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Diffstat (limited to 'modules/pam_faillock/faillock.c')
| -rw-r--r-- | modules/pam_faillock/faillock.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/modules/pam_faillock/faillock.c b/modules/pam_faillock/faillock.c new file mode 100644 index 0000000..091f253 --- /dev/null +++ b/modules/pam_faillock/faillock.c @@ -0,0 +1,176 @@ +/* + * 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; +} |