X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/898a4e2555438ff8adb08b4d82690d08715e1048..b817bfc642225b8c3c0b6a7e42d1fb949b61a606:/pkcs1.c

diff --git a/pkcs1.c b/pkcs1.c
index dd19569..3460467 100644
--- a/pkcs1.c
+++ b/pkcs1.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: pkcs1.c,v 1.3 2000/10/08 12:07:04 mdw Exp $
+ * $Id: pkcs1.c,v 1.4 2004/04/08 01:36:15 mdw Exp $
  *
  * PKCS#1 1.5 packing
  *
@@ -27,21 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: pkcs1.c,v $
- * Revision 1.3  2000/10/08 12:07:04  mdw
- * Don't do arithmetic on @void *@ pointers.
- *
- * Revision 1.2  2000/07/05 17:49:48  mdw
- * Fix decoding functions, so that they don't run off the end of the
- * buffer.
- *
- * Revision 1.1  2000/07/01 11:17:38  mdw
- * New support for PKCS#1 message encoding.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <string.h>
@@ -50,62 +35,71 @@
 #include <mLib/dstr.h>
 
 #include "grand.h"
-#include "pkcs1.h"
+#include "rsa.h"
 
 /*----- Main code ---------------------------------------------------------*/
 
 /* --- @pkcs1_cryptencode@ --- *
  *
- * Arguments:	@const void *msg@ = pointer to message data
+ * Arguments:	@mp *d@ = where to put the answer
+ *		@const void *m@ = pointer to message data
  *		@size_t msz@ = size of message data
- *		@void *buf@ = pointer to output buffer
- *		@size_t sz@ = size of the output buffer
+ *		@octet *b@ = spare buffer
+ *		@size_t sz@ = size of the buffer (big enough)
+ *		@unsigned long nbits@ = length of bits of @n@
  *		@void *p@ = pointer to PKCS1 parameter block
  *
- * Returns:	Zero if all went well, negative on failure.
+ * Returns:	The encoded result, or null.
  *
  * Use:		Implements the operation @EME-PKCS1-V1_5-ENCODE@, as defined
  *		in PKCS#1 v. 2.0 (RFC2437).
  */
 
-int pkcs1_cryptencode(const void *msg, size_t msz, void *buf, size_t sz,
-		      void *p)
+mp *pkcs1_cryptencode(mp *d, const void *m, size_t msz, octet *b, size_t sz,
+		      unsigned long nbits, void *p)
 {
   pkcs1 *pp = p;
   grand *r = pp->r;
-  octet *q, *qq;
+  octet *q;
   size_t i, n;
 
   /* --- Ensure that the buffer is sensibly sized --- */
 
   if (pp->epsz + msz + 11 > sz)
-    return (-1);
+    return (0);
 
-  /* --- Fill in the buffer --- */
+  /* --- Allocate the buffer and fill it in --- */
 
-  q = buf;
-  qq = q + sz;
-  *q++ = 0;
-  *q++ = 2;
+  q = b;
+  *q++ = 0x00;
+  *q++ = 0x02;
   n = sz - msz - pp->epsz - 3;
-  r->ops->fill(r, q, n);
+  GR_FILL(r, q, n);
   for (i = 0; i < n; i++) {
     if (*q == 0)
       *q = r->ops->range(r, 255) + 1;
     q++;
   }
   *q++ = 0;
-  memcpy(q, pp->ep, pp->epsz);
-  q += pp->epsz;
-  memcpy(q, msg, msz);
-  return (0);
+  if (pp->ep) {
+    memcpy(q, pp->ep, pp->epsz);
+    q += pp->epsz;
+  }
+  memcpy(q, m, msz);
+  q += msz;
+  assert(q == b + sz);
+
+  /* --- Collect the result --- */
+  
+  return (mp_loadb(d, b, sz));
 }
 
 /* --- @pkcs1_cryptdecode@ --- *
  *
- * Arguments:	@const void *buf@ = pointer to encoded buffer
- *		@size_t sz@ = size of the encoded buffer
- *		@dstr *d@ = pointer to destination string
+ * Arguments:	@mp *m@ = the decrypted message
+ *		@octet *b@ = pointer to a buffer to work in
+ *		@size_t sz@ = the size of the buffer (big enough)
+ *		@unsigned long nbits@ = the number of bits in @n@
  *		@void *p@ = pointer to PKCS1 parameter block
  *
  * Returns:	The length of the output string if successful, negative on
@@ -115,94 +109,113 @@ int pkcs1_cryptencode(const void *msg, size_t msz, void *buf, size_t sz,
  *		in PKCS#1 v. 2.0 (RFC2437).
  */
 
-int pkcs1_cryptdecode(const void *buf, size_t sz, dstr *d, void *p)
+static int memeq(const void *xx, const void *yy, size_t sz)
+{
+  int eq = 1;
+  const octet *x = xx, *y = yy;
+  while (sz) {				/* Always check every byte */
+    if (*x++ != *y++) eq = 0;
+    sz--;
+  }
+  return (eq);
+}
+
+int pkcs1_cryptdecode(mp *m, octet *b, size_t sz,
+		      unsigned long nbits, void *p)
 {
   pkcs1 *pp = p;
   const octet *q, *qq;
   size_t n, i;
+  int bad = 0;
 
   /* --- Check the size of the block looks sane --- */
 
-  if (pp->epsz + 11 > sz)
+  if (pp->epsz + 11 > sz)		/* OK: independent of ciphertext */
     return (-1);
-  q = buf;
+  mp_storeb(m, b, sz);
+  q = b;
   qq = q + sz;
 
   /* --- Ensure that the block looks OK --- */
 
-  if (*q++ != 0 || *q++ != 2)
-    return (-1);
+  bad |= (*q++ != 0x00 || *q++ != 0x02);
 
   /* --- Check the nonzero padding --- */
 
   i = 0;
   while (*q != 0 && q < qq)
     i++, q++;
-  if (i < 8 || qq - q < pp->epsz + 1)
-    return (-1);
+  bad |= (i < 8 || qq - q < pp->epsz + 1);
   q++;
 
   /* --- Check the encoding parameters --- */
 
-  if (memcmp(q, pp->ep, pp->epsz) != 0)
-    return (-1);
+  bad |= (pp->ep && !memeq(bad ? b : q, pp->ep, pp->epsz));
   q += pp->epsz;
 
   /* --- Done --- */
 
   n = qq - q;
-  dstr_putm(d, q, n);
-  return (n);
+  memmove(b, bad ? b + 1 : q, n);
+  return (bad ? -1 : n);
 }
 
 /* --- @pkcs1_sigencode@ --- *
  *
- * Arguments:	@const void *msg@ = pointer to message data
+ * Arguments:	@mp *d@ = where to put the answer
+ *		@const void *m@ = pointer to message data
  *		@size_t msz@ = size of message data
- *		@void *buf@ = pointer to output buffer
- *		@size_t sz@ = size of the output buffer
+ *		@octet *b@ = spare buffer
+ *		@size_t sz@ = size of the buffer (big enough)
+ *		@unsigned long nbits@ = length of bits of @n@
  *		@void *p@ = pointer to PKCS1 parameter block
  *
- * Returns:	Zero if all went well, negative on failure.
+ * Returns:	The encoded message representative, or null.
  *
  * Use:		Implements the operation @EMSA-PKCS1-V1_5-ENCODE@, as defined
  *		in PKCS#1 v. 2.0 (RFC2437).
  */
 
-int pkcs1_sigencode(const void *msg, size_t msz, void *buf, size_t sz,
-		      void *p)
+mp *pkcs1_sigencode(mp *d, const void *m, size_t msz, octet *b, size_t sz,
+		    unsigned long nbits, void *p)
 {
   pkcs1 *pp = p;
-  octet *q, *qq;
+  octet *q;
   size_t n;
 
   /* --- Ensure that the buffer is sensibly sized --- */
 
   if (pp->epsz + msz + 11 > sz)
-    return (-1);
+    return (0);
 
   /* --- Fill in the buffer --- */
 
-  q = buf;
-  qq = q + sz;
-  *q++ = 0;
-  *q++ = 1;
+  q = b;
+  *q++ = 0x00;
+  *q++ = 0x01;
   n = sz - msz - pp->epsz - 3;
   memset(q, 0xff, n);
   q += n;
   *q++ = 0;
-  memcpy(q, pp->ep, pp->epsz);
-  q += pp->epsz;
-  memcpy(q, msg, msz);
-  return (0);
+  if (pp->ep) {
+    memcpy(q, pp->ep, pp->epsz);
+    q += pp->epsz;
+  }
+  memcpy(q, m, msz);
+  q += msz;
+  assert(q == b + sz);
+  return (mp_loadb(d, b, sz));
 }
 
 /* --- @pkcs1_sigdecode@ --- *
  *
- * Arguments:	@const void *buf@ = pointer to encoded buffer
- *		@size_t sz@ = size of the encoded buffer
- *		@dstr *d@ = pointer to destination string
- *		@void *p@ = pointer to PKCS1 parameter block
+ * Arguments:	@mp *s@ = the message representative
+ *		@const void *m@ = the original message, or null (ignored)
+ *		@size_t msz@ = the message size (ignored)
+ *		@octet *b@ = a scratch buffer
+ *		@size_t sz@ = size of the buffer (large enough)
+ *		@unsigned long nbits@ = number of bits in @n@
+ *		@void *p@ = pointer to PKCS1 parameters
  *
  * Returns:	The length of the output string if successful, negative on
  *		failure.
@@ -211,7 +224,8 @@ int pkcs1_sigencode(const void *msg, size_t msz, void *buf, size_t sz,
  *		in PKCS#1 v. 2.0 (RFC2437).
  */
 
-int pkcs1_sigdecode(const void *buf, size_t sz, dstr *d, void *p)
+int pkcs1_sigdecode(mp *s, const void *m, size_t msz, octet *b, size_t sz,
+		    unsigned long nbits, void *p)
 {
   pkcs1 *pp = p;
   const octet *q, *qq;
@@ -221,12 +235,13 @@ int pkcs1_sigdecode(const void *buf, size_t sz, dstr *d, void *p)
 
   if (pp->epsz + 10 > sz)
     return (-1);
-  q = buf;
+  mp_storeb(s, b, sz);
+  q = b;
   qq = q + sz;
 
   /* --- Ensure that the block looks OK --- */
 
-  if (*q++ != 0 || *q++ != 1)
+  if (*q++ != 0x00 || *q++ != 0x01)
     return (-1);
 
   /* --- Check the padding --- */
@@ -239,14 +254,14 @@ int pkcs1_sigdecode(const void *buf, size_t sz, dstr *d, void *p)
 
   /* --- Check the encoding parameters --- */
 
-  if (memcmp(q, pp->ep, pp->epsz) != 0)
+  if (pp->ep && memcmp(q, pp->ep, pp->epsz) != 0)
     return (-1);
   q += pp->epsz;
 
   /* --- Done --- */
 
   n = qq - q;
-  dstr_putm(d, q, n);
+  memmove(b, q, n);
   return (n);
 }