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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
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