File openssh-7.7p1-fips_checks.patch of Package openssh-askpass-gnome.28809
# HG changeset patch
# Parent e9b69da9a0f8dca923f8fc2836b38fe6590c791a
#
# Simple implementation of FIPS 140-2 selfchecks. Use OpenSSL to generate and
# verify checksums of binaries. Any hash iused in OpenSSH can be used (MD5 would
# obviously be a poor choice, since OpenSSL would barf and abort immediately in
# FIPS mode). SHA-2 seems to be a reasonable choice.
#
# The logic of the checks is as follows: decide whether FIPS mode is mandated
# (either by checking /proc/sys/crypto/fips_enabled or envoroinment variable
# SSH_FORCE_FIPS. In FIPS mode, checksums are required to match (inability to
# retrieve pre-calculated hash is a fatal error). In non-FIPS mode the checks
# still must be performed, unless the hashes are not installed. Thus if the hash
# file is not found (or the hash matches), proceed in non-FIPS mode and abort
# otherwise.
diff --git a/fips-check.c b/fips-check.c
new file mode 100644
index 0000000..eceb031
--- /dev/null
+++ b/fips-check.c
@@ -0,0 +1,34 @@
+#include "includes.h"
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "digest.h"
+#include "fips.h"
+
+#include <openssl/err.h>
+
+#define PROC_NAME_LEN 64
+
+static const char *argv0;
+
+void
+print_help_exit(int ev)
+{
+ fprintf(stderr, "%s <-c|-w> <file> <checksum_file>\n", argv0);
+ fprintf(stderr, " -c verify hash of 'file' against hash in 'checksum_file'\n");
+ fprintf(stderr, " -w write hash of 'file' into 'checksum_file'\n");
+ exit(ev);
+}
+
+int
+main(int argc, char **argv)
+{
+ fips_ssh_init();
+ return 0;
+}
diff --git a/fips.c b/fips.c
index 23e3876..297ae99 100644
--- a/fips.c
+++ b/fips.c
@@ -35,30 +35,293 @@
#include "log.h"
#include "xmalloc.h"
+#include <errno.h>
+#include <fcntl.h>
#include <string.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
#include <openssl/crypto.h>
+#include <openssl/err.h>
+#include <openssl/hmac.h>
static int fips_state = -1;
+/* calculates HMAC of contents of a file given by filename using the hash
+ * algorithm specified by FIPS_HMAC_EVP in fips.h and placing the result into
+ * newly allacated memory - remember to free it when not needed anymore */
static int
-fips_check_required_env(void)
+hmac_file(const char *filename, u_char **hmac_out)
+{
+ int check = -1;
+ int fd;
+ struct stat fs;
+ void *hmap;
+ unsigned char *hmac;
+ unsigned char *hmac_rv = NULL;
+
+ hmac = xmalloc(FIPS_HMAC_LEN);
+
+ fd = open(filename, O_RDONLY);
+ if (-1 == fd)
+ goto bail_out;
+
+ if (-1 == fstat(fd, &fs))
+ goto bail_out;
+
+ hmap = mmap(NULL, fs.st_size, PROT_READ, MAP_SHARED, fd, 0);
+
+ if ((void *)(-1) != hmap) {
+ hmac_rv = HMAC(FIPS_HMAC_EVP(), FIPS_HMAC_KEY
+ , strlen(FIPS_HMAC_KEY), hmap, fs.st_size, hmac, NULL);
+ check = CHECK_OK;
+ munmap(hmap, fs.st_size);
+ }
+ close(fd);
+
+bail_out:
+ if (hmac_rv) {
+ check = CHECK_OK;
+ *hmac_out = hmac;
+ } else {
+ check = CHECK_FAIL;
+ *hmac_out = NULL;
+ free(hmac);
+ }
+ return check;
+}
+
+/* find pathname of binary of process with PID pid. exe is buffer expected to
+ * be capable of holding at least max_pathlen characters
+ */
+static int
+get_executable_path(pid_t pid, char *exe, int max_pathlen)
+{
+ char exe_sl[PROC_EXE_PATH_LEN];
+ int n;
+ int rv = -1;
+
+ n = snprintf(exe_sl, sizeof(exe_sl), "/proc/%u/exe", pid);
+ if ((n <= 10) || (n >= max_pathlen)) {
+ fatal("error compiling filename of link to executable");
+ }
+
+ exe[0] = 0;
+ n = readlink(exe_sl, exe, max_pathlen);
+ /* the file doesn't need to exist - procfs might not be mounted in
+ * chroot */
+ if (n == -1) {
+ rv = CHECK_MISSING;
+ } else {
+ if (n < max_pathlen) {
+ exe[n] = 0;
+ rv = CHECK_OK;
+ } else {
+ rv = CHECK_FAIL;
+ }
+ }
+ return rv;
+}
+
+/* Read HMAC from file chk, allocating enough memory to hold the HMAC and
+ * return it in *hmac.
+ * Remember to free() it when it's not needed anymore.
+ */
+static int
+read_hmac(const char *chk, u_char **hmac)
+{
+ int check = -1;
+ int fdh, n;
+ u_char *hmac_in;
+
+ *hmac = NULL;
+
+ fdh = open(chk, O_RDONLY);
+ if (-1 == fdh) {
+ switch (errno) {
+ case ENOENT:
+ check = CHECK_MISSING;
+ debug("fips: checksum file %s is missing\n", chk);
+ break;
+ default:
+ check = CHECK_FAIL;
+ debug("fips: ckecksum file %s not accessible\n", chk);
+ break;
+
+ }
+ goto bail_out;
+ }
+
+ hmac_in = xmalloc(FIPS_HMAC_LEN);
+
+ n = read(fdh, (void *)hmac_in, FIPS_HMAC_LEN);
+ if (FIPS_HMAC_LEN != n) {
+ debug("fips: unable to read whole checksum from checksum file\n");
+ free (hmac_in);
+ check = CHECK_FAIL;
+ } else {
+ check = CHECK_OK;
+ *hmac = hmac_in;
+ }
+bail_out:
+ return check;
+}
+
+static int
+fips_hmac_self(void)
+{
+ int check = -1;
+ u_char *hmac = NULL, *hmac_chk = NULL;
+ char *exe, *chk;
+
+ exe = xmalloc(PATH_MAX);
+ chk = xmalloc(PATH_MAX);
+
+ /* we will need to add the suffix and the null terminator */
+ check = get_executable_path(getpid(), exe
+ , PATH_MAX - strlen(CHECKSUM_SUFFIX) - 1);
+ if (CHECK_OK != check)
+ goto cleanup;
+
+ strncpy(chk, exe, PATH_MAX);
+ strlcat(chk, CHECKSUM_SUFFIX, PATH_MAX);
+
+ check = read_hmac(chk, &hmac_chk);
+ if (CHECK_OK != check)
+ goto cleanup;
+
+ check = hmac_file(exe, &hmac);
+ if (CHECK_OK != check)
+ goto cleanup;
+
+ check = memcmp(hmac, hmac_chk, FIPS_HMAC_LEN);
+ if (0 == check) {
+ check = CHECK_OK;
+ debug("fips: checksum matches\n");
+ } else {
+ check = CHECK_FAIL;
+ debug("fips: checksum mismatch!\n");
+ }
+
+cleanup:
+ free(hmac);
+ free(hmac_chk);
+ free(chk);
+ free(exe);
+
+ return check;
+}
+
+static int
+fips_check_required_proc(void)
{
int fips_required = 0;
- char *env = getenv(SSH_FORCE_FIPS_ENV);
-
- if (env) {
- errno = 0;
- fips_required = strtol(env, NULL, 10);
- if (errno) {
- debug("bogus value in the %s environment variable, ignoring\n"
- , SSH_FORCE_FIPS_ENV);
- fips_required = 0;
- } else
- fips_required = 1;
+ int fips_fd;
+ char fips_sys = 0;
+
+ struct stat dummy;
+ if (-1 == stat(FIPS_PROC_PATH, &dummy)) {
+ switch (errno) {
+ case ENOENT:
+ case ENOTDIR:
+ break;
+ default:
+ fatal("Check for system-wide FIPS mode is required and %s cannot"
+ " be accessed for reason other than non-existence - aborting"
+ , FIPS_PROC_PATH);
+ break;
+ }
+ } else {
+ if (-1 == (fips_fd = open(FIPS_PROC_PATH, O_RDONLY)))
+ fatal("Check for system-wide FIPS mode is required and %s cannot"
+ " be opened for reading - aborting"
+ , FIPS_PROC_PATH);
+ if (1 > read(fips_fd, &fips_sys, 1))
+ fatal("Check for system-wide FIPS mode is required and %s doesn't"
+ " return at least one character - aborting"
+ , FIPS_PROC_PATH);
+ close(fips_sys);
+ switch (fips_sys) {
+ case '0':
+ case '1':
+ fips_required = fips_sys - '0';
+ break;
+ default:
+ fatal("Bogus character %c found in %s - aborting"
+ , fips_sys, FIPS_PROC_PATH);
+ }
}
return fips_required;
}
+static int
+fips_check_required_env(void)
+{
+ return (NULL != getenv(SSH_FORCE_FIPS_ENV));
+}
+
+static int
+fips_required(void)
+{
+ int fips_requests = 0;
+ fips_requests += fips_check_required_proc();
+ fips_requests += fips_check_required_env();
+ return fips_requests;
+}
+
+/* check whether FIPS mode is required and perform selfchecksum/selftest */
+void
+fips_ssh_init(void)
+{
+ int checksum;
+
+ checksum = fips_hmac_self();
+
+ if (fips_required()) {
+ switch (checksum) {
+ case CHECK_OK:
+ debug("fips: mandatory checksum ok");
+ break;
+ case CHECK_FAIL:
+ fatal("fips: mandatory checksum failed - aborting");
+ break;
+ case CHECK_MISSING:
+ fatal("fips: mandatory checksum data missing - aborting");
+ break;
+ default:
+ fatal("Fatal error: internal error at %s:%u"
+ , __FILE__, __LINE__);
+ break;
+ }
+ fips_state = FIPS_mode_set(1);
+ if (1 != fips_state) {
+ ERR_load_crypto_strings();
+ u_long err = ERR_get_error();
+ error("fips: OpenSSL error %lx: %s"
+ , err, ERR_error_string(err, NULL));
+ fatal("fips: unable to set OpenSSL into FIPS mode - aborting");
+ }
+ } else {
+ switch (checksum) {
+ case CHECK_OK:
+ debug("fips: checksum ok");
+ break;
+ case CHECK_FAIL:
+ fatal("fips: checksum failed - aborting");
+ break;
+ case CHECK_MISSING:
+ debug("fips: checksum data missing, but not required - continuing non-FIPS");
+ break;
+ default:
+ fatal("Fatal error: internal error at %s:%u",
+ __FILE__, __LINE__);
+ break;
+ }
+ }
+ return;
+}
+
int
fips_mode(void)
{
diff --git a/fips.h b/fips.h
index a115a61..3404684 100644
--- a/fips.h
+++ b/fips.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2012 Petr Cerny. All rights reserved.
+ * Copyright (c) 2012-2014 Petr Cerny. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -27,6 +27,15 @@
#include "sshkey.h"
#define SSH_FORCE_FIPS_ENV "SSH_FORCE_FIPS"
+#define FIPS_PROC_PATH "/proc/sys/crypto/fips_enabled"
+
+#define PROC_EXE_PATH_LEN 64
+#define CHECKSUM_SUFFIX ".hmac"
+#define FIPS_HMAC_KEY "HMAC_KEY:OpenSSH-FIPS@SLE"
+#define FIPS_HMAC_EVP EVP_sha256
+#define FIPS_HMAC_LEN 32
+
+void fips_ssh_init(void);
typedef enum {
FIPS_FILTER_CIPHERS,
@@ -34,6 +43,12 @@ typedef enum {
FIPS_FILTER_KEX_ALGS
} fips_filters;
+typedef enum {
+ CHECK_OK = 0,
+ CHECK_FAIL,
+ CHECK_MISSING
+} fips_checksum_status;
+
int fips_mode(void);
int fips_correct_dgst(int);
int fips_dgst_min(void);
@@ -41,4 +56,3 @@ enum fp_type fips_correct_fp_type(enum fp_type);
int fips_filter_crypto(char **, fips_filters);
#endif
-
diff --git a/sftp-server.c b/sftp-server.c
index b133cbc..c3086b6 100644
--- a/sftp-server.c
+++ b/sftp-server.c
@@ -53,6 +53,8 @@
char *sftp_realpath(const char *, char *); /* sftp-realpath.c */
+#include "fips.h"
+
/* Our verbosity */
static LogLevel log_level = SYSLOG_LEVEL_ERROR;
@@ -1595,6 +1597,9 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
extern char *optarg;
extern char *__progname;
+ /* initialize fips */
+ fips_ssh_init();
+
__progname = ssh_get_progname(argv[0]);
log_init(__progname, log_level, log_facility, log_stderr);
diff --git a/ssh.c b/ssh.c
index ee51823..882d1da 100644
--- a/ssh.c
+++ b/ssh.c
@@ -113,6 +113,8 @@
#include "ssh-pkcs11.h"
#endif
+#include "fips.h"
+
extern char *__progname;
/* Saves a copy of argv for setproctitle emulation */
@@ -596,6 +598,10 @@ main(int ac, char **av)
struct ssh_digest_ctx *md;
u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
+ /* initialize fips - can go before ssh_malloc_init(), since that is a
+ * OpenBSD-only thing (as of OpenSSH 7.6p1) */
+ fips_ssh_init();
+
/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
sanitise_stdfd();
diff --git a/sshd.c b/sshd.c
index c8086cd..bb20eec 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1443,6 +1443,10 @@ main(int ac, char **av)
Authctxt *authctxt;
struct connection_info *connection_info = NULL;
+ /* initialize fips - can go before ssh_malloc_init(), since that is a
+ * OpenBSD-only thing (as of OpenSSH 7.6p1) */
+ fips_ssh_init();
+
#ifdef HAVE_SECUREWARE
(void)set_auth_parameters(ac, av);
#endif
