path: root/debian_security_patches.patch

diff -NurbBp libgcrypt-1.4.5.orig/src/libgcrypt-config.in libgcrypt-1.4.5/src/libgcrypt-config.in
--- libgcrypt-1.4.5.orig/src/libgcrypt-config.in	2009-04-02 11:25:32.000000000 +0200
+++ libgcrypt-1.4.5/src/libgcrypt-config.in	2009-12-12 09:37:05.000000000 +0100
@@ -151,7 +151,8 @@ if test "$echo_libs" = "yes"; then
     fi
 
     # Set up `libs_final'.
-    libs_final="$libs_final $gpg_error_libs"
+    #libs_final="$libs_final $gpg_error_libs"
+    libs_final="-lgcrypt"
 
     tmp=""
     for i in $libdirs $libs_final; do
From 410d70bad9a650e3837055e36f157894ae49a57d Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Mon, 23 Feb 2015 11:39:58 +0100
Subject: [PATCH] cipher: Use ciphertext blinding for Elgamal decryption.

* cipher/elgamal.c (USE_BLINDING): New.
(decrypt): Rewrite to use ciphertext blinding.
--

CVE-id: CVE-2014-3591

As a countermeasure to a new side-channel attacks on sliding windows
exponentiation we blind the ciphertext for Elgamal decryption.  This
is similar to what we are doing with RSA. This patch is a backport of
the GnuPG 1.4 commit ff53cf06e966dce0daba5f2c84e03ab9db2c3c8b.

Unfortunately, the performance impact of Elgamal blinding is quite
noticeable (i5-2410M CPU @ 2.30GHz TP 220):

  Algorithm         generate  100*priv  100*public
  ------------------------------------------------
  ELG 1024 bit             -     100ms        90ms
  ELG 2048 bit             -     330ms       350ms
  ELG 3072 bit             -     660ms       790ms

  Algorithm         generate  100*priv  100*public
  ------------------------------------------------
  ELG 1024 bit             -     150ms        90ms
  ELG 2048 bit             -     520ms       360ms
  ELG 3072 bit             -    1100ms       800ms

Signed-off-by: Werner Koch <wk@gnupg.org>
---
 cipher/elgamal.c | 46 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 5 deletions(-)

--- a/cipher/elgamal.c
+++ b/cipher/elgamal.c
@@ -38,6 +38,12 @@
 } ELG_public_key;
 
 
+/* Blinding is used to mitigate side-channel attacks.  You may undef
+   this to speed up the operation in case the system is secured
+   against physical and network mounted side-channel attacks.  */
+#define USE_BLINDING 1
+
+
 typedef struct
 {
   gcry_mpi_t p;	    /* prime */
@@ -486,12 +492,42 @@
 static void
 decrypt(gcry_mpi_t output, gcry_mpi_t a, gcry_mpi_t b, ELG_secret_key *skey )
 {
-  gcry_mpi_t t1 = mpi_alloc_secure( mpi_get_nlimbs( skey->p ) );
+  gcry_mpi_t t1, t2, r;
+  unsigned int nbits = mpi_get_nbits (skey->p);
+
+  t1 = mpi_snew (nbits);
+
+#ifdef USE_BLINDING
+
+  t2 = mpi_snew (nbits);
+  r  = mpi_new (nbits);
+
+  /* We need a random number of about the prime size.  The random
+     number merely needs to be unpredictable; thus we use level 0.  */
+  _gcry_mpi_randomize (r, nbits, GCRY_WEAK_RANDOM);
+
+  /* t1 = r^x mod p */
+  mpi_powm (t1, r, skey->x, skey->p);
+  /* t2 = (a * r)^-x mod p */
+  mpi_mulm (t2, a, r, skey->p);
+  mpi_powm (t2, t2, skey->x, skey->p);
+  mpi_invm (t2, t2, skey->p);
+  /* t1 = (t1 * t2) mod p*/
+  mpi_mulm (t1, t1, t2, skey->p);
+
+  mpi_free (r);
+  mpi_free (t2);
+
+#else /*!USE_BLINDING*/
 
   /* output = b/(a^x) mod p */
-  gcry_mpi_powm( t1, a, skey->x, skey->p );
-  mpi_invm( t1, t1, skey->p );
-  mpi_mulm( output, b, t1, skey->p );
+  mpi_powm (t1, a, skey->x, skey->p);
+  mpi_invm (t1, t1, skey->p);
+
+#endif /*!USE_BLINDING*/
+
+  mpi_mulm (output, b, t1, skey->p);
+
 #if 0
   if( DBG_CIPHER )
     {
@@ -502,7 +538,7 @@
       log_mpidump("elg decrypted M= ", output);
     }
 #endif
-  mpi_free(t1);
+  mpi_free (t1);
 }
 
 
From 653a9fa1a3a4c35a4dc1841cb57d7e2a318f3288 Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Wed, 11 Feb 2015 21:42:22 +0900
Subject: [PATCH] mpi: Add mpi_set_cond.

* mpi/mpiutil.c (_gcry_mpi_set_cond): New.
(_gcry_mpi_swap_cond): Fix types.
* src/mpi.h (mpi_set_cond): New.
---
 mpi/mpiutil.c | 33 +++++++++++++++++++++++++++++----
 src/mpi.h     |  3 +++
 2 files changed, 32 insertions(+), 4 deletions(-)

--- a/mpi/mpiutil.c
+++ b/mpi/mpiutil.c
@@ -386,6 +386,31 @@
                              / BITS_PER_MPI_LIMB );
 }
 
+gcry_mpi_t
+_gcry_mpi_set_cond (gcry_mpi_t w, const gcry_mpi_t u, unsigned long set)
+{
+  mpi_size_t i;
+  mpi_size_t nlimbs = u->alloced;
+  mpi_limb_t mask = ((mpi_limb_t)0) - !!set;
+  mpi_limb_t x;
+
+  if (w->alloced != u->alloced)
+    log_bug ("mpi_set_cond: different sizes\n");
+
+  for (i = 0; i < nlimbs; i++)
+    {
+      x = mask & (w->d[i] ^ u->d[i]);
+      w->d[i] = w->d[i] ^ x;
+    }
+
+  x = mask & (w->nlimbs ^ u->nlimbs);
+  w->nlimbs = w->nlimbs ^ x;
+
+  x = mask & (w->sign ^ u->sign);
+  w->sign = w->sign ^ x;
+  return w;
+}
+
 
 gcry_mpi_t
 gcry_mpi_snew( unsigned int nbits )
--- a/src/mpi.h
+++ b/src/mpi.h
@@ -116,8 +116,11 @@
 #define mpi_swap(a,b)         _gcry_mpi_swap ((a),(b))
 #define mpi_new(n)            _gcry_mpi_new ((n))
 #define mpi_snew(n)           _gcry_mpi_snew ((n))
+#define mpi_set_cond(w,u,set) _gcry_mpi_set_cond ((w),(u),(set))
 
 void _gcry_mpi_clear( gcry_mpi_t a );
+gcry_mpi_t _gcry_mpi_set_cond( gcry_mpi_t w, const gcry_mpi_t u,
+                               unsigned long swap );
 gcry_mpi_t  _gcry_mpi_alloc_like( gcry_mpi_t a );
 gcry_mpi_t  _gcry_mpi_alloc_set_ui( unsigned long u);
 gcry_err_code_t _gcry_mpi_get_ui (gcry_mpi_t w, ulong *u);
From 1fa8cdb933505960d4e4b4842b122d4e06953e88 Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Wed, 11 Feb 2015 22:30:02 +0900
Subject: [PATCH] mpi: Revise mpi_powm.

* mpi/mpi-pow.c (_gcry_mpi_powm): Rename the table to PRECOMP.

--

The name of precomputed table was b_2i3 which stands for BASE^(2*I+3).
But it's too cryptic, so, it's renamed.  Besides, we needed to
distinguish the case of I==0, that was not good.  Since it's OK to
increase the size of table by one, it's BASE^(2*I+1), now.
---
 mpi/mpi-pow.c | 60 ++++++++++++++++++-----------------------------------------
 1 file changed, 18 insertions(+), 42 deletions(-)

--- a/mpi/mpi-pow.c
+++ b/mpi/mpi-pow.c
@@ -381,7 +381,7 @@
      *xsize_p = rsize + ssize;
 }
 
-#define SIZE_B_2I3 ((1 << (5 - 1)) - 1)
+#define SIZE_PRECOMP ((1 << (5 - 1)))
 
 /****************
  * RES = BASE ^ EXPO mod MOD
@@ -417,8 +417,8 @@
   unsigned int bp_nlimbs = 0;
   unsigned int ep_nlimbs = 0;
   unsigned int xp_nlimbs = 0;
-  mpi_ptr_t b_2i3[SIZE_B_2I3]; /* Pre-computed array: BASE^3, ^5, ^7, ... */
-  mpi_size_t b_2i3size[SIZE_B_2I3];
+  mpi_ptr_t precomp[SIZE_PRECOMP]; /* Pre-computed array: BASE^1, ^3, ^5, ... */
+  mpi_size_t precomp_size[SIZE_PRECOMP];
   mpi_size_t W;
   mpi_ptr_t base_u;
   mpi_size_t base_u_size;
@@ -555,31 +555,23 @@
     memset( &karactx, 0, sizeof karactx );
     negative_result = (ep[0] & 1) && bsign;
 
-    /* Precompute B_2I3[], BASE^(2 * i + 3), BASE^3, ^5, ^7, ... */
+    /* Precompute PRECOMP[], BASE^(2 * i + 1), BASE^1, ^3, ^5, ... */
     if (W > 1)                  /* X := BASE^2 */
       mul_mod (xp, &xsize, bp, bsize, bp, bsize, mp, msize, &karactx);
-    for (i = 0; i < (1 << (W - 1)) - 1; i++)
-      {                         /* B_2I3[i] = BASE^(2 * i + 3) */
-        if (i == 0)
-          {
-            base_u = bp;
-            base_u_size = bsize;
-          }
-        else
-          {
-            base_u = b_2i3[i-1];
-            base_u_size = b_2i3size[i-1];
-          }
-
+    base_u = precomp[0] = mpi_alloc_limb_space (bsize, esec);
+    base_u_size = precomp_size[0] = bsize;
+    MPN_COPY (precomp[0], bp, bsize);
+    for (i = 1; i < (1 << (W - 1)); i++)
+      {                         /* PRECOMP[i] = BASE^(2 * i + 1) */
         if (xsize >= base_u_size)
           mul_mod (rp, &rsize, xp, xsize, base_u, base_u_size,
                    mp, msize, &karactx);
         else
           mul_mod (rp, &rsize, base_u, base_u_size, xp, xsize,
                    mp, msize, &karactx);
-        b_2i3[i] = mpi_alloc_limb_space (rsize, esec);
-        b_2i3size[i] = rsize;
-        MPN_COPY (b_2i3[i], rp, rsize);
+        base_u = precomp[i] = mpi_alloc_limb_space (rsize, esec);
+        base_u_size = precomp_size[i] = rsize;
+        MPN_COPY (precomp[i], rp, rsize);
       }
 
     i = esize - 1;
@@ -667,16 +659,8 @@
               rsize = xsize;
             }
 
-          if (e0 == 0)
-            {
-              base_u = bp;
-              base_u_size = bsize;
-            }
-          else
-            {
-              base_u = b_2i3[e0 - 1];
-              base_u_size = b_2i3size[e0 -1];
-            }
+	  base_u = precomp[e0];
+	  base_u_size = precomp_size[e0];
 
           mul_mod (xp, &xsize, rp, rsize, base_u, base_u_size,
                    mp, msize, &karactx);
@@ -703,16 +687,8 @@
 
     if (e != 0)
       {
-        if ((e>>1) == 0)
-          {
-            base_u = bp;
-            base_u_size = bsize;
-          }
-        else
-          {
-            base_u = b_2i3[(e>>1) - 1];
-            base_u_size = b_2i3size[(e>>1) -1];
-          }
+	base_u = precomp[(e>>1)];
+	base_u_size = precomp_size[(e>>1)];
 
         mul_mod (xp, &xsize, rp, rsize, base_u, base_u_size,
                  mp, msize, &karactx);
@@ -761,8 +737,8 @@
     MPN_NORMALIZE (rp, rsize);
 
     _gcry_mpih_release_karatsuba_ctx (&karactx );
-    for (i = 0; i < (1 << (W - 1)) - 1; i++)
-      _gcry_mpi_free_limb_space( b_2i3[i], esec ? b_2i3size[i] : 0 );
+    for (i = 0; i < (1 << (W - 1)); i++)
+      _gcry_mpi_free_limb_space( precomp[i], esec ? precomp_size[i] : 0 );
   }
 
   /* Fixup for negative results.  */
From 6636c4fd0c6ceab9f79827bf96967d1e112c0b82 Mon Sep 17 00:00:00 2001
From: NIIBE Yutaka <gniibe@fsij.org>
Date: Thu, 26 Feb 2015 21:07:01 +0900
Subject: [PATCH] mpi: Avoid data-dependent timing variations in mpi_powm.

* mpi/mpi-pow.c (mpi_powm): Access all data in the table by
mpi_set_cond.

--

Access to the precomputed table was indexed by a portion of EXPO,
which could be mounted by a side channel attack.  This change fixes
this particular data-dependent access pattern.

Cherry-picked from commit  5e72b6c76ebee720f69b8a5c212f52d38eb50287
in LIBGCRYPT-1-6-BRANCH.
---
 mpi/mpi-pow.c | 51 +++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 45 insertions(+), 6 deletions(-)

--- a/mpi/mpi-pow.c
+++ b/mpi/mpi-pow.c
@@ -422,6 +422,7 @@
   mpi_size_t W;
   mpi_ptr_t base_u;
   mpi_size_t base_u_size;
+  mpi_size_t max_u_size;
 
   esize = expo->nlimbs;
   msize = mod->nlimbs;
@@ -540,7 +541,7 @@
 
   /* Main processing.  */
   {
-    mpi_size_t i, j;
+    mpi_size_t i, j, k;
     mpi_ptr_t xp;
     mpi_size_t xsize;
     int c;
@@ -559,7 +560,7 @@
     if (W > 1)                  /* X := BASE^2 */
       mul_mod (xp, &xsize, bp, bsize, bp, bsize, mp, msize, &karactx);
     base_u = precomp[0] = mpi_alloc_limb_space (bsize, esec);
-    base_u_size = precomp_size[0] = bsize;
+    base_u_size = max_u_size = precomp_size[0] = bsize;
     MPN_COPY (precomp[0], bp, bsize);
     for (i = 1; i < (1 << (W - 1)); i++)
       {                         /* PRECOMP[i] = BASE^(2 * i + 1) */
@@ -571,9 +572,14 @@
                    mp, msize, &karactx);
         base_u = precomp[i] = mpi_alloc_limb_space (rsize, esec);
         base_u_size = precomp_size[i] = rsize;
+        if (max_u_size < base_u_size)
+          max_u_size = base_u_size;
         MPN_COPY (precomp[i], rp, rsize);
       }
 
+    base_u = mpi_alloc_limb_space (max_u_size, esec);
+    MPN_ZERO (base_u, max_u_size);
+
     i = esize - 1;
 
     /* Main loop.
@@ -659,8 +665,24 @@
               rsize = xsize;
             }
 
-	  base_u = precomp[e0];
-	  base_u_size = precomp_size[e0];
+          /*
+           *  base_u <= precomp[e0]
+           *  base_u_size <= precomp_size[e0]
+           */
+          base_u_size = 0;
+          for (k = 0; k < (1<< (W - 1)); k++)
+            {
+              struct gcry_mpi w, u;
+              w.alloced = w.nlimbs = precomp_size[k];
+              u.alloced = u.nlimbs = precomp_size[k];
+              w.sign = u.sign = 0;
+              w.flags = u.flags = 0;
+              w.d = base_u;
+              u.d = precomp[k];
+
+              mpi_set_cond (&w, &u, k == e0);
+              base_u_size |= (precomp_size[k] & ((mpi_size_t)0 - (k == e0)) );
+            }
 
           mul_mod (xp, &xsize, rp, rsize, base_u, base_u_size,
                    mp, msize, &karactx);
@@ -687,8 +709,24 @@
 
     if (e != 0)
       {
-	base_u = precomp[(e>>1)];
-	base_u_size = precomp_size[(e>>1)];
+        /*
+         * base_u <= precomp[(e>>1)]
+         * base_u_size <= precomp_size[(e>>1)]
+         */
+        base_u_size = 0;
+        for (k = 0; k < (1<< (W - 1)); k++)
+          {
+            struct gcry_mpi w, u;
+            w.alloced = w.nlimbs = precomp_size[k];
+            u.alloced = u.nlimbs = precomp_size[k];
+            w.sign = u.sign = 0;
+            w.flags = u.flags = 0;
+            w.d = base_u;
+            u.d = precomp[k];
+
+            mpi_set_cond (&w, &u, k == (e>>1));
+            base_u_size |= (precomp_size[k] & ((mpi_size_t)0 - (k == (e>>1))) );
+          }
 
         mul_mod (xp, &xsize, rp, rsize, base_u, base_u_size,
                  mp, msize, &karactx);
@@ -739,6 +777,7 @@
     _gcry_mpih_release_karatsuba_ctx (&karactx );
     for (i = 0; i < (1 << (W - 1)); i++)
       _gcry_mpi_free_limb_space( precomp[i], esec ? precomp_size[i] : 0 );
+    _gcry_mpi_free_limb_space (base_u, esec ? max_u_size : 0);
   }
 
   /* Fixup for negative results.  */