1 files changed, 365 insertions, 0 deletions

diff --git a/src/lib/libc/crypt/bcrypt.c b/src/lib/libc/crypt/bcrypt.c
new file mode 100644
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+++ b/src/lib/libc/crypt/bcrypt.c
@@ -0,0 +1,365 @@
+/*      $OpenBSD: bcrypt.c,v 1.37 2014/04/08 20:14:25 tedu Exp $        */
+
+/*
+ * Copyright (c) 2014 Ted Unangst <tedu@openbsd.org>
+ * Copyright (c) 1997 Niels Provos <provos@umich.edu>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+/* This password hashing algorithm was designed by David Mazieres
+ * <dm@lcs.mit.edu> and works as follows:
+ *
+ * 1. state := InitState ()
+ * 2. state := ExpandKey (state, salt, password)
+ * 3. REPEAT rounds:
+ *      state := ExpandKey (state, 0, password)
+ *      state := ExpandKey (state, 0, salt)
+ * 4. ctext := "OrpheanBeholderScryDoubt"
+ * 5. REPEAT 64:
+ *      ctext := Encrypt_ECB (state, ctext);
+ * 6. RETURN Concatenate (salt, ctext);
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <string.h>
+#include <pwd.h>
+#include <blf.h>
+
+/* This implementation is adaptable to current computing power.
+ * You can have up to 2^31 rounds which should be enough for some
+ * time to come.
+ */
+
+#define BCRYPT_VERSION '2'
+#define BCRYPT_MAXSALT 16       /* Precomputation is just so nice */
+#define BCRYPT_BLOCKS 6         /* Ciphertext blocks */
+#define BCRYPT_MINLOGROUNDS 4   /* we have log2(rounds) in salt */
+
+#define BCRYPT_SALTSPACE        (7 + (BCRYPT_MAXSALT * 4 + 2) / 3 + 1)
+
+char   *bcrypt_gensalt(u_int8_t);
+
+static int encode_base64(char *, const u_int8_t *, size_t);
+static int decode_base64(u_int8_t *, size_t, const char *);
+
+/*
+ * Generates a salt for this version of crypt.
+ */
+static int
+bcrypt_initsalt(int log_rounds, uint8_t *salt, size_t saltbuflen)
+{
+        uint8_t csalt[BCRYPT_MAXSALT];
+
+        if (saltbuflen < BCRYPT_SALTSPACE)
+                return -1;
+
+        arc4random_buf(csalt, sizeof(csalt));
+
+        if (log_rounds < 4)
+                log_rounds = 4;
+        else if (log_rounds > 31)
+                log_rounds = 31;
+
+        snprintf(salt, saltbuflen, "$2a$%2.2u$", log_rounds);
+        encode_base64(salt + 7, csalt, sizeof(csalt));
+
+        return 0;
+}
+
+/*
+ * the core bcrypt function
+ */
+static int
+bcrypt_hashpass(const char *key, const char *salt, char *encrypted,
+    size_t encryptedlen)
+{
+        blf_ctx state;
+        u_int32_t rounds, i, k;
+        u_int16_t j;
+        size_t key_len;
+        u_int8_t salt_len, logr, minor;
+        u_int8_t ciphertext[4 * BCRYPT_BLOCKS] = "OrpheanBeholderScryDoubt";
+        u_int8_t csalt[BCRYPT_MAXSALT];
+        u_int32_t cdata[BCRYPT_BLOCKS];
+        char arounds[3];
+
+        /* Discard "$" identifier */
+        salt++;
+
+        if (*salt > BCRYPT_VERSION) {
+                return -1;
+        }
+
+        /* Check for minor versions */
+        if (salt[1] != '$') {
+                 switch (salt[1]) {
+                 case 'a':      /* 'ab' should not yield the same as 'abab' */
+                 case 'b':      /* cap input length at 72 bytes */
+                         minor = salt[1];
+                         salt++;
+                         break;
+                 default:
+                         return -1;
+                 }
+        } else
+                 minor = 0;
+
+        /* Discard version + "$" identifier */
+        salt += 2;
+
+        if (salt[2] != '$')
+                /* Out of sync with passwd entry */
+                return -1;
+
+        memcpy(arounds, salt, sizeof(arounds));
+        if (arounds[sizeof(arounds) - 1] != '$')
+                return -1;
+        arounds[sizeof(arounds) - 1] = 0;
+        logr = strtonum(arounds, BCRYPT_MINLOGROUNDS, 31, NULL);
+        if (logr == 0)
+                return -1;
+        /* Computer power doesn't increase linearly, 2^x should be fine */
+        rounds = 1U << logr;
+
+        /* Discard num rounds + "$" identifier */
+        salt += 3;
+
+        if (strlen(salt) * 3 / 4 < BCRYPT_MAXSALT)
+                return -1;
+
+        /* We dont want the base64 salt but the raw data */
+        decode_base64(csalt, BCRYPT_MAXSALT, salt);
+        salt_len = BCRYPT_MAXSALT;
+        if (minor <= 'a')
+                key_len = (u_int8_t)(strlen(key) + (minor >= 'a' ? 1 : 0));
+        else {
+                /* strlen() returns a size_t, but the function calls
+                 * below result in implicit casts to a narrower integer
+                 * type, so cap key_len at the actual maximum supported
+                 * length here to avoid integer wraparound */
+                key_len = strlen(key);
+                if (key_len > 72)
+                        key_len = 72;
+                key_len++; /* include the NUL */
+        }
+
+        /* Setting up S-Boxes and Subkeys */
+        Blowfish_initstate(&state);
+        Blowfish_expandstate(&state, csalt, salt_len,
+            (u_int8_t *) key, key_len);
+        for (k = 0; k < rounds; k++) {
+                Blowfish_expand0state(&state, (u_int8_t *) key, key_len);
+                Blowfish_expand0state(&state, csalt, salt_len);
+        }
+
+        /* This can be precomputed later */
+        j = 0;
+        for (i = 0; i < BCRYPT_BLOCKS; i++)
+                cdata[i] = Blowfish_stream2word(ciphertext, 4 * BCRYPT_BLOCKS, &j);
+
+        /* Now do the encryption */
+        for (k = 0; k < 64; k++)
+                blf_enc(&state, cdata, BCRYPT_BLOCKS / 2);
+
+        for (i = 0; i < BCRYPT_BLOCKS; i++) {
+                ciphertext[4 * i + 3] = cdata[i] & 0xff;
+                cdata[i] = cdata[i] >> 8;
+                ciphertext[4 * i + 2] = cdata[i] & 0xff;
+                cdata[i] = cdata[i] >> 8;
+                ciphertext[4 * i + 1] = cdata[i] & 0xff;
+                cdata[i] = cdata[i] >> 8;
+                ciphertext[4 * i + 0] = cdata[i] & 0xff;
+        }
+
+
+        i = 0;
+        encrypted[i++] = '$';
+        encrypted[i++] = BCRYPT_VERSION;
+        if (minor)
+                encrypted[i++] = minor;
+        encrypted[i++] = '$';
+
+        snprintf(encrypted + i, 4, "%2.2u$", logr);
+
+        encode_base64(encrypted + i + 3, csalt, BCRYPT_MAXSALT);
+        encode_base64(encrypted + strlen(encrypted), ciphertext,
+            4 * BCRYPT_BLOCKS - 1);
+        memset(&state, 0, sizeof(state));
+        memset(ciphertext, 0, sizeof(ciphertext));
+        memset(csalt, 0, sizeof(csalt));
+        memset(cdata, 0, sizeof(cdata));
+        return 0;
+}
+
+/*
+ * user friendly functions
+ */
+int
+bcrypt_newhash(const char *pass, int log_rounds, char *hash, size_t hashlen)
+{
+        char salt[BCRYPT_SALTSPACE];
+
+        if (bcrypt_initsalt(log_rounds, salt, sizeof(salt)) != 0)
+                return -1;
+
+        if (bcrypt_hashpass(pass, salt, hash, hashlen) != 0)
+                return -1;
+
+        explicit_bzero(salt, sizeof(salt));
+        return 0;
+}
+
+int
+bcrypt_checkpass(const char *pass, const char *goodhash)
+{
+        char hash[_PASSWORD_LEN];
+
+        if (bcrypt_hashpass(pass, goodhash, hash, sizeof(hash)) != 0)
+                return -1;
+        if (strlen(hash) != strlen(goodhash) ||
+            timingsafe_bcmp(hash, goodhash, strlen(goodhash)) != 0)
+                return -1;
+
+        explicit_bzero(hash, sizeof(hash));
+        return 0;
+}
+
+/*
+ * internal utilities
+ */
+const static u_int8_t Base64Code[] =
+"./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+
+const static u_int8_t index_64[128] = {
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+        255, 255, 255, 255, 255, 255, 0, 1, 54, 55,
+        56, 57, 58, 59, 60, 61, 62, 63, 255, 255,
+        255, 255, 255, 255, 255, 2, 3, 4, 5, 6,
+        7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+        17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
+        255, 255, 255, 255, 255, 255, 28, 29, 30,
+        31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
+        41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
+        51, 52, 53, 255, 255, 255, 255, 255
+};
+#define CHAR64(c)  ( (c) > 127 ? 255 : index_64[(c)])
+
+/*
+ * read buflen (after decoding) bytes of data from b64data
+ */
+static int
+decode_base64(u_int8_t *buffer, size_t len, const char *b64data)
+{
+        u_int8_t *bp = buffer;
+        const u_int8_t *p = b64data;
+        u_int8_t c1, c2, c3, c4;
+
+        while (bp < buffer + len) {
+                c1 = CHAR64(*p);
+                c2 = CHAR64(*(p + 1));
+
+                /* Invalid data */
+                if (c1 == 255 || c2 == 255)
+                        return -1;
+
+                *bp++ = (c1 << 2) | ((c2 & 0x30) >> 4);
+                if (bp >= buffer + len)
+                        break;
+
+                c3 = CHAR64(*(p + 2));
+                if (c3 == 255)
+                        break;
+
+                *bp++ = ((c2 & 0x0f) << 4) | ((c3 & 0x3c) >> 2);
+                if (bp >= buffer + len)
+                        break;
+
+                c4 = CHAR64(*(p + 3));
+                if (c4 == 255)
+                        break;
+                *bp++ = ((c3 & 0x03) << 6) | c4;
+
+                p += 4;
+        }
+        return 0;
+}
+
+/*
+ * Turn len bytes of data into base64 encoded data.
+ * This works without = padding.
+ */
+static int
+encode_base64(char *b64buffer, const u_int8_t *data, size_t len)
+{
+        u_int8_t *bp = b64buffer;
+        const u_int8_t *p = data;
+        u_int8_t c1, c2;
+
+        while (p < data + len) {
+                c1 = *p++;
+                *bp++ = Base64Code[(c1 >> 2)];
+                c1 = (c1 & 0x03) << 4;
+                if (p >= data + len) {
+                        *bp++ = Base64Code[c1];
+                        break;
+                }
+                c2 = *p++;
+                c1 |= (c2 >> 4) & 0x0f;
+                *bp++ = Base64Code[c1];
+                c1 = (c2 & 0x0f) << 2;
+                if (p >= data + len) {
+                        *bp++ = Base64Code[c1];
+                        break;
+                }
+                c2 = *p++;
+                c1 |= (c2 >> 6) & 0x03;
+                *bp++ = Base64Code[c1];
+                *bp++ = Base64Code[c2 & 0x3f];
+        }
+        *bp = '\0';
+        return 0;
+}
+
+/*
+ * classic interface
+ */
+char *
+bcrypt_gensalt(u_int8_t log_rounds)
+{
+        static char    gsalt[BCRYPT_SALTSPACE];
+
+        bcrypt_initsalt(log_rounds, gsalt, sizeof(gsalt));
+
+        return gsalt;
+}
+
+char *
+bcrypt(const char *pass, const char *salt)
+{
+        static char    gencrypted[_PASSWORD_LEN];
+        static char    gerror[2];
+
+        /* How do I handle errors ? Return ':' */
+        strlcpy(gerror, ":", sizeof(gerror));
+        if (bcrypt_hashpass(pass, salt, gencrypted, sizeof(gencrypted)) != 0)
+                return gerror;
+
+        return gencrypted;
+}
+