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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:22:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:22:51 +0000 |
commit | 9ada0093e92388590c7368600ca4e9e3e376f0d0 (patch) | |
tree | a56fe41110023676d7082028cbaa47ca4b6e6164 /modules/pam_timestamp/hmacsha1.c | |
parent | Initial commit. (diff) | |
download | pam-upstream/1.5.2.tar.xz pam-upstream/1.5.2.zip |
Adding upstream version 1.5.2.upstream/1.5.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | modules/pam_timestamp/hmacsha1.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/modules/pam_timestamp/hmacsha1.c b/modules/pam_timestamp/hmacsha1.c new file mode 100644 index 0000000..45a3cac --- /dev/null +++ b/modules/pam_timestamp/hmacsha1.c @@ -0,0 +1,295 @@ +/* An implementation of HMAC using SHA-1. + * + * Copyright (c) 2003 Red Hat, Inc. + * Written by Nalin Dahyabhai <nalin@redhat.com> + * + * 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. + * + */ +/* See RFC 2104 for descriptions. */ +#include "config.h" +#include <sys/types.h> +#include <sys/stat.h> +#include <errno.h> +#include <fcntl.h> +#include <grp.h> +#include <pwd.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <syslog.h> +#include <security/pam_ext.h> +#include "hmacsha1.h" +#include "sha1.h" + +#define MINIMUM_KEY_SIZE SHA1_OUTPUT_SIZE +#define MAXIMUM_KEY_SIZE SHA1_BLOCK_SIZE + +static void +hmac_key_create(pam_handle_t *pamh, const char *filename, size_t key_size, + uid_t owner, gid_t group) +{ + int randfd, keyfd, i; + size_t count; + char *key; + + /* Open the destination file. */ + keyfd = open(filename, + O_WRONLY | O_CREAT | O_EXCL | O_TRUNC, + S_IRUSR | S_IWUSR); + if (keyfd == -1) { + pam_syslog(pamh, LOG_ERR, "Cannot create %s: %m", filename); + return; + } + + + if (fchown(keyfd, owner, group) == -1) { + pam_syslog(pamh, LOG_ERR, "Cannot chown %s: %m", filename); + close(keyfd); + return; + } + + /* Open the random device to get key data. */ + randfd = open("/dev/urandom", O_RDONLY); + if (randfd == -1) { + pam_syslog(pamh, LOG_ERR, "Cannot open /dev/urandom: %m"); + close(keyfd); + return; + } + + /* Read random data for use as the key. */ + key = malloc(key_size); + count = 0; + if (!key) { + close(keyfd); + close(randfd); + return; + } + while (count < key_size) { + i = read(randfd, key + count, key_size - count); + if ((i == 0) || (i == -1)) { + break; + } + count += i; + } + + close(randfd); + + /* If we didn't get enough, stop here. */ + if (count < key_size) { + pam_syslog(pamh, LOG_ERR, "Short read on random device"); + memset(key, 0, key_size); + free(key); + close(keyfd); + return; + } + + /* Now write the key. */ + count = 0; + while (count < key_size) { + i = write(keyfd, key + count, key_size - count); + if ((i == 0) || (i == -1)) { + break; + } + count += i; + } + memset(key, 0, key_size); + free(key); + close(keyfd); +} + +static void +hmac_key_read(pam_handle_t *pamh, const char *filename, size_t default_key_size, + uid_t owner, gid_t group, + void **key, size_t *key_size) +{ + char *tmp; + int keyfd, i, count; + struct stat st; + + tmp = NULL; + *key = NULL; + *key_size = 0; + + /* Try to open the key file. */ + keyfd = open(filename, O_RDONLY); + if (keyfd == -1) { + /* No such thing? Create it. */ + if (errno == ENOENT) { + hmac_key_create(pamh, filename, default_key_size, + owner, group); + keyfd = open(filename, O_RDONLY); + } else { + pam_syslog(pamh, LOG_ERR, "Cannot open %s: %m", filename); + } + if (keyfd == -1) + return; + } + + /* If we failed to open the file, we're done. */ + if (fstat(keyfd, &st) == -1) { + close(keyfd); + return; + } + + /* Read the contents of the file. */ + tmp = malloc(st.st_size); + if (!tmp) { + close(keyfd); + return; + } + + count = 0; + while (count < st.st_size) { + i = read(keyfd, tmp + count, st.st_size - count); + if ((i == 0) || (i == -1)) { + break; + } + count += i; + } + close(keyfd); + + /* Require that we got the expected amount of data. */ + if (count < st.st_size) { + memset(tmp, 0, st.st_size); + free(tmp); + return; + } + + /* Pass the key back. */ + *key = tmp; + *key_size = st.st_size; +} + +static void +xor_block(unsigned char *p, unsigned char byte, size_t length) +{ + size_t i; + for (i = 0; i < length; i++) { + p[i] = p[i] ^ byte; + } +} + +void +hmac_sha1_generate(void **mac, size_t *mac_length, + const void *raw_key, size_t raw_key_size, + const void *text, size_t text_length) +{ + unsigned char key[MAXIMUM_KEY_SIZE], tmp_key[MAXIMUM_KEY_SIZE]; + size_t maximum_key_size = SHA1_BLOCK_SIZE, + minimum_key_size = SHA1_OUTPUT_SIZE; + const unsigned char ipad = 0x36, opad = 0x5c; + struct sha1_context sha1; + unsigned char inner[SHA1_OUTPUT_SIZE], outer[SHA1_OUTPUT_SIZE]; + + *mac = NULL; + *mac_length = 0; + +#ifndef HMAC_ALLOW_SHORT_KEYS + /* If the key is too short, don't bother. */ + if (raw_key_size < minimum_key_size) { + return; + } +#endif + + /* If the key is too long, "compress" it, else copy it and pad it + * out with zero bytes. */ + memset(key, 0, sizeof(key)); + if (raw_key_size > maximum_key_size) { + sha1_init(&sha1); + sha1_update(&sha1, raw_key, raw_key_size); + sha1_output(&sha1, key); + } else { + memmove(key, raw_key, raw_key_size); + } + + /* Generate the inner sum. */ + memcpy(tmp_key, key, sizeof(tmp_key)); + xor_block(tmp_key, ipad, sizeof(tmp_key)); + + sha1_init(&sha1); + sha1_update(&sha1, tmp_key, sizeof(tmp_key)); + sha1_update(&sha1, text, text_length); + sha1_output(&sha1, inner); + + /* Generate the outer sum. */ + memcpy(tmp_key, key, sizeof(tmp_key)); + xor_block(tmp_key, opad, sizeof(tmp_key)); + + sha1_init(&sha1); + sha1_update(&sha1, tmp_key, sizeof(tmp_key)); + sha1_update(&sha1, inner, sizeof(inner)); + sha1_output(&sha1, outer); + + /* We don't need any of the keys any more. */ + memset(key, 0, sizeof(key)); + memset(tmp_key, 0, sizeof(tmp_key)); + + /* Allocate space to store the output. */ + *mac_length = sizeof(outer); + *mac = malloc(*mac_length); + if (*mac == NULL) { + *mac_length = 0; + return; + } + + memcpy(*mac, outer, *mac_length); +} + +void +hmac_sha1_generate_file(pam_handle_t *pamh, void **mac, size_t *mac_length, + const char *keyfile, uid_t owner, gid_t group, + const void *text, size_t text_length) +{ + void *key; + size_t key_length; + + hmac_key_read(pamh, keyfile, + MAXIMUM_KEY_SIZE, owner, group, + &key, &key_length); + if (key == NULL) { + *mac = NULL; + *mac_length = 0; + return; + } + hmac_sha1_generate(mac, mac_length, + key, key_length, + text, text_length); + memset(key, 0, key_length); + free(key); +} + +size_t +hmac_sha1_size(void) +{ + return SHA1_OUTPUT_SIZE; +} |