nss/0001-sync-up-with-upstream-softokn-changes.patch

From d6dbecfea317a468be12423595e584f43d84d8ec Mon Sep 17 00:00:00 2001
From: Elio Maldonado <emaldona@redhat.com>
Date: Sat, 9 Feb 2013 17:11:00 -0500
Subject: [PATCH] Sync up with upstream softokn changes

- Disable RSA OEP case in FormatBlock, RSA_OAEP support is experimental and in a state of flux
- Numerous change upstream due to the work for TLS/DTLS 'Lucky 13' vulnerability CVE-2013-0169
- It now compiles with the NSS_3_14_3_BETA1 source
---
 mozilla/security/nss/lib/ckfw/pem/rsawrapr.c |  338 +++++++-------------------
 1 files changed, 82 insertions(+), 256 deletions(-)

diff --git a/nss/lib/ckfw/pem/rsawrapr.c b/nss/lib/ckfw/pem/rsawrapr.c
index 5ac4f39..3780d30 100644
--- a/nss/lib/ckfw/pem/rsawrapr.c
+++ b/nss/lib/ckfw/pem/rsawrapr.c
@@ -46,6 +46,7 @@
 #include "sechash.h"
 #include "base.h"
 
+#include "lowkeyi.h"
 #include "secerr.h"
 
 #define RSA_BLOCK_MIN_PAD_LEN		8
@@ -54,9 +55,8 @@
 #define RSA_BLOCK_PRIVATE_PAD_OCTET	0xff
 #define RSA_BLOCK_AFTER_PAD_OCTET	0x00
 
-#define OAEP_SALT_LEN		8
-#define OAEP_PAD_LEN		8
-#define OAEP_PAD_OCTET		0x00
+/* Needed for RSA-PSS functions */
+static const unsigned char eightZeros[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
 
 #define FLAT_BUFSIZE 512        /* bytes to hold flattened SHA1Context. */
 
@@ -78,127 +78,39 @@ pem_PublicModulusLen(NSSLOWKEYPublicKey *pubk)
     return 0;
 }
 
-static SHA1Context *SHA1_CloneContext(SHA1Context * original)
-{
-    SHA1Context *clone = NULL;
-    unsigned char *pBuf;
-    int sha1ContextSize = SHA1_FlattenSize(original);
-    SECStatus frv;
-    unsigned char buf[FLAT_BUFSIZE];
-
-    PORT_Assert(sizeof buf >= sha1ContextSize);
-    if (sizeof buf >= sha1ContextSize) {
-        pBuf = buf;
-    } else {
-        pBuf = nss_ZAlloc(NULL, sha1ContextSize);
-        if (!pBuf)
-            goto done;
-    }
-
-    frv = SHA1_Flatten(original, pBuf);
-    if (frv == SECSuccess) {
-        clone = SHA1_Resurrect(pBuf, NULL);
-        memset(pBuf, 0, sha1ContextSize);
-    }
-  done:
-    if (pBuf != buf)
-        nss_ZFreeIf(pBuf);
-    return clone;
+/* Constant time comparison of a single byte.
+ * Returns 1 iff a == b, otherwise returns 0.
+ * Note: For ranges of bytes, use constantTimeCompare.
+ */
+static unsigned char constantTimeEQ8(unsigned char a, unsigned char b) {
+    unsigned char c = ~(a - b | b - a);
+    c >>= 7;
+    return c;
 }
 
-/*
- * Modify data by XORing it with a special hash of salt.
+/* Constant time comparison of a range of bytes.
+ * Returns 1 iff len bytes of a are identical to len bytes of b, otherwise
+ * returns 0.
  */
-static SECStatus
-oaep_xor_with_h1(unsigned char *data, unsigned int datalen,
-                 unsigned char *salt, unsigned int saltlen)
-{
-    SHA1Context *sha1cx;
-    unsigned char *dp, *dataend;
-    unsigned char end_octet;
-
-    sha1cx = SHA1_NewContext();
-    if (sha1cx == NULL) {
-        return SECFailure;
-    }
-
-    /*
-     * Get a hash of salt started; we will use it several times,
-     * adding in a different end octet (x00, x01, x02, ...).
-     */
-    SHA1_Begin(sha1cx);
-    SHA1_Update(sha1cx, salt, saltlen);
-    end_octet = 0;
-
-    dp = data;
-    dataend = data + datalen;
-
-    while (dp < dataend) {
-        SHA1Context *sha1cx_h1;
-        unsigned int sha1len, sha1off;
-        unsigned char sha1[SHA1_LENGTH];
-
-        /*
-         * Create hash of (salt || end_octet)
-         */
-        sha1cx_h1 = SHA1_CloneContext(sha1cx);
-        SHA1_Update(sha1cx_h1, &end_octet, 1);
-        SHA1_End(sha1cx_h1, sha1, &sha1len, sizeof(sha1));
-        SHA1_DestroyContext(sha1cx_h1, PR_TRUE);
-        PORT_Assert(sha1len == SHA1_LENGTH);
-
-        /*
-         * XOR that hash with the data.
-         * When we have fewer than SHA1_LENGTH octets of data
-         * left to xor, use just the low-order ones of the hash.
-         */
-        sha1off = 0;
-        if ((dataend - dp) < SHA1_LENGTH)
-            sha1off = SHA1_LENGTH - (dataend - dp);
-        while (sha1off < SHA1_LENGTH)
-            *dp++ ^= sha1[sha1off++];
-
-        /*
-         * Bump for next hash chunk.
-         */
-        end_octet++;
-    }
-
-    SHA1_DestroyContext(sha1cx, PR_TRUE);
-    return SECSuccess;
+static unsigned char constantTimeCompare(const unsigned char *a,
+                                         const unsigned char *b,
+                                         unsigned int len) {
+    unsigned char tmp = 0;
+    unsigned int i;
+    for (i = 0; i < len; ++i, ++a, ++b)
+        tmp |= *a ^ *b;
+    return constantTimeEQ8(0x00, tmp);
 }
 
-/*
- * Modify salt by XORing it with a special hash of data.
+/* Constant time conditional.
+ * Returns a if c is 1, or b if c is 0. The result is undefined if c is
+ * not 0 or 1.
  */
-static SECStatus
-oaep_xor_with_h2(unsigned char *salt, unsigned int saltlen,
-                 unsigned char *data, unsigned int datalen)
+static unsigned int constantTimeCondition(unsigned int c,
+                                          unsigned int a,
+                                          unsigned int b)
 {
-    unsigned char sha1[SHA1_LENGTH];
-    unsigned char *psalt, *psha1, *saltend;
-    SECStatus rv;
-
-    /*
-     * Create a hash of data.
-     */
-    rv = SHA1_HashBuf(sha1, data, datalen);
-    if (rv != SECSuccess) {
-        return rv;
-    }
-
-    /*
-     * XOR the low-order octets of that hash with salt.
-     */
-    PORT_Assert(saltlen <= SHA1_LENGTH);
-    saltend = salt + saltlen;
-    psalt = salt;
-    psha1 = sha1 + SHA1_LENGTH - saltlen;
-    while (psalt < saltend) {
-        *psalt++ ^= *psha1++;
-    }
-
-    return SECSuccess;
+    return (~(c - 1) & a) | ((c - 1) & b);
 }
 
 /*
@@ -212,7 +124,7 @@ static unsigned char *rsa_FormatOneBlock(unsigned modulusLen,
     unsigned char *block;
     unsigned char *bp;
     int padLen;
-    int i;
+    int i, j;
     SECStatus rv;
 
     block = (unsigned char *) nss_ZAlloc(NULL, modulusLen);
@@ -260,124 +172,58 @@ static unsigned char *rsa_FormatOneBlock(unsigned modulusLen,
          */
     case RSA_BlockPublic:
 
-        /*
-         * 0x00 || BT || Pad || 0x00 || ActualData
-         *   1      1   padLen    1      data->len
-         * Pad is all non-zero random bytes.
-         */
-        padLen = modulusLen - data->len - 3;
-        PORT_Assert(padLen >= RSA_BLOCK_MIN_PAD_LEN);
-        if (padLen < RSA_BLOCK_MIN_PAD_LEN) {
-            nss_ZFreeIf(block);
-            return NULL;
-        }
-        for (i = 0; i < padLen; i++) {
-            /* Pad with non-zero random data. */
-            do {
-                rv = RNG_GenerateGlobalRandomBytes(bp + i, 1);
-            } while (rv == SECSuccess
-                     && bp[i] == RSA_BLOCK_AFTER_PAD_OCTET);
-            if (rv != SECSuccess) {
-                nss_ZFreeIf(block);
-                return NULL;
-            }
-        }
-        bp += padLen;
-        *bp++ = RSA_BLOCK_AFTER_PAD_OCTET;
-        nsslibc_memcpy(bp, data->data, data->len);
-
-        break;
-
-        /*
-         * Blocks intended for public-key operation, using
-         * Optimal Asymmetric Encryption Padding (OAEP).
-         */
-    case RSA_BlockOAEP:
-        /*
-         * 0x00 || BT || Modified2(Salt) || Modified1(PaddedData)
-         *   1      1     OAEP_SALT_LEN     OAEP_PAD_LEN + data->len [+ N]
-         *
-         * where:
-         *   PaddedData is "Pad1 || ActualData [|| Pad2]"
-         *   Salt is random data.
-         *   Pad1 is all zeros.
-         *   Pad2, if present, is random data.
-         *   (The "modified" fields are all the same length as the original
-         * unmodified values; they are just xor'd with other values.)
-         *
-         *   Modified1 is an XOR of PaddedData with a special octet
-         * string constructed of iterated hashing of Salt (see below).
-         *   Modified2 is an XOR of Salt with the low-order octets of
-         * the hash of Modified1 (see farther below ;-).
-         *
-         * Whew!
-         */
-
-
-        /*
-         * Salt
-         */
-        rv = RNG_GenerateGlobalRandomBytes(bp, OAEP_SALT_LEN);
-        if (rv != SECSuccess) {
-            nss_ZFreeIf(block);
-            return NULL;
-        }
-        bp += OAEP_SALT_LEN;
-
-        /*
-         * Pad1
-         */
-        nsslibc_memset(bp, OAEP_PAD_OCTET, OAEP_PAD_LEN);
-        bp += OAEP_PAD_LEN;
-
-        /*
-         * Data
-         */
-        nsslibc_memcpy(bp, data->data, data->len);
-        bp += data->len;
-
-        /*
-         * Pad2
-         */
-        if (bp < (block + modulusLen)) {
-            rv = RNG_GenerateGlobalRandomBytes(bp,
-                                               block - bp + modulusLen);
-            if (rv != SECSuccess) {
-                nss_ZFreeIf(block);
-                return NULL;
-            }
-        }
-
-        /*
-         * Now we have the following:
-         * 0x00 || BT || Salt || PaddedData
-         * (From this point on, "Pad1 || Data [|| Pad2]" is treated
-         * as the one entity PaddedData.)
-         *
-         * We need to turn PaddedData into Modified1.
-         */
-        if (oaep_xor_with_h1(block + 2 + OAEP_SALT_LEN,
-                             modulusLen - 2 - OAEP_SALT_LEN,
-                             block + 2, OAEP_SALT_LEN) != SECSuccess) {
-            nss_ZFreeIf(block);
-            return NULL;
-        }
-
-        /*
-         * Now we have:
-         * 0x00 || BT || Salt || Modified1(PaddedData)
-         *
-         * The remaining task is to turn Salt into Modified2.
-         */
-        if (oaep_xor_with_h2(block + 2, OAEP_SALT_LEN,
-                             block + 2 + OAEP_SALT_LEN,
-                             modulusLen - 2 - OAEP_SALT_LEN) !=
-            SECSuccess) {
-            nss_ZFreeIf(block);
-            return NULL;
-        }
-
-        break;
+	/*
+	 * 0x00 || BT || Pad || 0x00 || ActualData
+	 *   1      1   padLen    1      data->len
+	 * Pad is all non-zero random bytes.
+	 *
+	 * Build the block left to right.
+	 * Fill the entire block from Pad to the end with random bytes.
+	 * Use the bytes after Pad as a supply of extra random bytes from 
+	 * which to find replacements for the zero bytes in Pad.
+	 * If we need more than that, refill the bytes after Pad with 
+	 * new random bytes as necessary.
+	 */
+	padLen = modulusLen - (data->len + 3);
+	PORT_Assert (padLen >= RSA_BLOCK_MIN_PAD_LEN);
+	if (padLen < RSA_BLOCK_MIN_PAD_LEN) {
+	    nss_ZFreeIf (block);
+	    return NULL;
+	}
+	j = modulusLen - 2;
+	rv = RNG_GenerateGlobalRandomBytes(bp, j);
+	if (rv == SECSuccess) {
+	    for (i = 0; i < padLen; ) {
+		unsigned char repl;
+		/* Pad with non-zero random data. */
+		if (bp[i] != RSA_BLOCK_AFTER_PAD_OCTET) {
+		    ++i;
+		    continue;
+		}
+		if (j <= padLen) {
+		    rv = RNG_GenerateGlobalRandomBytes(bp + padLen,
+					  modulusLen - (2 + padLen));
+		    if (rv != SECSuccess)
+		    	break;
+		    j = modulusLen - 2;
+		}
+		do {
+		    repl = bp[--j];
+		} while (repl == RSA_BLOCK_AFTER_PAD_OCTET && j > padLen);
+		if (repl != RSA_BLOCK_AFTER_PAD_OCTET) {
+		    bp[i++] = repl;
+		}
+	    }
+	}
+	if (rv != SECSuccess) {
+	    /*sftk_fatalError = PR_TRUE;*/
+	    nss_ZFreeIf (block);
+	    return NULL;
+	}
+	bp += padLen;
+	*bp++ = RSA_BLOCK_AFTER_PAD_OCTET;
+	nsslibc_memcpy(bp, data->data, data->len);
+	break;
 
     default:
         PORT_Assert(0);
@@ -427,26 +273,6 @@ rsa_FormatBlock(SECItem * result, unsigned modulusLen,
 
         break;
 
-    case RSA_BlockOAEP:
-        /*
-         * 0x00 || BT || M1(Salt) || M2(Pad1||ActualData[||Pad2])
-         *
-         * The "2" below is the first octet + the second octet.
-         * (The other fields do not contain the clear values, but are
-         * the same length as the clear values.)
-         */
-        PORT_Assert(data->len <= (modulusLen - (2 + OAEP_SALT_LEN
-                                                + OAEP_PAD_LEN)));
-
-        result->data = rsa_FormatOneBlock(modulusLen, blockType, data);
-        if (result->data == NULL) {
-            result->len = 0;
-            return SECFailure;
-        }
-        result->len = modulusLen;
-
-        break;
-
     case RSA_BlockRaw:
         /*
          * Pad || ActualData
-- 
1.7.1