Adding upstream version 1:4.13+dfsg1.upstream/1%4.13+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 566 insertions, 0 deletions

diff --git a/libmisc/salt.c b/libmisc/salt.c
new file mode 100644
index 0000000..e5f633a
--- /dev/null
+++ b/libmisc/salt.c
@@ -0,0 +1,566 @@
+/*
+ * SPDX-FileCopyrightText:  Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>
+ * SPDX-FileCopyrightText:  J.T. Conklin <jtc@netbsd.org>
+ *
+ * SPDX-License-Identifier: Unlicense
+ */
+
+/*
+ * salt.c - generate a random salt string for crypt()
+ *
+ * Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
+ * it is in the public domain.
+ *
+ * l64a was Written by J.T. Conklin <jtc@netbsd.org>. Public domain.
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#if HAVE_SYS_RANDOM_H
+#include <sys/random.h>
+#endif
+#include "prototypes.h"
+#include "defines.h"
+#include "getdef.h"
+#include "shadowlog.h"
+
+#if (defined CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY && \
+     CRYPT_GENSALT_IMPLEMENTS_AUTO_ENTROPY)
+#define USE_XCRYPT_GENSALT 1
+#else
+#define USE_XCRYPT_GENSALT 0
+#endif
+
+/* Add the salt prefix. */
+#define MAGNUM(array,ch)	(array)[0]=(array)[2]='$',(array)[1]=(ch),(array)[3]='\0'
+
+#ifdef USE_BCRYPT
+/* Use $2b$ as prefix for compatibility with OpenBSD's bcrypt. */
+#define BCRYPTMAGNUM(array)	(array)[0]=(array)[3]='$',(array)[1]='2',(array)[2]='b',(array)[4]='\0'
+#define BCRYPT_SALT_SIZE 22
+/* Default number of rounds if not explicitly specified.  */
+#define B_ROUNDS_DEFAULT 13
+/* Minimum number of rounds.  */
+#define B_ROUNDS_MIN 4
+/* Maximum number of rounds.  */
+#define B_ROUNDS_MAX 31
+#endif /* USE_BCRYPT */
+
+#ifdef USE_SHA_CRYPT
+/* Fixed salt len for sha{256,512}crypt. */
+#define SHA_CRYPT_SALT_SIZE 16
+/* Default number of rounds if not explicitly specified.  */
+#define SHA_ROUNDS_DEFAULT 5000
+/* Minimum number of rounds.  */
+#define SHA_ROUNDS_MIN 1000
+/* Maximum number of rounds.  */
+#define SHA_ROUNDS_MAX 999999999
+#endif
+
+#ifdef USE_YESCRYPT
+/*
+ * Default number of base64 characters used for the salt.
+ * 24 characters gives a 144 bits (18 bytes) salt. Unlike the more
+ * traditional 128 bits (16 bytes) salt, this 144 bits salt is always
+ * represented by the same number of base64 characters without padding
+ * issue, even with a non-standard base64 encoding scheme.
+ */
+#define YESCRYPT_SALT_SIZE 24
+/* Default cost if not explicitly specified.  */
+#define Y_COST_DEFAULT 5
+/* Minimum cost.  */
+#define Y_COST_MIN 1
+/* Maximum cost.  */
+#define Y_COST_MAX 11
+#endif
+
+/* Fixed salt len for md5crypt. */
+#define MD5_CRYPT_SALT_SIZE 8
+
+/* Generate salt of size salt_size. */
+#define MAX_SALT_SIZE 44
+#define MIN_SALT_SIZE 8
+
+/* Maximum size of the generated salt string. */
+#define GENSALT_SETTING_SIZE 100
+
+/* local function prototypes */
+static long read_random_bytes (void);
+#if !USE_XCRYPT_GENSALT
+static /*@observer@*/const char *gensalt (size_t salt_size);
+#endif /* !USE_XCRYPT_GENSALT */
+#if defined(USE_SHA_CRYPT) || defined(USE_BCRYPT)
+static long shadow_random (long min, long max);
+#endif /* USE_SHA_CRYPT || USE_BCRYPT */
+#ifdef USE_SHA_CRYPT
+static /*@observer@*/unsigned long SHA_get_salt_rounds (/*@null@*/const int *prefered_rounds);
+static /*@observer@*/void SHA_salt_rounds_to_buf (char *buf, unsigned long rounds);
+#endif /* USE_SHA_CRYPT */
+#ifdef USE_BCRYPT
+static /*@observer@*/unsigned long BCRYPT_get_salt_rounds (/*@null@*/const int *prefered_rounds);
+static /*@observer@*/void BCRYPT_salt_rounds_to_buf (char *buf, unsigned long rounds);
+#endif /* USE_BCRYPT */
+#ifdef USE_YESCRYPT
+static /*@observer@*/unsigned long YESCRYPT_get_salt_cost (/*@null@*/const int *prefered_cost);
+static /*@observer@*/void YESCRYPT_salt_cost_to_buf (char *buf, unsigned long cost);
+#endif /* USE_YESCRYPT */
+
+#if !USE_XCRYPT_GENSALT && !defined(HAVE_L64A)
+static /*@observer@*/char *l64a (long value)
+{
+	static char buf[8];
+	char *s = buf;
+	int digit;
+	int i;
+
+	if (value < 0) {
+		errno = EINVAL;
+		return(NULL);
+	}
+
+	for (i = 0; value != 0 && i < 6; i++) {
+		digit = value & 0x3f;
+
+		if (digit < 2) {
+			*s = digit + '.';
+		} else if (digit < 12) {
+			*s = digit + '0' - 2;
+		} else if (digit < 38) {
+			*s = digit + 'A' - 12;
+		} else {
+			*s = digit + 'a' - 38;
+		}
+
+		value >>= 6;
+		s++;
+	}
+
+	*s = '\0';
+
+	return buf;
+}
+#endif /* !USE_XCRYPT_GENSALT && !defined(HAVE_L64A) */
+
+/* Read sizeof (long) random bytes from /dev/urandom. */
+static long read_random_bytes (void)
+{
+	long randval = 0;
+
+#ifdef HAVE_ARC4RANDOM_BUF
+	/* arc4random_buf, if it exists, can never fail.  */
+	arc4random_buf (&randval, sizeof (randval));
+	goto end;
+#endif
+
+#ifdef HAVE_GETENTROPY
+	/* getentropy may exist but lack kernel support.  */
+	if (getentropy (&randval, sizeof (randval)) == 0) {
+		goto end;
+	}
+#endif
+
+#ifdef HAVE_GETRANDOM
+	/* Likewise getrandom.  */
+	if ((size_t) getrandom (&randval, sizeof (randval), 0) == sizeof (randval)) {
+		goto end;
+	}
+#endif
+
+	/* Use /dev/urandom as a last resort.  */
+	FILE *f = fopen ("/dev/urandom", "r");
+	if (NULL == f) {
+		goto fail;
+	}
+
+	if (fread (&randval, sizeof (randval), 1, f) != 1) {
+		fclose(f);
+		goto fail;
+	}
+
+	fclose(f);
+	goto end;
+
+fail:
+	fprintf (log_get_logfd(),
+		 _("Unable to obtain random bytes.\n"));
+	exit (1);
+
+end:
+	return randval;
+}
+
+#if defined(USE_SHA_CRYPT) || defined(USE_BCRYPT)
+/*
+ * Return a random number between min and max (both included).
+ *
+ * It favors slightly the higher numbers.
+ */
+static long shadow_random (long min, long max)
+{
+	double drand;
+	long ret;
+
+	drand = (double) (read_random_bytes () & RAND_MAX) / (double) RAND_MAX;
+	drand *= (double) (max - min + 1);
+	/* On systems were this is not random() range is lower, we favor
+	 * higher numbers of salt. */
+	ret = (long) (max + 1 - drand);
+	/* And we catch limits, and use the highest number */
+	if ((ret < min) || (ret > max)) {
+		ret = max;
+	}
+	return ret;
+}
+#endif /* USE_SHA_CRYPT || USE_BCRYPT */
+
+#ifdef USE_SHA_CRYPT
+/* Return the the rounds number for the SHA crypt methods. */
+static /*@observer@*/unsigned long SHA_get_salt_rounds (/*@null@*/const int *prefered_rounds)
+{
+	unsigned long rounds;
+
+	if (NULL == prefered_rounds) {
+		long min_rounds = getdef_long ("SHA_CRYPT_MIN_ROUNDS", -1);
+		long max_rounds = getdef_long ("SHA_CRYPT_MAX_ROUNDS", -1);
+
+		if ((-1 == min_rounds) && (-1 == max_rounds)) {
+			rounds = SHA_ROUNDS_DEFAULT;
+		}
+		else {
+			if (-1 == min_rounds) {
+				min_rounds = max_rounds;
+			}
+
+			if (-1 == max_rounds) {
+				max_rounds = min_rounds;
+			}
+
+			if (min_rounds > max_rounds) {
+				max_rounds = min_rounds;
+			}
+
+			rounds = (unsigned long) shadow_random (min_rounds, max_rounds);
+		}
+	} else if (0 == *prefered_rounds) {
+		rounds = SHA_ROUNDS_DEFAULT;
+	} else {
+		rounds = (unsigned long) *prefered_rounds;
+	}
+
+	/* Sanity checks. The libc should also check this, but this
+	 * protects against a rounds_prefix overflow. */
+	if (rounds < SHA_ROUNDS_MIN) {
+		rounds = SHA_ROUNDS_MIN;
+	}
+
+	if (rounds > SHA_ROUNDS_MAX) {
+		rounds = SHA_ROUNDS_MAX;
+	}
+
+	return rounds;
+}
+
+/*
+ * Fill a salt prefix specifying the rounds number for the SHA crypt methods
+ * to a buffer.
+ */
+static /*@observer@*/void SHA_salt_rounds_to_buf (char *buf, unsigned long rounds)
+{
+	const size_t buf_begin = strlen (buf);
+
+	/* Nothing to do here if SHA_ROUNDS_DEFAULT is used. */
+	if (rounds == SHA_ROUNDS_DEFAULT) {
+		return;
+	}
+
+	/*
+	 * Check if the result buffer is long enough.
+	 * We are going to write a maximum of 17 bytes,
+	 * plus one byte for the terminator.
+	 *    rounds=XXXXXXXXX$
+	 *    00000000011111111
+	 *    12345678901234567
+	 */
+	assert (GENSALT_SETTING_SIZE > buf_begin + 17);
+
+	(void) snprintf (buf + buf_begin, 18, "rounds=%lu$", rounds);
+}
+#endif /* USE_SHA_CRYPT */
+
+#ifdef USE_BCRYPT
+/* Return the the rounds number for the BCRYPT method. */
+static /*@observer@*/unsigned long BCRYPT_get_salt_rounds (/*@null@*/const int *prefered_rounds)
+{
+	unsigned long rounds;
+
+	if (NULL == prefered_rounds) {
+		long min_rounds = getdef_long ("BCRYPT_MIN_ROUNDS", -1);
+		long max_rounds = getdef_long ("BCRYPT_MAX_ROUNDS", -1);
+
+		if ((-1 == min_rounds) && (-1 == max_rounds)) {
+			rounds = B_ROUNDS_DEFAULT;
+		} else {
+			if (-1 == min_rounds) {
+				min_rounds = max_rounds;
+			}
+
+			if (-1 == max_rounds) {
+				max_rounds = min_rounds;
+			}
+
+			if (min_rounds > max_rounds) {
+				max_rounds = min_rounds;
+			}
+
+			rounds = (unsigned long) shadow_random (min_rounds, max_rounds);
+		}
+	} else if (0 == *prefered_rounds) {
+		rounds = B_ROUNDS_DEFAULT;
+	} else {
+		rounds = (unsigned long) *prefered_rounds;
+	}
+
+	/* Sanity checks. */
+	if (rounds < B_ROUNDS_MIN) {
+		rounds = B_ROUNDS_MIN;
+	}
+
+#if USE_XCRYPT_GENSALT
+	if (rounds > B_ROUNDS_MAX) {
+		rounds = B_ROUNDS_MAX;
+	}
+#else /* USE_XCRYPT_GENSALT */
+	/*
+	 * Use 19 as an upper bound for now,
+	 * because musl doesn't allow rounds >= 20.
+	 * If musl ever supports > 20 rounds,
+	 * rounds should be set to B_ROUNDS_MAX.
+	 */
+	if (rounds > 19) {
+		rounds = 19;
+	}
+#endif /* USE_XCRYPT_GENSALT */
+
+	return rounds;
+}
+
+/*
+ * Fill a salt prefix specifying the rounds number for the BCRYPT method
+ * to a buffer.
+ */
+static /*@observer@*/void BCRYPT_salt_rounds_to_buf (char *buf, unsigned long rounds)
+{
+	const size_t buf_begin = strlen (buf);
+
+	/*
+	 * Check if the result buffer is long enough.
+	 * We are going to write three bytes,
+	 * plus one byte for the terminator.
+	 *    XX$
+	 *    000
+	 *    123
+	 */
+	assert (GENSALT_SETTING_SIZE > buf_begin + 3);
+
+	(void) snprintf (buf + buf_begin, 4, "%2.2lu$", rounds);
+}
+#endif /* USE_BCRYPT */
+
+#ifdef USE_YESCRYPT
+/* Return the the cost number for the YESCRYPT method. */
+static /*@observer@*/unsigned long YESCRYPT_get_salt_cost (/*@null@*/const int *prefered_cost)
+{
+	unsigned long cost;
+
+	if (NULL == prefered_cost) {
+		cost = getdef_num ("YESCRYPT_COST_FACTOR", Y_COST_DEFAULT);
+	} else if (0 == *prefered_cost) {
+		cost = Y_COST_DEFAULT;
+	} else {
+		cost = (unsigned long) *prefered_cost;
+	}
+
+	/* Sanity checks. */
+	if (cost < Y_COST_MIN) {
+		cost = Y_COST_MIN;
+	}
+
+	if (cost > Y_COST_MAX) {
+		cost = Y_COST_MAX;
+	}
+
+	return cost;
+}
+
+/*
+ * Fill a salt prefix specifying the cost for the YESCRYPT method
+ * to a buffer.
+ */
+static /*@observer@*/void YESCRYPT_salt_cost_to_buf (char *buf, unsigned long cost)
+{
+	const size_t buf_begin = strlen (buf);
+
+	/*
+	 * Check if the result buffer is long enough.
+	 * We are going to write four bytes,
+	 * plus one byte for the terminator.
+	 *    jXX$
+	 *    0000
+	 *    1234
+	 */
+	assert (GENSALT_SETTING_SIZE > buf_begin + 4);
+
+	buf[buf_begin + 0] = 'j';
+	if (cost < 3) {
+		buf[buf_begin + 1] = 0x36 + cost;
+	} else if (cost < 6) {
+		buf[buf_begin + 1] = 0x34 + cost;
+	} else {
+		buf[buf_begin + 1] = 0x3b + cost;
+	}
+	buf[buf_begin + 2] = cost >= 3 ? 'T' : '5';
+	buf[buf_begin + 3] = '$';
+	buf[buf_begin + 4] = '\0';
+}
+#endif /* USE_YESCRYPT */
+
+#if !USE_XCRYPT_GENSALT
+static /*@observer@*/const char *gensalt (size_t salt_size)
+{
+	static char salt[MAX_SALT_SIZE + 6];
+
+	memset (salt, '\0', MAX_SALT_SIZE + 6);
+
+	assert (salt_size >= MIN_SALT_SIZE &&
+	        salt_size <= MAX_SALT_SIZE);
+	strcat (salt, l64a (read_random_bytes ()));
+	do {
+		strcat (salt, l64a (read_random_bytes ()));
+	} while (strlen (salt) < salt_size);
+
+	salt[salt_size] = '\0';
+
+	return salt;
+}
+#endif /* !USE_XCRYPT_GENSALT */
+
+/*
+ * Generate 8 base64 ASCII characters of random salt.  If MD5_CRYPT_ENAB
+ * in /etc/login.defs is "yes", the salt string will be prefixed by "$1$"
+ * (magic) and pw_encrypt() will execute the MD5-based FreeBSD-compatible
+ * version of crypt() instead of the standard one.
+ * Other methods can be set with ENCRYPT_METHOD
+ *
+ * The method can be forced with the meth parameter.
+ * If NULL, the method will be defined according to the ENCRYPT_METHOD
+ * variable, and if not set according to the MD5_CRYPT_ENAB variable,
+ * which can both be set inside the login.defs file.
+ *
+ * If meth is specified, an additional parameter can be provided.
+ *  * For the SHA256 and SHA512 method, this specifies the number of rounds
+ *    (if not NULL).
+ *  * For the YESCRYPT method, this specifies the cost factor (if not NULL).
+ */
+/*@observer@*/const char *crypt_make_salt (/*@null@*//*@observer@*/const char *meth, /*@null@*/void *arg)
+{
+	static char result[GENSALT_SETTING_SIZE];
+	size_t salt_len = MAX_SALT_SIZE;
+	const char *method;
+	unsigned long rounds = 0;
+
+	memset (result, '\0', GENSALT_SETTING_SIZE);
+
+	if (NULL != meth)
+		method = meth;
+	else {
+		method = getdef_str ("ENCRYPT_METHOD");
+		if (NULL == method) {
+			method = getdef_bool ("MD5_CRYPT_ENAB") ? "MD5" : "DES";
+		}
+	}
+
+	if (0 == strcmp (method, "MD5")) {
+		MAGNUM(result, '1');
+		salt_len = MD5_CRYPT_SALT_SIZE;
+		rounds = 0;
+#ifdef USE_BCRYPT
+	} else if (0 == strcmp (method, "BCRYPT")) {
+		BCRYPTMAGNUM(result);
+		salt_len = BCRYPT_SALT_SIZE;
+		rounds = BCRYPT_get_salt_rounds ((int *) arg);
+		BCRYPT_salt_rounds_to_buf (result, rounds);
+#endif /* USE_BCRYPT */
+#ifdef USE_YESCRYPT
+	} else if (0 == strcmp (method, "YESCRYPT")) {
+		MAGNUM(result, 'y');
+		salt_len = YESCRYPT_SALT_SIZE;
+		rounds = YESCRYPT_get_salt_cost ((int *) arg);
+		YESCRYPT_salt_cost_to_buf (result, rounds);
+#endif /* USE_YESCRYPT */
+#ifdef USE_SHA_CRYPT
+	} else if (0 == strcmp (method, "SHA256")) {
+		MAGNUM(result, '5');
+		salt_len = SHA_CRYPT_SALT_SIZE;
+		rounds = SHA_get_salt_rounds ((int *) arg);
+		SHA_salt_rounds_to_buf (result, rounds);
+	} else if (0 == strcmp (method, "SHA512")) {
+		MAGNUM(result, '6');
+		salt_len = SHA_CRYPT_SALT_SIZE;
+		rounds = SHA_get_salt_rounds ((int *) arg);
+		SHA_salt_rounds_to_buf (result, rounds);
+#endif /* USE_SHA_CRYPT */
+	} else if (0 != strcmp (method, "DES")) {
+		fprintf (log_get_logfd(),
+			 _("Invalid ENCRYPT_METHOD value: '%s'.\n"
+			   "Defaulting to DES.\n"),
+			 method);
+		salt_len = MAX_SALT_SIZE;
+		rounds = 0;
+		memset (result, '\0', GENSALT_SETTING_SIZE);
+	}
+
+#if USE_XCRYPT_GENSALT
+	/*
+	 * Prepare DES setting for crypt_gensalt(), if result
+	 * has not been filled with anything previously.
+	 */
+	if ('\0' == result[0]) {
+		/* Avoid -Wunused-but-set-variable. */
+		salt_len = GENSALT_SETTING_SIZE - 1;
+		rounds = 0;
+		memset (result, '.', salt_len);
+		result[salt_len] = '\0';
+	}
+
+	char *retval = crypt_gensalt (result, rounds, NULL, 0);
+
+	/* Should not happen, but... */
+	if (NULL == retval) {
+		fprintf (log_get_logfd(),
+			 _("Unable to generate a salt from setting "
+			   "\"%s\", check your settings in "
+			   "ENCRYPT_METHOD and the corresponding "
+			   "configuration for your selected hash "
+			   "method.\n"), result);
+
+		exit (1);
+	}
+
+	return retval;
+#else /* USE_XCRYPT_GENSALT */
+	/* Check if the result buffer is long enough. */
+	assert (GENSALT_SETTING_SIZE > strlen (result) + salt_len);
+
+	/* Concatenate a pseudo random salt. */
+	strncat (result, gensalt (salt_len),
+		 GENSALT_SETTING_SIZE - strlen (result) - 1);
+
+	return result;
+#endif /* USE_XCRYPT_GENSALT */
+}