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-rw-r--r--modules/pam_faillock/faillock.c176
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diff --git a/modules/pam_faillock/faillock.c b/modules/pam_faillock/faillock.c
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+/*
+ * Copyright (c) 2010 Tomas Mraz <tmraz@redhat.com>
+ * Copyright (c) 2010, 2016, 2017 Red Hat, Inc.
+ *
+ * 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, and the entire permission notice in its entirety,
+ * including the disclaimer of warranties.
+ * 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.
+ *
+ * ALTERNATIVELY, this product may be distributed under the terms of
+ * the GNU Public License, in which case the provisions of the GPL are
+ * required INSTEAD OF the above restrictions. (This clause is
+ * necessary due to a potential bad interaction between the GPL and
+ * the restrictions contained in a BSD-style copyright.)
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 "config.h"
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <security/pam_modutil.h>
+
+#include "faillock.h"
+
+#define ignore_return(x) if (1==((int)x)) {;}
+
+int
+open_tally (const char *dir, const char *user, uid_t uid, int create)
+{
+ char *path;
+ int flags = O_RDWR;
+ int fd;
+
+ if (dir == NULL || strstr(user, "../") != NULL)
+ /* just a defensive programming as the user must be a
+ * valid user on the system anyway
+ */
+ return -1;
+ path = malloc(strlen(dir) + strlen(user) + 2);
+ if (path == NULL)
+ return -1;
+
+ strcpy(path, dir);
+ if (*dir && dir[strlen(dir) - 1] != '/') {
+ strcat(path, "/");
+ }
+ strcat(path, user);
+
+ if (create) {
+ flags |= O_CREAT;
+ if (access(dir, F_OK) != 0) {
+ mkdir(dir, 0755);
+ }
+ }
+
+ fd = open(path, flags, 0660);
+
+ free(path);
+
+ if (fd != -1) {
+ struct stat st;
+
+ while (flock(fd, LOCK_EX) == -1 && errno == EINTR);
+ if (fstat(fd, &st) == 0) {
+ if (st.st_uid != uid) {
+ ignore_return(fchown(fd, uid, -1));
+ }
+
+ /*
+ * If umask is set to 022, as will probably in most systems, then the
+ * group will not be able to write to the file. So, change the file
+ * permissions just in case.
+ * Note: owners of this file are user:root, so if the permissions are
+ * not changed the root process writing to this file will require
+ * CAP_DAC_OVERRIDE.
+ */
+ if (!(st.st_mode & S_IWGRP)) {
+ ignore_return(fchmod(fd, 0660));
+ }
+ }
+ }
+
+ return fd;
+}
+
+#define CHUNK_SIZE (64 * sizeof(struct tally))
+#define MAX_RECORDS 1024
+
+int
+read_tally(int fd, struct tally_data *tallies)
+{
+ void *data = NULL, *newdata;
+ unsigned int count = 0;
+ ssize_t chunk = 0;
+
+ do {
+ newdata = realloc(data, count * sizeof(struct tally) + CHUNK_SIZE);
+ if (newdata == NULL) {
+ free(data);
+ return -1;
+ }
+
+ data = newdata;
+
+ chunk = pam_modutil_read(fd, (char *)data + count * sizeof(struct tally), CHUNK_SIZE);
+ if (chunk < 0) {
+ free(data);
+ return -1;
+ }
+
+ count += chunk/sizeof(struct tally);
+
+ if (count >= MAX_RECORDS)
+ break;
+ }
+ while (chunk == CHUNK_SIZE);
+
+ tallies->records = data;
+ tallies->count = count;
+
+ return 0;
+}
+
+int
+update_tally(int fd, struct tally_data *tallies)
+{
+ void *data = tallies->records;
+ unsigned int count = tallies->count;
+ ssize_t chunk;
+
+ if (tallies->count > MAX_RECORDS) {
+ data = tallies->records + (count - MAX_RECORDS);
+ count = MAX_RECORDS;
+ }
+
+ if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
+ return -1;
+ }
+
+ chunk = pam_modutil_write(fd, data, count * sizeof(struct tally));
+
+ if (chunk != (ssize_t)(count * sizeof(struct tally))) {
+ return -1;
+ }
+
+ if (ftruncate(fd, count * sizeof(struct tally)) == -1)
+ return -1;
+
+ return 0;
+}