

		#include <sys/socket.h>
		#include <sys/stat.h>
		#include <sys/types.h>

		#include <cutils/klog.h>
		#include <private/android_filesystem_config.h>

		#include <linux/capability.h>
		#include <linux/prctl.h>

		#include "auditd.h"
		#include "libaudit.h"
		#include "audit_log.h"

		/*
		* TODO:
		* Just Ideas:
		* 1. Add a socket interface for sending events
		*/

		#define LOG_DIR "/data/misc/audit"
		#define LOG_FILE LOG_DIR "/audit.log"
		#define OLD_LOG_FILE LOG_DIR "/audit.old"

		#define MAX_LOG_FILE_SIZE (1024 * 100)

		static volatile int quit = 0;

		static void signal_handler(int sig) {
		switch (sig) {
		case SIGINT:
		quit = 1;
		break;
		}
		return;
		}

		static void usage(char *cmd) {
		printf("%s - log audit events from the kernel\n"
		"OPTIONS\n"
		"-k - search dmesg on startup for audit events\n"
		"\n",
		cmd);
		}

		#define RAISE(ary, c) ary[CAP_TO_INDEX(c)].permitted \|= CAP_TO_MASK(c);

		static void drop_privileges_or_die(void) {
		struct __user_cap_header_struct capheader;
		struct __user_cap_data_struct capdata[2];

		if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
		ERROR("Failed on prctl KEEPCAPS: %s\n", strerror(errno));
		exit(1);
		}

		if (setgid(AID_AUDIT) < 0) {
		ERROR("Failed on setgid: %s\n", strerror(errno));
		exit(1);
		}

		if (setuid(AID_AUDIT) < 0) {
		ERROR("Failed on setuid: %s\n", strerror(errno));
		exit(1);
		}

		memset(&capheader, 0, sizeof(capheader));
		memset(&capdata, 0, sizeof(capdata));
		capheader.version = _LINUX_CAPABILITY_VERSION_3;
		capheader.pid = 0;

		RAISE(capdata, CAP_AUDIT_CONTROL);
		RAISE(capdata, CAP_SYSLOG);

		capdata[0].effective = capdata[0].permitted;
		capdata[1].effective = capdata[1].permitted;
		capdata[0].inheritable = 0;
		capdata[1].inheritable = 0;

		if (capset(&capheader, &capdata[0]) < 0) {
		ERROR("Failed on capset: %s\n", strerror(errno));
		exit(1);
		}
		}

		int main(int argc, char *argv[]) {

		int c;

		struct audit_reply rep;
		struct sigaction action;

		int rc;
		int audit_fd = -1;
		int check_kernel_log = 0;

		audit_log *l = NULL;
		ssize_t total_bytes = 0;
		struct pollfd pfds;

		INFO("auditd: starting up\n");

		drop_privileges_or_die();

		/* register the signal handler */
		action.sa_handler = signal_handler;
		sigemptyset (&action.sa_mask);
		action.sa_flags = 0;
		rc = sigaction (SIGINT, &action, NULL);
		if (rc < 0) {
		rc = errno;
		ERROR("Failed on set signal handler: %s\n", strerror(errno));
		goto err;
		}

		while((c = getopt(argc, argv, "k")) != -1) {
		switch(c) {
		case 'k':
		check_kernel_log = 1;
		break;
		default:
		usage(argv[0]);
		goto err;
		}
		}

		/* Open the netlink socket for audit events */
		audit_fd = audit_open();
		if (audit_fd < 0) {
		rc = errno;
		ERROR("Failed on audit_set_pid with error: %s\n", strerror(errno));
		goto err;
		}

		l = audit_log_open(LOG_FILE, OLD_LOG_FILE, MAX_LOG_FILE_SIZE);
		if(!l) {
		ERROR("Failed on audit_log_open\n");
		goto err;
		}

		if (audit_set_pid(audit_fd, getpid(), WAIT_YES) < 0) {
		rc = errno;
		ERROR("Failed on audit_set_pid with error: %s\n", strerror(errno));
		goto err;
		}

		pfds.fd = audit_fd;
		pfds.events = POLLIN;

		if(check_kernel_log) {
		audit_log_put_kmsg(l);
		}

		while (!quit) {

		/* Start reading for events */
		rc = poll(&pfds, 1, -1);
		if (rc == 0) {
		continue;
		}
		else if(rc < 0) {
		if (errno != EINTR) {
		ERROR("Failed to poll audit log socket: %d : %s\n", errno, strerror(errno));
		}
		continue;
		}

		if (audit_get_reply(audit_fd, &rep, GET_REPLY_BLOCKING, 0) < 0) {
		ERROR("Failed on audit_get_reply with error: %s\n", strerror(errno));
		continue;
		}

		audit_log_write(l, &rep);
		/* Keep reading for events */
		}

		err:
		INFO("auditd: exiting\n");
		if (audit_fd >= 0) {
		audit_set_pid(audit_fd, 0, WAIT_NO);
		audit_close(audit_fd);
		}
		audit_log_close(l);
		return rc;
		}