/*
- * SHA core transform algorithm, used here solely as a `stirring'
- * function for the PuTTY random number pool. Implemented directly
- * from the specification by Simon Tatham.
+ * SHA1 hash algorithm. Used in SSH-2 as a MAC, and the transform is
+ * also used as a `stirring' function for the PuTTY random number
+ * pool. Implemented directly from the specification by Simon
+ * Tatham.
*/
#include "ssh.h"
-#define rol(x,y) ( ((x) << (y)) | (((word32)x) >> (32-y)) )
+/* ----------------------------------------------------------------------
+ * Core SHA algorithm: processes 16-word blocks into a message digest.
+ */
+
+#define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) )
+
+static void SHA_Core_Init(uint32 h[5])
+{
+ h[0] = 0x67452301;
+ h[1] = 0xefcdab89;
+ h[2] = 0x98badcfe;
+ h[3] = 0x10325476;
+ h[4] = 0xc3d2e1f0;
+}
-void SHATransform(word32 *digest, word32 *block) {
+void SHATransform(word32 * digest, word32 * block)
+{
word32 w[80];
- word32 a,b,c,d,e;
+ word32 a, b, c, d, e;
int t;
+#ifdef RANDOM_DIAGNOSTICS
+ {
+ extern int random_diagnostics;
+ if (random_diagnostics) {
+ int i;
+ printf("SHATransform:");
+ for (i = 0; i < 5; i++)
+ printf(" %08x", digest[i]);
+ printf(" +");
+ for (i = 0; i < 16; i++)
+ printf(" %08x", block[i]);
+ }
+ }
+#endif
+
for (t = 0; t < 16; t++)
- w[t] = block[t];
+ w[t] = block[t];
for (t = 16; t < 80; t++) {
- word32 tmp = w[t-3] ^ w[t-8] ^ w[t-14] ^ w[t-16];
- w[t] = rol(tmp, 1);
+ word32 tmp = w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16];
+ w[t] = rol(tmp, 1);
}
a = digest[0];
e = digest[4];
for (t = 0; t < 20; t++) {
- word32 tmp = rol(a, 5) + ( (b&c) | (d&~b) ) + e + w[t] + 0x5a827999;
- e = d; d = c; c = rol(b, 30); b = a; a = tmp;
+ word32 tmp =
+ rol(a, 5) + ((b & c) | (d & ~b)) + e + w[t] + 0x5a827999;
+ e = d;
+ d = c;
+ c = rol(b, 30);
+ b = a;
+ a = tmp;
}
for (t = 20; t < 40; t++) {
- word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0x6ed9eba1;
- e = d; d = c; c = rol(b, 30); b = a; a = tmp;
+ word32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0x6ed9eba1;
+ e = d;
+ d = c;
+ c = rol(b, 30);
+ b = a;
+ a = tmp;
}
for (t = 40; t < 60; t++) {
- word32 tmp = rol(a, 5) + ( (b&c) | (b&d) | (c&d) ) + e + w[t] + 0x8f1bbcdc;
- e = d; d = c; c = rol(b, 30); b = a; a = tmp;
+ word32 tmp = rol(a,
+ 5) + ((b & c) | (b & d) | (c & d)) + e + w[t] +
+ 0x8f1bbcdc;
+ e = d;
+ d = c;
+ c = rol(b, 30);
+ b = a;
+ a = tmp;
}
for (t = 60; t < 80; t++) {
- word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0xca62c1d6;
- e = d; d = c; c = rol(b, 30); b = a; a = tmp;
+ word32 tmp = rol(a, 5) + (b ^ c ^ d) + e + w[t] + 0xca62c1d6;
+ e = d;
+ d = c;
+ c = rol(b, 30);
+ b = a;
+ a = tmp;
}
digest[0] += a;
digest[2] += c;
digest[3] += d;
digest[4] += e;
+
+#ifdef RANDOM_DIAGNOSTICS
+ {
+ extern int random_diagnostics;
+ if (random_diagnostics) {
+ int i;
+ printf(" =");
+ for (i = 0; i < 5; i++)
+ printf(" %08x", digest[i]);
+ printf("\n");
+ }
+ }
+#endif
+}
+
+/* ----------------------------------------------------------------------
+ * Outer SHA algorithm: take an arbitrary length byte string,
+ * convert it into 16-word blocks with the prescribed padding at
+ * the end, and pass those blocks to the core SHA algorithm.
+ */
+
+void SHA_Init(SHA_State * s)
+{
+ SHA_Core_Init(s->h);
+ s->blkused = 0;
+ s->lenhi = s->lenlo = 0;
+}
+
+void SHA_Bytes(SHA_State * s, const void *p, int len)
+{
+ const unsigned char *q = (const unsigned char *) p;
+ uint32 wordblock[16];
+ uint32 lenw = len;
+ int i;
+
+ /*
+ * Update the length field.
+ */
+ s->lenlo += lenw;
+ s->lenhi += (s->lenlo < lenw);
+
+ if (s->blkused && s->blkused + len < 64) {
+ /*
+ * Trivial case: just add to the block.
+ */
+ memcpy(s->block + s->blkused, q, len);
+ s->blkused += len;
+ } else {
+ /*
+ * We must complete and process at least one block.
+ */
+ while (s->blkused + len >= 64) {
+ memcpy(s->block + s->blkused, q, 64 - s->blkused);
+ q += 64 - s->blkused;
+ len -= 64 - s->blkused;
+ /* Now process the block. Gather bytes big-endian into words */
+ for (i = 0; i < 16; i++) {
+ wordblock[i] =
+ (((uint32) s->block[i * 4 + 0]) << 24) |
+ (((uint32) s->block[i * 4 + 1]) << 16) |
+ (((uint32) s->block[i * 4 + 2]) << 8) |
+ (((uint32) s->block[i * 4 + 3]) << 0);
+ }
+ SHATransform(s->h, wordblock);
+ s->blkused = 0;
+ }
+ memcpy(s->block, q, len);
+ s->blkused = len;
+ }
+}
+
+void SHA_Final(SHA_State * s, unsigned char *output)
+{
+ int i;
+ int pad;
+ unsigned char c[64];
+ uint32 lenhi, lenlo;
+
+ if (s->blkused >= 56)
+ pad = 56 + 64 - s->blkused;
+ else
+ pad = 56 - s->blkused;
+
+ lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3));
+ lenlo = (s->lenlo << 3);
+
+ memset(c, 0, pad);
+ c[0] = 0x80;
+ SHA_Bytes(s, &c, pad);
+
+ c[0] = (lenhi >> 24) & 0xFF;
+ c[1] = (lenhi >> 16) & 0xFF;
+ c[2] = (lenhi >> 8) & 0xFF;
+ c[3] = (lenhi >> 0) & 0xFF;
+ c[4] = (lenlo >> 24) & 0xFF;
+ c[5] = (lenlo >> 16) & 0xFF;
+ c[6] = (lenlo >> 8) & 0xFF;
+ c[7] = (lenlo >> 0) & 0xFF;
+
+ SHA_Bytes(s, &c, 8);
+
+ for (i = 0; i < 5; i++) {
+ output[i * 4] = (s->h[i] >> 24) & 0xFF;
+ output[i * 4 + 1] = (s->h[i] >> 16) & 0xFF;
+ output[i * 4 + 2] = (s->h[i] >> 8) & 0xFF;
+ output[i * 4 + 3] = (s->h[i]) & 0xFF;
+ }
+}
+
+void SHA_Simple(const void *p, int len, unsigned char *output)
+{
+ SHA_State s;
+
+ SHA_Init(&s);
+ SHA_Bytes(&s, p, len);
+ SHA_Final(&s, output);
+}
+
+/*
+ * Thin abstraction for things where hashes are pluggable.
+ */
+
+static void *sha1_init(void)
+{
+ SHA_State *s;
+
+ s = snew(SHA_State);
+ SHA_Init(s);
+ return s;
+}
+
+static void sha1_bytes(void *handle, void *p, int len)
+{
+ SHA_State *s = handle;
+
+ SHA_Bytes(s, p, len);
+}
+
+static void sha1_final(void *handle, unsigned char *output)
+{
+ SHA_State *s = handle;
+
+ SHA_Final(s, output);
+ sfree(s);
+}
+
+const struct ssh_hash ssh_sha1 = {
+ sha1_init, sha1_bytes, sha1_final, 20, "SHA-1"
+};
+
+/* ----------------------------------------------------------------------
+ * The above is the SHA-1 algorithm itself. Now we implement the
+ * HMAC wrapper on it.
+ */
+
+static void *sha1_make_context(void)
+{
+ return snewn(3, SHA_State);
+}
+
+static void sha1_free_context(void *handle)
+{
+ sfree(handle);
+}
+
+static void sha1_key_internal(void *handle, unsigned char *key, int len)
+{
+ SHA_State *keys = (SHA_State *)handle;
+ unsigned char foo[64];
+ int i;
+
+ memset(foo, 0x36, 64);
+ for (i = 0; i < len && i < 64; i++)
+ foo[i] ^= key[i];
+ SHA_Init(&keys[0]);
+ SHA_Bytes(&keys[0], foo, 64);
+
+ memset(foo, 0x5C, 64);
+ for (i = 0; i < len && i < 64; i++)
+ foo[i] ^= key[i];
+ SHA_Init(&keys[1]);
+ SHA_Bytes(&keys[1], foo, 64);
+
+ smemclr(foo, 64); /* burn the evidence */
+}
+
+static void sha1_key(void *handle, unsigned char *key)
+{
+ sha1_key_internal(handle, key, 20);
+}
+
+static void sha1_key_buggy(void *handle, unsigned char *key)
+{
+ sha1_key_internal(handle, key, 16);
+}
+
+static void hmacsha1_start(void *handle)
+{
+ SHA_State *keys = (SHA_State *)handle;
+
+ keys[2] = keys[0]; /* structure copy */
+}
+
+static void hmacsha1_bytes(void *handle, unsigned char const *blk, int len)
+{
+ SHA_State *keys = (SHA_State *)handle;
+ SHA_Bytes(&keys[2], (void *)blk, len);
+}
+
+static void hmacsha1_genresult(void *handle, unsigned char *hmac)
+{
+ SHA_State *keys = (SHA_State *)handle;
+ SHA_State s;
+ unsigned char intermediate[20];
+
+ s = keys[2]; /* structure copy */
+ SHA_Final(&s, intermediate);
+ s = keys[1]; /* structure copy */
+ SHA_Bytes(&s, intermediate, 20);
+ SHA_Final(&s, hmac);
+}
+
+static void sha1_do_hmac(void *handle, unsigned char *blk, int len,
+ unsigned long seq, unsigned char *hmac)
+{
+ unsigned char seqbuf[4];
+
+ PUT_32BIT_MSB_FIRST(seqbuf, seq);
+ hmacsha1_start(handle);
+ hmacsha1_bytes(handle, seqbuf, 4);
+ hmacsha1_bytes(handle, blk, len);
+ hmacsha1_genresult(handle, hmac);
}
+
+static void sha1_generate(void *handle, unsigned char *blk, int len,
+ unsigned long seq)
+{
+ sha1_do_hmac(handle, blk, len, seq, blk + len);
+}
+
+static int hmacsha1_verresult(void *handle, unsigned char const *hmac)
+{
+ unsigned char correct[20];
+ hmacsha1_genresult(handle, correct);
+ return !memcmp(correct, hmac, 20);
+}
+
+static int sha1_verify(void *handle, unsigned char *blk, int len,
+ unsigned long seq)
+{
+ unsigned char correct[20];
+ sha1_do_hmac(handle, blk, len, seq, correct);
+ return !memcmp(correct, blk + len, 20);
+}
+
+static void hmacsha1_96_genresult(void *handle, unsigned char *hmac)
+{
+ unsigned char full[20];
+ hmacsha1_genresult(handle, full);
+ memcpy(hmac, full, 12);
+}
+
+static void sha1_96_generate(void *handle, unsigned char *blk, int len,
+ unsigned long seq)
+{
+ unsigned char full[20];
+ sha1_do_hmac(handle, blk, len, seq, full);
+ memcpy(blk + len, full, 12);
+}
+
+static int hmacsha1_96_verresult(void *handle, unsigned char const *hmac)
+{
+ unsigned char correct[20];
+ hmacsha1_genresult(handle, correct);
+ return !memcmp(correct, hmac, 12);
+}
+
+static int sha1_96_verify(void *handle, unsigned char *blk, int len,
+ unsigned long seq)
+{
+ unsigned char correct[20];
+ sha1_do_hmac(handle, blk, len, seq, correct);
+ return !memcmp(correct, blk + len, 12);
+}
+
+void hmac_sha1_simple(void *key, int keylen, void *data, int datalen,
+ unsigned char *output) {
+ SHA_State states[2];
+ unsigned char intermediate[20];
+
+ sha1_key_internal(states, key, keylen);
+ SHA_Bytes(&states[0], data, datalen);
+ SHA_Final(&states[0], intermediate);
+
+ SHA_Bytes(&states[1], intermediate, 20);
+ SHA_Final(&states[1], output);
+}
+
+const struct ssh_mac ssh_hmac_sha1 = {
+ sha1_make_context, sha1_free_context, sha1_key,
+ sha1_generate, sha1_verify,
+ hmacsha1_start, hmacsha1_bytes, hmacsha1_genresult, hmacsha1_verresult,
+ "hmac-sha1",
+ 20,
+ "HMAC-SHA1"
+};
+
+const struct ssh_mac ssh_hmac_sha1_96 = {
+ sha1_make_context, sha1_free_context, sha1_key,
+ sha1_96_generate, sha1_96_verify,
+ hmacsha1_start, hmacsha1_bytes,
+ hmacsha1_96_genresult, hmacsha1_96_verresult,
+ "hmac-sha1-96",
+ 12,
+ "HMAC-SHA1-96"
+};
+
+const struct ssh_mac ssh_hmac_sha1_buggy = {
+ sha1_make_context, sha1_free_context, sha1_key_buggy,
+ sha1_generate, sha1_verify,
+ hmacsha1_start, hmacsha1_bytes, hmacsha1_genresult, hmacsha1_verresult,
+ "hmac-sha1",
+ 20,
+ "bug-compatible HMAC-SHA1"
+};
+
+const struct ssh_mac ssh_hmac_sha1_96_buggy = {
+ sha1_make_context, sha1_free_context, sha1_key_buggy,
+ sha1_96_generate, sha1_96_verify,
+ hmacsha1_start, hmacsha1_bytes,
+ hmacsha1_96_genresult, hmacsha1_96_verresult,
+ "hmac-sha1-96",
+ 12,
+ "bug-compatible HMAC-SHA1-96"
+};
projects / u / mdw / putty / blobdiff